IITRI Project C6187
COOLING TOWER STUDY
      Final Report

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                   HER I Report No. C6187-3
                        (Final Report)
                     COOLING TOWER STUDY
             June 23, 1969 through June 22, 1970
                 Contract No. CPA 22-69-122
                    IITRI Project C6187
                       Prepared by

                      John Stockham
                           of
                 IIT RESEARCH INSTITUTE
                    Te chnology Center
                Chicago, Illinois  60616
                           for
Environmental Protection Agency Air Pollution Control Office
                411 W. Chapel Hill Street
              Durham, North Carolina  27701
            Attention:   Dr. James Peterson
                                          January,  1971

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                             FOREWORD


     This Cooling Tower Study was performed under Contract No.
CPA 22-69-122 by the IIT Research Institute during the period
June 23, 1969 to June 22, 1970.  The project was sponsored by
the Division of Meteorology, Air Pollution Control Office,
Environmental Protection Agency, 3820 Merton Drive, Raleigh,
North Carolina, 27609.    The program was monitored by Dr. James
T. Peterson.  The project leader at the IIT Research Institute
was Dr. Eric Aynsley.  The plume modeling studies were conducted
by Dr. Hugo Nielson; Mr. W. Boynton Beckwith evaluated the
local climatological effects .   Mr. Beckwith was a consultant
to IIT Research Institute.
     Dr. Aynsley acknowledges the assistance of Mr. K. Gray and
other staff members of the Keystone Station, Mr. Frank Schiermeier
of the Air Pollution Control Office, the Keystone Helicopter
Corporation, Philadelphia, Pennsylvania, and the Analytical
Services Corporation, New Castle, Delaware.
                                   Respectfully submitted,
                                   IIT RESEARCH INSTITUTE
                                         6
                                   John D. Stockham
                                   Manager, Fine Particles Research
 Approved by:
        J.
 Directory Chemistry
 Research Division

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                             ABSTRACT

                        COOLING TOWER STUDY

     The purpose of this study was to describe and evaluate
the potential effects that the emissions of water vapor and
heat from natural draft cooling towers have on the local en-
vironment, climate, and nearby electrical power station
emissions.  Field tests were conducted at the Keystone gen-
erating station near Shelocta, Pennsylvania.  Observations
and measurements were made intermittently during September,
November, and December 1969.
     Natural draft cooling towers are being selected with
increasing frequency by the electrical power utilities to
dispose of their waste heat.  Currently there are 18 such
towers in operation and between 32 and 40 will be operational
by 1974.  These towers will be located predominantly in the
Northern Appalachian area; 22 will be in Pennsylvania.
     Although cooling towers have the potential to  produce
fog and drizzle, to initiate clouds, and to enhance rainfall,
the Keystone Plant produced none of these adverse effects
while under observation during this study.  Moreover, historical
precipitation records from 9 U.S. Weather Bureau stations,
located between 13 and 51 kilometers from Keystone, were
analyzed for possible influence from the Keystone effluent.
Only in July of 1969, is there a suggestion of precipitation
enhancement as a result of station operation.  The monthly
precipitation totals for all other months during which Keystone
was in operation fall within the natural variability range for
the area.  Based on the observations of a resident Air Pollution
Control Office meteorologist over a 12 month period, cloud
initiation during periods of otherwise clear skies is infrequent.
However, the cooling tower plume often merges with low stratus
clouds.


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     Natural draft towers vent large quantities of heat and
water vapor to the atmosphere.  At Keystone approximately
10,000 gal/min of water are evaporated and 120 million BTU/min
of heat are released when the station is operating at 80-86%
of its rated 1800-megawatt capacity.  During our observations
the visible portion of the tower plume normally rose to an
altitude of less than 200 meters and traveled downwind about
200 meters before evaporating.  However, the dimensions of
the visible portion of the plume were greatly dependent on
the temperature and humidity of the ambient air.  When tem-
peratures were 25-30F and the relative humidity was high,
the plume could be seen for thousands of meters.  Even when
the plume was visible over only a short distance, its path
could be traced up to 11,000 meters by aerial relative
humidity measurements.
     The plume travels downwind of the plant with an oscil-
latory motion in the vertical direction.  Using inputs from
the field studies, a mathematical model indicated that a plume
moisture content 50% in excess of saturation at the tower exit
would produce the observed oscillatory pattern.
     The effluents from the power station stacks and the
cooling towers at Keystone do mix.  This mixing is shown by
the presence of acid droplets in the visible portion of the
cooling tower plume and the humidity and sulfur dioxide pro-
files obtained along the axis of the plume path after the
humid plume had evaporated.
     The full environmental effects of natural draft cooling
towers can not be stated conclusively for three reasons.  The
station effluents were observed and sampled over a short-time
period that represented only one season of the year; the
station was generating power at only 1/6 of its rated capacity

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during a portion of the field tests; and field instrumentation
was lacking in several essential areas.  It is recommended that
the power station be instrumented to aid in evaluating the
volume and nature of water losses, and weather stations in the
vicinity of Keystone be expanded in both numbers and facilities,

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                         TABLE OF CONTENTS
                                                     Page
                                                     No.
POREWARD                                              ii

ABSTRACT                                              ill

LIST OF TABLES                                        viii

LIST OF FIGURES                                       xi

INTRODUCTION                                           1

NATURAL DRAFT COOLING TOWERS: GROWTH TRENDS
  IN THE U.S.                                          3

LOCAL CLIMATE MODIFICATIONS RESULTING FROM THE
  KEYSTONE TOWERS                                      8

DIFFUSION OF HEAT AND WATER VAPOR; PLUME PROFILES     17

MIXING OF THE TOWER AND STACK PLUMES                  38

POSSIBLE LOCAL EFFECTS OF HEAT AND WATER
  VAPOR RELEASE                                       41

CONCLUSIONS                                           43

RECOMMENDATIONS                                       45

REFERENCES                                            46

APPENDIX A

    Keystone: Site, Climatology, Tower Operation      A-l

    Reference                                         A-14

APPENDIX B

    Aerial Survey: Equipment, Procedures, Results     B-l

    References                                        B-29

APPENDIX C

    Impactor Samples: Slide Preparation, Droplet
      Sizes and Acidity                               C-l

    References                                        C-ll




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                   TABLE OF CONTENTS (Cont'd)
APPENDIX D

    Model Analysis of Moist Bent-Over Plumes

    References
                                                     Page
                                                     No.
        D-l

        D-8
                               Vll

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                          LIST OF TABLES
Table                                                    Page
 No.                                                     No.
 1       Summary of U.S. Natural Draft Cooling Towers     4
 2       Vital Statistics of Stations Used in this
            Study                                        10
 3       Annual Station Precipitation By Years           12
 4       Heat and Water Vapor Released to Atmosphere
           at Keystone                                   18
 5       Plume and Atmospheric Conditions Used in
           Dispersion Model                              33
 6       Plume Moisture Contents Used in Dispersion
           Model                                         34
 7       Distance Light Transmitted Through a Fog
           Containing 0.54% Mole Fraction Liquid Water   37
A-l      Pumping Pressures and Water Flows at Keystone   A-7
A-2      Essential Temperature Data at Keystone          A-g
A-3      Evaporation and Heat Release by Cooling Towers
           at Keystone                                   A-10
B-l      Monitoring Equipment Mounted in the Bell J-2
           Helicopter                                    B-2
B- 2      Efficiency of the Cascade Impactor Stage?       B-6
B-3      Aerial Survey: Calendar of Events               B-8
B-4      Surface Winds at Pittsburgh, Altoona, and
           Blairsville, Pa.                              B-27
B-5      Upper Air Winds at Pittsburgh, Pa.              B-28
C-l      Acidity and Residue Sizes of Cooling Tower
           Plume Droplets                                C-3

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                         LIST OF FIGURES

Figure                                                   Page
  No.                                                    No.
  1      Number of Natural Draft Cooling Towers in
           the United States                              5
  2      Locations of Natural Draft Cooling Towers
           Through 1977                                   6
  3      Locations of Climatological Stations             9
  4      Station Annual Precipitation Totals
           1960 Through 1969                             13
  5      Stratification of Station Precipitation Data:
           1960 - 1967                                   14
  6      Stratification of Station Precipitation Data:
           1968 - 1969                                   16
  7      Prevailing Ambient Conditions Prior to
           Plume Traverses                               20
  8      Sulfur Dioxide (ppm) Profile at 640 Meters
           Downwind of Tower                             22
  9      Relative Humidity Profile (% points above
           background) at 640 Meters Downwind of Tower   23
 10      Temperature Profile  (F) at 640 Meters Down-
           wind of Tower                                 24
 11      Sulfur Dioxide (ppm) Profile at 4800 Meters
           Downwind of Tower                             25
 12      Relative Humidity Profile (% points above
           background) at 4800 Meters Downwind of Tower  26
 13      Temperature Profile  (F) at 4800 Meters
           Downwind of Tower                             27
 14      Sulfur Dioxide (ppm) Profile at 10,800 Meters
           Downwind of Tower                             28
 15      Relative Humidity Profile (% points above
           background) at 10,800 Meters Downwind of lower 29
 16      Temperature Profile  (F) at 10,800 Meters
           Downwind of Tower                             30
 17      Ground Level Traverses Beneath Plume            31
 18      Effect of Plume Initial Moisture on Plume
           Behavior                                      35
 19      Variation of Acid Drop Concentration with
           Humidity                                      39

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                    LIST OF FIGURES (Cont'd)

Figure                                                     Page
  No.                                                       No.

 A-l      Photograph of the Keystone Power  Station         A-2

 A-2      Cooling Water Schematic for Keystone Station     A-4

 A-3      Evaporation Losses from Cooling Tower            A-6

 A-4      The Effects of Wet Bulb Temperature and          A-13
          Relative Humidity on Density Difference
          Driving Force

 B-l      The Helicopter used for Aerial Sampling          B-3

 B-2      Sampling Probe and Interior Installation of
            Equipment in the Helicopter                    B-4

 B-3      Plume Monitoring Pattern                         B-7

 B-4      Prevailing Ambient Conditions Prior
            to Plume Traverses                             B-9

 B-5      Sulfur Dioxide (ppm)  Profile at 2093 Meters
            Downwind of Tower                              B-10

 B-6      Relative Humidity Profile (% point above
            background)  at 2093 Meters Downwind
            of Tower                                       B-ll

 B-7      Temperature Profile (F)  at 2093 Meters
            Downwind of Tower                              B-l2

 E-8      Sulfur Dioxide (ppm)  Profile at 9960 Meters
            Downwind of Tower                              B-13

 B-9      Relative Humidity Profile (% point above
            background)  at 9960 Meters Downwind
            of Tower                                       B-l4
 B-10     Temperature Profile (F)  at 9960 Meters
            Downwind of Tower                              B-l5

 B-ll     Prevailing Ambient Conditions Prior to
            Plume Traverses                                B-16

 B-12     Ground Level Traverses Beneath Plume             B-17

 B-13     Sulfur Dioxide (ppm)  Profile at 644 Meters
            Downwind of Tower                              B-18

 B-14     Relative Humidity Profile (% point above
            background)  at 644 Meters Downwind
            of Tower                                       B-19

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                    LIST OF FIGURES (Cont'd)

Figure                                                     Page
  No.                                                      No.
 B-15     Temperature Profile (F) at 644 Meters
            Downwind of Tower                              B-20

 B-16     Sulfur Dioxide (ppm) Profile at 3220 Meters
            Downwind of Tower                              B-21

 B-17     Relative Humidity Profile (% point above
            background) at 3220 Meters Downwind
            of Tower                                       B-22

 B-18     Temperature Profile (F) at 3220 Meters
            Downwind of Tower                              B-23
 B-19     Sulfur Dioxide (ppm) Profile at 10765 Meters
            Downwind of Tower                              B-24
 B-20     Relative Humidity Profile (% point above
            background) at 10765 Meters Downwind
            of Tower                                       B-25

 B-21     Temperature Profile (F) at 10765 Meters
            Downwind of Tower                              B-26

 C-l      Plume Droplet Residue Size Distribution
            Sample Number 1                                C-4

 C-2      Plume Droplet Residue Size Distribution
            Sample Number 3                                C-5

 C-3      Plume Droplet Residue Size Distribution
            Sample Number 6                                C-6

 C-4      Plume Droplet Residue Size Distribution
            Sample Numbers 7 and 8                         C-7

 C-5      Plume Droplet Residue Size Distribution
            Sample Numbers 12 and 13                       C-8
 C-6      Tower and Stack Plumes Mixed.  Droplets of
            pH 2-3, 4-5, 6-7 present                       C-9

 C-7      Tower and Stack Plumes not Mixed pH of
            Droplets 6-7                                   C-10

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                        INTRODUCTION

     The environmental effects produced by the discharge of large

quantities of water and waste heat to the atmosphere by natural

draft cooling towers are described and evaluated.  Five specific

tasks were performed during the course of this program.  These

tasks were:

     Task 1 - A list of natural draft cooling towers in operation,
              under construction, and being planned was compiled.
              The data include information on tower sizes, capa-
              cities ,operating characteristics, and geographical
              location.

     Task 2 - The diffusion of heat, water vapor, and chemical
              carry-over emitted by natural draft cooling towers
              was described and evaluated.  A theoretical plume
              diffusion model was developed and applied to the
              study findings.

     Task 3 - The local climate modifications resulting from the
              increase in moisture content discharged from natural
              draft cooling towers were assessed.

     Task 4 - The effect of the emissions from natural draft
              cooling towers on the chemical and physical composi-
              tion of the emissions from nearby power station
              effluent was evaluated.

     Task 5 - Possible deleterious effects on the local environ-
              ment from the release of large amounts of water
              vapor and heat by natural draft cooling towers
              were listed.

     Field studies were conducted at the Keystone electrical power

generating station located near Shelocta, Pennsylvania.  Keystone

is a mine mouth, coal-fired  plant with a generating capacity of

1800 megawatts.  The station has twin power generating units each

with a capacity of 900 megawatts.  Associated with each unit is
a chimney stack 244 meters in height and two natural draft, hyper-

bolic cooling towers, each 99 meters in height.  One unit of the
station went into operation in 1967; the second unit was placed

on stream in 1968.  The plant, its site, the local climatology,


                       NT  RESEARCH INSTITUTE


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and the operation of the cooling towers are described in Appendix A.
Keystone was selected as a study site because of on-going studies
related to power station emissions.  These studies include an
evaluation of tall stacks and sulfur dioxide emissions and washout
effects.  Also, a nearby airport provides a suitable base for aerial
surveys; and the four natural draft cooling towers are the greatest
concentration of such towers at a single location.
     The disposal of waste heat is of great concern to the electric
power generating industry.  This industry must dispose of large
quantities of waste heat.  It is necessary to dispose of 4.4 BTus
of waste heat for every watt of generating capacity in today's
design of a coal-fired steam electric power station and 6.6 BTUs
for every watt in a nuclear electric station.  Thus, a 1000 megawatt
steam station must dispose of 1300 megawatts of waste heat; a
nuclear station of similar capacity must dispose of 1950 megawatts
of waste heat.
                      IIT RESEARCH  INSTITUTE


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     NATURAL DRAFT COOLING TOWERS; GROWTH TRENDS IN THE U.S.
     Table I contains a summary of the natural draft cooling
towers currently operating, under construction, or being planned
throughout the United States.  The first natural draft cooling
tower was at Big Sandy near Louisa, Kentucky.  It began operation
in December 1962.  Since this date there has been a rapid in-
crease in the use of such cooling towers.  This trend is shown
in Figure 1.  About 18 towers were in operation by mid 1970;
projections indicate that 32 to 40 towers will be completed in
two to three years.  The time laspe between start and completion
of natural draft cooling towers is about 24 to 30 months; for
this reason, the number of towers projected beyond 1972 could be
underestimated.  Without exception all the towers listed are
associated with the electrical utility industry.  To date, all
the operational towers serve coal-fired, steam electric stations,
but about half of the future towers will serve nuclear stations.
The vast majority of the towers are and will be located in the
Northern Appalachian area, Figure 2.
     There are a number of factors that currently favor the
selection of cooling towers as a means of disposing of waste heat.
The two most prominent factors are present economics of power
station siting and antipollution regulations pertaining to both
thermal and air pollution.  The electrical generating industry
is selecting rural sites for new stations and mine mouth locations
for coal-fired units because the cost of overland power trans-
mission  is   more than offset by the lower rural property values
and bulk fuel transportation costs.  The lack of large bodies of
water at these sites and the antipollution regulations dictates
the use of either forced or natural draft cooling towers.  As
shown in Appendix A, the climatic conditions favorable to the
efficient use of natural draft towers are low ambient temperatures
and high relative humidities.  Also, the natural draft capacity
and power demand ideally should be in phase.  These factors pre-
                      IIT  RESEARCH INSTITUTE

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                                                                       TABLE I
SUMMARY OF U.S. NATURAL DRAFT


P
Plant
Big Sandy #1
Keystone #1  #2

Ft. Martin #1
Ft. Martin #2
Paradise #1,2&3
Muskingum River
Big Sandy #2
Homer City #15c2
Conemaugh #1
Mitchell #1
Conemaugh #2
Mitchell #2
Hatfield #3
Rancho Seco #1
Etowah il
Montour *1
John E. Amos 4
Peach Bottom #1
Burlington 41
Etowah #2
John E. Amos #5
Three Mile
Island #1
Rancho Seco #2

Montour #2
Peach Bottom #2
Burlington #2
John E. Amos #3
Harrison
Three Mile
Island #2
Trojan
U n s p e c
Etowah *3
Martins Creek #1
Limerick #1
Newbold #1
U n s p e c
Martins Creek #2
Homer City
U n s p e c
Limerick *2
Newbold #2


R 0 J E C
Location
nr. Louisa, Ky.
nr. Shelocta, Pa.

nr. Morgantown,
West Virginia
Green River, Ky.
nr. Beverly, Ohio
nr. Louisa, Ky.
Homer City, Pa.
nr. Johnstown, Pa.
nr. Moundsville, Pa.
nr. Johnstown, Pa.
nr. Moundsville, Pa.
Masontown, Pa
Sacramento, Calif.
_
_
Charleston, W. Va.
York County, Pa.
Burlington, N. J.
_
Charleston, W. Va.
Harrisburg, Pa.
Sacramento, Calif.

_
York County, Pa.
Burlington, N. J.
Charleston, W. Va.
_
Harrisburg, Pa.
Columbia River, Ore.
i f i e ci
_
_
_
_
i f i e d

Homer City, Pa.
i f i e d
_
-


T
Utility
Kentucky Power AEP
Pennelectric
Keystone Group
Alleghany Power
Duquesne Power
TVA
Ohio Power AEP
Kentucky Power AEP
Pennelectric, New
York State E&G
Pennelectric,
Conemaugh Group
A. E. P.
Pennelectric,
Conemaugh Group
Appalachian Power
Alleghany Power
Sacramento Muni-
cipal District
Georgia Power
Pa. P. & L.
A. E. P.
Philadelphia Elec.
Public Service E&G
Georgia Power
A. E. P.
General Public
Utilities
Sacramento Muni-
cipal Utility
Pa. P. 6. L.
Philadelphia Elec.
Public Service E&G
A. E. P.
Alleghany Power
General Public
Utilities
Portland General
Electric
A. E. P.
Georgia Power
Pa. P. & L.
Philadelphia Elec.
Public Serv. Elec.
A. E. P.
Pa. P. & L.
New York State E&G
A. E. P.
Philadelphia Elec.
Public Serv. Elec.
ELECTRIC

Size \~ \^^t v~uiu. ^*-ati_ w Uf^ n- o
STATION
Type
r1 r>-*-,i
COOLING TOWERS
NATURAL
DRAFT

TOWERS T O
_
C*-n-+- _!!-, I3e
si *-*Vi+-
W E R

MW N-Nuclear Number Total Date Meters Meters
265

2 x 900
540
540
2 x 700
1150
615
800
2 x 640
820
800
820
800
2 x 540
850
700
785
800
1065
1000
700
800
830
850

785
1065
1000
1300
3 x 650
830
1118
1300
875
800
1100
1100
1300
800
640
1300
1100
1100
C

c
c
c
c
c
c
c
c
c
c
c
N
N
C
C
C
N
N
C
c
N
N

C
N
N
C
C
N
N
C
(J
C
N
N
C
C
C
C
N
N
1

4
1
1
3
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1

1
1
1
1
2
2
1
1
1
1
1
2
1
1
1
1
1
2
1

5
6
7
10
11
12
14
15
16
17
18
19
20
21
22
23
24
25
26
27
29
30

31
32
33
34
36
38
39
40
41
42
43
45
46
47
48
49
50
52
Dec. 1962

Spring 1967
Spring 1967
Spring 1968
Spring 1968
Fall 1963
Spring 1969
Fsll 1969
Winter 1969
Winter 1969
Spring 1970
Spring 1970
Winter 1970
1970
1971
1971
1971
Winter 1971
Winter 1971
1972
1972
1972
1972

1973
Spring 1973
Fall 1973
1973
1973
1974
1974
1974
1974
1974
1975
1975
1975
1975
Proposed 1976
1976
1977
1977
98

99
113
133
113
113
119
113
113
113
113
114
122

113
122



122
116
122

113


152

116
152
152
122
113
152
122
152
113
74.5

75.2
115
97.5
120
121
84.0
87.7
119
119
87.9
119
100
915


97.5



97.5
113
91.5






113








Total
Water
Flow **.. *_ n 4.vu_.< uu^u
TOWER DESIGN

Danrt e>


Wet
K nnlK
qpmxlO^CU F (3 F (3) F
120

560
250
250
260
220
248
208
280
248
280
248
265
223
258
261
248


258
248
215
223

261




215
130


261



261
22.7

28
24
27.5
24
28.7
23
28
28.7
28
28.7
18
28
25.6
27.6
23.7


25.6
28.7
28
28

27.6




28



27.6



27.6
Addition to

152
122









15

18
18
22.6
16
16
20
18
16
18
16
16
23
19
17
16


19
16
16
23

17




16



17



17
present



72

72
72
72.6
70
70
82
72
70
72
70
72
52
76
73
70


76
70
72
52

73




72



73



73
plant



BASIS

Dry Relative
Bulb Hum
F
79.5

86.5
86.5
78
77
77
86.5
86.5
77
86.5
77
86.5
59.5
88
88
77


88
77
86.3
59.5

88




86.3



88



88
expected



lidity
% 	
70

50
50
78
71
71
50
50
71
50
71
50
60
58
50
71


58
71
50
60

50




50



50



50




(1)   Rated capacity.
(2)   Temperature difference between hot water in and cold water out.

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f      I
f      i      (
                                   /     f     r     r  .t   r ,    j
              60
              50
             40
          -S
          O

          &  30

          M-I
          O

          l-i
          0)
             20
             10
              0
Operating



Constructing or Planned
              1962      1964      1966       1968       1970      1972      1974       1976      1978

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I      I     I      I     J
i      f     r      r     f     i      f     f
       Location
    Unspecified  11

                                                                    O O"   5

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viously have limited the use of natural draft towers to Europe
where the low ambient temperature and high humidity prevail in
the winter when power demand is at its peak.  In the United States
peak power demand is in the summer due to the widespread use of
air conditioners.  As a result, mechanical draft units are favored
in the States.  However, the economics of the two types of cooling
towers favor the selection of natural draft towers in certain
situations especially for electrical power plants, where large
volumes of water must be cooled.
     Although this study concerns hyperbolic towers a number of
electrical utilities operate large mechanical draft units on
condenser cooling service.  Some of the utilities employing
mechanical draft units are:
              American Electric Power Service Corporation
              Arizona Public Service Company
              Boston Edison Company
              Columbus & Southern Ohio Electric Company
              Dallas Power & Light Company
              Duke Power Company
              Georgia Power Company
              Gulf States Utilities Company
              Houston Light & Power Company
              Iowa Electric Light & Power Company
              Kentucky Utilities Company
              Oklahoma Gas & Electric Company
              Public Service Company of Colorado
              South Carolina Electric I Gas Company
              Southern California Edison Company
              Southwestern Public Service Company
              Texas Electric Service Company
              Texas Power & Light Company
              United Illuminating Company
              Utah Power & Light Company
     Generating stations currently under construction for which
mechanical draft towers are to be used include the Monticello,
Allen S. King, and Prairie Stations of the Northern States Power
Company; the Altamaha River Station of the Georgia Power Companies;
the Centralia station of the Pacific Power & Light Company; and the
Trenton Channel Station of the Detroit Edison Company.

                      IIT  RESEARCH  INSTITUTE

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 LOCAL CLIMATE MODIFICATIONS RESULTING FROM THE KEYSTONE TOWERS
     It is postulated that the discharge of vast quantities of
water vapor and heat to the atmosphere from natural draft cooling
towers would modify the climatology of the region.  In order to
determine if the Keystone plant has produced any noticable effect
during its short period of existence, the available climatological
data for a 10 year period were studied.
     Keystone is located rurally and is distant from a first-order
U.S. Weather Bureau station having long-term climatological records
for the several meteorological elements required to assess the
effect of the cooling tower plumes.  Precipitation data, however,
are available from records maintained by the U.S. Weather Bureau
and other recording and non-recording weather stations.  Precip-
itation,   therefore, is the only element that could be evaluated
for any possible effect of the plume.  Elements such as fog
frequency, changes in relative humidity, hours of sunshine, days
with precipitation, and thunderstorms would have to be evaluated
to determine the full effect of the plume.
     Precipitation data sources consulted in this study included:
     1.  Monthly and Annual Local Climatological Data
         issued by the U.S.  Department of Commerce,
         ESSA Environmental Data Service.
     2.  World-Wide Airfield Summaries compil.ed by the
         U.S. Naval Weather Service.
     3.  The Office of the State Climatologist  (ESSA-
         U.S. Weather Bureau) at Pennsylvania State University.
         Stations for which climatological data at this
         office were studied and tabulated are shown in
         Figure 3.  Station vital statistics are tabulated
         in Table 2.
     4.  The complete data record for the Greater Pittsburgh
         Airport was used to establish a control for the
         area under study and to determine the monthly and
         annual prevailing wind.

                      (IT  RESEARCH  INSTITUTE

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f     f
r     f,    f     r
f     f
f     (    f
                                                                      f    f     i     f
                      VANDERGRIFT
                                                 JIMMY STEWART
                                                 .AIRPORT
                                           /

                                          /     INDIANA


                                       /        '       i
                                      "'         /  STRONQ6TOWN*

                                           HOMER CITY     /



                                                                /



                                             o*X         /

-------
n
en

oo

i
OJ
                                             Table  2



                             VITAL STATISTICS OF  STATIONS USED IN THIS STUDY



!_.
0




H-
D
Q)
I-1
$
0
n
rt

Station
- Creeks ide
 Ford City Dam
m
 Home
so
Q Indiana
z Johnstown
-t
^ Strongstown
c
m Tunnelton
Vander grift
Greater Pittsburgh Airport



Location
from Keystone
Miles
8
9
14

12
32
24

14
12
47

Direction
ENE
NW
ENE

ESE
SE
ESE

S
WSW
WSW


Elevation
(meters)
314
290
372

336
389
572

272
244
346


Type of Record
Non-recording rain gauge
Recording rain gauge
Recording rain gauge

Recording rain gauge
Recording rain gauge
Recording rain gauge

Recording rain gauge
Non-recording rain gauge
Complete observations

-------
     The precipitation records for the stations shown in Figure 3
were analyzed for evidence of possible precipitation enhancement.
The annual precipitation totals for each station for the years
1960-1969 are given in Table 3 and plotted in Figure 4.  For the
period 1960 to mid-1967, the precipitation pattern was not in-
fluenced by the Keystone Station, since this facility went on
stream at partial capacity in the spring of 1967 and at full
capacity in mid-1968.  The annual prevailing wind for Pittsburgh
each year during the 10-year period (1960-1969) was SSW.  On
an annual basis, then, Creekside and Home are downstream from
Keystone and any large scale climatological effects should show
up at these two reporting stations.  From Figure 4, it is apparent
that no such effects are evident.  The 1968 and 1969 precipitation
totals fall off sharply in agreement with the Pittsburgh control
data, and with the other stations for which data totals are
available.  These two relatively "dry" years are within the limits
of variability expected with changing synoptic scale weather patterns,
     To establish the existence of any seasonal pattern of in-
fluence from Keystone, the data were analyzed on a monthly basis.
These are plotted as Figure 5.  If any anomalous convective activity
generated from the stacks and cooling towers is a significant
factor on precipitation patterns, it would be expected to show
its strongest effect during the spring and summer months.  Pre-
vailing surface winds for Pittsburgh for each month in 1968 and
1969 were considered in evaluating the precipitation data.  Also
considered was the mean monthly wind direction for the 700 mb
level, because the movement of large convective cells are governed
more by upper level flow than surface winds.  The mean monthly
700 mb charts (Reference 1) were the source of this information.
Since flow aloft tended to be from the W or even WNW during some
of the spring and summer months, the Indiana and Strongstown
reporting stations assume importance in assessing downwind effects.
The Strongstown monthly means for the 8 years 1960-67 plotted on

                      IIT  RESEARCH  INSTITUTE

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                                                 Table 3


                                   ANNUAL STATION PRECIPITATION BY YEARS


                                                (Inches)
 NJ
H-

0)
H

50


o

ft

o

H1
CD

I
OJ
  Creekside



^ Ford City

TO           **

 Home
m


o Indiana
z

z Johnstown

-i

2 Strongstown

m
  Tunnelton



  Vandergrift



  Pittsburgh(3)
                       1960   1961   1962   1963   1964   1965   1966   1967   1968     1969


                      37.36  41.47  37.65  36.78  43.90  42.20  44.63  47.87  36.01    30.13
                      38.89  39.76  36.80  29.44  41.91  34.77  39.61  40.85  34.27    Inc



                      36.72  38.71  35.38  34.17  38.52  36.90  39.73  42.61  38.10    37.92(2)



                      39.44  43.68  42.57  32.09  38.77  34.78  37.75  40.84  31.99    36.53(2)
                      40.30  43.55  44.19  35.98  40.34  34.81  39.40  42.31  37.01    37.97


                      39.51  50.07  40.86  36.43  42.43  40.21  42.79  50.91  42.95    Inc
34.98  38.49  39.92  29.56  41.05  32.97  34.65  41.43   Inc  x"   Inc


30.26  39.35  39.61  31.44  42.36  33.49  36.30  39.03   Inc  ^'   Inc


31.29  38.10  31.62  26.79  37.89  30.24  34.06  36.38   36.07     29.58


(1)  Incomplete.
(2)  Annual total estimated - some monthly data incomplete.
(3)  Used as a control.

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      two
      1300
      1200
      1100


I   
H;   1000
i    a
   ae.
       900
       800
      700
55
                        50
                                      CREEKSIDE  (C)
                                  X  FORD  CITY
                                      HOME  (H)
                                  -h  INDIANA
                                  0  JOHNSTOWN
 a  STRONGSTOWN
 A  TUNNELTON
 0  VANDERGRIFT
	  PITTSBURGH (P)
KEYSTONE ON STREAM
I PART. CPCY     I FULL CPCY

  Q
                                  I960        1961         1962        1963        1964        1965        1966

                                                                                       YEAR

                                                                 FIG. 4     STATION ANNUAL PRECIPITATION TOTALS
                                                                                   I960 THROUGH 1969
                                                                                             1967
                                                1968

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280
260
220
200
180
160
120
100
 80
 60
40
20
                     10
                  S  6
                  =  5
C  CREEKS IDE
X  FORD CITY
H  HOME
-(-  INDIANA
O  JOHNSTOW
                                                                                                        D   STRONGSTOWN
                                                                                                        A   TUNNELTON
                                                                                                        0   VANDERGRIFT
                                                                                                        P   PITTSBURGH
                                                                                                                                   9.71
                                  JAN.
                                              FEB.        MAR.
                                                                     APR.
                                                                                 MAY
                                                                                                                     AUG.        SEPT.
                                                                                             JUNE        JULY
                                                                                            MONTH
                                                              FIG. 5     STRATIFICATION OF STATION PRECIPITATION DATA:  I960-  1967
                                                                                                                                             OCT.

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Figure 5 run slightly higher than the other stations during the
winter and spring months.  This tendency is probably caused by
the stronger orographic effects at the site which is 180 to 305
meters higher than the other stations.  Because of this factor,
Strongstown is not included in the plot of maximum and minimum
precipitation values in Figure 5.
     Monthly precipitation data for 1968 and 1969, when the
Keystone Station was in operation, are shown in Figure 6.  The
maximum and minimum monthly precipitation totals recorded during
the 8 years prior to Keystone going on stream are repeated in
Figure 6 for reference points.  If Keystone's steam plumes
significantly increased the monthly precipitation at the down-
wind stations, the fact should be reflected in the monthly totals
for Creekside, Home, and Indiana,   provided a similar increase
did not occur at Pittsburgh.  It can be seen that in April 1969,
a trend towards increased precipitation was indicated; but the
values did not exceed the 8-year mean (Figure 5) by more than
0.75 inch.  In July 1969 the records of Home and Indiana exceeded
the 8-year extremes substantially.  However,Creekside was 1.25
inches greater than the 8-year mean for July;and Pittsburgh
exceeded its mean by 0.95 inch.
                      IIT RESEARCH  INSTITUTE


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(          I           i           f         .t.       .. I          I
            f           f          I          I
f  ,        i           f          i
      'i  110 I
         120 I
          10 \
          20  I
                                                                                          C  CREEKSIOE
                                                                                          H  HOME
                                                                                          -f  INDIANA
                                                                                          P  PITTSBURGH
                                                                                                                                            g  ?|
                                           JAN.
                                                       FEB.
                                                                   MAR.        APR.
                           JUNE        JULY

                               MONTH

FIG. 6     STRATIFICATION OF STATION PRECIPITATION  DATA:  1968-1969
                                                                                                                              AUG.        SEPT.         OCT.        NOV.

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     DIFFUSION OF HEAT AND WATER VAPOR; PLUME PROFILES

     The heat and water vapor released to the atmosphere by the
Keystone cooling towers is given in Table 4.  The data were
obtained from the monograph, Figure A-3, using pump pressures
to determine water flows and temperature data to obtain the
cooling tower range and the relative humidity of the ambient
air.  The procedure is described in Appendix A.  When the station
was operating at 80 to 86% of its rated capacity, approximately
10,000 gal/min of water were evaporated; and the total heat
released was about 120 million BTU/min.  Unfortunately, at the
time the most complete aerial survey data was obtained, December
6, 1969, the station was operated at 16% of its rated capacity;
only one generating unit was in use.  On this day, it was
estimated that the two cooling towers in use released 1880 gal/
min of water vapor and 28 million BTU/min of heat.  On December
2, 1969, when a partial aerial survey was made, all four towers
were in operation and 120 million BTU/min of heat were released.
Evaporation rate on this date was 8950 gal/min.  Because some
pressure gauges were in error the values reported are reasonable
estimates only.  Also, the use of the monograph ties the results
to design data rather than performance measurements.  Because
of the dependency of natural draft cooling tower performance
on climatic conditions, the data should not be extrapolated
to other seasons.  Future tests of tower emissions should
follow the testing technique described  in British Standard 4485
(1969); this standard was not available in time for use during
this study.
     The visual portion of the cooling tower plumes were observed
from the ground during the period of November 24 to December 7,
1969.  Usually the visible portion of the plumes rose to an
altitude of less than 200 meters and was less than 200 meters
in length.  However, the visible portion of the plume was
                     IIT RESEARCH INSTITUTE

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 " I
                           Table  4
HEAT AND WATER VAPOR RELEASED TO  ATMOSPHERE AT KEYSTONE
                                                         (1)
Power Generated Number of







M
00





^
H-
3
01
50
(D
o
O
ft
O
00
-0
1

Date
9/20/69
-* 9/21/69
TO
S 9/22/69
m
 9/23/69
X
_ 9/24/69
z
" 10/28/69
= 11/29/69
m
11/30/69


12/2/69
12/5/69

12/6/69

(1) Data
loss

% of rated
capacity
84
63

73

85

86

85
80

83


77
13

16

are a summary of
is described in

Towers
in operation
4
4

4

4

4

4
4

4


4
2

2

Table A- 3, Appendix
Appendix A.

Total Evaporation
loss
crpm
9480
6920

8380

9760

9890

11080
9440

9550


8950
1640

1880

A. The method for


Total heat
..Released
10 BTU/Min
112
84

98

113

115

145
127

130


120
22

28

calculating eva]


-------
dependent on the temperature and humidity of the ambient air.
When temperatures were 25-30F  and the relative humidity was
high (~80%), the visual portion of the plume persisted for many
miles and could be seen to merge with the stratus cloud cover.
At higher ambient temperatures and lower relative humidities,
the visible plume attained altitudes of less than 200 meters and
downwind distances of 100 to 200 meters.
     Aerial surveys of the plume were made on December 2 and 6,
1969.  The surveys were made with a helicopter instrumented to
measure the dry bulb and wet bulb temperatures, relative humidity,
sulfur dioxide, and the size and acidity of the plume droplets.
The instrumentation, flight procedures, and results, with one
exception, are given in Appendix B.  The data obtained during
the morning of December 6, 1969,are discussed in the following
paragraphs.  Because of turbulence, flights through the visible
portion of the plume were not possible; the droplet samples
were obtained at the edge of the visible portion of the plume.
     The aerial survey on the morning of December 6, 1969, was
initiated with a vertical ascent upwind of the Keystone Station.
The aircraft then proceeded downwind of the station and sampled
the invisible portion of the plume at downwind distances of 640,
4800, and 10,800 meters.  Finally, the aircraft backtracked to the
station at treetop level beneath the plume.  The upwind ascent
data are shown in Figure 7.  A temperature inversion just under
600 meters was present.  A marked decrease in the relative
humidity and increase in the wet bulb depression coincided with
the inversion.  The sulfur dioxide concentration decreased with
altitude; it was about 0.03 ppm at ground level and less than
0.01 ppm at 600 meters.  The relative humidity up to about 550
meters was steady at about 80-85%.  In the afternoon (Figure B-ll),
the relative humidity had dropped to 40-43%;and the temperature
inversion was not detected/although the decrease in relative
humidity and the increase in wet bulb depression was still
observed.  The profiles for air temperatures, relative humidity,
                      IIT RESEARCH INSTITUTE

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co
H
W
S
   600 |
   300
     0
                                       Wet bulb
                                       depression
                                           Date
                                           12/6/69
                                           morning
      25
      10
       0
       0
26^27   28   29   30   31   32       Temp.,F
20   30   40   50   60   70   80   90  R.H.,%
    0.01      0.02      0.03      0.04 S02/ ppm
      123            Wet bulb Depr.,C
      Figure  7:   Prevailing Ambient Conditions Prior to
                          Plume Traverses.

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and sulfur dioxide at distances of 640, 4800, and 10/800 meters
downwind of the cooling towers are given in Figures 8 through
16.  The profiles were drawn as if the plume was viewed by an
observer standing at the tower base and looking downwind along
the plume axis.  No contours were drawn through the temperature
data because they appear to vary randomly and no discernable
pattern could be detected.  Temperatures both higher and lower
than the surrounding air are indicated.  The plume's vertical
height oscillated from 545 to 565 to 450 meters at downwind
distances of 640, 4800, and 10,800 meters, respectfully.  Var-
iations in vertical depth with downwind distance were insigni-
ficant; average plume depth was 150 to 170 meters.  Horizon-
tally, however, there was great spreading of the plume from
about 2500 meters at a downwind distance of 640 meters to 5000
meters at a distance of 10,800 meters.  In all instances, the
humid plume was comingled with the stack plume as shown by the
sulfur dioxide profiles.  In Figure 17., the ambient air results
beneath the plume are presented.  These data were obtained about
2 hours after the upwind ascent data given in  Figure 7.  The
most significant differences are the decrease in relative humidity
from about 80% to 62% and a decrease in the sulfur dioxide con-
centration near to station from about 0.03 ppm to 0.017 ppm.
No enhancement of the ground level humidity is indicated as a
result of the overhead plume.
     The plume profiles for the afternoon of December 6, 1969,
Appendix B, showed similar altitude oscillations and vertical
and horizontal spreadings as the morning profiles.  The altitute
of the plume varied from 380 to 420 to 475 meters at downwind
distances of 640, 3200, and 10,800 meters.  Again, the stack and
tower plumes were comingled.
     On December 2, 1969, all four cooling towers were in opera-
tion.  The upwind ascent data, Figure B-4, show  a steady de-
crease in temperature with altitude.  Thus, no inversion was
present on this date.  The profiles indicate a vertical as well
                     IIT RESEARCH  INSTITUTE

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:.3
                                                                                                  LU
   900
   600
CO
W
S
     w
M
            427.2  X29'6  X29'5  X29'8 X29-0 X29'0 X29'3
             28.0  X28.0  j7.7  X27.7 X27.6 X27.5 X27.8

             27.8   27.8   27.7  27.0   27;50.127.5 02P-0^
              !.    ^     "     "   ^ ^W^    ^     A    ^^

                               ^Ts   26Ji   2). 5 ^25.8^/26.
                               26.3'526\l ^2%. I ^-J<5^ 26.
        ,26.8
            t25.7
             26.6
   300
                                          X26.6
        26.0  X26.3 X26.6X26.5 X26.5  X26.7  X26.5 X26.3 X27.0
                                                                 Date  12/6/69
                                                                   morning
                                                                                          5000
                                                                                                     "SoTjO
                    1000
  2000           3000            4000
GROUND LEVEL DISTANCE  TRAVERSED:   METERS
              Figure  8:  Sulfur Dioxide  (ppm)  Profile

-------
     900
     600
          ,27.2 X29'6 X29'5  X29'8  X29-0 X29>  X29'3
                          X27.7 X27.6 X27.5 X27.8
                                   .5  27.5   28.0
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                                                  26'6
                              .3 X27.0
                                                                    Date 1.
                                                                       r.crr.
1000
                                     2000           3000           4000

                                   GROUND  LEVL DISTANCE TRAVERSED:   METERS
5000
                                                                            60 00
                    Figure  9:  Relative Humidity Profile (% points  accve  'c-

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i
to
            900
                 ,27.2  X29'6  X29'5  X29'8  X29-0  X29'^X29-3

                 28.0  x28-0  X27'7  X27'7 X27'6  X27'5  X27'8
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                                                                           Date 12/6/69
                                                                              morning
                             1000
                                     2000           3000            4000
                                  GROUND  LEVrIL DISTANCE  TRAVERSED:   METERS
                                                 5000
60QO

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                                                                                                          LU
to


I
   CO
H
W
S
   W
       900
       600
c 26.H  x 26.it x25-7 X26'7

 26. H   26.6  26.2 ,.26.1
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                                                                         Date  12/6/69
                                                                           morning
                                   26
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                                        ' s
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            25.8
       25.9 -25.9
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X26.8X27.7X


X 27-3X 27'5x
28.0

27.2

27.5
                        1000
                                    2000           3000           4000

                                  GROUND LEVEL  DISTANCE TRAVERSED:   METERS
                                                                           5000
               Figure  11:  Sulfur Dioxide (ppm)  Profile


-------
17
 L -~j
                                                       rza
    900
                                                                Date  __
    600
                                               X28.0 X27.3 X27.3 x27-7  X 27.7 x 27. 6 x 27-6 X27-6
CO
EH
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26.4  x 26
25.8
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  28.0
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EH
M
EH
S
    300
                     1000
                                          2000           3000           4000
                                        GROUND LEVEL  DISTANCE TRAVERSED:   METERS
                                                                           5000
6000
         Figure  32:  Relative  Humidity >jicfi.lc  (-.-. points  above c = ~'?.'.~ r _:.::

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    900
                                                                          Date  12/6/69
                                                                            morning
w
fi
EH
W

    600
                          X27.4  X27.5 X28.0 X28.0X28-0  X27.3 X27.3 X27.7 x 27. 7 x 27. 6 x 27.6 X27.6
X26.4 X25.7 X26.7
26.4  X26.6
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       25.9 x 25.9
x 26.7 x 26.6 x 26.4 ^
x 26.6 x 26.6 X26.6 x
X26.2 X27.4 X27.8 x
                                          27.0 - 27.1 -27.0 -27.2  -27.5
X26.7 X26.5
                  26.7 - 27.2
X 27.6X27.5
x 27.3X 27.0
27.4  *27.5
            X27.2  X27.5 x 27.5X27.5
x 28.2 X28.2 x  28.0
  26.8 x 27.7 x  27.2
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W

EH
    300
      0,
                      1000
                        2000            3000           4000
                      GROUND LEVEL DISTANCE TRAVERSED:  METERS
                                                                              5000
                                                6000

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ro
CO
              900
              600
          to
          W
          w
              300
                                                                      Date  12/6/69
                                                                        morning
                  29.0
X29.l  X29.2  X29.2 X29.2 X29.2 X30. I  X30.1 X29.1   x28.9  x29-5


                 X28.5 X28.5 X29.0  X28.8 X28.8  X29.0 X29.5


                 X27.7 X26.5  X27.8  X27.7 X27.1  X27.5  X27.0
27.3
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           0.02

,28.5  X28.5  X28.5  x28.5
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                                                                                        0.02'
                                                                I
                             I
                                                                               I
                               1000
                         Figure  14:
        2000           3000           4000

   GROUND LEVEL DISTANCE  TRAVERSED:  METERS

Sulfur Dioxide  (ppm)  Profile
at  10,800  Meters  Downwind of  Tower.
                                           5000

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?~-"T|
L-.J
    900
    600
to
w
w
    300
                                                               Date  12/6/69
                                                                 morning
29.0   29.0   29.0   29.0   28.8  29.0   29.l
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27.3  X27.7,
        28.5  X28.5  X28.5  x28.5  X28.
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                                                                        X29.0 X28.8  X28.8  X29.0 X29.5
                                                                                          X27.5  X27.0
                     1000
                              2000           3000          4000

                         GROUND LfiVEJ, DISTANCE TRAViSRSfiD:   METFTiS
5000
6000
                 Figure  1L>:  i-.t '-.'t j ,.c  Kuaadity  I'joiiJe (% points  above  background)

-------
CO

o

W





W
H

EH
            900
            600
            300
                                                                            Date  12/6/69

                                                                              morning
                29.0 X29.0 X29.0 X29.0 X28.8  X29.0  X29.l  ^9.2  X29.2 X29.2  X29.2 X30. I  X30. 1  X29. 1   X28.9  X29.5






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                                   27.0   27.0  X27.0  X27.0  X27.4  X27.0 X27.7  X26.5  X27-8  X27-7  x27'4  X27'5 X27'0
                  X.   X


 27.3  X27.7  X27.0  X27.0 X27.0  X27.0  X27.0  X27.0 X27.0 X27.6 X27.0 X27.0 X27.





[28.5  X28.5  X28.5  x28.5 X28.5  x28. 5 x28-6  X28-6 X27-3 X28.4 X28.0  x28.0  x28.0 x28.0  X28-0  X28-0
                                                                 I
                              1000             2000            3000           4000


                                          GROUND LEVEL  DISTANCE  TRAVERSED:   METERS
                                                                                         5000
                                                                                                 6000

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i

OJ
0.03


0.02


0.01



0.0
     Pm
     o
        70
        60
        50
 34
 33
 32
                                  Sulfur Dioxide, ppm
                                                             Date  12/6/69
                                                              morning
                                  Relative Humidity %
Temperature F
                                      234
                                           Downwind  Distance:   Miles
                                                                                              i.O
                                                                                             70
                                                                                             60
                                                                                             50
34
33
32
                                                                                 4-

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as horizontal expansion of the plume.  The profiles for relative
humidity data showed tower plumes at two altitudes; two stack
plumes were also indicated by the sulfur dioxide profiles.
Evaporation and heat release data for this date, Table A-3,
indicate Unit #1 was generating 803 MW/hr of electricity while
Unit #2 was generating only 535 MW/hr.  This difference in
generating capacity would cause the discharge from the cooling
towers serving Unit #1 to have greater buoyancy and thus reach
a greater altitude.  The tower plumes rose from about 300 and
500 meters at a downwind distance of 2090 meters to 545 and
775 meters at a distance of 9960 meters.
     A mathematical model was developed to explain the oscillation
of the plume once it became nearly horizontal.  The model covers
both the visible and invisible portions of the plume and is
derived in Appendix D.  It is an adaptation of a simple cylin-
drical thermal model rising in a neutral atmosphere; such a
model has been previously applied to bent-over plumes.  For
application to Keystone, the model was extended to include the
latent heat of evaporation and condensation.  For the rising
plume from the tower, the equations of motion given by Morton
(Reference 2) were used.  This type of model is an entrainment
model in which the admixture of ambient air into the plume takes
place by turbulence induced by the plume motion.  The results
show the effect of buoyance removed or created by the evaporation
or condensation of liquid water.
     The data in Table 5 were used in the model and to obtain
the dispersion pattern of the plume with distance downwind
of the tower.  Three cases of initial water content were treated,
Table 6; the results are plotted in Figure 18.  The model in-
dicates that the plume will reach the ground when the moisture
content is 70% in excess of saturation.  The plume pattern for
Case 2, plume moisture content 50% in excess of saturation,
best fitted the observed motion of plume on the afternoon of
December 6, 1969.

                     IIT RESEARCH INSTITUTE

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                         Table 5
  PLUME AND ATMOSPHERIC CONDITIONS USED IN DISPERSION MODEL
          Condition
Tower air flow



Tower diameter



Tower height



Tower air temperature



Relative humidity of exit air



Atmospheric temperature



Potential temperature gradient



Atmospheric relative humidity



Wind speed
       Value
8050 meter /sec



61.3 meters



99 meters



59F



100%



38F



9.73 x 10~4F/meter



40%



3.7 meters/sec
                     IIT  RESEARCH  INSTITUTE






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                         Table 6
      PLUME MOISTURE CONTENTS USED IN DISPERSION MODEL
                                              Case
Total Mass Fraction of Water
  (liquid plus vapor)

Mass Fraction of Liquid Water

Mass Fraction of Water Vapor
0.0140   0.0162   0.0183


0.0032   0.0054   0.0075

0.0108   0.0108   0.0108
(1) saturated air at 59F.
                      IT  RESEARCH INSTITUTE


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f      f
!      (
I      f     f     (
(      (
         900
i
OJ
         600
     EH
     W
     S
     EH
     M
     EH
         300
                                                        Cases  are  described in Table 6
                          3000
                       6000           9000          12000
                         DOWNWIND DISTANCE:  METERS
                                                                                      15000

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     The presence of moisture in the plume over and above that
necessary to saturate the exit air was not anticipated prior
to the study, and no assessment of the exit air at the tower
was planned.  However, while measuring the inlet water tempera-
ture at the distributors within the tower, a dense water fog
was invariably present.  Penetration of a light beam from a
flash, light was on the order of a meter.  Estimates of the
distance light would penetrate through a fog, containing a mass
fraction of liquid water of 0.54% as a function of droplet size,
were made using the equation:

              -K7Tr2NL
     f = t =e
      o
where
     t = the fraction of incident light transmitted through
         through the plume of depth, L
     K = scattering coefficient for water droplets
     r = droplet radius
     N = droplet concentration -
     The results, Table 7, indicate that the visibility re-
strictions observed within the tower support the plume model
contention that the tower effluent has a liquid water content
50% in excess of saturation.
                     IIT  RESEARCH INSTITUTE


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                         Table 7
           DISTANCE LIGHT TRANSMITTED THROUGH A FOG

          CONTAINING 0.54% MOLE FRACTION LIQUID WATER
  Size of
   water              	Path Length, L, Meters	
droplet, / Lm           50% Transmission    10% Transmission

    5                       0.19                 0.64

   10                       0.38                 1.30

   25                       0.95                 3.20

   50                       1.90                 6.40

   75                       2.90                 9.60
                      IIT  RESEARCH INSTITUTE


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           MIXING OF THE TOWER AND STACK PLUMES

     The humid plumes from the cooling towers become mixed with
the discharges from the power station stacks at downwind distances
ranging from 200 to 1000 meters.  The plumes from the two sources
remained mixed at downwind distances of 11,270 meters, the farthest
point at which aerial traverses were made.  While the cooling
tower plume was visible, normally 200 to 300 meters, the mixing
was visually observed.  After evaporation of the cooling tower
plumes mixing was confirmed by the aerial sampling of the humidity
and sulfur dioxide content of the atmosphere, Figures 8,9,11,12,14,
15, B-5, B-6, B-8, B-9, B-13, B-14, B-16, B-17, B-19, and B-20-
     The mixing of plumes, while the cooling tower plumes were
visible, was further shown by the presence of acid droplets and
fly ash particles found in the cascade impactor samples, Appendix
C.  Because the cooling tower water supplies were neutralized,
the presence of acid droplets in the plume is a priori evidence
that sulfur dioxide from the stack gases had reacted with the
moisture in the cooling tower plume.  Most of the droplets were
collected on the first stage of the cascade impactor and, there-
fore, exceed llu m in size.  Since the collections were mainly
on one stage it was not possible to obtain a droplet size dis-
tribution based on the aerodynamic collection efficiency of the
collector.  In Appendix C size distribution of the residue rings
left after evaporation of the collected droplets are reportede
but the residue size was not correlated to droplet size.  While
a relationship apparently exists between the humidity of the air
and the ratio of acid to neutral droplets, Figure 19, no rela-
tionship was found between the sulfur dioxide content and the
presence of acid droplets.
     Almost without exception, the plume droplets,, both acid
and neutral, contained a large number of solid particles.
Usually these particles were small- less than a few microns in
                     IIT RESEARCH  INSTITUTE

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    10
 t-
  I

 a
  o.

 4J
  (0

  CO
(0


CO

D
  TJ
  H
  CJ
  ID


  C.
 a
 Q;
  0.01
                                   1
                  20
40           60         80


RELATIVE  HUMIDITY, %
100
          Figure  19:   Variation  of Acid Drop Concentration

                            with  Humidity.




-------
size.  However, on occasion particles up to a few hundred microns
in size were sampled.  The particles were presumed to be fly
ash.
     The mixing of the plume can produce significant changes
in the composition of the power station emissions.  It is known
that humidity enhances the oxidation of sulfur dioxide and the
formation of sulfuric acid.  The presence of particulate matter
can promote condensation and provide heat-sinks for chemical
reactions.
     When the two units of the power station were operating at
greatly different capacities, as they were on December 2, 1969,
two distinct stack plumes were discernible from the sulfur
dioxide profiles at downwind distances up to 9960 meters, Figures
B-5 and B-8.  Plume spreading was much greater in a horizontal
direction than in the vertical direction.
     The degree of mixedness between the plumes cannot be
stated precisely.  The plumes occupy the same space; and the
visible humid plume is highly turbulent, as determined by its
action on the aircraft.  However, the lack of a correlation
between the acid droplets and sulfur dioxide concentration
suggests the plumes are not uniformly mixed and may be just
coming led.   Also, it is obvious that the altitude reached by
the plumes is dependent upon their buoyancy; and a critical
factor in determining buoyancy is the operating capacity of the
plant.  From the profiles obtained, it was apparent that the
discharges from the 244-meter stacks comingled with the humid
plume effluent from 99-meter towers.  The two heights apparently
balance out the differences in plume buoyancy.   This may rep-
resent a deficiency in station design if mixing of the stack
and tower plumes is undesirable.
                     IIT  RESEARCH  INSTITUTE

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  POSSIBLE LOCAL EFFECTS OF HEAT AND WATER VAPOR RELEASE

     Cooling towers have the potential to inadvertently modify
the weather surrounding their location.  The weather effects
that could be modified are fog,  rain, drizzle, and cloud ini-
tiation.  Any modification would be the result of the release
of large quantities of heat and water vapor into the atmosphere
from the towers.
     Local fogging and the creation of road hazards due to icing
and visibility restriction are a well documented (Reference 3)
nuisance associated with forced draft cooling towers.  Natural
draft towers present a much larger point emission source of
water vapor than forced draft towers and have lower exit ve-
locities (~3.7 meters/second).  However, they also have a greater
heat content and are discharged from much greater heights.   At
Keystone, no increase in ground level humidity was detected by
the low level helicoper traverses.
     It was observed that the Keystone towers do not produce
drizzle precipitation in the immediate vicinity of the towers.
No droplets were detected by sensitized (Ozalid)  paper swatches
laid out beneath the Keystone towers.
     Juxtapositioning of cooling towers emitting heat and
water vapor provides circumstances favorable to the formation
of convective cells under certain climatic conditions.  On
occasion the Keystone plumes were witnessed to evaporate and
then recondense at higher altitudes further downwind.  Under
stable temperature conditions and high ambient air humidities,
the Keystone plume persisted and merged downwind with the
existing stratus cloud cover.  Initiation of cumulus clouds
during periods of otherwise clear skies was observed at
Keystone on one occasion by Mr. Frank Schiermeier of the Air
Pollution Control Office, but the clouds triggered by the
                     IIT RESEARCH INSTITUTE
                              41

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cooling tower emissions only prededed natural cloud formation.
On the basis of the available climatological data (Figure 4),
there is no evidence that annual precipitation has been altered
by the presence of the Keystone station.   Only in July 1969,
is there a possibility of rainfall enhancement downwind of
Keystone (Figure 6) .
                     IIT  RESEARCH INSTITUTE


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                             CONCLUSIONS

     Natural draft cooling towers are being selected with
increasing frequency as a means of disposing of large quanti-
ties of waste heat.  The first natural draft tower in the
United States went on stream on 1962.  Currently, there are
18 operational towers; projections indicate that between 32 and
40 will be operational by 1974.  These towers will be located
predominantly in the Northern Appalachian areas; 22 will be in
Pennsylvania.  Without exception, the natural draft cooling
towers are associated with electrical utilities.  They are
being used despite an unfavorable relationship between their
cooling capacity and the demand for power.
     Natural draft towers vent large quantities of heat and
water vapor to the atmosphere.  At Keystone approximately
10,000 gal/min of water are evaporated, and 120 million BTU/min
of heat are released when the station is operating at 80 to
86% of its rated 1800-megawatt capacity.  While under obser-
vation during this study, the visible portion of the tower
plume normally rose to an altitude of less than 200 meters
and traveled downwind about 200 meters before evaporating.
However, the dimensions of the visible portion of the plume
are greatly dependent on the temperature and humidity of the
ambient air.  When temperatures are 25-30F and the relative
humidity is high, the plume can be seen for thousands of meters.
Even when the plume was visible over only a short distance,
its path could be traced up to 11,000 meters by aerial measure-
ments of humidity.  An entrainment model indicated that plume
moisture content 50% in excess of saturation at the lower exit
would produce the observed plume pattern.
     The cooling tower plume comingles with the effluent from
the power station stacks.  The mixing of the plumes from the
two sources takes place between 200 and 1000 meters downwind

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of the station; the plumes remain mixed for distances up to
11,200 meters, the farthest downwind point at which aerial
samples were taken.  Mixing of the plumes was confirmed by
the presence of acid droplets and fly ash particles in the
visible portion of the cooling tower plume.  When the two
power-generating units at Keystone were operating at different
rates, the  effluents from the units reached different alti-
tudes.  It appears, though, that the tower and stack plumes
serving a generating unit have similar total buoyancies since
they reach the same altitude.
     While under observation during this study, no adverse
weather effects due to the operation of the Keystone Station
could be shown conclusively.  Drizzle beneath the tower from
water droplet carry-over was not detected, and no increase in
ground level humidity underneath the plume path was observed.
Only in July 1969 was there a possibility of precipitation
enhancement according to existing local Weather Bureau
climatogical records.  At all other times the monthly precipi-
tation totals during the period since Keystone was placed in
operation were within the envelope of natural variation for
the area.  Cloud initiation is infrequent, but the merging of
the plume with the stratus cloud cover is relatively common.
     The full environmental effects of natural draft cooling
towers cannot be stated conclusively from the study for three
reasons.  The station  effluents were observed and sampled over
a short time period that represented only one season; the sta-
tion was operated at 1/6 capacity during a portion of the field
tests; and field instrumentation was lacking in several
essential areas.

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                      RECOMMENDATIONS

     Recommendations to further the study of the effects of
natural draft cooling towers serving Keystone are suggested in
three areas.  First, the station should be instrumented to
obtain reliable water balance and heat loss data.  The nature
of the water losses from the towers should be determined.  The
British Standard  (BS 4485, 1969) should be reviewed to determine
its application to American use.  Visual observations of the
plume at Keystone should become part of the daily station log.
     Secondly, the present network of weather stations should
be expanded and upgraded.  At least one, and ideally two, stations
should be added in the easterly quadrant, 8000 meters from
Keystone.  Another station should be placed similarly east to
east northeast of Homer City.  Observations at cooperative non-
recording rain gauge stations should be extended to include
such elements as fog occurrence, thunderstorms, precipitation
days, and relative humidity and dew point data.  The facilities
at the Jimmy Stewart Airport should be expanded to read these
elements.  Siting of a weather radar station in the area to
study precipitation patterns over a period of several years
would help to answer questions concerning the weather effects
produced by the towers.
     Thirdly, if the mixing of cooling tower plumes and station
effluent is undesirable, the factors affecting plume buoyancy
should be studied.  The design at Keystone apparently imparts
to the two effluents the same total buoyancy, despite differences
in heights of the towers and stacks.
                     IIT  RESEARCH  INSTITUTE

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                          REFERENCES
1.   "Monthly Weather Review" U.S. Dept. of Commerce,
     Environmental Science Services Administration,
     Vols. 96 and 97.

2.   Morton, B. R.  "Buoyant Plumes in a Moist Atmosphere"
     J. Fluid Mechanics 2, 1957.

3.   Hall, W. A. "Elimination of Cooling Tower Fog from a
     Highway" Air Pollution Control Assoc. J 12, p. 379, 1962,

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Keystone; Site, Climatology, Tower Operation



     Keystone is an 1800-megawatt, mine mouth, coal-fired



electrical power generating station having two identical 900-



megawatt units.  Associated with each unit is a 244-meter



chimney stack and two 99-meter natural draft cooling towers.



A photograph of the station is shown in Figure A-l.  The first



unit went on stream in 1967 and the second unit in 1968.  Keystone



is operated by Pennelec on behalf of a consortium of owners.



The electric power produced is transmitted primarily to the



Northeastern Atlantic States.



     Keystone is located near Shelocta, Indiana County, Penn-




sylvania.  Similar generating stations are located at nearby



Homer City and Johnstown, Pennsylvania.  A map of the area



surrounding Keystone is shown in Figure 3.  The area is rural



and hilly.  Jimmy Stewart Airport at Indiana provides a con-



venient operational base for aerial surveys of the Keystone



plumes and source of local meteorological data.



     The area surrounding Keystone has relatively high precipi-



tation levels,  about 890 to 1016 mm/yr.  The precipitation is



distributed evenly throughout the year.  Snowfall during the



winter averages around 1270 to 1530 mm/yr.  There is a 50% chance



of measurable precipitation on any date.  Thunderstorms normally



occur during all seasons except mid-winter; thunderstorms are



most frequent in mid-summer.  Temperature inversions occur



frequently between altitudes of 152 to 305 meters; surface in-



versions also occur often.  Cold air drainage induced by the







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Figure A-l:  Photograph of the Keystone Power Station.

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many hills leads to the formation of early morning fog.  Fog


can be presistent in the river valleys during the colder months.


Wind speed averages between 8 to 10 mph and is predominantly


from the west.southwest.


     Natural draft cooling towers dissipate the waste heat at


Keystone.  Two cooling towers serve each power generating unit.


The four towers at Keystone represent the most concentrated


number of natural draft towers at any one site in the United


States.  The Keystone towers have the typical hyperbolic shape


and are 99 meters in height.  They were designed and built by


Research-Cottrell, operate with counter-current flow,and have


a total cooling capacity of 560,000 gpm.  Makeup water to
                  /             /

balance water evaporation and other losses is obtained from


Plum Creek.  The flew in this creek is controlled by an up-


stream reservoir.  The reservoir permits the extraction of


makeup water from the creek during draught periods without


damage to the creek.  Figure A-2 is a water flow schematic


for one of the 900-megawatt units.  Sources of water addition


to the system are the makeup pumps (MUP) and sources of water


loss; in addition to tower evaporation, are the service water


pump (SWP) , ash handling pumps (AP),  diesel fire suction pump,


and blowdown.  Only the service water pumps operate continuously.

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>
*
                                                 Hot Water
                                                                Unit
                                                Slowdown
                                                (hot & cold)
            T
Circulating
Water Pumps
   (CWP)
                                                                           Ash Pump
                                                                            (AP)
Service
 Water
 Pumps
 (SWP)
                                                                                        Diesel
                                                                                      Fire Pump

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     The determination of water and heat released by the cooling

towers was hampered by the lack of suitable equipment and an

accepted test technique.  Only after this study was completed

was British Standard 4485 (1969)  available.  The method used

during this study to evaluate the cooling towers was to measure

essential temperatures and pumping pressures throughout the  .
                                                      &rG-'fi ' >
system and determine the evaporation loss from the monograph

supplied by Research-Cottrell, Figure A-3 .   The heat released

by the towers was then calculated.  Pumping pressures were used

to obtain water flows from pump characteristic curves supplied

by the suppliers of the pumps.  Table A-l shows the pressures

and water flows for the CWP, SWP, and MUP pumps.  Data for the

ash pumps were not available.  It was found that some pressure

gauges were reading erroneously; consequently, some water flows

were estimated.  As a result, the water flow data reported is

only a reasonable estimate.

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>
                                                               NATURAL  DRAFT COOLING  TOWERS

                                                                   Evaporation Losses as Function of Wet Bulb Air
                                                                   Temperature, Relative Humidity, Range and Waterflow

                                                                   Example: Find the evaporation losses for the
                                                                            following conditions :
                                                                            Wet Bulb         :  62 F
                                                                            Relative Humidity =  7O %
                                                                            Range           =  26 F
                                                                            Waterflow       =  15O.OOO G.P.M.

                                                                   Following the dashed lines on the diagram we find
                                                                   1.95 percent Losses, i.e.  2,925 G.P.M.

-------
                                                                        Table A-l

                                                       Pumping Pressures and Water Flows at Keystone
PuxnDina Head, osia
UNIT #
Bate
9/19/69
9/20/69
9/20/69
9/21/69
9/21/69
9/22/69
9/22/69
9/23/69
9/23/69
9/24/69
9/24/69
9/24/69
11/28/69
1V29/69
11/30/69
12/2/69
12/2/69
12/5/69(S)
12/6/69 t5)
12/6/69 (S)
local
Time
1555
1100
1515
0900
1500
1015
1405
1030
1545
0850
1040
1340
1S2S
1435
1053
0943
1430
0935
0830
1525

A
29.2
30.7
30.7
30.7
30.7
30.7
30.7
30.7
30.7
30.7
30.7
30.7
31.2
31.7
35.2
35.2
39.7
CWP
B
32.0
33.0
34.0
34.0
34.0
33.5
33.8
33.7
33.8
34.0
33.9
33.9
32.9
34.5
34.5
36.5
38.0

C
s
s
s
s
s
s
s
B
s
s
s
30.6
30.1
30.1
34.3
34.4
1




SWP(2>
D
30.0
33.5
33.5
33.5
34. C
34.0
33.5
33.5
33.5
33.3
33.4
33.4
3

S
37.3
37.4
A
178
179
184
178
190
177
177
178
178
182
180
179
-
-
-
-
-
8
178
179
184
178
190
177
177
178
178
182
180
179
-
-
-
-
-
C
178
179
184
178
190
177
177
178
178
182
180
179
-
-
-
-
-
A
s
s
s
s
s
s
s
s
s
s
s
s
31.0
30.3
29.7
30.8
30.8
s
s
s
UNIT * 2
CWP
B
30.0
29.7
29.0
29.1
31.0
30.5
32.0
31.0
31.6
31.0
32.0
31.5
30.5
30.0
30.2
29.8
29.8
39.9
30.3
31.6

C
31.0
31.3
29.2
31.7
31.5
30.4
31.5
31.1
31.1
31.7
31.5
31.6
s
s
s
s
s
33.8
31.4
31.9

D
35.5
35.5
35.5
36.6
36.0
36.0
35.8
36.0
36.0
35.5
35.8
35.6
32.3
35.5
36.5
36.2
36.2
37.5
36.1
36.5

A
95
95
90
102
100
107
94
95
98
89
93
91
-
-
-
-
-
SWP
B
95
95
90
102
100
107
94
95
98
89
93
91
-
-
-
-
-

C
95
95
90
102
100
107
94
95
98
89
93
91
-
-
-
-
-
UNITS=1
A
44
45
48
47
46
45
46
46
44
45
44
-
-
_
-
-
MUF
B
-
58
57
.61
59
59
58
55
58
56
57
56
-
-
-
-
-
42
Water
Flows, thousands
Coolina Water'1' Ser\
C
41
41
44
43
43
40
43
40
41
42
41
-
-
_
-
-
Unit=>l
253.5
243.0
240.6
240.8
238.5
240.7
240.3
240.5
240.6
240.5
240.6
240.6
248.5
244.9
238.5
296.4
281.5
Unit2 Unit*!
243.3
243.3
253.5
243.0
243.0
243.5
240.0
240.6
240.9
240.6
240.0
240.9
249.7
243.6
244.0
243.7
241.9
231.6
242.3
238.0
of eta lions
rice Water
21 Unit* 2
14.25
14
16
12
12
9
14
14
13
16
15
16





.25
.50
.00
.24
.84
.70
.25
.20
.80
.30
.05
.
-
-
-
-
per minute
Make-up Water
Units*l&2
31.5
31.1
28.6
29.5
30.1
31.6
30.1
30.9
31.5
30.8
31.5
-
_
_
_
-
Cooling water flow for two towers per unit.
Divide Flow in half to determine evaporation
loss in Figure A-3.
Pressure gauge in error,  flow not calculated-
Standby,  not operating.

-------
     Table A-2 presents the essential temperature data in the



Keystone cooling water "system.  The time required to gather all



the temperature data was usually about 30 to 45 minutes.  During



this time some minor changes in the ambient air wet and dry bulb



temperatures occurred.  These changes did not affect materially



the relative humidity of the air.  Tower exit air temperatures



were taken within the tower about 3 meters above the point of



water distribution; the water distribution sprays system is



located approximately 12 to 15 meters from the base of the towers.



The data in Table A-2 were used to calculate the relative humidity



of the ambient air and the cooling tower range, the tower range



being the difference between the inlet and outlet water tempera-



tures.  Data on relative humidity, tower range, and water flow



were used in Figure A-3 to find the evaporation loss.  The amount



of heat released was calculated from the evaporation loss.  Heat



released is reported in Table A-3.  Also reported is an estimate



of the electrical power being produced at the time the data were



obtained.



     Several alternate techniques to evaluate the cooling towers



were examined.  All proved unsatisfactory.  The use of pitot tube



to measure flow, while providing reliable data, was discarded



because additional manpower would be needed, scaffolding would



be required, and suitable equipment could not be made available.



The use of pump motor power input data (amps) to calculate water



flows gave data that was variable and suspect.  Although the



automatic data monitoring system at the Keystone station was

-------
                                                                          Table A-2


                                                              Essential Temperature Data at Keystone
Water Temperature. F
Date
9/19/69
9/20/69
9/20/69
9/21/69
>, 9/21/69
* 9/22/69
9/22/69
9/23/69
9/23/69
9/24/69
9/24/69
9/24/69
11/28/69
11/29/69
11/30/69
12/2/69
12/2/69
12/5/69(3)
12/6/69 (3)
1 2/6/69 <3)

1
Local Time
Start Finish
1555 1625
1100
1515
0900
1500
1015
1405
1030
1545
0850
1040
1340
1525
1435
1053
0945
1430
0935
0830
1525
1230
1600
0945
1550
1115
1455
1105
1600
0940
1107
1415
1630
1523
1135
1032
1520
1005
0858
1555

Air F
Start Finish
55.0 55.3
54.0
54.0
50.3
61.0
55.0
62.6
56.6
64.8
59.9
63.3
64.0
-
-
_
-
-
55.8
54. 9
50.8
60.0
59.8
62.8
59.3
64.0
62.0
62.5
64.4
38.0
32.0
30.0
28.0
31.5
31.0
(4)
38.0
Dry
Start
64.2
58.0
57.0
52.8
72.0
58.0
73.7
61.5
71.2
60.0
53.3
67.3
-
-
_
-
-
Bulb
Finish
63.8
62.1
58.7
54.8
72.3
65.8
74.3
65.0
72.9
64.0
66.5
68.1
40.0
34.0
32.0
31.5
32.0
31.5
22.5
38.2



Tower
Unit #1
A


Tower B

Tower
( 1)  (2) (1) ( 1
Pond ilet dajie^un. fiond inlet Pond
72.0
70.0
71.5
66.0
74.5
68.3
75.2
68.7
79.0
74.9
76.7
78.4
61.5
71.0
70.8
60.1
64.2
-
98.0
99.0
89.2
96.0
95.5
102.4
95.0
103.8
100.0
102.8
104.5
101.0
108.3
108.1
98.0
98.0
58.5
59.0
6O.O
58.0
60.0
58.5
60.0
58.0
60.0
61.0
62.0
61.9
39.0
38.0
37.5
36.5
36.0
77.0
75.0
75.5
69.5
78.0
72.0
79.4
71.7
80.0
77.0
79.4
80.9
71.0
74.2
74.0
67.1
69.0
-
98.0
100.0
89.0
96.0
96.0
102.9
95.0
104.5
101.1
103.5
104.2
101.0
108.0
107.5
97.0
98.0
80.5
79.0
80.5
72.7
78.0
77.5
82.3
79.7
84.3
82.7
84.9
86.0
72.0
77.8
76.1
78.7
78.8
84.2
57.3
64.5
Unit
A
'inlet
111.5
113.0
93.5
100.0
101.5
106.3
111.8
117.5
115.0
117.2
118.4
105.0
102.0
103.0
90.5
93.0
97.2
78.0
83.5
*2 Tower Exit Air Temperature
Tower B Unit #1 Unit #2
Pond (1) inlet ABA
80.0
79.0
79.0
72.0
79.0
76.5
82.3
78.2
84.5
81.3
83.0
83.5
69.0
69.5
66.2
60.0
68.1
77.9
69.0
75.0
-
111.0 -
113.3 -
93.8 -
99.5 -
101.0 -
105.8 -
112.0 -
117.7 -
115.0 -
117.1 -
117.8 -
105.0 52.0 54.0 68.0
102.0 74.5 72.6 76.0
100.2 78.0 74.0 71.5
91.5 (5) 67.5 (6)
93.5 (5) 75.0 (6)
93.0 - - (5)
76.0 - - 54.5
84.0 - - 59.0
B
-
-
-
-
_
-
-
-
-
-
-
70.0
68.0
72.5
67.0
70.0
(6)
(5)
(6)
* *'
    Value used as  tower exit temperature
    to calculate tower range.

(2)  Make-up supplied tc tower  1A only.
   	  #1  shut  down,  not
(4)Wet bulb froze.
operating.       Access door frozen and could not be opened-
               (6)Tower in partial use; temperature was  in error due to ambient air

-------
                                                                          Table A-3
Evaporation
Local
Date Time
9/19/69
9/20/69
9/20/69
9/21/69
9/21/69
9/22/69
9/22/69
9/23/69
9/23/69
9/24/69
9/24/69
9/24/69
11/28/69
11/29/69
11/30/69
12/2/69
12/2/69
12/5/69 (4)
12/6/69 (4)
12/6/69 (4)
1555
1100
1515
0900
1500
1015
1405
1030
1545
0850
1040
1340
1525
1435
1053
0943
1430
0935
0830
1525
Tower Rancre, F
1A
_
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
30.0
34.1
34.1
30.9
29.0
_
_
-
IB
_
23.0
24.5
20.5
18.0
24.0
23.5
23.3
24.5
24.1
24.1
23.3
30.0
33.8
33.5
29.9
29.0
_
_
-
2A
_
32.0
32.5
20.8
22.0
24.0
24.0
32.1
33.2
32.3
32.3
32.4
33.0
24.2
26.9
11.9
14.2
8.0
20.7
19.0
2B
_
32.0
34.3
21.8
20.5
24.5
23.5
33.8
33.2
33.7
34.1
34.3
46.0
32.5
34.0
31.5
25.4
15.1
7.0
9.0
Ambient Air
Relative
Humidity, %
Start
56
75
80
84
50
80
54
76
71
99
91
85
-
-
-
-
-
_
_
-
Finish
58
69
78
79
49
74
53
73
62
89
84
83
84
82
80
64
95
90
_
97
and Heat Release bv
Tower
Evaporation loss.
JA

(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
2380
2580
2500
2840
2500
_
_
-
ii
_
1980
2040
1700
1640
2080
2190
2020
2250
2080
2130
2070
2380
2560
2500
2930
2500
_
_
-
2A
_
2760
2700
1720
2040
2080
2240
2780
3050
2800
2870
2910
2650
1840
2010
900
1040
600
1540
1400
Coolincr Towers at Keystone
qpm
2B

2760
2840
1800
1870
2140
2190
2940
3050
2930
3030
3060
3670
2460
2540
2380
1870
1040
300
800

Total jj
_
9480
9480
6920
7190
8380
8810
9760
10600
9890
10160
10110
11080
9440
9550
8950
7910
1640
1880
2220
Total Hea
Released
06BTU/Min
_
112
120
84
75
98
95
113
116
115
115
113
145
127
130
120
108
22
28
28
Estimated
Electrical Power
- Generated, MW/hr
Unitttl Unit* 2

" 1510(2)
1615 (2)
1140 (2)
1062(2)
1318(2)
1280 <2)
1525(2)
1560(2)
1550(2)
1550 (2)
1525(2)
803(3) 734(3)
804 635
796 695
803 535
803 535
239
289
289
(1)  Value  assumed  to  be  identical to tower  IB because ot  exit  temperature reduction by make up water.
(2)  Value  calculated  from BTUs  of heat  released and  the assumption that  each 1000 MW of power products 1300 MW of waste heat.
(3)  These  values and  subsequent values  obtained from station data.
(4)  Unit #1  shut down, not operating.
                                                                                                                                   rated
                                                                                                                                 Capacity
                                                                                                                                    84
                                                                                                                                    90
                                                                                                                                    63
                                                                                                                                    59
                                                                                                                                    73
                                                                                                                                    71
                                                                                                                                    85
                                                                                                                                    87
                                                                                                                                    86
                                                                                                                                    86
                                                                                                                                    85
                                                                                                                                    85
                                                                                                                                    80
                                                                                                                                    83
                                                                                                                                    77
                                                                                                                                    77
                                                                                                                                    13
                                                                                                                                    16

-------
programmed to print out all essential temperatures/the information



was unreliable.  The temperature data for Unit #1 were out of



order during the test period and could not be decoded.  The data



for Unit #2  appeared to indicate trends only.  Further,, manual



checks with thermometers showed that the pond temperature varied



with location and the tower inlet water temperature was subject



to stratification.  The wet and dry bulb ambient air temperatures



supplied by the automatic unit were also in error.  A further



problem with the automatic data occurred at Unit #1  where the



make-up water was piped directly to the tower pond.  Because the



make-up water temperature was invariably cooler than the pond,



the recorded temperature did not reflect true tower performance.



As all make-up water was fed to tower 1A,it had to be assumed



that the pond temperature of this tower was the same as for



tower IB.  This was not a problem with Unit #2  nor with manually



obtained data.



     Natural draft towers are designed so a chimney effect is



produced inside the tower shell.  The density difference between



the air entering and leaving the tower and the effective tower



height provide the driving force from the natural draft.  Water



is sprayed into the tower and emerges at the base at a lower



temperature; it is subsequently recycled or held in a storage



basin.  The thermodynamic properties of the ambient air have a



significant effect on the natural draft driving force (Reference



A-l) .

-------
     The effect of wet bulb temperature and relative humidity


is shown in Figure A-4.  Climatic conditions favorable to the


efficient operation of natural draft cooling towers are a low


ambient temperature and a high relative humidity.  This


dependence on climatic conditions has limited the use of


natural draft towers to locales where the ideal conditions are


met during peak demands for power.  In the United States peak


power demands occur in the summer, and the climatic conditions


are unfavorable to the efficient use of natural draft towers.
                                           Final Report C6187-3

-------
  ro
   4J
   O
   O
   O
U
OS

s

O
a
H
   w
   U
   a
   Q
   a
   w
   Q
        Cooling Range

        L/G Ratio
                                   Relative

                                   humidity, %
              40     50    60      /O     81

                WET BULB TEMPERATURE,  F
Figure A-4:  The Effects of Wet Bulb Temperature  and Relative

             Humidity on Density Difference  Driving Force.

-------
                         Reference


A-l.  Campbell, J. S. "A New Look at Cooling Towers  for the
      Power Generation Industry" Cooling Tower  Institute
      Meeting, Jan. 19-22, 1968, Houston, Texas.

-------
                   Appendix B

-------
Aerial Survey;  Equipment, Procedures, Results
     The purpose of the aerial survey was to sample contents of
the cooling tower plumes and determine their diffusion pattern.
The results were to be related to tower operation and their
effect on the local climate and the emissions from the power
station stacks.
     A Bell J-2 helicopter, leased from the Keystone Helicopter
Corporation of Philadelphia, was instrumented for the aerial
studies.  The aircraft was instrumented to measure dry bulb
temperature, wet bulb temperature, relative humidity, sulfur
dioxide, and size and acidity of the droplets in the visible
plume.  The equipment used for these measurements is given in
Table B-l.  The instrumentation was installed by Keystone
Helicopter personnel; Analytical Services Corporation, New
Castle, Delaware, was retained to make sure that the installa-
tion met the Federal Aviation Administration's regulations.
The electrical power for the instrumentation was supplied by
a gasoline-driven generator mounted external to the aircraft.
The temperature and humidity sensors and the cascade impactor
used to collect plume droplets were mounted on a probe on the
port side of the aircraft.  The probe was designed so that it
could be moved forward up to 3 meters in front of the helicopter
while in-flight.  At this distance and at flying speeds between
50-55 knots, the plume would be undisturbed by the rotor action
(References B-l,B-2).  Figure B-l shows the probe and power
generator mounted on the aircraft.  Figure B-2 shows a close-
up photograph of the probe and the interior installation.
     The cascade impactor was used to collect droplets from the
visible plume.  The impactor slides were coated with a gelatin
film containing a pH indicator.  Droplet impressions and color
changes were preserved for later evaluation.  The pH indicator
gave distinctive colors when the droplet pH was in the range of
pH 6-7, pH 4-5, and pH 2-3.  The technique used to coat the


-------
                         Table B-l
    Monitoring Equipment Mounted in the Bell J-2 Helicopter
      Item
    Measured
Wet and dry bulb
  temperatures
Relative humidity
Sulfur dioxide
               Equipment
Sign X temperature and wet bulb de-
pression sensors with a Hewlett-Packard
recorder

American Instrument Company hygrometer
and Moseley chart recorder

Davis S0_ monitor with a Bausch and

Lamb recorder
Droplet collection
Casella cascade impactor with treated
slides (Appendix C)
                              B - 2

-------

Figure B-l:  The Helicopter used for Aerial Sampling.

-------
Figure B-2:
Sampling Probe and Interior Installation of
     Equipment in the Helicopter.

-------
slides is given in Appendix C.  The Casella impactor is a four-
stage impactor.  The efficiency of each stage for droplets of
unit density is given in Table B-2.
     A plume monitoring flight pattern, Figure B-3, was adopted.
The pattern was initiated by a vertical ascent upwind of the
Keystone station.  The ascent gave data on ambient variations
in temperature, wet bulb depression, relative humidity, and
sulfur dioxide.  The plume was then sampled as shown in Figure
B-3.  A constant air speed of either 50 or 55 knots was main-
tained throughout the plume traverses.  After the traverses of
the plume were completed, the aircraft backtracked at tree-top
level beneath the plume to record ground-level data.  Visual
navigation was used to locate the position of the aircraft during
the survey.  Flying within the visible plume was not possible
because of excessive turbulence.  Therefore, all traverses
were made downwind of the visible portion of the plume.  Plume
droplet samples were obtained at the edges of the visible plume.
     A calendar of events for the aerial survey is given in
Table B-3.  Weather conditions at Keystone during November and
December 1969, were extremely poor and severely restricted flying
time.  Only three complete traverses were possible during this
period.  One of these traverses was made on December 2,and two
were made on December 6, 1969.  The December 6 AM-data were the
most complete and are described in Figures 7 through 17 in the
body of the report.  The data from the other plume traverses
are presented in Figures B-4 to B-21.  No ground-level traverse
beneath the plume was made on December 2, 1969, due to deteri-
orating weather conditions.  All plume profiles are drawn as if
viewed from the cooling towers and looking downwind along the
plume axis.  The Keystone station was operating at 77% of rated
capacity on December 2e and at 16% on December 6, 1969.  Surface
and upper wind data for the survey data are given in Tables B-4
and B-5.  Droplet data are presented in Appendix C.


-------
                         Table B-2
         Efficiency of the Cascade Impactor Stages




Stage                    Cut-off droplet size,urn

  1                               12

  2                                4

  3                                2

  4                                1.1
(1)  50% of the droplets this size will evade collection
    at the design flow rate-

-------
(      I
                                 r      i
(      f  .,  r.    f      f      i
           Wind
Upwind
vertical
ascent
                                 -Monitoring  traverses-
                                    vertical section
                                               Cooling tower
                                                   plxome
                                                        Ground  level traverse
                                                           beneath plume
                                          Helicopter depart

                                    Helicopter arrive

-------
                        Table B^3
    Date
11/24/69 Mon.



11/25/69 Tues.


11/26/69 Wed.


11/27/69 Thurs,

11/28/69 Fri.



11/29/69 Sat.

11/30/69 Sun.

12/1/69  Mon.

12/2/69  Tues.


12/3/69  Wed.

12/4/69  Thurs.

12/5/69  Fri.


12/6/69  Sat.

12/7/69  Sun.
            Aerial Survey;  Calendar of Events
          Comments
Helicopter ferry time,
Philadelphia partway to
Keystone

Ferry time.  Helicopter arrived
at Keystone

Checkout instruments & APU
Familiarization with local area

        Thanksgiving

Initiated plume traverses.
Unable to attain sufficient
altitude due to poor visibility

Weather unsuitable

Partial plume traverses & samples

Weather unsuitable

Plume traverses & samples,
Low stratus

Weather unsuitable

Weather unsuitable

Weather unsuitable: plume
samples only

Plume traverses & samples

Remove equipment from helicopter.
Return to Chicago
Flying Time
    1.1
    2.7


    1.7


No flying

    2.1



No flying

    1.6

No flying

    3.4


No flying

No flying

    1.7


    4.7
                       Total flying time
                                       19.0 hours
                             B~8

-------
g
w
a
E-
H
   600
   300
Sulfur
Dioxide
      25

       0

       0

       0
                Wet bulb
                 depression
Relative
 humidity
                                          Date:  12-2-69
                                                 afternoon
                                                     II
      27        29        31        33        35    Temp.,  F

      20        40        60        80       100    R.H., %

       0.01      0.02      0.03      0.04      0.05 S02/ ppm

       12345    Wet  bulb
                                                    Depr.,  F
       Figure B-4:  Prevailing Ambient Conditions  Prior  to
                              Plume Traverses.

-------
C_J
 to
 i
            to

            ti
            E-
            W
           W


           g

           EH
                900
                                                   .6  X25-6   X25-6 X 25.6
                600
                300
                     28.6 x28-0 X
                                                            X26.5 X26.5
                                        X 27'5 X 27'5
                                               28-5
  29.6X 29-6 x29-7 X 29'9 X 30'5  X 29'7 X 29'5 X29-7 X
  30.9 ^ 30.9

   X  0.0
                                                         30.6  30.6  30.6

                                                       XX     x
                      3l.^v 3I.6X 32.0 x 31.60x02-5 x31-5  x31'5 x3'
                                       10
                      32.6  32
                        33.0
                                                    -   X
                                                        32'6   32'6   32'6
                      33.3_ 33.3  33.3   33.3   33.3  33.3   33.3   33-3   33.3

                         A     A     A     J%     ^     M    A     A
                                                   I
                                                                               Date:   12/2/69

                                                                                       afternoon
                                                               I
                                 1000            2000           3000            4000


                                           GROUND LEVEL  DISTANCE TRAVERSED:   METERS


                       Figure  B-5:   Sulfur  Dioxide  (ppm)  Profile

                                       at 2093  Meters  Downwind of  Tower.
I
                                                                              5000

-------
cm  LT;.J   r i   era  .Es
                                               ESI
                900 r=
      td
      i
           w
           w
           Q
H

S
                600
                300
                     26.0 x 26.0 x 26. I  X25.5 X25.5  X25.6  X25.6  X25.6X25.6
         ^6.5 X26.5 x
                    , 27.5 x 27.5
                     28.6 x 28.0
                                26,
X26.5  X26.8   X26.5 X26.5
                                        7  X28.0 x 27.5 x 27.5
                                           x28-6  X28-5 X 28.5
                                                       29.5  X29.7 x  29.7
                                                        30.6   30.6 v 30.6
                                                      X     X     x
                                                      -31.5 ^31.5  -  31.5
                                                      *     X .    A
                                                 .,32.6 ,32.6 ,32.6  x 32.6
                                                 *     K     A     *
                      33.3, 33.3   33.3   33.3  33.3   33.3  33.3  33-3    33.3
                         A     A     MA"      AA
                                   I
                                                                               Date:   12/2/69

                                                                                        afternoon
                                                                       I
                                 1000
                                                  1
                                      2000-          3000            4000

                               GROUND LRVfiL DISTANCE TRAVERSED:   METERS

             Figure B-b:   Relat.ive  JIunidity  Profile-  (% point above background)

                            st  2093 Meters  Downwind 01 Tower
                                                5000

-------
03
I
I-1
to
        E-i
        W
             900
             600
             300
               0
                  26.0 x 26.0 x 26. I  X25.5 X25.5 X25-6 x25-6  X25- 6x25.6
                    . 5 X26.5 x26-6 X27-5 X27'2 X26-5 x26-8   x26-5  X26.5
                   27.5 x 27.5 X27.7
                             -27.7  x28-0  v 27.5 - 27.5
                             M     *     A     **
28.6 x28-0 X28'6  *29-' *31'8  *28'7  X28-6 X28-5X 28-5




29.6X 29-6 x29-7  X 29'9 X 30'5 X 29'7 X 29> 5 X29'7 * '7



30.9   30.9  30.9   31.5  30.9  31.0   30.6   30.6X 30.6




31.6* 31.6V 32.0  .. 31.6 w32.5 x3l-5 -31.5  31.5 - 31.5
    Jin**'*****


32.6X 32.6 x 32.6  x 32. 6 x 33-0 X32.6 X32.6 X32.6 x 32.6



33.3, 33.3  33.3  .,33.3  33.3  33 3  33.3  33-3   33.3
    MMAA^     ^AA
                                  I
                                                                                 Date:  12/2/69
                                                                                         afternoon
                                                                                  I
                               1000            2000           3000            4000

                                         GROUND  LEVEL DISTANCE TRAVERSED:  METERS
                                                                                5000
6000

-------
                                  ..era
                                              t-^-T'ai
                                              	j
td
i
            900
_   X23.8  X23.9
            600
          to
          W
          s
          H
            300
25.6 X25. 8  X25.8  X25.8  X25.7  X25.7 X25.7 X25.7 X25.7 X26.0 X25.5
                                                                                        X25-7  X26-0  X25-7  X25-7 X25.7
27.0 ^27.0  X27.0  X27.l
                                  X28.0  X27.9
26.7  26.7. <>6.7  -27.1  x 27.2 x 27.2 X27.1JX27.1   27.0 \

    X ^^     *r                   ^***^             \


          /    	0.10	""                 0.05

          X27.8^*X27.9  X28.0 x 27.9 x 27.9 X28.0  x28-2
                 29.2  X29.2 X29.ii  x 29.4  jj29.5xj29.it  X29.2  X29.l  x 29.2  X29.2\X29.2
                                                                       X29.l X29.1 X29.l  X29.l  X29.l
                                                                          Date:    12/2/69

                                                                                   afternoon
                                                                                                                     I
                               1000           2000             3000

                                         GROUND LEVEL DISTANCE TH?V'


                  Figure  B-8:   Sulfur Dioxide  (pprrO  Profile

                                  at 9960 Meters  Downwind  of Tower.
                                                                4000

                                                            *f>.   METERS
                               5000

-------
                          ?-^=-3   r*~~~-*
                          i- 3  , t ... :J
                                                      ELJ
                                                   L  .3
to
i
        900
       _   -23.8  X23.9 -23.8 x23-8 x23-7' X23-6 X23-5 X23-8  X23-8  X23-5  X21*-2
        600
OT

fi
E-i
W
      E-i
      H
        300
                                              .71 v23.<
                       .8  x24-2  X23-8  X23-9  X2t;-
                                                                                                               25'2
              25.6 X25.8 X25.8 X25.8  X25.7
              27.0   27.0
                               X28.0  X27.9
       ,29.2 X29.2 X29.t x 29.4  x 29.5 X29
                                                                o  X25'5  X25'7 /"-7 X26-0 X25-7  X25-7  25-7
                                                                7  ..26.7  V27.1 \27.2 w 27.2 .27.1  27.1  V27.0
91  X27.8 2
28.0 v 27.9  x27-9 x28-0  X28-2
                                                                   ^29.2  x29-2  X29'1  X29-1  X29'1  X29'1  X29'1  X29'1
                                                                           Date:   12/2/69
                                                                                    afternoon
                                                                                                                  J
                            1000           2000             3000            4000

                                      GROUND LEVEL  DISTANCE  TRAVERSED:   KETKRS
                                                                                        5000
                                                                                                               6000
                   Figure  B-9:   Relative Hxir.idJ.Ly Profile  (c/i point,  above backgro.:c;;

-------
I       I
                          I       I
               I       I      i      I      1       II       I
 w

 M
 in
          900
          600
        CO
        E-l
        w
        H


        *
          300
     X23.8  X23.9 X23.8 X23.8 x23-7 X23-6 li23-5 X23-8  x23-8 X23-* X21*-2  X2**-2  X23-8  X21*-2 X23-8  X23-9
                                     25.6
                                                                       .4 X25.0
{25.6 X25.8  X25.8 X25.8  X25.7  X25.7  X25.7  X25.7  X25.7 X26.0 X25.5  x
                                                                                             X26.0  X25.7  X25.7  x25.7
 27.0   27.0   27.0 -27.1

 S__    X     *     *
1.8  X26.7  X27.2  x 26.7 X26.7
                                                                             .7 X27.l  x 27.2 x 27.2 X27. 1  X27.l  X27.0
                 X28.0 X27.9 X27.9  X28.0X27.8  X28.1 x 27.9  X27.8  X27.9  x 28.0 x 27.9 X27.9X28.0 X28.2






.29.2 -29.2 -29.4 -29.4 -29.5-29.4  -29.2  -29.1  -29.2  -29.2  29.2  V29.1  .29.1  v 29.1  -29.1  .29.1  -29.1
                                                                              .Date:   12/2/69

                                                                                       afternoon
                             1000           2000            3000            4000


                                       GROUND  LEVEL DISTANCE  TRAVERSED:  METERS
                                                                                5000
                                                                  6000

-------
600



METERS
Q 300
P
EH
H
CH







^ ^-
\. '^X ^-"^ Wet bulb
\ \ ^  depression
\ \
\ / \
Temperature NV f \Date: 12/6/69
\x
\
1 v afternoon
\
\
IX *
\ 1




\ i
\ \
* \
\ \
i '^v.. W
Relative
humidity,

1 1 1 1
-* w
4s
\ NV
1 1 1 IV l\^
30 31 32 33 34 35 36 37 38 ~ 39 40
0 10 20 30 40 50 60 70 80 90 100
? 12 3 4 5
                                                    Temperature, F
                                               100  Relative Humidity,0/
                                                    Wet bulb depr.,  F
Figure B-ll:  Prevailing Ambient Conditions Prior
                  to Plume Traverses.

-------
                        I '    -f
td
i
      0)
      !
      x
      o
      Q g
    o.o:
     IM
     rH
     3
     co
         o.o;
         0.0]
 0)

 H 4J
 4-) -H
 fl3 *0
 rH -H
 V 
 a; 3

-------
900
o>
o
o
TERS
ALTITUDE
w
2
0
     32.5  32.5 X33.0
   33./> j 33.0 x 33.0

0.20 0. 10 0.05

        33.0 x 33.0


            X 33'7

            X 33.8

     .0 V31.0 x 33.9

            - 31.3
                                                       Date
                           12/6/69
                           afternoon
0            1000



     Figure B-13:
                                 2000
            3000
4000
5000
6000
                         Sulfur Dioxide (ppm)  Profile


-------
   LTJ
to
i
!-
VO
            900
            600
         w
         ti
         E-i
         W
W
Q
         H
         E-i
        ,32.5 x 32.5 X33.0  X33.0  x 33.0 x 33.0 x 33.0 x 33.0 x 33.0
            300
                                                   I x 33.0

                                              'jpS.B x 33.7
                                                      34.3
            X 33.8

J 3'.0 X31.0  x 33.9
/3H_3  ..     -., ~
A
                                                             Date:   12/6/69
                                                                     afternoon
                              1000
                                     2000
           3000
4000
5000
6000
                      Figure  B-14
                             Relative  Hurv,irlity  Profile  (% point above  background)

-------
CO
I
       M
       w
       s
       w
       p
           900
           600
          300
            0
                                                                               Date:
                                                                        12/6/69

                                                                        afternoon
32.5
                      32.5 X33.0 X33.0
                         33.0   33.0   33.0  33.0
33.1 X33. I x33-2 X32-9 X 32-X 32'' X32-9 x33'0


                              33.5 x33-7 X33'5
                                                33.0
                                                33.0


                                                33.7
 33.8 X33.7 X33.6 X33.7  x 33.



(34.0 x34-0 X33-5 X33-7  X 33'3 X 33'8 X 33'8  X33-8 X 33.8


 34.3 X34.3 x33-7 X33-5  X 33-8 X 34- X 3U- X34-0 X 33'9
 34.5
                              3t*'3   34'3   34'3
                                                                34'3
               0
             1000
                               2000
                                              3000
4000
5000
6000

-------
                                                                                      CL3
ca
i
N)
       w
       W
w
O
       H
           900
           600
           300
                                                              Date:   12/6/69
                                                                      afternoon
                                  X3U.O x 33.9  X33.8 x 33.8 x 33.9



                                               >7 .34.5  34.U
                                                                      '   X
                                                                          3H'
                                                                         I
                            1000           2000         3000          4000            5000


                                        GROUND LEVEL DISTANCE  TRAVERSED:  METERS


               Figure B-16:  Sulfur  Dioxide  (ppm)  Profile at 3220 Meters  Downwind of Tower

-------
                                                                                   -'^- -^--.^
           900
CD
I
0
to
       W4


       fi
       H
       W
       S
w
a
           600
                                                                Date:
                                                                 12/6/69
                                                                 afternoon
                                                                   34.0
                                      6  W3H. 5  ..JJK 5^^34.8^^34.8  ., 34.8
                                                                        I
                                                                                1
                           1000
                                   2000          3000          4000


                                 GROUND LEVL DISTANCE TRAVERSED:  METERS
5000
6000
               Figure B-17:  Relative Humidity Profile  (% point above background) at 3220 Meters

-------
CO

to
UJ
      w
      I
      w
      s
w
Q
           900
           600
          300
                                                                 Date:   12/6/69
                                                                         afternoon
         {34.0X34.0  X34.0  X34.0 X34.0 X34.0  X33.9  X33. 8 x 33. 8 x 33-9 X34.0
         31.1  33.8   33.8
                34.5
X35.0 X3i*.7
t. 5
                                          34. 6

                                          34.5
                                                                  34. 8
                     1000           2000          3000           4000            5000

                                   GROUND LEVEL DISTANCE TRAVERSED:  METERS

        Figure  B-18:   Temperature  Profile  (F)  at 3220 Meters  Downwind  of Tower.

-------
  I..J
                                                  ess
            900
           600
        w
03
I
to
*>
       H
           300
                                                                          Date:   12/6/69
                                                                            afternoon
                 31. 8 x 31. 8
35.1 X35.2 X35
                                               34.1 i\34.2
         0.05
    ,35.2  W35.2
                                     34.3 X34. 5
                              W?I X3U. 6 X34. 8
                                                                           ,34.5
X35.3 X35.3 x  35.3X35.3
                                                                35.2
35. I x 35.
                                                             1  .35.1
                               1
                                               I
                                         I
                              1000            2000           3000           4000

                                      GROUND LEVEL DISTAUL't: TRAVF ^Lr;D-   METERS
                                                                            5000
                                                                       6000
               B-19:   Sulfur D.i -.
                       at  10,765;
                                                        t: (p;--  ';  >'i'-"'ilc

-------
                                       ES3
DO
I
to
l/l
         W
         H
         EH
         H
         E-i
            900
            600
            300
                                                                   Date:   12/6/69
                                                                     afternoon
    x31*'3 X34'5

    X34. 6 X34. 8
                                                                     ,34.5  -34.5
35. I  X35. I
.35.1
                            1000           2000          3000          4000

                                    GROUND LEVEL DISTANCE TRAVERSED:   METERS
                     5000
                          6000
                    Figure B-20:  Relative  Humidity Profile  (% point above background)

-------
            900
            600
                                                                         Date:   12/6/69
                                                                            afternoon
03
        EH
        W
                                            X3H.7  X
35. I X35.2 X35.7  x 35.2 X35.0
           34. 6
                                                                      . 6
                                                              34'5
                                                              3H. 8
        E-i
        H
35.2X35.2 X35.2  x 35.2 x 35. I X35.0
35.3 X35.3 ^5.3  x 35.3 x 35.3 x 35.3
            300
34.8,.34.7 w 34.6 W34.6 ..34.5  W34.5
    X     X     X     X     X
35.3X35.3   35.2 x 35. I  x 35. I  X35. I
              0
                                                               I
                                                            I
                              1000           2000          3000           4000

                                     GROUND LEVEL DISTANCE TRAVERSED:   METERS
                                                                         5000
                                                       6000

-------
                                            Table B-4
f3
Surface Winds at Pittsburgh, Altoona,




12/2/69
and Blairsville, Pa.





Pittsburgh (Airport)
Wind
Local
1207
1255
1310
1355
1419
1455
1555
1619
1656
Direction
00-36
23
22
22
22
23
21
24
25
24
Speed
Kts
16
17
13
19
16
18
14
14
16

Local
Time
1158
1258
1358
1459
1557
1658



Altoona , Pa
Wind
Direction
00 36
30
30
28
27
25
28



Blairsville,

Speed
Kts
13
12
12
10
13
10




Wind
Local Direction
Time 00-36
1150
1248
1350
1448
1550
1650



24
22
20
20
23
23



Pa.

Speed
Kts
09
09
13
20
16
12



12/6/9
0755
0858
0958
1058
1158
1258
1358
1458
1558
1658
00
04
05
05
06
05
06
06
06
06
00
04
07
10
09
07
08
07
07
07
0757
0858
0956
1058
1158
1258
1357
1458
1558
1656
25
29
00
00
00
00
00
00
00
06
04
05
00
00
00
00
00
00
00
06
0751
0850
0948
1050
1151
1250
1352
1452
1550
1648
06
07
08
10
08
10
09
10
 11
10
05
05
07
05
06
07
08
08
11

-------
Table B-5
Upper Air Winds at
Pittsburgh, Pa.

Wind
Local
Date Time
12/2/69 1115


2315


12/5/69 2315


12/6/69 1115


2315


Height,
Meters
608
912
1215
608
912
1215
608
912
1215
608
912
1215
608
912
1215
Direction
00-360
30
30
30
240
255
265
330
330
340
09
09
09
08
08
09
Speed
Kts
12
13
13
26
37
43
11
11
10
12
12
13
14
14
14

-------
                         REFERENCES
B-l.  Landgrebe, A.J. "An Analytical Method for Predicting Rotor
      Wake Geometry" J. Amer. Helicopter Soc..l4/.P  ,20,  1969.

B-2.  Gorosko, B.B., Elisen, V.S., and Nazarewko,  V.J.,  "On  the
      Technique of Observations of Atmospheric Pollution  by
      Helicopter," Leningrad, Glav. Gecf., Obs. T. Vyp.  207.
      p. 76,  1968.

-------
                         Appendix C






-------
Impactor Samples;  Slide Preparation,  Droplet Sizes and Acidity

     Cascade  impactors were used to collect plume droplets for
size and acidity analysis.  Samples were collected from the
helicopter at the edges of the visible plume.  Because of high
turbulence, it was not prudent to fly within the visible portion
of the plume.   It was anticipated that the mixing of the cooling
tower plume with the station effluent would produce acid droplets
and the ratio of acid droplets to neutral droplets would provide
information on the degree of mixing.
      To determine droplet acidity the impactor slides were
coated with a gelatin film containing a pH indicator.   The method
used was similar to that described by Waller (Reference C-l)  and
Liddell and Wootten (Reference C-2) .  Approximately 2 g  of
gelatin were wetted with a little acetone and then dissolved in
50 ml  of distilled water heated in a water bottle.  A solution
containing 1 g of methyl red in 50 ml  of IN ammonia was mixed
into the warm gelatin solution.   A drop of the gelatin solution
was placed on clean, glass microscope slides inclined  at 45 and
allowed to spread and dry as a thin film.  This operation was
repeated until the desired thickness of the film was achieved.
Methyl red indicator was used because it gave distinct color
changes at three levels of acidity as follows:
                            pH 6-7  clear
                            pH 4-5  yellow
                            pH 2-3  red
The color changes were tested in the laboratory using a hydraulic
spray nozzle to generate neutral and mildly acid water droplets.
Droplet residues on the slide were clearly apparent and did not
deteriorate with time; also,  no obvious fading of the color was
observed for periods up to a few weeks.  Subsequent tests showed
that the slides did not react to the gaseous sulfur dioxide
concentrations in the power station plume.

-------
      The results of the plume droplet sampling are given in
Table C-l.  A size distribution of the plume droplets was not
possible.  Most of the droplets were captured on the first im-
pactor stage; the cut-off size for this stage is 12nm (unit
droplet density).  The problem is further complicated by the fly
ash particles often associated with the plume droplets that would
alter the density of the droplet.  The sizes reported in Table
C-l are for the diameters of the residue impressions left on the
gelatin film after the droplet evaporated.   Their relationship
to the original droplet diameter was not determined.  While such
a relationship is determinable, it would not apply to droplets
containing rather large particulates such as fly ash.  Size
distributions of the residual impressions for some of the droplet
collections are given in Figures C-l through C-5.  Photomicrographs
of representative collections are shown in Figures C-6 and C-7.

-------


Number
1
2
3
4
5
6
7
8
9
.0
11
12
13
14
15

Pate
11/29/69
11/30/69
11/30/69
12/2/69
12/2/69
12/5/69
12/5/69
12/5/69
12/6/69
12/6/69
12/6/69
12/6/69
12/6/69
12/6/69
12/6/69
Local
Time
1100
1100
1100
1000
1435
1425
1425
1425
1045
1045
1045
1230
1230
1230
1240
Position Of Aircraft Durimr Samnliivi
Altitude. m
336
305
274
228
228
183
352
413
183
244
336
305
216
1B3
305
Position
end of visible plume
end of visible plume
1} mile downwind of tower
-4 mile downwind of tower
near unit #1 stack
200m downwind of tower
400m downwind of tower
400m downwind of tower


30O to 40Om
't downwind of tower
'

'
rtolino Tower Plume Drcnlpi
Ambient Air Conditions
Temp..T Re:
29.2
29.0
30.4
24.2
30.9
31.9
30.7
29.5
26.2
25.8
25.0
33.5
35.6
36.2
34.0
(1) refers to the mixing of the cooling tower plune


and t
were
he stati
used to
on effluent.
determine if
Relative SO- concentrate
plumes were mixed.
3ns

l.Humi
81
83
84
96
58
78
81
80
85
85
85
44
44
45
43
(3)

(4)
d.% S02'ppt
0.035
0.035
0.035
0.030
0.018
0.040
0.030
0.020
0.035
0.035
0.035
0.045
0.040
0.035
0.35

" Temp.. 
31.2
31.7
32.1
30.2
34.0
35. e
30.7
31.0
30.4
29.3
27.2
36.0
41.8
44.9
37.6
no droplets present

the sizes

reported
(2)  insufficient'number of droplets available for
    accurate size measurements.
0.975
0.145
0.040
0.110
0.018
0.200
0.110
0.295
0.035
0.035
0.340
0.065
0.040
0.03S
1.07
                                                                                                                          yes
                                                                                                                          yes
                                                                                                                                          PH 6--
                                                                                                                                       Residue dia.^ftr.
                                                                                                                                       Median  Range
                                                                                                                                       40
                                                                         TTT
                                                                                                                                       46
                                                                                                                                       39
                                                           33
                                                          165
                                                          178
                                                          (3)
                                                          225 <
                                                          325
                                                          237
                                                          220
                                                          270
                                                           90
                                                                                                                                         (2)
impressions left on the gelatin film after evaporation
of the droplet.  The relationship between the residue
size and the size of droplet  leaving the residue was
not determined.
15-150
10-110
10-90
10-110
20-500
 5-120
25-350
50-325
                                                                                                                                                     (2)
                                                                                                                                                     (2)
                                                                                                                                                            pH-4-5
                                                                                                                                                                  Droplet pH and Residue Size
                                                                                                                                                                                  PH 2-3
                                                                              Residue dia.iim
                                                                              Median  Range
                                                                              35
                                                                                             (4)
36
29

(3)
(3)
(3)
(3)
38
(3)
10
(3)
(3)
50
(3)
                                                                                      6-275
                                                                                      5-120
                                                                                      6-90
                                                                                      10-60
                                                                                                                                                                       (2)
                                                                                                                                                                   4-90
                                                                                                                 <)
Median
 13

 13
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 (3)
 35
Range
4-30
5-15'2'
3-40
                                              Ratio
                                           DH4-S droolel
                                           DH6-7 droplet
                                              1.57
                                              1.10
                  ,09
                  .00
                                                                                                                                                                                                        1.3
                                                                                                                                                                                                        1.42

-------
  100,
 0)
 N
H
0)
.p
<0
4-1
CO

VI

-P

0)
O
U
0)
              Number of  drops
              available  for  sizing
   20
               20
     40         60          80

Residue Size:  Microns
                                                           100
      Figure C-l:  Plume  Droplet Residue Size Distribution
                               Sample Number 1.

-------
   100
 0)
 N
H
 
-------
  100
   80
0)
N
H
O
0)
4J

CO

VI

4J
c
0)
u
S-l
(U
60
40
    20
     0
                         pH

                      D 6~
        Number of drops
        available for sizing

               94
      0
             20
40
60
80
                                                          100
                      Residue Size:  Microns
    Figure  C-3:   Plume Droplet Residue  Size  Distribution
                             Sample Number  6.

-------
           100
O
       N
       H
       T3
       0)
       4J
       VI

       -P

       0)
       0
       U
       0)
       04
           80  
           60  
40 
           20
            0
                                              Droplet pH 6-7
                                                         Number of drops
                                                         available for sizing
                                                  Sample Number 7
                                   U  Sample  Number 8
                              100
                          150
200     250     300     350

  Residue Size:  Microns
400
450
500

-------
          100
o

CD
           80
8

w  60

o
0>
4J
ID
4i
(O
       VI
        c
        o>
        o
        U
        0>
        04
           40
           20
                                                                 Droplet pH 6-7
                                                                  Number of drops
                                                                  Available for sizing
                                              Sample Number  12


                                              Sample Number  13
                                 i    I
                                                          ill
i        i
                                           Residue Size:  Microns
                    50

-------
 -

                                 Scale:  microns

                                  0    100  200
                                  I	I	I
          Figure  C-6:
   Plume Droplet Sample Number 2


Tower and Stack Plumes Mixed.  Droplets of
        pH 2-3, 4-5, 6-7 present.

-------
 -

-
 .

I
                                    Scale: Microns


                                      0   100   200
                                      I	i	I
              Figure C-7:
   Plume Droplet Sample Number 14


Tower and Stack Plumes not Mixed
        pH of Droplets 6-7.

-------
                         References
C-l.  Waller/ R. E., "Acid Droplets in Town Air,"  Int.  J.  Air
      Water Polln. 7, 773-8,  1963.
C-2.  Liddell, H. F,  and Wootten, N. W.,  "The  Determination
      and Measurement of Water Droplets,"  Quart. J.  Roy Meteorol.
      Soc. 83, p. 263, 1957.

-------
               Appendix D




-------
            MODEL ANALYSIS OF MOIST BENT-OVER PLUMES
     Since the vertical motion of a plume eventually becomes
small and the horizontal motion is almost identical with that
of the wind at the altitude of the plume, the plume bends over
and becomes nearly horizontal at a sufficient distance down-
wind of the stack.  The behavior of this part of the plume thus
becomes the same as that of a cylindrical thermal.  Solutions
for simple cylindrical thermals rising in a neutral atmosphere
have been applied to bent-over plumes by Scorer (Reference D-l).
For the purpose of the problem considered here, this analysis
is extended to include the latent heat of evaporation and
condensation.
     The equations governing the change of mass and momentum
in a cylindrical thermal are:
     mass

     dR2
     dt
         = 2 a R
                  w
(1)
     momentum

     d R2 w _     2  Af
       ^   "  9 R   r                           (2)
                     I 00                           V '
where
     g = acceleration corresponding to gravity
     R = effective plume radius
     t = time
     w = mean vertical velocity
     u = entrainment coefficient - 0.433
    AP = mean density difference
       = density of atmosphere at same altitude.
    oo
                              D-l

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     The effective plume radius is a  measure  of  the  distance the
plume extends from its natural axis such that the  velocity and
buoyancy can be expressed in the dimensionless form:
               y-y   z-z
                  2'
    *.t   ,a. !,
          *2  v  R     R  '

where
     w = local vertical velocity
     y = cross wind distance
     z = vertical distance
Y ,  z  = coordinate of plume axis
    A]?' = local density difference.
     The plume radius is shown not  to require  an interpretation
of being a literal radius,  but merely as being a reference  di-
mension of the distance the plume extends from its  axis.
     To evaluate the effect of evaporation and condensation,
the equations for ordinarily encountered cylindrical  thermals
are supplemented with an equation which is obtained from  a
water balance on the plume:
                                                  (5,
                    oo

where
     Y = mass fraction of water,  vapor plus liquid,  in plume
   YOQ = mass fraction of water in atmosphere at  the same
         altitude.
     This equation merely states  that the rate at which the
water content of the plume increases is equal to  the entrainment
of water vapor from the atmosphere.
     An energy equation for the plume may be derived from  the
partial differential equation for energy conservation:


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                       Ill
         +  'V 6  -^--pf  V" q

where
     c  = specific heat at constant pressure
     P  = pressure
     P  = reference pressure at sea level
     q  = heat flow by conduction or turbulent convection
  Q     = heat produced per unit volume by latent heat effects
     6  = potential temperature = T (P/PQ)~2//7      (7)
     p  = density.
     Because consideration has to be given to a stably stratified
atmosphere in which the potential temperature is not constant,
it is more convenient to work with the difference between the
potential temperature in the plume and in the atmosphere at the
same altitude, than with the potential temperature itself..  Thus:
     e-  = e -
               oo
where 6QO = potential temperature of atmosphere.
Substitution of Equations  (8) and  (6) gives:
                                 11
                                            v
Integration of Equation  (9) over a cross-section enclosing the
plume gives:
                                                 dV
                                                   (10)
                               r-p J
where dV = volume element.
                                -  f  V  '
                                 D J

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From the divergence theorem, the volume integrals can be expressed
as equivalent surface integrals:
                        .J
     J  x7  q dV = j q  n dS                       (11)

     j  tT  \7 6' dV = J 0'u   n dS                  (12)
where
     n = unit vector normal to the surface
    dS = surface element.
From Equations (11) and (12), (10) becomes:
                   .  V __*        [ 1 I  I I
                  0  u-n dS = j ^-
                                   P

                                                   (13)
                           -       q-ndS

Because the boundary of the region over which the integration
was performed is outside of the plume, the temperature excess,
9', and heat flux, q, are both zero:
                  '   P
It is also possible to make the substitution:
         e- av =
                   '   P
The volume integrals  are precisely related to the expressions
appearing in Equations  (1),  (2)/and  (5) by the following:

     5 w dV = R2 w                                (16)

     J 6' dV =   R2 I7                            (17)
          ' '
            dV = R  Q1 '                            (18)

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where

     0' = mean potential temperature excess

   Q' '  ' = mean heat production.
The plume energy equation may thus be expressed as:
         dt       Pcp

     The production or loss of heat by condensation or evapora-
tion is related to the change in the mass fraction of liquid
water present as shown in the expression below:
     Q'" = + p AH  ^f!^                       (20)
where
    AH = latent heat of vaporization
    YI = mass fraction of water present as liquid.
Substitution of Equations (20) in (19) gives:
       [R2(9' -    Y] = -   k R2 w             (21)
     Rather than seek analytical solutions for Equations (1) ,
(2) ,  (5)/ and (21)/ they were programmed for numerical solution.
A fourth order Runge Kutta method was used to perform the
required integrations.  At each step in the Runge Kutta inte-
gration, values are returned for the quantity designated as F,
Equation (19)
     P = 9. _     Y.
              c    i
               P
and the mass fraction of water, Y, (liquid plus vapor) Equation  (5)
The separate mass fractions of water in the liquid and vapor
states were determined by the iterative procedure described
be low .

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      1.  Assume  no  liquid water  is present  initially.
      2.  Calculate  temperature from assumed liquid
         mass  fraction.
          0. .= F  +    Y.
                   CP   "
          Calculate vapor pressure  from value obtained
          for the  temperature obtained in  2.
          Log pv  = 8. 1076-1750. 3/(T+235)
              T  = temperature  C
             p   = vapor pressure,  mm Hg
         Calculate mole fraction of water vapor present.

               P,,
         x =
             760-pv
     5.  Calculate mass fraction of water vapor present.

              0.622 x	
          v ~ 0.622 x + 1-x
     6.  If the mass fraction of water from Equation (5) exceeds
         the mass fraction of water vapor calculated in
         step 5, calculate the fraction present as liquid.
         Y, = Y - Y
          1        v
     7.  Go back to step 2 and repeat procedure with a
         new value of liquid mass fraction until assumed
         value agrees with value calculated in step 6.
     The techniques described here were used to calculate the
plume's altitude and properties for distances downwind of the
tower where the vertical velocity was less than that of the
wind at the altitude of the plume.  Both visible and invisible
regions of the plume were calculated.  For that part of the plume
close to the tower where the vertical velocity of the plume
exceeded that of the wind, the plumefs motion was calculated
from the equations for vertical plumes given by Morton
(Reference D-2) .  The partitioning of water between liquid and
vapor phases was calculated by the same method used for hori-
zontal plumes.  In this calculation, the horizontal motion was
also assumed equal to the speed of the wind.

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     The results obtained show the effects of buoyancy removed
or created by evaporation or condensation of liquid water.
This type of plume model is an entrainment model in which the
admixture of ambient air into the plume takes place by the
turbulence induced by the plume's motion.  At sufficiently
great distances from the tower, the admixture of ambient air
by this mechanism falls below that due to the natural turbulence
of the atmosphere? and it is more appropriate to a diffusion
type model at these large distances.
     Owing to the difficulty of measuring effluent conditions
at the tower exit a detailed comparison between the modeling
results and the observed plume behavior could not be made.

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                         References

D-l.  Scorer, R. S., "The Rise of Bent-Over Plumes," Advances
      in Geophysics, Vol. 6, Academic Press, 1959.

D-2.  Morton, B. R., "Buoyant Plumes in a Moist Atmosphere,"
      J. Fluid Mechanics  2, 1957.

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