United States
Environmental
Protection
Indoor Environments
Division (6609J)
Office of air and Radiation
EPA-402-S-01 -001F
January 2000
Aaencv	
Energy Cost and IAQ
Performance of Ventilation
Systems and Controls
Project # 6
Meeting Outdoor Air Requirements in Very High
Occupant Density Buildings
A Study of Auditoriums and Schools

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Energy Cost and IAQ Performance of Ventilation Systems
and Controls
Project Report # 6	Meeting Outdoor Air Requirements in Very High
Occupant Density Buildings
A Study of Auditoriums and Schools
Indoor Environments Division
Office of Radiation and Indoor Air
Office of Air and Radiation
United States Environmental Protection Agency
Washington, D.C. 20460
January 2000

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Energy Cost and IAQ Performance of Ventilation Systems and Controls
Project Report # 6	Meeting Outdoor Air Requirements in Very High Occupant
Density Buildings
A Study of Auditoriums and Schools
INTRODUCTION
Purpose and Scope of this Report
ASHRAE Standard 62-1989 (and the subsequent Standard 62-19991) raised the outdoor air
requirements for acceptable indoor air quality for very high occupant density buildings such as
schools and auditoriums from its previous level of 5 cfm per occupant to 15 cfm per occupant.
Since occupant densities in these buildings can be very high (e.g. 30-150 occupants per 1000
square feet), the absolute increase in outdoor air volumes in these buildings due to ASHRAE
Standard 62 is exceptionally large, and outdoor air fractions (proportion of supply air which is
outdoor air) rise significantly. Therefore, air flows in these buildings become heavily dominated by
indoor air quality requirements rather than by thermal load requirements. This raises questions as
to whether VAV systems can effectively meet the ASHRAE requirements under part load
conditions. At part load conditions, supply airflows may be less than the required outdoor airflows
unless VAV box minimum flow settings are sufficiently high. However, as VAV box minimum flow
settings are raised in VAV systems, the operational characteristics of the VAV system approach
that of a CV system (see Project Report #3), so that the energy savings of VAV systems over CV
systems may be diminished or lost in these buildings. This further suggests that VAV systems in
very high occupant density buildings whose design settings are meant to achieve the ASHRAE
requirement of 15 cfm per occupant, may not in actuality be meeting that requirement unless their
VAV box minimum flow settings are higher than normal practice would provide.
In addition, other reports in this project document that the impact on annual energy cost and peak
energy load which results from raising outdoor air flow rates from 5 cfm to 20 cfm per occupant
tends to be larger for high occupant density office buildings than for average occupant density
office buildings (see Project Reports # 4 and #5). In these reports, a high occupant density office
building was defined as having only 15 occupants per 1000 square feet. This raises the possibility
1 This project was initiated while ASHRAE Standard 1989 was in effect. However, since the outdoor air flow rates for both the
1989 and 1999 versions are the same, all references to ASHRAE Standard 62 in this report are stated as ASHRAE Standard 62-
1999.
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that the energy impact of raising outdoor air flow rates to 15 cfm per occupant in education
buildings, auditoriums, or other very high occupant density structures could be exceptionally high.
On the other hand, very high occupant density buildings also have large internal latent loads.
Provided that the outdoor air is dry relative to the return air, raising the outdoor airflow rate should
reduce latent loads in these buildings and may tend to reduce, rather than increase, cooling energy
use.
The purpose of this report is to examine these issues in detail. This report quantifies the supply
and outdoor airflow requirements, assesses outdoor air fractions required, and establishes
appropriate VAV box minimum flow settings for a prototype school and a prototype auditorium in
three climates. The report also quantifies the energy cost and peak load impacts of raising
outdoor air flow rates from 5 to 15 cfm per occupant in these buildings, and examines the potential
of energy recovery for reducing annual energy costs and peak loads.
Background
This report is part of a larger modeling project that assesses the compatibilities and trade-offs
between energy, indoor air, and thermal comfort objectives in the design and operation of HVAC
systems for commercial buildings. The report also attempts to shed light on potential strategies for
simultaneously achieving superior performance on each objective. It is hoped that this project will
contribute to the body of new data needed by professionals and practitioners who design and
operate ventilation systems as they attempt to reduce costs and save energy without sacrificing
thermal comfort or outdoor air flow performance.
The methodology used in this project has been to refine and adapt the DOE-2.1 E building energy
analysis computer program for the specific needs of this study, and to generate a detailed
database of the energy use, indoor climate, and outdoor air flow rates of various ventilation
systems and control strategies. Constant volume (CV) and variable air volume (VAV) systems in
different buildings, with different outdoor air control strategies, in alternative climates provide the
basis for parametric variations in the database.
Seven reports, covering the following topics, describe the findings of this project:
Project Report #1: Project objective and detailed description of the modeling methodology and
database development
Project Report #2: Assessment of energy and outdoor air flow rates in CV and VAV ventilation
systems for large office buildings:
Project Report #3: Assessment of the distribution of outdoor air and the control of thermal
comfort in CV and VAV systems for large office buildings
Project Report #4: Energy impacts of increasing outdoor air flow rates from 5 to 20 cfm per
occupant in large office buildings
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 Project Report #5:
Peak load impacts of increasing outdoor airflow rates from 5 to 20 cfm per
occupant in large office buildings
	Project Report #6: Potential problems in IAQ and energy performance of HVAC systems when
outdoor airflow rates are increased from 5 to 15 cfm per occupant in
auditoriums, education, and other buildings with very high occupant density
	Project Report #7: The energy cost of protecting indoor environmental quality during energy
efficiency projects for office and education buildings
DESCRIPTION OF THE BUILDING AND VENTILATION SYSTEMS MODELED
A 2 story L shaped education building, and a single story auditorium were modeled in three
different climates representing cold (Minneapolis), temperate (Washington, D.C.), and hot/humid
(Miami) climate zones. The education building has 6 perimeter zones representing the four
compass directions, and two core zones. The auditorium building includes a core zone auditorium
and four perimeter zones representing lobby and office spaces. Exhibit 1 shows key building and
HVAC system parameters. Exhibit 2 details the occupancy and HVAC equipment operating
schedules modeled. A more complete description of the buildings is contained in Project Report
#1.
A dual duct constant volume (CV) system with temperature reset, and a single duct variable volume
(VAV) system with reheat were modeled. Constant volume systems control the thermal conditions
in the space by altering the temperature of a constant volume of supply air. VAV systems provide
control by altering the supply air volume, while maintaining a constant supply air temperature.
For this report, only two basic outdoor air control strategies were employed: constant outdoor air
(COA), and temperature-controlled air-side economizer (ECONt). The COA strategy maintains a
constant volume of outdoor air irrespective of the supply air volume. The economizer uses
additional quantities of outdoor air to provide "free cooling" when the outdoor air temperature is
lower than the return air temperature, but is automatically shut off when the outdoor temperature
exceeds 65F to reduce the risk of excess humidity indoors. Below 65F, the quantity of outdoor
air is adjusted so that the desired supply air discharge temperature can be achieved with minimum
mechanical cooling. An enthalpy-based economizer is not included for these buildings.
A third basic outdoor air control strategy for VAV systems which was assessed in other reports is a
fixed outdoor air fraction (FOAF). The FOAF strategy maintains a constant outdoor air fraction
(percent outdoor air) irrespective of the supply air volume. The FOAF strategy does not supply the
design outdoor air volumes at part load conditions and is therefore not considered a viable
strategy (see Project Reports #2 and #3). The VAV (FOAF) system is therefore not modeled for
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these buildings. For the CV system, the FOAF strategy is equivalent to the COA strategy since the
supply air volume does not change2.
A more detailed description of these HVAC systems and outdoor air control strategies is provided
in Project Report #1.
APPROACH
In this report, the outdoor air quantities for each HVAC system and OA control strategy are
determined over the full range of thermal loads. The systems design settings are 5 and 15 cfm of
outdoor air per occupant.
Annual energy use (KBtu/ft2) is converted to energy cost assuming several different energy price
structures for all climates. In the base price structure, the price of electricity were assumed to be
$.044 per kilowatt-hour, and $7.89 per kilowatt. Gas, which was used in the space and water
heating equipment, was modeled at $0.49 per therm. For comparison purposes, energy costs
were also computed for four additional price structures that alter the relative price of gas and
electricity, and the electricity demand charge. A detailed description of the derivation of these
price structures is shown in Project Report #1. Exhibit 3 presents the utility prices under each
price structure. Unless otherwise noted, energy costs refer to costs under the base price structure.
The purpose of these pricing variations is to determine how sensitive the conclusions on energy
costs are to relative energy prices. Since Minneapolis, Washington, D.C. and Miami are used only
to represent different climate conditions, no attempt was made to use the actual energy prices in
these individual cities.
RESULTS
The presentation of results is organized to shed light on the following questions:
a.	How high must minimum VAV box settings be to accommodate both the ASHRAE
Standard 62-1999 outdoor air requirements, and the thermal load requirements of
very high occupant density buildings? How do these settings affect the viability and
operational integrity of HVAC system controls in these buildings?
b.	What are the energy cost and peak load impacts of raising the outdoor air
requirements from 5 cfm per occupant to 15 cfm per occupant in very high occupant
density buildings?
c.	Given the large outdoor air volumes required in these buildings, what gains may be
derived from energy recovery technologies in these buildings?
2 For consistency with other project reports, the CV(FOAF) rather than the CV(COA) designation is used in this
report.
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Design Versus Actual Outdoor Air Flows
Exhibit 4 presents the percent of occupied hours that specified outdoor air volumes were achieved
in the simulations for design outdoor air volumes of 5 and 15 cfm per occupant. For the VAV
systems in these runs, the VAV box minimums are set at 30% of peak flow.
As expected, CV systems for both the education and assembly building brought in the requisite
quantities of outdoor air 100% of the time in all climates at both outdoor air settings of 5 and 15
cfm per occupant. The VAV(COA) system also delivered requisite quantities of outdoor air 100%
of the time at a design setting of 5 cfm per occupant, with a VAV box setting of 30%. However,
when the outdoor air setting was changed to 15 cfm per occupant, the VAV box minimum setting of
30% was inadequate, and less than 15 cfm per occupant entered the building at part load
conditions. This is most notable for the assembly building which has a higher occupant density.
For example, for the assembly building in Washington, D.C. and in Minneapolis, the VAV(COA)
system delivered less than 10 cfm of outdoor air per occupant 70% and 79% of the time
respectively. The problem is less dramatic for Miami because there is a smaller proportion of time
spent in part load conditions in the Miami climate.
VA V Box Minimum Setting
The inadequate outdoor air flow with the VAV(COA) system is not due to the outdoor air flow
strategy at the air handler. By definition, the COA strategy insures an adequate supply of outdoor
air by increasing the outdoor air fraction at part load conditions. Rather, the problem in this case is
with the VAV box minimum settings. Under part load conditions, a VAV box minimum setting of
30% allowed the supply air volume to fall below the outdoor air volume required to meet the 15 cfm
per occupant outdoor air requirement. This means that the supply air needed to meet thermal
loads at part load is insufficient to meet the outdoor air requirement, even at 100% outdoor air.
To solve this problem, simulations were run allowing DOE-2.1 E to automatically establish the VAV
box minimum settings necessary to guarantee 15 cfm per occupant of outdoor air under all
operating conditions. The minimum settings required are presented in Exhibit 5.
The VAV box minimum settings required are substantially higher than 30%. VAV box minimum
settings for perimeter zones ranged from 38% - 56% in the education building, and from 39% -
65% in the assembly building. However, in the core zone, minimums ranged from 54%-71 % in the
education building, and from 95% -100% for the assembly building. These settings are much
higher than are normally provided.
Exhibit 6 demonstrates that only properly adjusted (higher) VAV box minimum settings insured that
the design outdoor air volume of 15 cfm per occupant is actually met at all operating conditions.
Outdoor Air Fraction
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The high VAV box settings suggest that the supply air volumes cannot be reduced substantially in
these buildings in response to reduced thermal loads. Exhibit 7 presents the supply volumes and
outdoor air fractions which result from HVAC systems in which the VAV box minimum settings are
properly adjusted. It is clear that these HVAC systems are easily dominated by the outdoor air
requirement rather than the thermal requirement. In this case the VAV system operates very
similarly to the CV system. Further, the outdoor air fractions under both design and minimum load
conditions are considerably higher than the 10% to 30% normally assumed for office buildings. A
design outdoor air fraction of 42%-48% is required for the education building, and 65%-75% for
the assembly building. The outdoor air fraction at minimum load is 100% for both buildings.
Control of Temperature and Relative Humidity
Exhibit 8 presents data showing the proportion of time the average space air temperature for all
zones fell within specified temperature bins. This data suggests that all the HVAC systems kept
indoor temperatures between 70F and 79F virtually all the time. This is true for both the
education and assembly building in all three climates. Examination of zone specific temperatures
showed a similar pattern in each zone for all systems. All the HVAC systems appear to adequately
control indoor temperature. This indicates the systems were adequately sized to meet sensible
loads.
These systems, however, depend on the cooling system to control relative humidity in the occupied
spaces. Given the high occupant densities in these buildings, the internal latent loads are high.
Since the required outdoor air quantities are also high, the cooling system may not adequately
control relative humidity as it controls temperature. Exhibit 9 shows that, without specific humidity
controls, the average zone relative humidity often exceeded 60%, and occasionally exceeded 70%.
Because of this, the buildings were also modeled to control relative humidity to 60% by lowering
the cooling coil temperature when required to meet the latent load.
Annual Energy Cost
Exhibit 10 and Exhibit 11 present the annual energy costs for outdoor air settings of 5 and 15 cfm
per occupant for the education and assembly building respectively. Exhibit 12 and Exhibit 13
present the absolute and percentage changes in cost.
Energy Cost Impact of Raising Outdoor Air Flow Rates from 5 to 15 CFM Per Occupant
Project Report # 4 suggests that raising outdoor airflow rates would have only modest impacts on
energy use and energy costs for most office buildings, and may, in some buildings, actually reduce
rather than raise costs. However, the picture is quite different for very high occupant density
buildings such as education and assembly buildings. Raising outdoor airflow rates in these
buildings can raise energy costs substantially.
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Exhibit 12 and Exhibit 13 demonstrate that only part of the energy cost increase results from raising
the outdoor air design setting from 5 cfm to 15 cfm per occupant. For CV systems, a change in
design setting alone raised energy costs by 14% to 31% for education buildings and by 19% to
50% in auditoriums. For the VAV system, a change in design setting alone raised energy costs by
14% to 19% for education buildings and by 16% to 23% for assembly buildings. However, as
noted above, for VAV systems, changing the outdoor air setting alone, without changing the VAV
box setting, did not provide 15 cfm of outdoor air under part load conditions. Therefore, these costs
do not reflect the full costs of raising the outdoor air flow rates. When the VAV box minimum flow
settings are also adjusted to insure adequate outdoor air flow, the energy costs of raising outdoor
air flow rates to15 cfm per occupant for VAV systems were 15%-32% for education buildings, and
25% - 67% for auditoriums.
Finally, because controlling temperature in both the CV and VAV systems did not adequately
control the relative humidity in the occupied space when outdoor air flows were 15 cfm per
occupant, adding humidity control to 60% relative humidity raised the energy cost impact to
between 17% and 39% for CV systems in education buildings, and between 26% and 58% for CV
systems in auditoriums. The energy cost impact for VAV systems was 15% to 35% in education
buildings, and 35% to 81 % in auditoriums. These increases are much larger than is normally
assumed.
These increases reflect utility prices under the base price structure used in this study. However,
Exhibit 14 and Exhibit 15 demonstrate that the energy cost increase is very large under all the price
structures analyzed in this project (Exhibit 3).
Climate Effects
The energy cost impacts of raising outdoor air flow rates from 5 cfm to 15 cfm per occupant were
greater in the cold and temperate climates of Minneapolis and Washington, D.C., than in the hot
and humid climate of Miami. This conclusion also runs contrary to popular belief. The reason is
that while hot humid climates experience the largest absolute increment in cooling costs, heating
costs rose dramatically in temperate and cold climates when outdoor airflow rates are raised to 15
cfm per occupant, but rose only slightly in the hot and humid climate. As a result, the annual energy
cost increase in both absolute and percentage terms was much greater for the cold and temperate
climate than it was in the hot and humid climate. This is true for all five utility price structures.
Heating System Effects of CV and VA V Systems
The CV and VAV systems modeled have significantly different relative heating cost impacts of
increased outdoor air. In both systems the OA requirement was the same. In the CV systems,
heating costs rose substantially when outdoor air flow rates were increased from 5 to 15 cfm per
occupant because of the need to heat cold outside air during cold weather. The effect on heating
energy for VAV systems, however, was not the same. Since the VAV system has zone reheat,
heating does not occur until after the air passes through the cooling coil. Since the discharge
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temperature of the supply air from the cooling coil is approximately the same at 5 cfm as it is at 15
cfm per occupant, there would ordinarily be no substantial impact on heating energy.
In office (lower occupant density) buildings, the outdoor air fraction is usually too low to force the
mixed air temperature below 45F so that preheat was not normally necessary. But for the very
high occupant density buildings modeled here, the outdoor air fraction is very high. This means
that in very cold weather, preheat coils in the VAV system are activated to heat the air before it
enters the cooling coil to avoid freezing the coil. The large volumes of outdoor air during cold
weather may reduce cooling energy costs in VAV systems, as would an economizer, but at a
heating cost penalty, which in this case is a preheat penalty 3.
The large jump in heating costs in the VAV system occured when the VAV box minimum settings
are adjusted to raise the outdoor air volumes at part load conditions. This raised the outdoor air
fraction and resulted in colder mixed air temperature on cold winter days. This created a larger
outdoor air heating burden at the preheat coil.
In very high occupant density buildings with VAV systems, most of the increase in heating was the
additional preheat coil load, while heating coil loads were only moderately affected. In contrast, CV
systems in the same buildings had much more profound central heating coil loads, and less burden
on the preheat coil.
Economizers
At 5 cfm of outdoor air per occupant, the economizer reduced cooling energy costs by
approximately $.05 per square foot in the Minneapolis and Washington, D.C. climates, by raising
outdoor air volumes when the outdoor air was cooler than the return air. Economizers have little or
no advantage in Miami4. However, when the outdoor air volume was raised to 15 cfm per occupant
in these very high occupant density buildings, much of the economizer advantage was already
accounted for by these high outdoor air flow rates. In fact, for VAV systems, the economizers never
became operational because additional quantities of outdoor air were not needed to reduce
cooling costs. The VAV(COA) and the VAV(COA)(ECON) systems were therefore operationally
identical.
Integrity of VA V Systems
At 5 cfm of outdoor air per occupant, the VAV system had a significant energy advantage over the
CV systems because of reduced fan energy and cooling energy costs for both the education and
assembly building. At 15 cfm per occupant, with appropriate adjustments of the VAV box and
control of relative humidity at 60%, the VAV system had similar advantages in the education
building. However, when occupant densities rose again, as in the auditorium, the advantages of
3	See Project Report # 5 for discussion of this effect in office buildings
4	For a more detailed explanation of economizer advantages, see Project Report # 2.
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the VAV system disappeared. In fact, in the auditorium, the VAV system cost more to operate than
the CV system. Both the cooling cost and the heating cost were higher for the VAV system than for
the CV system in the auditorium. The air flows of the VAV system were operating similar to the air
flows of the CV system, but the CV system, with its dual duct and temperature reset capability is
more efficient than the single duct VAV system with zone reheat under these conditions. This
suggests that VAV systems may not be appropriate in auditoriums, or similar buildings where the
occupant densities are extraordinarily high.
Peak Load Impacts of Raising Outdoor Air Flow Rates to 15 CFM Per Occupant
Exhibit 16-19 present peak load data for both 5 and 15 cfm of outdoor air per occupant. Changes
in peak loads shed light on whether or not existing systems sized to provide 5 cfm of outdoor air
per occupant are likely to have sufficient capacity to also provide 15 cfm per occupant without
retrofit. In addition, peak loads at 15 cfm per occupant provide some measure of the potential for
downsizing equipment in energy conservation retrofits.
Peak Cooling Load
Peak cooling loads for CV systems were increased by 20% - 26% in the education building and by
30% - 32% in the auditorium. For the VAV system, peak cooling loads were increased 20%- 26%
in the education building, and by 21 %- 28% in the auditorium. These increases are substantial. It
suggests that buildings sized for 5 cfm per occupant will probably not be capable of achieving 15
cfm per occupant with the same cooling equipment, and that energy retrofits of existing buildings
which are also being redesigned to meet ASHRAE 62-1999 may be severely limited in how much
downsizing can actually take place.
Peak Heating Coil Loads
Peak heating loads for CV systems in Minneapolis and Washington, D.C. increased by 12% - 30%
in the education building, and by 3% - 22% in the auditorium. For VAV systems in Minneapolis and
Washington, D.C., peak heating loads increased less than 10% for the education building, and by
9%-22% for the auditorium. In Miami, the peak heating loads were negligible at 5 cfm of outdoor
air per occupant for both the education building and the auditorium. However, at 15 cfm per
occupant, peak heating coil loads rose to 480 - 520 k BTU/hr.
These results suggest raising outdoor air flow rates to 15 cfm per occupancy results in only modest
increases on the main heating coil, and these increases could probably be accommodated with
existing systems designed for 5 cfm per occupant. However, in hot and humid climates such as
Miami, the peak heating coil loads at 15 cfm per occupant, while small, may be more than current
systems are designed to handle.
Peak Preheat Coil Loads
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At 5 cfm of outdoor air per occupant, no preheat coil loads were experienced for any CV system in
either the education or assembly building in any climate modeled. When outdoor air volumes were
increased to 15 cfm per occupant, preheat coil requirements appeared in Minneapolis and
Washington, D.C. They were highest in Minneapolis and were greater in the auditorium than in the
education building. In the auditorium in Minneapolis, peak preheat coil loads exceeded 1000
kBTU/hr. No preheat requirements were experienced for CV systems in Miami either at 5 or 15
cfm per occupant.
A similar pattern is presented for VAV systems. In Minneapolis, peak preheat coil loads went from
246 to 1282 kBTU/hr in education buildings, and from 330 to 919 kBTU/hr in auditoriums when
outdoor air volumes were increased from 5 to 15 cfm per occupant. Smaller increases were
experienced in Washington, D.C. and Miami.
Many systems have little or no preheat coil loads at 5 cfm per occupant. The emergence of a
preheat load means that existing systems designed at 5 cfm per occupant may experience
significant damage from coil freezing if run to accommodate 15 cfm per occupant without adding
preheat coil capacity. It also means that new systems must include preheat coils to accommodate
15 cfm of outdoor air per occupant. The problem is especially prevalent in cold climates (e.g.,
Minneapolis), but the emergence of even a small preheat coil requirement could portend freezing
damage if it is not available.
Potential for Energy Recovery Technology
The substantial increase in energy cost associated with raising outdoor air flow to meet ASHRAE
Standard 62-1999 for education and assembly buildings constitutes a significant potential savings
for efficient energy recovery technology. The extent to which such a potential could be realized was
not modeled because DOE-2.1 E is extremely limited in its ability to model energy recovery
systems. However, some literature suggests that available energy recovery technology can
significantly reduce or eliminate the increased energy cost and further improve the potential to
downsize equipment in these buildings (Rengarajan, et al. 1996; Shirey et al. 1996)
SUMMARY & CONCLUSIONS
VAV systems derive much of their attractiveness for energy conservation by their ability to save fan
energy during part load conditions. However, in buildings with high occupant densities, such as the
schools and auditoriums, the high outdoor air volumes required by ASHRAE Standard 62-1999
places a floor on the extent to which VAV systems can pinch down during part load, so that VAV
systems in these buildings operate more like CV systems when meeting the outdoor air
requirements of ASHRAE Standard 62-1999. The VAV box minimum settings must necessarily be
much higher than are typically used for office environments in order to provide sufficient outdoor air.
This, in part, explains the higher energy cost associated with raising the outdoor air setting from 5
cfm to 15 cfm per occupant in these buildings. Economizers may not have much advantage in high
occupant density buildings because much of the advantage of economizers is already accounted
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for by the higher outdoor air flow rates. In fact, the economizer for the VAV system never became
operational when 15 cfm of outdoor air was maintained in the school and education building.
In most office buildings, when the cooling plant is sized to meet the sensible load, the latent load is
most often also satisfied. However, in schools and auditoriums, when the cooling plan twas sized
to meet the sensible load at 15 cfm per occupant, the latent load was most often not
accommodated, raising the relative humidity often above 60% and occasionally above 70% in the
occupied spaces.
Unlike office buildings, when outdoor air flow rates were raised from 5 to 20 cfm per occupant in
the education and assembly buildings, energy costs increased substantially. The HVAC energy
cost increase of raising outdoor air flow rates was 17% to 39% for CV systems in education
buildings, and 26% to 58% for CV systems in auditoriums. The HVAC energy cost impact for VAV
systems was 15% to 35% in education buildings, and 35% to 81 % in auditoriums. These
increases were partly due to raising the outdoor air flow settings, partly due to changing the VAV
box minimum settings to insure adequate outdoor air flow, and partly due to the need to control
humidity to below 60%.
Peak cooling loads increased 20%-32% when raising outdoor air flow rates from 5-15 cfm per
occupant, while only modest increases in the main heating coil were experienced. However, peak
preheat coil loads were also substantially increased. Many systems have little or no preheat coil
loads at 5 cfm per occupant. Thus, existing systems designed for 5 cfm of outdoor air per
occupant may not be capable of maintaining thermal comfort during heavy loads. In addition, the
emergence of a preheat load means that existing systems designed at 5 cfm per occupant may
experience significant damage from coil freezing if run at 15 cfm per occupant without adding
preheat coil capacity.
The higher peak loads also suggest that meeting ASHRAE 62-1999 during an energy retrofit
places severe limitations on the extent to which cooling equipment can be downsized. The
increased annual energy cost and the effect on equipment capacity make the use of energy
recovery systems potentially very attractive to high occupant density building, and further research
into this potential would be useful.
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BIBLIOGRAPHY
ASHRAE , 1999, ASHRAE Standard 62-1999: Ventilation for Acceptable Indoor Air Quality.
American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta.
Cowan, J., 1986?, "Implications of Providing Required Outside Air Quantities in Office Buildings",
ASHRAE Transactions. V. Pt. , Atlanta.
Curtis, R., Birdsall, B., Buhl, W., Erdem, E., Eto, J., Hirsch, J., Olson, K., and Winkelmann, F., 1984,
DOE-2 Building Energy Use Analysis Program. Lawrence Berkeley Laboratory, LBL-18046.
Eto, J., and Meyer, C., 1988, "The HVAC Costs of Fresh Air Ventilation in Office Buildings",
ASHRAE Transactions. V. 94, Pt.2.
Eto, J., 1990, "The HVAC Costs of Increased Fresh Air Ventilation Rates in Office Buildings, Part
2", from Proc. of Indoor Air 90: The Fifth International Conference on Indoor Air Quality and
Climate, Toronto, Canada.
Levenhagen, J., 1992, "Control Systems to Comply with ASHRAE Standard 62-1999", ASHRAE
Journal. Atlanta, September.
Mutammara, A., and Hittle, D., 1990, "Energy Effects of Various Control Strategies for Variable Air
Volume Systems", ASHRAE Transactions. V. 96, Pt. 1, Atlanta.
Rengarajan, K.; Shirey, D. B. Ill, and Raustad, R.1996. Cost-effective HVAC technologies to meet
ASHRAE Standard 62-1999 in hot and humid climates. ASHRAE Transactions, V. 102(1).
Shirey D.B. and Rengarajan, K. 1996. Impacts of ASHRAE Standard 62-1999 on small florida
offices. ASHRAE Transactions, V. 102(1).
Sauer, H., and Howell, R., 1992, "Estimating the Indoor Air Quality and Energy Performance of
VAV Systems", ASHRAE Journal. Atlanta, July.
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Exhibit 1: Characteristics of the Base Buildings Modeled in this Study

Education
Assembly
Building Characteristics


shape
L-shaped
square
zones/floor
6
5
floor area (ft2)
50,600
19,600
number of floors
2
1
floor height (ft)
15
30
wall construction
concrete block
concrete block
net window area (%)
34%
7%
window U-value (Btu/hr ft2 F)
0.59
0.59
window shading coefficient
0.6
0.6
wall R-value (hr ft2 F/Btu)
R-8
R-8
roof R-value (hr ft2 F/Btu)
R-12
R-12
perimeter/core ratio*
1.0
0.6
infiltration rate (ach)
0.25
0.25
Occupancy


number of occupants
1,518
588
occupant density (occup/1000ft2)
30
60
11 V AC


air distribution system
central (CVorVAV)
central (CVorVAV)
heating and DHW
central gas boiler - 80%
efficiency
central gas boiler - 80%)
efficiency
cooling
chiller - 4 COP w/cooling
tower
chiller - 4 COP w/cooling
tower
* Ratio of perimeter to core floor area, where perimeter space is up to 15 ft. from the exterior walls
Energy Cost and IAQ
13
Report # 6

-------
Exhibit 2: Occupant & Operating Schedules for Office, Education, and Assembly Buildings

Office Building
Education Building
Assembly

Occupancy HVAC
Occupancy
HVAC
Occupancy
HVAC
Hour
Mo
n-Fri
WE/
Hoi
Mon
Tue-
Fri
WE/
Hoi
Mon-
Fri
Sat.
Sun/
Hoi
Mon-
Fri
Sat
Sun/
Hoi
Mon-
Fri
WE/
Hoi
Mon-Fri
WE/
Hoi
1-5
0%
0%
night
night
night
0%
0%
0%
night
night
night
0%
0%
night
night
6
0%
0%
St Up
night
night
0%
0%
0%
St Up
St Up
night
0%
0%
night
night
7
0%
0%
St Up
St Up
night
0%
0%
0%
St Up
St Up
night
0%
0%
night
night
8
25%
0%
day
day
night
10%
0%
0%
day
day
night
0%
0%
night
night
9
75%
0%
day
day
night
100%
10%
0%
day
day
night
10%
10%
St Up
St Up
10-12
95%
0%
day
day
night
100%
10%
0%
day
day
night
10%
10%
day
day
13
75%
0%
day
day
night
100%
10%
0%
day
day
night
50%
75%
day
day
14-15
95%
0%
day
day
night
100%
0%
0%
day
day
night
50%
75%
day
day
16
95%
0%
day
day
night
50%
0%
0%
day
day
night
50%
75%
day
day
17
75%
0%
day
day
night
50%
0%
0%
day
day
night
50%
75%
day
day
18
50%
0%
day
day
night
50%
0%
0%
day
day
night
50%
75%
day
day
19
25%
0%
night
night
night
15%
0%
0%
day
night
night
100%
100%
day
day
20-21
10%
0%
night
night
night
20%
0%
0%
day
night
night
100%
100%
day
day
22
10%
0%
night
night
night
10%
0%
0%
day
night
night
100%
100%
day
day
23-24
0%
0%
night
night
night
0%
0%
0%
night
night
night
50%
75%
day
day
St Up = startup; day = full operation; night = operating with night temperature set back of 10F.
Energy Cost and IAQ
14
Report # 6

-------
Exhibit 3
Utility Rate Structures Modeled

Rate Class
Rate Structure
Rate
Structures
Gas
Rate
Electric
Rate
Electric
Demand
Gas
Rate
Electric
Rate
Electric
Demand
Ratche
t
Clause
Base
Average
Average
Average
$0,490
$0,044
$7,890
No
Option 1
Low
High
Average
$0,330
$0,063
$7,890
No
Option 2
High
Low
Average
$0,650
$0,025
$7,890
No
Option 3
Average
Average
High
$0,490
$0,044
$11,710
No
Option 4
Average
Average
Low
$0,490
$0,044
$4,070
No
Energy Cost and IAQ
15
Report # 6

-------
Exhibit 4
Percent of Occupied Hours Air Flows are Achieved for Education Buildings
HVAC System

Minneapolis, MN
Washington, DC
Miami, FL
Design OA Flow Rate
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
CV (FOAF)








<5
100.0%
0.0%
100.0%
0.0%
100.0%
0.0%

6-10
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%

11-15
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%

16-19
0.0%
100.0%
0.0%
100.0%
0.0%
100.0%

>20
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
CV (FOAF) EconT








<5
67.5%
0.0%
73.3%
0.0%
92.6%
0.0%

6-10
18.9%
0.0%
12.4%
0.0%
0.4%
0.0%

11-15
4.0%
0.0%
3.9%
0.0%
0.8%
0.0%

16-19
2.3%
93.4%
2.9%
93.4%
0.7%
94.6%

>20
7.3%
6.6%
7.4%
6.6%
5.4%
5.4%
VAV (COA)








<5
100.0%
0.0%
100.0%
0.0%
100.0%
0.0%

6-10
0.0%
0.0%
0.0%
46.2%
0.0%
0.0%

11-15
0.0%
76.8%
0.0%
23.7%
0.0%
12.8%

16-19
0.0%
23.2%
0.0%
30.0%
0.0%
87.2%

>20
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
VAV (COA) EconT








<5
44.8%
0.0%
50.5%
0.0%
92.6%
0.0%

6-10
34.7%
0.0%
39.8%
46.2%
0.4%
0.0%

11-15
19.1%
76.8%
9.3%
23.7%
4.4%
12.8%

16-19
1.2%
23.0%
0.4%
30.0%
1.9%
86.4%

>20
0.2%
0.2%
0.0%
0.0%
0.8%
0.8%
Energy Cost and IAQ
16
Report # 6

-------
Exhibit 4 (cont.)
Percent of Occupied Hours Air Flows are Achieved for Assembly Buildings
HVAC System
Design OA Flow Rate
Minneapolis, MN
5 cfm 15 cfm
Washington, DC
5 cfm 15 cfm
Miami, FL
5 cfm 15 cfm
CV (FOAF)
<5
6-10
11-15
16-19
>20
100.0% 0.0%
0.0% 0.0%
0.0% 0.0%
0.0% 100.0%
0.0% 0.0%
100.0% 0.0%
0.0% 0.0%
0.0% 0.0%
0.0% 100.0%
0.0% 0.0%
100.0% 0.0%
0.0% 0.0%
0.0% 0.0%
0.0% 100.0%
0.0% 0.0%
CV (FOAF) EconT
<5
6-10
11-15
16-19
>20
61.8% 0.0%
30.1% 0.0%
3.6% 0.0%
1.6% 97.1%
3.0% 2.9%
76.8% 0.0%
13.1% 0.0%
3.3% 0.0%
2.1% 95.3%
4.7% 4.7%
91.2% 0.0%
0.9% 0.0%
1.4% 0.0%
1.3% 94.7%
5.2% 5.3%
VAV (COA)
<5
6-10
11-15
16-19
>20
100.0% 0.0%
0.0% 78.5%
0.0% 17.8%
0.0% 3.7%
0.0% 0.0%
100.0% 0.0%
0.0% 69.8%
0.0% 22.5%
0.0% 7.8%
0.0% 0.0%
100.0% 0.0%
0.0% 8.5%
0.0% 37.0%
0.0% 54.5%
0.0% 0.0%
VAV (COA) EconT
<5
6-10
11-15
16-19
>20
68.4% 0.0%
29.2% 78.5%
2.4% 17.8%
0.0% 3.7%
0.0% 0.0%
69.9% 0.0%
26.4% 69.8%
3.6% 22.5%
0.1% 7.8%
0.0% 0.0%
91.1% 0.0%
3.8% 8.5%
4.8% 37.0%
0.4% 54.5%
0.0% 0.0%
Energy Cost and IAQ
17
Report # 6

-------
Exhibit 5
VAV Box Minimum Settings Necessary to Guarantee 15 cfm/person
During All Occupied Hours (Percent of Peak Zone Supply Air Flow)
Building Type
Minneapolis, MN
Washington, DC
Miami, FL
Zone



Education



Core
71.0%
68.4%
53.7%
East
39.4%
45.1%
37.8%
North
53.6%
55.5%
43.8%
West
48.5%
52.2%
43.4%
South
47.1%
51.1%
42.6%
Assembly



Core
100.0%
100.0%
95.0%
East
38.9%
65.1%
46.5%
North
40.7%
41.8%
62.7%
West
42.0%
57.4%
52.7%
South
43.8%
52.3%
54.1%
Energy Cost and IAQ
18
Report # 6

-------
Exhibit 6
Percent of Occupied Hours Outdoor Air Flow Rates are Achieved
with and without VAV Box Adjustments at a Design Setting of 15 cfm/person
Building
Minneapolis, MN
Washington
DC
Miami,
FL
HVAC System
Unadjusted
Adjusted
Unadjusted
Adjusted
Unadjusted
Adjusted
Education






VAV (COA)






<5
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
6-10
0.0%
0.0%
46.2%
0.0%
0.0%
0.0%
11-15
76.8%
0.0%
23.7%
0.0%
12.8%
0.0%
16-19
23.2%
100.0%
30.0%
100.0%
87.2%
100.0%
>20
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
VAV (COA) EconT






<5
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
6-10
0.0%
0.0%
46.2%
0.0%
0.0%
0.0%
11-15
76.8%
0.0%
23.7%
0.0%
12.8%
0.0%
16-19
23.0%
99.4%
30.0%
100.0%
86.4%
98.9%
>20
0.2%
0.6%
0.0%
0.0%
0.8%
1.1%
Assembly






VAV (COA)






<5
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
6-10
78.5%
0.0%
69.8%
0.0%
8.5%
0.0%
11-15
17.8%
0.0%
22.5%
0.0%
37.0%
0.0%
16-19
3.7%
100.0%
7.8%
100.0%
54.5%
100.0%
>20
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
VAV (COA) EconT






<5
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
6-10
78.5%
0.0%
69.8%
0.0%
8.5%
0.0%
11-15
17.8%
0.0%
22.5%
0.0%
37.0%
0.0%
16-19
3.7%
100.0%
7.8%
100.0%
54.5%
100.0%
>20
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Energy Cost and IAQ
19
Report # 6

-------
Exhibit 7
Supply Volume and Outdoor Air Fractions for 5 and 15 cfm Outddor Air per person
at Design and Minimum Load Conditions
Building
Minneapolis, MN
Washing
ton, DC
Miami, FL

Supply
Volume
OA Fraction
Supply
Volume
OA Fraction
Supply
Volume
OA Fraction
HVAC System
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
Education












CV (FOAF)












Design Load
53684
53684
0.140
0.419
45123
45123
0.161
0.484
50944
50944
0.143
0.428
Minimum Load
53684
53684
0.140
0.419
45123
45123
0.161
0.484
50944
50944
0.143
0.428
VAV (COA)












Design Load
53684
53684
0.140
0.419
45123
45123
0.161
0.484
50944
50944
0.143
0.428
Minimum Load
16105
22478
0.465
1.000
13537
21823
0.537
1.000
15283
21823
0.476
1.000
Assembly












CV (FOAF)












Design Load
26185
26185
0.216
0.647
23415
23415
0.234
0.703
22496
22496
0.244
0.732
Minimum Load
26185
26185
0.216
0.647
23415
23415
0.234
0.703
22496
22496
0.244
0.732
VAV (COA)












Design Load
26185
26185
0.216
0.647
22100
22100
0.248
0.745
22496
22496
0.244
0.732
Minimum Load
7856
16955
0.719
1.000
6630
16461
0.828
1.000
6749
16461
0.813
1.000
Energy Cost and IAQ
Report # 6

-------
Exhibit 8
Percent of Occupied Hours with Specified Indoor Air Temperatures
for Education Buildings
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL
Temperature
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
CV(FOAF)






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
88.4%
89.7%
78.0%
78.8%
4.8%
6.3%
75-79
11.6%
10.3%
22.0%
21.2%
95.2%
93.7%
79
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
CV (FOAF) EconT






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
88.4%
89.7%
78.0%
78.8%
4.8%
6.4%
75-79
11.6%
10.3%
22.0%
21.2%
95.2%
93.6%
79
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
VAV (COA)






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
76.8%
76.9%
58.8%
59.0%
1.8%
2.1%
75-79
23.2%
23.1%
41.2%
41.0%
98.2%
97.9%
79
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
VAV (COA) EconT






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
77.0%
76.9%
59.1%
59.0%
2.0%
2.1%
75-79
23.0%
23.1%
40.9%
41.0%
98.0%
97.9%
79
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Energy Cost and IAQ
21
Report # 6

-------
Exhibit 8 (cont.)
Percent of Occupied Hours with Specified Indoor Air Temperatures
for Assembly Buildings
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL
Temperature
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
CV(FOAF)






70
2.9%
2.9%
2.5%
2.6%
0.0%
0.0%
71-74
57.8%
66.5%
41.6%
51.6%
0.5%
2.1%
75-79
39.4%
30.6%
55.9%
45.8%
99.1%
97.5%
79
0.0%
0.0%
0.0%
0.0%
0.3%
0.3%
CV (FOAF) EconT






70
2.9%
2.9%
2.5%
2.6%
0.0%
0.0%
71-74
58.0%
66.6%
41.8%
51.7%
0.5%
2.2%
75-79
39.1%
30.6%
55.6%
45.7%
99.1%
97.5%
79
0.0%
0.0%
0.0%
0.0%
0.3%
0.3%
VAV (COA)






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
68.7%
69.3%
49.2%
49.6%
0.6%
0.7%
75-79
31.3%
30.7%
50.8%
50.4%
99.2%
97.6%
79
0.0%
0.0%
0.0%
0.0%
0.2%
1.7%
VAV (COA) EconT






70
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
71-74
68.9%
69.3%
49.4%
49.6%
0.7%
0.7%
75-79
31.1%
30.7%
50.6%
50.4%
99.1%
97.6%
79
0.0%
0.0%
0.0%
0.0%
0.2%
1.7%
Energy Cost and IAQ
22
Report # 6

-------
Exhibit 9
Percent of Occupied Hours with Specified Indoor Relative Humidity
for Education Buildings
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL
Relative Humidity
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
CV(FOAF)






<20%
11.7%
19.3%
7.4%
12.5%
0.2%
0.4%
21-29%
11.8%
19.5%
7.8%
12.3%
1.0%
1.2%
30-50%
34.3%
43.1%
30.6%
40.6%
27.3%
21.0%
51-60%
23.7%
13.8%
28.6%
24.2%
52.7%
51.4%
61-70%
13.7%
3.9%
17.1%
9.9%
18.3%
25.2%
>70%
4.9%
0.3%
8.5%
0.6%
0.5%
0.9%
CV (FOAF) EconT






<20%
12.1%
19.3%
8.0%
12.7%
0.5%
0.4%
21-29%
13.1%
20.0%
9.6%
12.7%
1.6%
1.5%
30-50%
36.2%
43.0%
32.7%
40.0%
27.3%
20.9%
51-60%
21.5%
13.5%
26.8%
24.2%
51.9%
50.9%
61-70%
12.5%
3.9%
15.5%
9.6%
18.2%
25.3%
>70%
4.6%
0.3%
7.5%
0.8%
0.5%
0.9%
VAV (COA)






<20%
12.7%
18.5%
8.3%
11.5%
0.1%
0.4%
21-29%
11.2%
15.6%
7.5%
9.2%
0.9%
1.3%
30-50%
26.9%
41.2%
24.1%
35.6%
14.8%
16.7%
51-60%
21.7%
14.7%
22.5%
24.3%
43.2%
38.5%
61-70%
17.4%
7.7%
20.4%
14.6%
32.7%
35.4%
>70%
10.1%
2.3%
17.3%
4.9%
8.4%
7.6%
VAV (COA) EconT






<20%
14.3%
18.5%
9.8%
11.5%
0.4%
0.4%
21-29%
12.4%
15.6%
8.9%
9.2%
1.2%
1.3%
30-50%
33.6%
41.2%
29.3%
35.6%
15.6%
16.7%
51-60%
22.4%
14.7%
23.0%
24.3%
42.8%
38.5%
61-70%
12.5%
7.6%
18.5%
14.6%
32.2%
35.4%
>70%
4.8%
2.3%
10.6%
4.9%
7.8%
7.6%
Energy Cost and IAQ
23
Report # 6

-------
Exhibit 9 (cont.)
Percent of Occupied Hours with Specified Indoor Relative Humidity
for Assembly Buildings
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL
Relative Humidity
5 cfm
15 cfm
5 cfm
15 cfm
5 cfm
15 cfm
CV(FOAF)






<20%
9.1%
19.6%
5.8%
10.8%
0.1%
0.1%
21-29%
9.2%
19.4%
5.7%
15.1%
0.8%
1.2%
30-50%
32.1%
34.8%
24.6%
31.8%
16.3%
18.0%
51-60%
25.1%
15.9%
24.8%
19.7%
47.0%
52.8%
61-70%
18.6%
8.9%
28.4%
20.5%
35.6%
27.5%
>70%
5.9%
1.4%
10.8%
2.1%
0.3%
0.2%
CV (FOAF) EconT






<20%
9.3%
19.6%
6.1%
11.1%
0.2%
0.2%
21-29%
9.4%
19.4%
6.5%
15.4%
1.2%
1.3%
30-50%
34.3%
35.0%
27.8%
31.6%
17.3%
18.3%
51-60%
24.3%
15.6%
25.2%
19.3%
45.9%
52.3%
61-70%
16.9%
8.9%
25.5%
20.3%
35.1%
27.7%
>70%
5.7%
1.5%
8.9%
2.2%
0.3%
0.2%
VAV (COA)






<20%
10.1%
14.1%
7.0%
7.9%
0.1%
0.1%
21-29%
11.6%
14.2%
9.0%
11.0%
0.8%
1.1%
30-50%
31.6%
36.2%
25.4%
30.7%
11.0%
16.3%
51-60%
17.1%
17.5%
18.7%
22.0%
40.1%
51.2%
61-70%
16.2%
11.4%
23.0%
21.3%
44.1%
30.3%
>70%
13.4%
6.6%
17.0%
7.1%
3.9%
0.9%
VAV (COA) EconT






<20%
10.2%
14.1%
7.1%
7.9%
0.1%
0.1%
21-29%
12.1%
14.2%
9.9%
11.0%
1.0%
1.1%
30-50%
34.7%
36.2%
27.2%
30.7%
12.4%
16.3%
51-60%
17.0%
17.5%
19.4%
22.0%
39.9%
51.2%
61-70%
15.2%
11.4%
22.3%
21.3%
42.8%
30.3%
>70%
10.8%
6.6%
14.1%
7.1%
3.9%
0.9%
Energy Cost and IAQ
24
Report # 6

-------
Exhibit 10
Annual HVAC Energy Costs for Education Buildings
at Alternative Outdoor Air Settings ($/sf)
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
End Use

No RH
Control
RH
Control

No RH
Control
RH
Control

No RH
Control
RH
Control
CV (FOAF)












Fan
0.28
0.28

0.28
0.23
0.23

0.23
0.26
0.26

0.25
Cooling
0.41
0.47

0.52
0.45
0.53

0.55
0.71
0.84

0.88
Heating
0.23
0.44

0.46
0.08
0.18

0.20
0.00
0.00

0.01
Total
0.92
1.19

1.25
0.76
0.95

0.97
0.97
1.10

1.14
CV (FOAF) EconT












Fan
0.28
0.28

0.28
0.23
0.23

0.23
0.26
0.26

0.25
Cooling
0.38
0.45

0.50
0.42
0.51

0.53
0.70
0.84

0.88
Heating
0.24
0.44

0.46
0.08
0.19

0.20
0.00
0.00

0.01
Total
0.89
1.17

1.24
0.73
0.93

0.96
0.96
1.10

1.14
VAV (COA)












Fan
0.17
0.17
0.18
0.17
0.16
0.16
0.17
0.16
0.20
0.20
0.20
0.17
Cooling
0.39
0.41
0.42
0.43
0.43
0.49
0.50
0.52
0.64
0.75
0.76
0.79
Heating
0.32
0.42
0.51
0.52
0.14
0.17
0.25
0.26
0.00
0.00
0.00
0.01
Total
0.87
1.01
1.11
1.12
0.73
0.83
0.92
0.93
0.84
0.95
0.96
0.97
VAV (COA) EconT












Fan
0.17
0.17
0.18
0.17
0.16
0.16
0.17
0.16
0.20
0.20
0.20
0.17
Cooling
0.35
0.41
0.42
0.43
0.40
0.49
0.50
0.51
0.64
0.75
0.76
0.79
Heating
0.32
0.42
0.51
0.52
0.14
0.17
0.25
0.26
0.00
0.00
0.00
0.01
Total
0.84
1.01
1.11
1.12
0.70
0.83
0.92
0.93
0.84
0.95
0.96
0.97
Energy Cost and IAQ
Report # 6

-------
Exhibit 11
Annual HVAC Energy Costs for Assembly Buildings
at Alternative Outdoor Air Settings ($/sf)
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
End Use

No RH
Control
RH
Control

No RH
Control
RH
Control

No RH
Control
RH
Control
CV (FOAF)












Fan
0.41
0.41

0.42
0.36
0.36

0.39
0.34
0.34

0.34
Cooling
0.65
0.77

0.86
0.71
0.83

0.92
1.25
1.56

1.66
Heating
0.49
1.08

1.09
0.17
0.50

0.52
0.00
0.00

0.01
Total
1.55
2.26

2.37
1.24
1.70

1.83
1.60
1.90

2.01
CV (FOAF) EconT












Fan
0.41
0.41

0.42
0.36
0.36

0.39
0.34
0.34

0.34
Cooling
0.58
0.73

0.82
0.64
0.79

0.89
1.23
1.55

1.66
Heating
0.50
1.08

1.10
0.18
0.51

0.53
0.00
0.00

0.01
Total
1.49
2.23

2.35
1.18
1.66

1.81
1.57
1.89

2.01
VAV (COA)












Fan
0.24
0.27
0.30
0.29
0.23
0.25
0.29
0.28
0.29
0.30
0.33
0.30
Cooling
0.52
0.58
0.68
0.82
0.63
0.74
0.80
0.97
1.10
1.32
1.41
1.55
Heating
0.58
0.76
1.22
1.27
0.23
0.28
0.61
0.67
0.00
0.00
0.01
0.03
Total
1.34
1.62
2.20
2.38
1.10
1.27
1.71
1.92
1.40
1.62
1.74
1.88
VAV (COA) EconT












Fan
0.24
0.27
0.30
0.29
0.23
0.25
0.29
0.28
0.29
0.30
0.33
0.30
Cooling
0.49
0.58
0.68
0.82
0.61
0.74
0.80
0.97
1.09
1.32
1.41
1.55
Heating
0.58
0.76
1.22
1.27
0.23
0.28
0.61
0.67
0.00
0.00
0.01
0.03
Total
1.31
1.62
2.20
2.38
1.07
1.27
1.71
1.92
1.39
1.62
1.74
1.88
Energy Cost and IAQ
Report # 6

-------
Exhibit 12
Change in HVAC Energy Costs for Education Buildings
Due to Increased Outdoor Air Flow Rates from 5 to 15 cfm/person ($/sf)
HVAC System
End Use
Minneapolis, MN
Washington, DC
Miami, FL
5 cfm/
person
($/sf)
Difference 15-5 cfm/person
5 cfm/
person
($/sf)
Difference 15-5 cfm/person
5 cfm/
person
Difference 15-5 cfm/person
VAV Box Min
30%
Adjusted
VAV Box
VAV Box Min
30%
Adjusted VAV
Box
VAV Box Min
30%
Adjusted VAV
Box
($/sf) (%)
($/sf) (%)
($/sf) (%)
($/sf) (%)
($/sf)
($/sf) (%)
($/sf) (%)
CV (FOAF)
Fan
Cooling
Heating
Total
0.28
0.41 0.06 14%
0.23 0.21 90%
0.92 0.27 29%
0.23
0.45 0.08 18%
0.08 0.11 135%
0.76 0.19 25%
0.26
0.71 0.13 19%
0.00
0.97 0.13 14%
CV (FOAF) EconT
Fan
Cooling
Heating
Total
0.28
0.38 0.07 18%
0.24 0.21 87%
0.89 0.27 31%
0.23
0.42 0.09 23%
0.08 0.10 130%
0.73 0.20 27%
0.26
0.70 0.14 19%
0.00
0.96 0.14 14%
VAV (COA)
Fan
Cooling
Heating
Total
0.17 0.01 5%
0.39 0.03 8% 0.04 9%
0.32 0.10 32% 0.19 60%
0.87 0.13 15% 0.24 27%
0.16 0.01 6%
0.43 0.06 15% 0.07 17%
0.14 0.03 25% 0.11 82%
0.73 0.10 14% 0.19 27%
0.20
0.64 0.11 17% 0.11 18%
0.00
0.84 0.11 14% 0.12 15%
VAV (COA) EconT
Fan
Cooling
Heating
Total
0.17 0.01 5%
0.35 0.06 18% 0.07 19%
0.32 0.10 31% 0.19 59%
0.84 0.16 19% 0.27 32%
0.16 0.01 6%
0.40 0.09 22% 0.10 25%
0.14 0.03 24% 0.11 81%
0.70 0.12 18% 0.22 31%
0.20
0.64 0.11 18% 0.12 18%
0.00
0.84 0.12 14% 0.13 15%
Energy Cost and IAQ
Report # 6

-------
Exhibit 13
Change in HVAC Energy Costs for Assembly Buildings
Due to Increased Outdoor Air Flow Rates from 5 to 15 cfm/person ($/sf)
Building

Minneapolis,
MN


Washington,
DC

Miami, FL
Configuration
5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person

person




person




person





VAV Box Min
30%
Adjusted
VAV Box
VAV Box Min
30%
Adjusted VAV
Box
VAV Box
Min 30%
Adjusted VAV
Box
End Use
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
CV (FOAF)















Fan
0.41




0.36




0.34




Cooling
0.65
0.12
18%


0.71
0.12
17%


1.25
0.30
24%


Heating
0.49
0.59
121%


0.17
0.33
197%


0.00




Total
1.55
0.71
46%


1.24
0.45
36%


1.60
0.31
19%


CV (FOAF) EconT















Fan
0.41




0.36




0.34




Cooling
0.58
0.15
26%


0.64
0.15
24%


1.23
0.32
26%


Heating
0.50
0.58
118%


0.18
0.33
184%


0.00




Total
1.49
0.74
50%


1.18
0.48
41%


1.57
0.32
20%


VAV (COA)















Fan
0.24
0.03
14%
0.06
24%
0.23
0.02
9%
0.06
26%
0.29
0.01
2%
0.03
11%
Cooling
0.52
0.07
13%
0.16
30%
0.63
0.10
17%
0.17
28%
1.10
0.21
19%
0.30
28%
Heating
0.58
0.18
31%
0.64
111 %
0.23
0.05
20%
0.38
162%
0.00


0.01
807%
Total
1.34
0.28
21%
0.86
64%
1.10
0.17
16%
0.61
56%
1.40
0.22
16%
0.35
25%
VAV (COA) EconT















Fan
0.24
0.03
14%
0.06
24%
0.23
0.02
9%
0.06
26%
0.29
0.01
2%
0.03
11%
Cooling
0.49
0.09
19%
0.18
37%
0.61
0.13
21%
0.20
33%
1.09
0.22
20%
0.31
29%
Heating
0.58
0.18
31%
0.64
111 %
0.23
0.05
20%
0.38
162%
0.00


0.01
786%
Total
1.31
0.30
23%
0.88
67%
1.07
0.20
18%
0.64
60%
1.39
0.23
16%
0.36
26%
Energy Cost and IAQ
Report # 6

-------
Exhibit 14
Utility Price Sensitivity of Annual HVAC Energy Costs for Education Buildings ($/sf)
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
w/RH
Difference (15-5)
person
w/RH
Difference (15-5)
person
w/RH
Difference (15-5)
Utility Option

Control
($/sf)
(%)

Control
($/sf)
(%)

Control
($/sf)
(%)
CV (FOAF)












Base Price
0.92
1.25
0.33
36%
0.76
0.97
0.22
28%
0.97
1.14
0.17
17%
Option 1
1.00
1.27
0.27
27%
0.89
1.08
0.19
21%
1.22
1.44
0.21
17%
Option 2
0.84
1.24
0.39
47%
0.63
0.87
0.24
38%
0.72
0.84
0.13
17%
Option 3
1.08
1.45
0.37
34%
0.91
1.16
0.25
27%
1.16
1.35
0.20
17%
Option 4
0.76
1.05
0.29
38%
0.60
0.78
0.18
30%
0.78
0.93
0.14
18%
CV (FOAF) EconT












Base Price
0.89
1.24
0.35
39%
0.73
0.96
0.23
32%
0.96
1.14
0.18
18%
Option 1
0.95
1.24
0.29
30%
0.84
1.06
0.21
25%
1.21
1.43
0.22
18%
Option 2
0.83
1.23
0.40
49%
0.61
0.87
0.26
41%
0.71
0.84
0.13
18%
Option 3
1.05
1.44
0.39
37%
0.89
1.15
0.27
30%
1.14
1.35
0.20
18%
Option 4
0.73
1.04
0.30
42%
0.57
0.77
0.20
35%
0.77
0.92
0.15
19%
VAV (COA)












Base Price
0.87
1.12
0.25
28%
0.73
0.93
0.21
28%
0.84
0.97
0.13
15%
Option 1
0.88
1.07
0.18
21%
0.80
0.98
0.18
22%
1.05
1.20
0.15
15%
Option 2
0.86
1.18
0.31
36%
0.65
0.89
0.24
36%
0.64
0.74
0.10
16%
Option 3
1.01
1.28
0.27
26%
0.88
1.11
0.23
27%
1.02
1.17
0.16
15%
Option 4
0.73
0.96
0.23
31%
0.58
0.75
0.18
31%
0.66
0.76
0.10
15%
VAV (COA) EconT












Base Price
0.84
1.12
0.28
33%
0.70
0.93
0.23
33%
0.84
0.97
0.13
16%
Option 1
0.84
1.07
0.23
27%
0.77
0.98
0.21
28%
1.04
1.20
0.16
15%
Option 2
0.85
1.18
0.33
38%
0.64
0.89
0.25
39%
0.63
0.74
0.11
17%
Option 3
0.98
1.28
0.30
30%
0.85
1.11
0.26
30%
1.01
1.17
0.16
16%
Option 4
0.70
0.96
0.26
37%
0.55
0.75
0.20
37%
0.66
0.76
0.10
16%
Exhibit 15
Utility Price Sensitivity of Annual HVAC Energy Costs for Assembly Buildings ($/sf)
Energy Cost and IAQ
Report # 6

-------
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
w/RH
Difference (15-5)
person
w/RH
Difference (15-5)
person
w/RH
Difference (15-5)
Utility Option

Control
($/sf)
(%)

Control
($/sf)
(%)

Control
($/sf)
(%)
CV (FOAF)












Base Price
1.55
2.37
0.82
53%
1.24
1.83
0.59
47%
1.60
2.01
0.42
26%
Option 1
1.64
2.28
0.63
39%
1.45
1.95
0.49
34%
2.05
2.56
0.51
25%
Option 2
1.46
2.46
1.01
69%
1.03
1.71
0.68
66%
1.14
1.46
0.33
29%
Option 3
1.78
2.69
0.91
51%
1.46
2.14
0.68
47%
1.85
2.37
0.51
28%
Option 4
1.32
2.05
0.73
55%
1.02
1.52
0.49
48%
1.34
1.66
0.32
24%
CV (FOAF) EconT












Base Price
1.49
2.35
0.86
58%
1.18
1.81
0.63
53%
1.57
2.01
0.43
27%
Option 1
1.55
2.23
0.69
44%
1.36
1.91
0.55
40%
2.02
2.55
0.53
26%
Option 2
1.43
2.46
1.03
72%
1.00
1.71
0.71
71%
1.13
1.46
0.34
30%
Option 3
1.72
2.67
0.95
55%
1.40
2.13
0.72
52%
1.83
2.36
0.53
29%
Option 4
1.26
2.02
0.77
61%
0.96
1.50
0.54
56%
1.32
1.65
0.34
26%
VAV (COA)












Base Price
1.34
2.38
1.04
78%
1.10
1.92
0.82
75%
1.40
1.88
0.48
35%
Option 1
1.31
2.20
0.89
68%
1.21
1.98
0.77
64%
1.79
2.39
0.60
34%
Option 2
1.36
2.56
1.20
88%
0.98
1.85
0.87
88%
1.01
1.37
0.37
36%
Option 3
1.52
2.65
1.13
74%
1.30
2.21
0.90
69%
1.64
2.20
0.56
34%
Option 4
1.15
2.11
0.96
83%
0.89
1.63
0.74
83%
1.16
1.57
0.41
35%
VAV (COA) EconT












Base Price
1.31
2.38
1.07
81%
1.07
1.92
0.85
79%
1.39
1.88
0.49
36%
Option 1
1.28
2.20
0.93
73%
1.17
1.98
0.81
69%
1.77
2.39
0.61
35%
Option 2
1.35
2.56
1.21
90%
0.97
1.85
0.88
91%
1.00
1.37
0.37
37%
Option 3
1.50
2.65
1.16
77%
1.28
2.21
0.93
72%
1.63
2.20
0.57
35%
Option 4
1.13
2.11
0.98
87%
0.87
1.63
0.77
89%
1.15
1.57
0.42
36%
Exhibit 16
Energy Cost and IAQ	Report # 6

-------
HVAC System Peak Coil Loads for Education Buildings
at Alternative Outdoor Air Settings (kBTU/Hr)
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
Coil

No RH
Control
RH
Control

No RH
Control
RH
Control

No RH
Control
RH
Control
CV (FOAF)












Cooling
2068
2478

2747
2071
2594

2633
2409
3030

2912
Heating
2459
3197

3197
1818
2118

2118
17
536

598
Preheat
0
683

683
0
183

183
0
0

0
CV (FOAF) EconT












Cooling
2068
2478

2747
2071
2594

2633
2409
3030

2912
Heating
2609
3197

3197
1884
2118

2118
17
536

580
Preheat
0
683

683
0
183

183
0
0

0
VAV (COA)












Cooling
1841
2211
2211
2210
1951
2453
2439
2421
2213
2785
2742
2760
Heating
2819
2819
2820
2820
1935
1981
2027
2027
391
464
668
669
Preheat
246
1344
1528
1528
90
521
840
840
0
140
200
200
VAV (COA) EconT












Cooling
1841
2211
2211
2210
1951
2453
2439
2421
2213
2785
2742
2760
Heating
2819
2819
2820
2820
1935
1981
2027
2027
397
464
668
670
Preheat
246
1344
1528
1528
90
521
840
840
0
140
200
200
Energy Cost and IAQ
31
Report # 6

-------
Exhibit 17
HVAC System Peak Coil Loads for Assembly Buildings
at Alternative Outdoor Air Settings (kBTU/Hr)
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
15 cfm/person
5 cfm/
15 cfm/person
5 cfm/
15 cfm/person

person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
person
VAV
Box Min
30%
Adjusted VAV Box
Coil

No RH
Control
RH
Control

No RH
Control
RH
Control

No RH
Control
RH
Control
CV (FOAF)












Cooling
1193
1568

1720
1144
1491

1679
1394
1838

2005
Heating
1449
1517

1517
1009
1227

1227
61
541

542
Preheat
0
1097

1097
0
577

577
0
0

0
CV (FOAF) EconT












Cooling
1193
1568

1720
1157
1505

1679
1394
1838

2005
Heating
1476
1517

1517
1153
1303

1227
63
541

542
Preheat
0
1097

1097
0
577

577
0
0

0
VAV (COA)












Cooling
958
1161
1230
1511
1067
1360
1342
1599
1229
1575
1577
1738
Heating
1134
1151
1240
1240
822
868
999
999
96
109
390
391
Preheat
330
1090
1249
1249
224
409
777
777
0
84
151
151
VAV (COA) EconT












Cooling
958
1161
1230
1511
1067
1360
1342
1599
1229
1575
1577
1738
Heating
1134
1151
1240
1240
822
868
999
999
99
109
390
391
Preheat
330
1090
1249
1249
224
409
777
777
0
84
151
151
Energy Cost and IAQ
Report # 6

-------
Exhibit 18
Change in HVAC System Peak Coil Loads for Education Buildings
Due to Increased Outdoor Air Flow Rates from 5 to 15 cfm/person
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person

person




perso




perso





(kBTU/
Hr)
VAV Box Min
30%
Adjusted VAV
Box
n
VAV Box Min
30%
Adjusted VAV
Box
n
VAV Box Min
30%
Adjusted VAV Box
Coil
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
CV (FOAF)















Cooling
2068
410
20%


2071
524
25%


2409
622
26%


Heating
2459
737
30%


1818
300
17%


17
519
3118%


Preheat
0
683
Increas
e


0
183
Increas
e


0




CV (FOAF) EconT















Cooling
2068
410
20%


2071
524
25%


2409
622
26%


Heating
2609
588
23%


1884
234
12%


17
520
3124%


Preheat
0
683
Increas
e


0
183
Increas
e


0




VAV (COA)















Cooling
1841
370
20%
370
20%
1951
502
26%
488
25%
2213
571
26%
529
24%
Heating
2819


1

1935
46
2%
93
5%
391
73
19%
277
71%
Preheat
246
1098
447%
1282
521
%
90
431
478%
750
832%
0
140
Increase
200
Increase
VAV (COA) EconT















Cooling
1841
370
20%
370
20%
1951
502
26%
488
25%
2213
571
26%
529
24%
Heating
2819


1

1935
46
2%
93
5%
397
67
17%
271
68%
Preheat
246
1098
447%
1282
521
%
90
431
478%
750
832%
0
140
Increase
200
Increase
Energy Cost and IAQ
Report # 6

-------
Exhibit 19
Change in HVAC System Peak Coil Loads for Assembly Buildings
Due to Increased Outdoor Air Flow Rates from 5 to 15 cfm/person
HVAC System
Minneapolis, MN
Washington, DC
Miami, FL

5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person
5 cfm/
Difference 15-5 cfm/person

perso




perso




perso





n
VAV Box Min 30%
Adjusted VAV
Box
n
VAV Box Min 30%
Adjusted VAV
Box
n
VAV Box Min 30%
Adjusted VAV
Box
Coil
(kBtu/
Hr)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
(kBtu /
Hr)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
(kBtu /
Hr)
(kBtu/
Hr)
(%)
(kBtu/
Hr)
(%)
CV(FOAF)















Cooling
1193
375
31%


1144
347
30%


1394
444
32%


Heating
1449
68
5%


1009
218
22%


61
480
791%


Preheat
0
1097
Increase


0
577
Increase


0




CV (FOAF) EconT















Cooling
1193
375
31%


1157
348
30%


1394
444
32%


Heating
1476
41
3%


1153
149
13%


63
478
758%


Preheat
0
1097
Increase


0
577
Increase


0




VAV (COA)















Cooling
958
203
21%
271
28%
1067
293
27%
275
26%
1229
346
28%
349
28%
Heating
1134
17
1%
106
9%
822
46
6%
177
22%
96
13
13%
294
306%
Preheat
330
760
230%
919
279%
224
185
83%
553
247%
0
84
Increase
151
Increas
e
VAV (COA) EconT















Cooling
958
203
21%
271
28%
1067
293
27%
275
26%
1229
346
28%
349
28%
Heating
1134
17
1%
106
9%
822
46
6%
177
22%
99
10
10%
291
293%
Preheat
330
760
230%
919
279%
224
185
83%
553
247%
0
84
Increase
151
Increas
e
Energy Cost and IAQ
Report # 6

-------
Exhibit 20
Annual HVAC Energy Cost Impacts with and without Sensible Heat Recovery
for Education Buildings
HVAC System
Minneapolis, MN

Washington,
DC

Miami, FL

5 cfm/
perso
n
15 cfm/person w/RH Control
5 cfm/
person
15 cfm/person w/RH Control
5 cfm/
person
15 cfm/person w/RH Control

without
Heat Recovery
with
Heat Recovery
without
Heat Recovery
with
Heat Recovery
without
Heat Recovery
with
Heat Recovery
End Use
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
CV(FOAF)















Fan
0.28
0.28

0.28

0.23
0.23

0.23

0.26
0.25
-3%
0.25
-3%
Cooling
0.41
0.52
27%
0.52
27%
0.45
0.55
22%
0.55
22%
0.71
0.88
24%
0.88
24%
Heating
0.23
0.46
95%
0.44
90%
0.08
0.20
149%
0.19
148%
0.00
0.01
79273%
0.01
77670%
Total
0.92
1.25
36%
1.24
35%
0.76
0.97
28%
0.97
28%
0.97
1.14
17%
1.14
17%
CV (FOAF) EconT















Fan
0.28
0.28

0.28

0.23
0.23

0.23

0.26
0.25
-3%
0.25
-3%
Cooling
0.38
0.50
32%
0.50
32%
0.42
0.53
27%
0.53
27%
0.70
0.88
25%
0.88
25%
Heating
0.24
0.46
95%
0.45
90%
0.08
0.20
150%
0.20
148%
0.00
0.01
87489%
0.01
85877%
Total
0.89
1.24
39%
1.22
37%
0.73
0.96
32%
0.96
32%
0.96
1.14
18%
1.14
18%
VAV (COA)















Fan
0.17
0.17

0.17

0.16
0.16

0.16

0.20
0.17
-12%
0.17
-12%
Cooling
0.39
0.43
12%
0.43
12%
0.43
0.52
20%
0.52
20%
0.64
0.79
22%
0.79
22%
Heating
0.32
0.52
63%
0.42
31%
0.14
0.26
92%
0.23
70%
0.00
0.01
1036%
0.01
1024%
Total
0.87
1.12
28%
1.02
16%
0.73
0.93
28%
0.90
24%
0.84
0.97
15%
0.97
15%
VAV (COA) EconT















Fan
0.17
0.17

0.17

0.16
0.16

0.16

0.20
0.17
-12%
0.17
-12%
Cooling
0.35
0.43
22%
0.43
22%
0.40
0.51
28%
0.51
28%
0.64
0.79
23%
0.79
23%
Heating
0.32
0.52
62%
0.42
30%
0.14
0.26
90%
0.23
69%
0.00
0.01
978%
0.01
967%
Total
0.84
1.12
33%
1.02
21%
0.70
0.93
33%
0.90
29%
0.84
0.97
16%
0.97
16%
Energy Cost and IAQ
Report # 6

-------
Exhibit 21
Annual HVAC Energy Cost Impacts with and without Sensible Heat Recovery
for Assembly Buildings
HVAC System
Minneapolis, MN

Washington,
DC

Miami, FL

5 cfm/
perso
n
15 cfm/person w/RH Control
5 cfm/
person
15 cfm/person w/RH Control
5 cfm/
person
15 cfm/person w/RH Control

without
Heat Recovery
with
Heat Recovery
without
Heat Recovery
with
Heat Recovery
without
Heat Recovery
with
Heat Recovery
End Use
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
($/sf)
($/sf)
(%)
($/sf)
(%)
CV(FOAF)















Fan
0.41
0.42
2%
0.42
2%
0.36
0.39
8%
0.39
8%
0.34
0.34

0.34

Cooling
0.65
0.86
31%
0.86
31%
0.71
0.92
30%
0.92
30%
1.25
1.66
33%
1.66
33%
Heating
0.49
1.09
124%
0.89
83%
0.17
0.52
207%
0.47
175%
0.00
0.01
2016%
0.01
1991%
Total
1.55
2.37
53%
2.17
40%
1.24
1.83
47%
1.78
43%
1.60
2.01
26%
2.01
26%
CV (FOAF) EconT















Fan
0.41
0.42
2%
0.42
2%
0.36
0.39
8%
0.39
8%
0.34
0.34

0.34

Cooling
0.58
0.82
41%
0.82
41%
0.64
0.89
39%
0.89
39%
1.23
1.66
34%
1.66
34%
Heating
0.50
1.10
123%
0.90
82%
0.18
0.53
199%
0.48
169%
0.00
0.01
801%
0.01
792%
Total
1.49
2.35
58%
2.14
44%
1.18
1.81
53%
1.76
49%
1.57
2.01
27%
2.01
27%
VAV (COA)















Fan
0.24
0.29
22%
0.29
22%
0.23
0.28
20%
0.28
20%
0.29
0.30

0.30

Cooling
0.52
0.82
57%
0.82
57%
0.63
0.97
54%
0.97
54%
1.10
1.55
41%
1.55
41%
Heating
0.58
1.27
120%
0.90
55%
0.23
0.67
187%
0.54
129%
0.00
0.03
2102%
0.03
2034%
Total
1.34
2.38
78%
2.00
50%
1.10
1.92
75%
1.78
63%
1.40
1.88
35%
1.88
35%
VAV (COA) EconT















Fan
0.24
0.29
22%
0.29
22%
0.23
0.28
20%
0.28
20%
0.29
0.30

0.30

Cooling
0.49
0.82
66%
0.82
66%
0.61
0.97
60%
0.97
60%
1.09
1.55
42%
1.55
42%
Heating
0.58
1.27
120%
0.90
54%
0.23
0.67
186%
0.54
129%
0.00
0.03
2047%
0.03
1984%
Total
1.31
2.38
81%
2.00
53%
1.07
1.92
79%
1.78
66%
1.39
1.88
36%
1.88
35%
Energy Cost and IAQ
Report # 6

-------
Exhibit 22
Effect of Sensible Heat Recovery on HVAC System Peak Coil Loads
for Education Buildings
HVAC System
Minneapolis, MN

Washington,
DC

Miami, FL

5 cfm/
15 cfm/person w/RH Control
5 cfm/
15 cfm/person w/RH Control
5 cfm/
15 cfm/person w/RH Control

perso




person




person





n
without
with

without
with

without
with


Heat Recovery
Heat Recovery
fkRtn/
Heat Recovery
Heat Recovery
fkRtn/
Heat Recovery
Heat Recovery
Coil
(kBtu/
(kBtu/
(%)
(kBtu/
(%)
Hr)
(kBtu/
(%)
(kBtu/
(%)
Hr)
(kBtu/
(%)
(kBtu/
(%)

Hr)
Hr)

Hr)


Hr)

Hr)


Hr)

Hr)

CV(FOAF)















Cooling
2068
2747
33%
2747
33%
2071
2633
27%
2633
27%
2409
2912
21%
2912
21%
Heating
2459
3197
30%
3197
30%
1818
2118
17%
2118
17%
17
598
3488%
594
3468%
Preheat
0
683
Increas
e
0

0
183
Increas
e
0

0
0

0

CV (FOAF) EconT















Cooling
2068
2747
33%
2747
33%
2071
2633
27%
2633
27%
2409
2912
21%
2912
21%
Heating
2609
3197
23%
3197
23%
1884
2118
12%
2118
12%
17
580
3387%
577
3366%
Preheat
0
683
Increas
e
0

0
183
Increas
e
77
Increas
e
0
0

0

VAV (COA)















Cooling
1841
2210
20%
2210
20%
1951
2421
24%
2421
24%
2213
2760
25%
2760
25%
Heating
2819
2820

2820

1935
2027
5%
2027
5%
391
669
71%
669
71%
Preheat
246
1528
521%
12
-95%
90
840
832%
3
-96%
0
200
Increas
e
0

VAV (COA) EconT















Cooling
1841
2210
20%
2210
20%
1951
2421
24%
2421
24%
2213
2760
25%
2760
25%
Heating
2819
2820

2820

1935
2027
5%
2027
5%
397
670
69%
670
69%
Preheat
246
1528
521%
12
-95%
90
840
832%
3
-96%
0
200
Increas
e
0

Energy Cost and IAQ
Report # 6

-------
Exhibit 23
Effect of Sensible Heat Recovery on HVAC System Peak Coil Loads
for Assembly Buildings
HVAC System
Minneapolis, MN

Washington,
DC

Miami, FL

5 cfm/
15 cfm/person w/RH Control
5 cfm/
15 cfm/person w/RH Control
5 cfm/
15 cfm/person w/RH Control

perso




person




person





n
without
with

without
with

without
with


Heat Recovery
Heat Recovery
fkRtn/
Heat Recovery
Heat Recovery
fkRtn/
Heat Recovery
Heat Recovery
Coil
(kBtu/
(kBtu/
(%)
(kBtu/
(%)
Hr)
(kBtu/
(%)
(kBtu/
(%)
Hr)
(kBtu/
(%)
(kBtu/
(%)

Hr)
Hr)

Hr)


Hr)

Hr)


Hr)

Hr)

CV(FOAF)















Cooling
1193
1720
44%
1720
44%
1144
1679
47%
1679
47%
1394
2005
44%
2005
44%
Heating
1449
1517
5%
1517
5%
1009
1227
22%
1227
22%
61
542
793%
541
790%
Preheat
0
1097
Increas
e
0

0
577
Increas
e
0

0
0

0

CV (FOAF) EconT















Cooling
1193
1720
44%
1720
44%
1157
1679
45%
1679
45%
1394
2005
44%
2005
44%
Heating
1476
1517
3%
1517
3%
1153
1227
6%
1227
6%
63
542
760%
541
758%
Preheat
0
1097
Increas
e
44
Increase
0
577
Increas
e
38
Increas
e
0
0

0

VAV (COA)















Cooling
958
1511
58%
1511
58%
1067
1599
50%
1599
50%
1229
1738
41%
1738
41%
Heating
1134
1240
9%
1240
9%
822
999
22%
999
22%
96
391
306%
385
301%
Preheat
330
1249
279%
71
-79%
224
777
247%
4
-98%
0
151
Increas
e
0

VAV (COA) EconT















Cooling
958
1511
58%
1511
58%
1067
1599
50%
1599
50%
1229
1738
41%
1738
41%
Heating
1134
1240
9%
1240
9%
822
999
22%
999
22%
99
391
294%
386
289%
Preheat
330
1249
279%
71
-79%
224
777
247%
4
-98%
0
151
Increas
e
0

Energy Cost and IAQ
Report # 6

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Exhibit 24
Annual HVAC Energy Cost Impacts with and without Desiccant Dehumidification
for Education Buildings
HVAC System
Minneapolis, MN

Washington,
DC

Miami, FL

5 cfm/
perso
n
($/sf)
15 cfm/person w/RH Control
5 cfm/
person
($/sf)
15 cfm/person w/RH Control
5 cfm/
person
($/sf)
15 cfm/person w/RH Control

without
Desiccant
Dehumidificatio
n
with
Desiccant
Dehumidificatio
n
without
Desiccant
Dehumidification
with
Desiccant
Dehumidificatio
n
without
Desiccant
Dehumidification
with
Desiccant
Dehumidification
End Use

($/sf)
(%)
($/sf)
(%)

($/sf)
(%)
($/sf)
(%)

($/sf)
(%)
($/sf)
(%)
CV(FOAF)















Fan
0.28
0.28

0.34
22%
0.23
0.23

0.28
21%
0.26
0.25
-3%
0.32
25%
Cooling
0.41
0.52
27%
0.50
21%
0.45
0.55
22%
0.51
14%
0.71
0.88
24%
0.78
10%
Heating
0.23
0.44
90%
0.51
118%
0.08
0.19
148%
0.34
329%
0.00
0.01
77670%
0.14
1996414
%
Total
0.92
1.24
35%
1.34
46%
0.76
0.97
28%
1.13
49%
0.97
1.14
17%
1.25
29%
CV (FOAF) EconT















Fan
0.28
0.28

0.34
21%
0.23
0.23

0.28
20%
0.26
0.25
-3%
0.32
25%
Cooling
0.38
0.50
32%
0.48
27%
0.42
0.53
27%
0.50
20%
0.70
0.88
25%
0.78
12%
Heating
0.24
0.45
90%
0.50
111 %
0.08
0.20
148%
0.31
291%
0.00
0.01
85877%
0.19
2664107
%
Total
0.89
1.22
37%
1.32
48%
0.73
0.96
32%
1.09
50%
0.96
1.14
18%
1.29
35%
VAV (COA)















Fan
0.17
0.17

0.22
33%
0.16
0.16

0.20
23%
0.20
0.17
-12%
0.25
25%
Cooling
0.39
0.43
12%
0.40
5%
0.43
0.52
20%
0.47
10%
0.64
0.79
22%
0.70
10%
Heating
0.32
0.42
31%
0.47
47%
0.14
0.23
70%
0.35
155%
0.00
0.01
1024%
0.17
22722%
Total
0.87
1.02
16%
1.10
26%
0.73
0.90
24%
1.02
40%
0.84
0.97
15%
1.12
33%
VAV (COA) EconT















Fan
0.17
0.17

0.22
32%
0.16
0.16

0.20
22%
0.20
0.17
-12%
0.25
25%
Cooling
0.35
0.43
22%
0.41
17%
0.40
0.51
28%
0.49
20%
0.64
0.79
23%
0.71
11%
Heating
0.32
0.42
30%
0.46
43%
0.14
0.23
69%
0.33
139%
0.00
0.01
967%
0.16
19936%
Total
0.84
1.02
21%
1.10
30%
0.70
0.90
29%
1.01
44%
0.84
0.97
16%
1.11
33%
Energy Cost and IAQ
Report # 6

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Exhibit 25
Annual HVAC Energy Cost Impacts with and without Desiccant Dehumidification
for Assembly Buildings
HVAC System
End Use
Minneapolis, MN
Washington, DC
Miami, FL
5 cfm/
perso
n
($/sf)
15 cfm/person w/RH Control
5 cfm/
person
($/sf)
15 cfm/person w/RH Control
5 cfm/
person
($/sf)
15 cfm/person w/RH Control
without
Desiccant
Dehumidificatio
n
with
Desiccant
Dehumidificatio
n
without
Desiccant
Dehumidification
with
Desiccant
Dehumidificatio
n
without
Desiccant
Dehumidification
with
Desiccant
Dehumidification
($/sf) (%)
($/sf) (%)
($/sf) (%)
($/sf) (%)
($/sf) (%)
($/sf) (%)
CV(FOAF)
Fan
Cooling
Heating
Total
0.41 0.42 2% 0.51 24%
0.65 0.86 31% 0.82 25%
0.49 0.89 83% 1.10 125%
1.55 2.17 40% 2.42 56%
0.36 0.39 8% 0.44 22%
0.71 0.92 30% 0.85 20%
0.17 0.47 175% 0.84 393%
1.24 1.78 43% 2.13 72%
0.34 0.34 0.45 33%
1.25 1.66 33% 1.47 17%
0.00 0.01 1991% 0.03 7181%
1.60 2.01 26% 1.95 22%
CV (FOAF) EconT
Fan
Cooling
Heating
Total
0.41 0.42 2% 0.51 24%
0.58 0.82 41% 0.78 35%
0.50 0.90 82% 1.09 119%
1.49 2.14 44% 2.38 60%
0.36 0.39 8% 0.44 22%
0.64 0.89 39% 0.83 29%
0.18 0.48 169% 0.81 353%
1.18 1.76 49% 2.07 75%
0.34 0.34 0.45 33%
1.23 1.66 34% 1.46 18%
0.00 0.01 792% 0.03 3020%
1.57 2.01 27% 1.94 24%
VAV (COA)
Fan
Cooling
Heating
Total
0.24 0.29 22% 0.38 60%
0.52 0.82 57% 0.75 45%
0.58 0.90 55% 1.07 84%
1.34 2.00 50% 2.20 65%
0.23 0.28 20% 0.36 53%
0.63 0.97 54% 0.86 36%
0.23 0.54 129% 0.86 267%
1.10 1.78 63% 2.07 89%
0.29 0.30 0.40 36%
1.10 1.55 41% 1.35 22%
0.00 0.03 2034% 0.17 11521%
1.40 1.88 35% 1.92 38%
VAV (COA) EconT
Fan
Cooling
Heating
Total
0.24 0.29 22% 0.38 60%
0.49 0.82 66% 0.76 54%
0.58 0.90 54% 1.06 82%
1.31 2.00 53% 2.20 67%
0.23 0.28 20% 0.35 52%
0.61 0.97 60% 0.87 44%
0.23 0.54 129% 0.83 254%
1.07 1.78 66% 2.05 91%
0.29 0.30 0.40 37%
1.09 1.55 42% 1.35 23%
0.00 0.03 1984% 0.17 11218%
1.39 1.88 35% 1.92 38%
Energy Cost and IAQ
40
Report # 6

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