IMPROVING ENERGY PERFORMANCE OF ARMY DINING FACILITIES
Michael Deru, Ph.D.
National Renewable Energy Lab
Alexander Zhivov, Ph.D and Dale Herron
Engineer Research and Development Center
Donald Fisher
Fisher Nickel, Inc
Vernon Smith
Architectural Energy Corporation
Energy and Water Conservation Design Requirements for SRM Projects
Table of Contents
Introduction...............................................................................................................................3
Approach ...................................................................................................................................4
Existing Army Dining Facilities, Their Systems, Equipment and Issues .................................4
Army Dining Facilities Description............................................................................................5
Locations...................................................................................................................................6
Energy Modeling .......................................................................................................................6
Air Tightness and Infiltration ....................................................................................................8
Envelope....................................................................................................................................9
Lighting......................................................................................................................................9
HVAC ........................................................................................................................................10
Ventilation and Outside Air.....................................................................................................10
Results.....................................................................................................................................11
Energy Conservation Measures ............................................................................................ 12
Total Energy Savings with Recommended Technology Sets .................................................19
Summary and Discussion.......................................................................................................21
Acknowledgement...................................................................................................................21
References ............................................................................................................................. 22
List of Figures and Tables
Figures
Page
1
Sketch of a Proposed Army Dining Facility ..................................................................................................... 24
2
Proposed DFAC floor plan from the Army........................................................................................................ 24
3
Thermal zoning for the DFAC energy model.................................................................................................... 25
4
Rendering of the energy simulation model for the DFAC.............................................................................. 25
5
Daily process load electricity consumption profiles ...................................................................................... 26
6
Daily process load gas consumption profiles ................................................................................................. 26
7
Daily total process load consumption profiles of electricity and gas.......................................................... 27
8
Energy use by end use for the baseline building ............................................................................................ 27
9
Energy use by end use for regulated loads in the baseline building............................................................ 28
10
Annual energy savings for each ECM .............................................................................................................. 28
11
Various canopy hoods for cooking equipment (source, ASHRAE Standard 154)....................................... 29
12
Example best-design practices within exhaust system design and specifications................................... 29
2
Energy and Water Conservation Design Requirements for SRM Projects
Tables
Page
1
Building Zones and Internal Loads (IP units).................................................................................................... 5
2
Building Zones and Internal Loads (SI units).................................................................................................... 5
3
Climate Zones and Cities used for Simulations ............................................................................................... 6
4
Building Model Parameters ................................................................................................................................ 7
5
Process Loads....................................................................................................................................................... 9
6
Baseline Building Model Outside Air Requirements...................................................................................... 10
7
Baseline Exhaust Hood Air Flows..................................................................................................................... 11
8
Energy Budgets by Climate Zone ..................................................................................................................... 12
9
Energy Conservation Measures........................................................................................................................ 12
10
Envelope Conservation Measures.................................................................................................................... 14
11
Building Lighting Power .................................................................................................................................... 15
12
Efficient Building Model Outside Air Requirements ...................................................................................... 16
13
Energy Efficient Exhaust Hood Air Flows ........................................................................................................ 16
14
HVAC systems ..................................................................................................................................................... 17
15
Annual Energy Savings for Individual ECMs (kBtu/ft2) ................................................................................. 18
16
Annual Energy Savings for Individual ECMs 1000Btu/ft2 (MJ/m2) ............................................................. 18
17
Final Energy Efficient Design Solutions without Process Loads.................................................................. 19
18
Final Energy Efficient Design Solutions with Process Loads ....................................................................... 19
19
Summary of ECMs in Final Models (grey shading indicates not recommended or investigate on a
case by case basis) ............................................................................................................................................ 20
Introduction
Section 109 of the Energy Policy Act of 2005 (EPAct 2005) states that, for new federal facilities, “the
buildings be designed to achieve energy consumption levels that are at least 30 percent below the
levels established in the version of the American Society of Heating, Refrigerating and Air-Conditioning
Engineers (ASHRAE) Standard or the International Energy Conservation Code, as appropriate” (U.S.
Congress 2005). The energy efficient designs must be life cycle cost effective; however, the term “cost
effective” is not defined in the law; it is left up to each federal agency to define. The U.S. Department of
Energy (DOE) issued additional guidance in the Federal Register (NARA 2006), which states that
savings calculations should not include the plug loads and implies that the savings shall be determined
through energy cost savings. The U.S. Army decided it would use site energy for the HVAC, lighting,
and hot water loads to determine the energy savings.
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Energy and Water Conservation Design Requirements for SRM Projects
The U.S. Army constructs buildings across the country and the Office of the Assistant Chief of Staff of
the Installations Management and the U.S. Army Corps of Engineers (HQUSACE) worked to streamline
the process of meeting the energy savings requirements. The U.S. Army Corps of Engineers (USACE)
worked in collaboration with the National Renewable Energy Laboratory (NREL), and the ASHRAE
Military Technology Group (MTG) to develop baseline and target energy budgets and design guides
with a prescriptive path for achieving energy savings of 30% or more over the baseline. The project
covers eight building types over all U.S. climate zones: basic training barracks, unaccompanied
enlisted personal housing, battalion headquarters, tactical equipment maintenance facilities, dining
facilities (DFAC), child development centers, Army reserve centers, and company operations. This
paper focuses on DFAC; however, the process for developing all the design guides is similar.
The concept for these design guides was adapted from the Advanced Energy Design Guides (AEDGs)
from ASHRAE (2008). Each AEDG was developed for a specific building type and provides
recommendation tables for each of the eight major climate zones and a “how-to” section on
implementing the recommendations. The AEDGs do not provide baseline and target energy budgets,
which are used by the Army in its requests for proposals.
Approach
A representative model of the DFAC building was developed based on the information provided by the
USACE Norfolk District – the DFAC Center of Standardization. Baseline and target energy budgets
were developed and energy savings using different sets of technologies were analyzed. Energy
conservation technology candidates were selected based on previous energy design guide work (FSTC
2004a) and input from commercial kitchen consultants, who have experience with military kitchens.
All energy simulations for the DFAC were carried out with EnergyPlus version 2.1 (DOE 2008). NREL is
part of the EnergyPlus development team and has developed additional programs that work with
EnergyPlus. These programs work together to create input files, manage the numerous simulations,
provide optimization, and post-process the results. The optimization engine, called Opt-E-Plus, is used
to help optimize building designs based on energy performance, energy cost performance, or life cycle
cost performance.
A baseline building energy model was created from the representative DFAC model meeting the
minimum requirements of ASHRAE Standard 90.1-2004 following Appendix G (ASHRAE 2004a). We
followed Appendix G with two exceptions, which were approved by DOE. For this project analysis we
used site energy based on the Army decision, and developed baseline and target energy budgets
without plug or process loads as our metric for savings following EPAct 2005 guidance from DOE.
Finally, Standard 90.1-2004 does not contain requirements to building air leakage and infiltration levels.
For the DFAC, we defined a baseline air leakage rate and an energy efficient leakage rate and included
this factor in our energy efficiency analysis.
Existing Army Dining Facilities, Their Systems, Equipment and Issues
Existing Army dining facilities were not designed with energy and water efficiency as a primary
objective. While minimizing construction costs have always been a goal within facility design, specifying
lower-first-cost equipment that is inherently energy inefficient has been a reality with the design of Army
dining facilities. Although the focus has changed within the context of the 2005 Energy Policy Act, it is
not possible to economically transform existing facilities into “Energy Star” models of institutional food
service. It is still practical, however, to implement such low-cost energy conservation measures as lowflow prerinse spray valves in the dishroom, or high-efficiency motors for evaporator fans in walk-in
coolers as energy efficiency transformation is approached on a step-by-step basis. Since dining
facilities are among the buildings on Army installations that use the most energy, comprehensive audits
4
Energy and Water Conservation Design Requirements for SRM Projects
should be initiated in existing dining facilities to address the many available no-cost, low-cost, and
investment grade retrofits of ventilation, lighting, and automation systems, and equipment replacement
opportunities. It is imperative that energy efficient options (e.g., Energy Star-qualified for applicable
equipment categories including fryers, steamers, holding cabinets, ice machines, reach-in refrigerators
and freezers) be considered when existing equipment is changed out (EPA 2008). Where Energy Star
categories do not exist, FEMP-recommended or California-rebate-qualified equipment should be
considered (FEMP 2008, FSTC 2008b).
Army Dining Facilities Description
The Army has developed standard designs for their dining facilities ranging in size from 251 to 500, 501
to 800, 801 to 1300, and 2600 meals based on the number of meals served in a single meal time. Most
of the building elements scale with the size of the building. However, the kitchen is nearly the same
size across all models to fit a standard set of food preparation equipment. The basic design is a single
story building with spaces for food preparation, serving, dining, dishwashing, take-out food area,
employee break area, storage, and utilities. The design must facilitate feeding the maximum number of
meals in an hour and a half. Much of the short-order cooking is accomplished in the serving area on
broilers or griddles, range tops, and in ovens. Several ventilation hoods are required to service the
cooking equipment. In addition to the cooking equipment, there is a walk-in cooler and a walk-in freezer
and several reach-in refrigerators and other ancillary equipment typically found in commercial
foodservice. Figure 1 shows a sketch of a proposed dining facility.
A dining facility serving between 801 and 1300 meals was selected for our study – this is a medium
sized building and the one most often constructed. The proposed floor plan from the Army shown in
Figure 2 has an area of 25,609 ft2 (2,379 m2). The building is occupied 7 days a week from 3 a.m. to 8
p.m. Tables 16-1 and 16-2 list the zones and thermal loading.
Table 1. Building Zones and Internal Loads (IP units).
Area
(ft2)
Zone
Volume
(ft3)
People
Lights
(W/ft2)
Electric Equipment
(W/ft2)
Gas Equipment
(W)
Dining
7,981
95,772
500
0.9
Storage/Receiving
2,622
31,465
5
0.8
3.76
0.25
Dish wash
1,120
13,439
5
1.2
51.79
Kitchen
2,763
33,150
12
1.2
14.84
54,000
Servery
4,277
51,324
50
1.2
23.85
29,000
Entry/Circulation
3,290
39,478
35
1.3
0.25
Carryout
1,044
12,528
6
1.2
12.45
Office
1,444
17,328
6
1.1
0.75
Utility
1,053
12,637
0
1.5
0.25
Total
25,593
307,120
619
26,486 W
246,824 W
14,000
93,000 W
Table 2. Building Zones and Internal Loads (SI units).
Area
(ft2)
Zone
Volume
(ft3)
People
Lights
(W/ft2)
Electric Equipment
(W/ft2)
Gas Equipment
(W)
Dining
741
2,712
500
9.68
40.46
Storage/Receiving
244
891
5
8.61
2.69
Dishwashing
104
381
5
12.91
557.46
Kitchen
257
939
12
12.91
159.75
54,000
Servery
397
1,453
50
12.91
256.70
29,000
Entry/Circulation
306
1,118
35
13.99
2.69
Carryout
97
355
6
12.91
134.04
5
14,000
Energy and Water Conservation Design Requirements for SRM Projects
Area
(ft2)
Zone
Volume
(ft3)
People
Lights
(W/ft2)
Electric Equipment
(W/ft2)
Office
134
491
6
11.84
8.07
Utility
98
358
0
16.14
2.69
Total
2,378
8,697
619
27,759
246,824
Gas Equipment
(W)
93,000 W
Locations
Fifteen locations were selected to represent 15 climate zones in the United States based on TMY2
weather files. The locations were selected as representative cities for the climate zones by the Pacific
Northwest National Laboratory (Briggs et al. 2003). We selected Colorado Springs for climate zone 5B
instead of Boise, ID to more closely align with the installations at Fort Carson, CO. Table 3 lists the 15
climate zones and the cities used to represent the climate zones.
Table 3. Climate Zones and Cities used for Simulations.
Climate Zone
City
HDD
Base
65ºF (18ºC)
CDD
Base
50ºF (10ºC)
1A
Miami, FL
200 (111)
9474 (5263)
2A
Houston, TX
1599 (888)
6876 (3820)
2B
Phoenix, AZ
1350 (750)
8425 (4681)
3A
Memphis, TN
3082 (1712)
5467 (3037)
3B
El Paso, TX
2708 (1504)
5488 (3049)
3C
San Francisco, CA
3016 (1676)
2883 (1602)
4A
Baltimore, MD
4707 (2615)
3709 (2061)
4B
Albuquerque, NM
4425 (2458)
3908 (2171)
4C
Seattle, WA
4908 (2727)
1823 (1013)
5A
Chicago, IL
6536 (3631)
2941 (1634)
5B
Colorado Springs, CO
6415 (3564)
2312 (1284)
6A
Burlington, VT
7771 (4317)
2228 (1238)
6B
Helena, MT
7699 (4277)
1841 (1023)
7A
Duluth, MN
9818 (5454)
1536 (853)
8A
Fairbanks, AK
13940 (7744)
1040 (578)
Energy Modeling
The energy simulations were completed using EnergyPlus version 2.1 (DOE 2008). All simulations
were completed with the NREL analysis platform based around Opt-E-Plus that manages EnergyPlus
simulations. This section describes the modeling assumptions used in the baseline and energy efficient
models.
Figure 3 shows the thermal model of the DFAC used for this study, a one story, 25,593 ft2 (2,378 m2)
building. Figure 4 shows the rendered view of the energy simulation model. The skylights in the servery
and dining zones are used for daylighting in the energy efficient models. The skylights must be included
in the baseline building as well according to Standard 90.1-2004 Appendix G modeling rules. The
skylights and daylighting did not provide energy savings in Fairbanks and are not included in the
energy models for this location. Table 4 lists the building model parameters.
There were some issues with modeling this building in EnergyPlus, which introduced some errors and
required some changes in the model inputs. There are several hours of unmet heating loads from a bug
in EnergyPlus control algorithms that lead to temperatures dropping about 1ºF (0.6ºC) below the
6
Energy and Water Conservation Design Requirements for SRM Projects
setpoint. This problem occurs in zones with high outside air and in cold climates. The result is a slightly
lower heating energy than what it should be, which was assumed to be small and was ignored in this
study. The bug is known to the EnergyPlus development team and may be fixed in a future release of
EnergyPlus. Another issue was undersizing of cooling coils in hot climates. This was corrected by
increasing the zone sizing factor for the kitchens in Houston, Phoenix, and El Paso. One final issue
concerns the outside air for zones with exhaust fans and transfer air, which is discussed further in the
section on ventilation.
Table 4. Building Model Parameters.
Building Component
Baseline Building Model
Efficient Building Model
Area
25,593 ft2 (2,378 m2)
Same as baseline
Floors
1
Same as baseline
Aspect ratio
4.4
Same as baseline
Fenestration type
Standard 90.1-2004
See Tables 16-10 and 16-11
Wall construction
Steel frame
Steel frame
Wall insulation
Standard 90.1-2004 steel frame
See Tables 16-10 and 16-11
Roof construction
Flat built up roof
Flat built up roof
Roof insulation
Standard 90.1-2004 equal to the “insulation entirely
above deck”
See Tables 16-10 and 16-11
Roof albedo
0.3
Same as baseline
Infiltration
0.4 cfm/ft2 @ 0.3 in w.g. (2.0 L/s·m2 @ 75 Pa)
0.25 cfm/ft2 at 0.3 in w.g. (1.25 L/s/m2 at 75 Pa)
Temp setpoints
70ºF (21ºC) heating; 75ºF (24ºC) cooling – set back/up Same as baseline
to 55ºF (13ºC) heating; 91ºF (33ºC) cooling
Kitchen: 80ºF (27ºC) cooling - set up to 91ºF (33ºC)
HVAC
PSZ with DX-AC (3.05 COP) and gas furnace (0.8 Et);
See Table 15
DHW
Natural gas boiler (0.8 Et)
Natural gas boiler (0.94 Et)
Plug and Process Loads
Several assumptions have to be made to include the plug and process loads in the energy models. The
process loads for a commercial kitchen are large and have a significant impact on the HVAC and
overall building energy use. The 2007 DOE Buildings Energy Data Book estimates that the cooking and
refrigeration loads in a typical “Food Service” building is approximately 45% of the total energy use
(DOE 2007).
The process loads associated with food preparation, serving, and cleaning for this model were
estimated by foodservice industry consultants. Kitchen appliances for both the baseline building and
the energy efficient building were all selected to be either ENERGY STAR-qualified, FEMPrecommended, or qualified for California utilities Rebate Program (EPA 2008, FEMP 2008, FSTC
2008b). USACE Norfolk District provided with the layout of the kitchen, the equipment specification
sheets, a 21-day menu, and the number of meals served per day. The cooking energy for each piece of
equipment was estimated for each space based on the menus and aggregated schedules were created
for each space including warm-up and idle times. Figures 16-5, 16-6, and 16-7 show (and Table 5 lists)
the total electricity and gas process loads by zone.
Service hot water (SHW) use in the food preparation and dish washing areas is considered a process
load and is removed from the energy savings calculations. It was assumed that 95% of the building
SHW use is for food preparation and washing (see Table 5). The remaining 5% is for hand washing in
the restrooms and hand washing stations in the entry and is included in the energy savings
calculations.
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Energy and Water Conservation Design Requirements for SRM Projects
Air Tightness and Infiltration
Infiltration is a difficult parameter to obtain good data on. Every building has different air leakage and
the infiltration varies with operation of the building and ambient conditions. There was a proposed
addendum to Standard 90.1-2004, which includes an air tightness standard. This document proposes
that one approach to meeting the standard would be to perform a pressurization test to show that the
building leakage does not exceed 0.4 cfm/ft2 at 0.3 in w.g. (2 L/s/m2 at 75 Pa). This air tightness level
provides a number that can be used for the energy simulations and was assumed to be the leakage
rate for the baseline building models in this analysis.
8
Energy and Water Conservation Design Requirements for SRM Projects
Table 5. Process Loads.
Zone
Dining
Peak Elec.
(kW)
30
Electric
(kWh/day)
Peak Gas
1000Btu (MJ)
Gas
1000Btu/day
(MJ/day)
1,989 (2,099)
165
Dishwashing
58
330
Kitchen
41
447
183 (193)
Servery
99
901
47 (50)
394 (416)
3
44
57 (60)
620 (654)
188
47 (50)
Bake shop
Carryout
Total
13
Service Hot Water
gal/day (L/day)
2,075
422 (445)
3,425 (3,614)
5,740 (21,728)
Based on input from building air tightness experts, the U.S. Army has proposed in their new
construction regulations that the leakage rate must not exceed 0.25 cfm/ft2 at 0.3 in w.g. (1.25 L/s/m2 at
75 Pa), which was assumed for the energy efficient building models in this study.
Several assumptions still have to be made to go from these leakage rates to the simple infiltration
model in the building energy simulation. The infiltration at these leakage rates and pressures were
calculated based on the above grade envelope area (exterior walls and roof) of the building then
converted to a pressure of 0.02 in w.g. (5 Pa) assuming a flow coefficient of 0.65. It was assumed that
the average pressure difference across the building envelope is 0.02 in w.g. (5 Pa). Tables 16-6 and
16-13 lists the infiltration values.
Infiltration is often assumed to go to zero when buildings are pressurized. This assumption is usually
made because there is a lack of evidence to know what really happens and lack of knowledge of how
to model it in an energy simulation. We have assumed that the uncontrolled infiltration is reduced to
10% of the value calculated at 5 Pa when the building ventilation system is running. When the
ventilation system is off (no outside air), the infiltration is modeled at the full leakage rate calculated at 5
Pa. Infiltration is modeled at constant air changes per hour. Wind pressure and temperature
differentials across the building envelope drive the infiltration and these driving forces vary throughout
the year; however, we are not modeling these variations in the simulation models. We are assuming
that a constant air changes per hour (ACH) models the average effects over the year and in different
locations. This is a gross assumption, but one that is necessary without moving to more complicated
flow network simulations.
Envelope
The baseline building envelope features are modeled as steel frame wall construction, roof insulation
entirely above deck, and door and fenestration types from ASHRAE Standard 90.1-2004. The door,
window, and skylight sizes and distribution are exactly the same in all building models. Skylights are
included at 4% of the roof area in the servery and dining zones for daylighting. Skylights are not
included near the exterior walls in the dining zone because adequate daylight can be harvested from
the exterior windows. Skylights are not included in the models for Fairbanks because the latitude and
cold climate reduce their effectiveness in saving energy.
Lighting
Tables 16-18 and 16-2 list the interior lighting power densities (LPD) for the baseline and the energy
efficient model for each space.
9
Energy and Water Conservation Design Requirements for SRM Projects
HVAC
The baseline HVAC system from Standard 90.1-2004 Appendix G is the system 3 package single zone
air conditioning (PTAC) system for each zone. The systems were auto-sized by EnergyPlus for each
simulation with a 1.2 sizing factor. The kitchen had over 300 hours of the cooling temperature setpoint
not met in Houston, Phoenix, and El Paso. A sizing factor of 2.0 was used for the kitchen in these
locations to ensure that the number of hours that the cooling setpoints were met did not exceed 300 as
required by Standard 90.1-2004 Appendix G.
Ventilation and Outside Air
The outside air requirements for each zone are determined by meeting the highest of the Standard
62.1-2004 (ASHRAE 2004c) outside air requirements and the make-up air requirements for the food
preparation exhaust hoods. Table 6 lists the building infiltration, ventilation, and outside air
requirements for the baseline building. The maximum outside air for the servery in the last column is
slightly greater than the maximum exhaust hood flow minus the transfer air because the hourly
operation of the individual hood flows and the transfer air cause the peak air flows to occur at different
times. Some of the make-up air for the servery exhaust hoods comes from the dining and
entry/circulation areas. The transfer air from the entry/circulation is very small and was not included in
the energy simulations. A small amount of make-up air for the kitchen comes from the adjacent storage
area; however, this transfer air is small and was not included in the simulations. The transfer air is the
same for all models; therefore, no credit is taken in the energy efficient models for transfer air.
Table 6. Baseline Building Model Outside Air Requirements.
Zone
Infiltration
cfm (L/s)
62.1-2004
Ventilation
cfm (L/s)
Dining
768 (362)
5,187 (2,448)
Storage/Receiving
248 (117)
315 (149)
Transfer Air
cfm (L/s)
Exhaust Hood
cfm (L/s)
-4,496 (2,122)
Maximum Outside
Air
cfm (L/s)
5,187 (2,448)
315 (149)
Dishwashing
77 (36)
784 (370)
750 (354)
750 (354)
Kitchen
190 (90)
1,934 (913)
13,250 (6,253)
13,250 (6,253)
Servery
294 (139)
1,145 (540)
Entry/Circulation
294 (139)
372 (176)
4,496 (2,122)
17,075 (8,058)
12,900 (6,088)
372 (176)
Carryout
131 (62)
93 (44)
Office
157 (74)
117 (55)
2,100 (991)
2,100 (991)
117 (55)
Utility
132 (62)
63 (30)
63 (30)
There is very little guidance for modeling kitchen exhaust hood systems for energy savings
calculations. The only guidance in 90.1-2004 is in Section 6.5.7, which requires that at least 50% of the
make-up air for hoods larger than 5000 cfm be provided by uncooled and heated to no more than 60ºF.
The Code of Federal Regulations Volume 71, Number 232 states that kitchen ventilation systems are to
be included as part of the HVAC system for energy savings calculations (NARA 2006). With the lack of
specific guidance on what the baseline exhaust system should be, we used the typical design for the
Army dining facility as the baseline. This design incorporates some improvements in layout and hood
design from previous designs. Establishing the baseline is very important because the exhaust hoods
and the make-up air requirements constitute a large portion of the energy consumption in the building.
There are 10 exhaust hoods for food preparation and one for the dish washer in this dining facility
model. Table 7 lists the exhaust hoods and the characteristics for the baseline model. The baseline
flow rates, fan pressure, and fan power were taken from the manufacturers equipment cut sheets for
the model building used for this study. There was no cut sheet for the double island hood in the kitchen.
It was assumed that this hood was 53 ft (16.2 m), counting both sides, and had a flow of 250 cfm/linear
10
Energy and Water Conservation Design Requirements for SRM Projects
foot (387 L/s/m) for a total flow of 13,250 cfm (6,253 L/s). The hood duty categories were determined
based on Table 1 from the Kitchen Ventilation chapter in the ASHRAE HVAC Applications Handbook
(ASHRAE 2007). The flow per unit length was determined from the flow and length specified in the
manufacturers cut sheets and they agree with the minimum flow ranges specified in Table 2 of the
Kitchen Ventilation chapter in the HVAC Applications Handbook.
Table 7. Baseline Exhaust Hood Air Flows.
Zone
Hood
Duty
Length
ft (m)
Flow per
Length
cfm/ft (L/s/m)
Flow
cfm (L/s)
Static Press.
in w.g. (Pa)
Fan Power
(kW)
Total Fan
Eff.
Dishwashing
Dishwasher
Light
Kitchen
Double Island
Medium
53.0 (16.2)
250 (387)
13,250 (6,253)
750 (354)
2 (426)
4.301
0.67
Carryout
Wall-Mounted
Medium
8.5 (2.6)
247 (382)
2,100 (991)
2 (426)
0.739
0.62
Servery
Wall-Mounted
Medium
5.5 (1.7)
350 (542)
1,925 (908)
2 (516)
0.747
0.67
Single Island
Medium
7.0 (2.1)
300 (465)
2,100 (991)
2 (426)
0.677
0.67
Single Island
Heavy
5.0 (1.5)
350 (542)
1,750 (826)
2 (426)
0.614
0.62
Single Island
Medium
7.0 (2.1)
300 (465)
2,100 (991)
2 (426)
0.739
0.62
Single Island
Medium
7.0 (2.1)
300 (465)
2,100 (991)
2 (426)
0.739
0.62
Wall-Mounted hood
over fryer
Medium
7.0 (2.1)
300 (465)
2,100 (991)
2 (426)
0.739
0.62
Wall-Mounted
Medium
9.0 (2.7)
250 (387)
2,250 (1,062)
1 (298)
0.555
0.64
Bake shop
Light
11.0 (3.4)
250 (387)
2,750 (1,298)
1 (292)
0.678
0.63
Servery Total
17,075 (8,058)
5.488
Building Total
32,425 (15,303)
10.528
There are two limitations in EnergyPlus version 2.1 that forced a workaround for the exhaust fans and
make-up air. Exhaust fans are only controlled with an on–off schedule and cannot have a fractional
schedule, which makes it impossible to model the various fans in the servery turning on and off at
different times. In addition, EnergyPlus does not account for the transfer air from the dining zone when
calculating the outside air requirements. EnergyPlus determines the outside air as the maximum of the
exhaust fan flow rate and the minimum outside air schedule times the peak outside air flow rate without
consideration of the transfer air. The outside air requirements for the servery goes up and down as the
various exhaust fans and the transfer air turn on and off on different schedules. To get around this
problem, the hourly energy use of the exhaust fans was calculated in a spreadsheet then entered in the
EnergyPlus model as an external load to the zones. The outside air requirements were entered with an
hourly schedule. The exhaust fan energy was then moved from the external load to the fan energy with
post-processing.
Results
The annual energy use intensity for each climate as simulated by EnergyPlus forms the baseline
energy budget. The target energy budget is 70% of these baseline values. Table 8 lists the site energy
use intensities (EUI) with and without plug and process loads for the baseline and target energy
budgets for each climate zone. Figure 8 shows breakouts of the energy consumption by end use.
11
Energy and Water Conservation Design Requirements for SRM Projects
Table 8. Energy Budgets by Climate Zone.
With Process Loads
Climate Zone
City
Without Process Loads
Baseline kBtu/ft2
(MJ/m2)
Target kBtu/ft2
(MJ/m2)
Baseline kBtu/ft2
(MJ/m2)
Target kBtu/ft2
(MJ/m2)
1A
Miami, FL
355 (1,229)
249 (862)
153 (530)
107 (370)
2A
Houston, TX
363 (1,256)
254 (879)
154 (533)
108 (374)
2B
Phoenix, AZ
348 (1,205)
244 (845)
143 (495)
100 (346)
3A
Memphis, TN
375 (1,298)
263 (910)
161 (557)
113 (391)
3B
El Paso, TX
355 (1,229)
248 (858)
143 (495)
100 (346)
3C
San Francisco, CA
331 (1,146)
232 (803)
112 (388)
78 (270)
4A
Baltimore, MD
402 (1,391)
282 (976)
182 (630)
127 (440)
4B
Albuquerque, NM
368 (1,274)
258 (893)
149 (516)
104 (360)
4C
Seattle, WA
372 (1,288)
260 (900)
149 (516)
104 (360)
5A
Chicago, IL
433 (1,499)
303 (1,049)
209 (723)
146 (505)
5B
Colorado Springs, CO
393 (1,360)
275 (952)
168 (581)
117 (405)
6A
Burlington, VT
464 (1,606)
325 (1,125)
236 (817)
165 (571)
6B
Helena, MT
435 (1,506)
304 (1,052)
206 (713)
144 (498)
7A
Duluth, MN
508 (1,758)
356 (1,232)
273 (945)
191 (661)
8A
Fairbanks, AK
630 (2,181)
441 (1,526)
388 (1,343)
271 (938)
Energy Conservation Measures
Tables 16-16 and 16-17 show the annual energy savings intensity for each of the ECMs. The energy
savings across all the ECMs in the final building are not additive because of the interactions between
all of the building systems. The lighting and envelope ECMs were modeled separately and in
combination to determine the best combinations by climate zone.
Table 9. Energy Conservation Measures.
ECM
Envelope air tightness
Description
Improved building air leakage to 0.25 cfm/ft2 at 0.3 in w.g. (1.25 L/s/m2 at
75 Pa)
Envelope insulation
Used 30% Small Office Advanced Energy Design Guide insulation
Envelope fenestration
Used 30% Small Office Advanced Energy Design Guide windows
Cool Roof
Increased solar reflectance to 0.65
Improved lighting design
Reduced lighting power densities
Daylighting
Added daylighting controls to the dining, servery, carryout, and office
Ventilation hood end panels
Added partial end panels on the kitchen hood and all wall-mounted hoods in
the servery, bake shop, and carryout areas
Eliminate single-island hoods
Replaced single-island hoods with wall-mounted hoods in servery
DCV ventilation hoods
Added DCV to the hoods in the servery, carryout, and kitchen
High efficiency HVAC
Increased the efficiency of all HVAC and water heating equipment
Low-flow pre-rinse nozzles
Added low-flow pre-rinse nozzles – 1.2 gpm (0.076 L/s)
Envelope Air Tightness. Based on input from building air tightness experts, the U.S. Army has
proposed in their new construction regulations that the leakage rate must not exceed 0.25 cfm/ft2 at 0.3
in w.g. (1.25 L/s/m2 at 75 Pa), which was assumed for the energy efficient building models in this study.
The energy savings for this ECM are small in all climates except for climate zones 6 and 8 where the
savings reaches 6%.
Improved Envelope. Tables 16-10 lists the recommended building envelope insulation levels and
fenestration for the energy efficient building. The opaque envelope insulation recommendations follow
Standard 90.1-2004 for climate zones 1 through 2B and the ASHRAE Small Office 30% Advanced
12
Energy and Water Conservation Design Requirements for SRM Projects
Energy Design Guide (AEDG) (ASHRAE 2004b) for the other climate zones. The recommended
fenestration follow Standard 90.1-2004 for climate zones 1 through 3C and follow the Small Office 30%
AEDG for climate zones 4 through 8. The opaque envelope ECM shows very little savings in climate
zone 3 and significant energy savings in the cold climates. This difference in windows shows negative
energy savings in climate zone 1A because of the higher solar heat gain in the AEDG windows.
A high roof solar reflectance was modeled as a separate case. The baseline roof solar reflectance was
0.3 and the “cool roof” solar reflectance was 0.65. This ECM shows small energy savings for climate
zones 1, 2, and 4B and a very small savings in 3A. There is negative energy savings in the other
climate zones. The energy use in this building is driven by the requirements to treat the make-up air;
therefore, this ECM has a small impact compared to other building types.
13
Energy and Water Conservation Design Requirements for SRM Projects
Table 10. Envelope Conservation Measures
Item
Component(1)
Climate Zones
1
Roof
2
3
4
5
6
7
8
Assembly Max U-value
U-0.0634
U-0.0634
U-0.0481
U-0.0481
U-0.0481
U-0.0388
U-0.0388
U-0.0388
Insulation Entirely
Above Deck
R-15ci
R-15ci
R-20ci
R-20ci
R-20ci
R-25ci
R-25ci
R-25ci
Attic and Other
R-19
R-19
R-30
R-30
R-30
R-38
R-38
R-38
Solar Reflectance (2)
0.65
0.65
0.65
0.65
0.65
0.30
0.30
0.30
Assembly Max U-value
U-0.1242
U-0.1242
U-0.0847
U-0.0676
U-0.0676
U-0.0676
U-0.0676
U-0.0391
Mass
R-6.5ci
R-6.5ci
R-10
R-13
R-13
R-13
R-13
R-11.4 +
R-3.0ci
Steel Framed
R-13
R-13
R-13 +
R-3.8ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
R-13 +
R-18.8ci
Wood Framed and
Other
R-13
R-13
R-13
R-13 +
R-3.8ci
R-13 +
R-3.8ci
R-13 +
R-3.8ci
R-13 +
R-3.8ci
R-13 +
R-19.5ci
Assembly Max U-value
U-0.1067
U-0.1067
U-0.0739
U-0.0739
U-0.0521
U-0.0377
U-0.0377
U-0.0377
Mass
R-6.3ci
R-6.3ci
R-10.4ci.
R-10.4ci.
R-16.7ci.
R-25.1ci.
R-25.1ci.
R-25.1ci.
Steel Joists
R-13
R-13
R-13
R-13
R-19
R-30
R-30
R-30
Wood Framed and
Others
R-13
R-13
R-13
R-13
R-19
R-30
R-30
R-30
Assembly Max F-value;
F-0.730 ;
F-0.730 ;
F-0.730 ;
F-0.520 ;
F-0.520 ;
F-0.510 ;
F-0.510 ;
F-0.434 ;
NR (3)
NR (3)
NR (3)
R-15.0 for
24 in.
R-15.0 for
24 in.
R-20.0 for
24 in.
R-20.0 for
24 in.
R-20.0 for
48 in.
F-1.020;
F-1.020;
F-0.860 ;
F-0.843 ;
F-0.688;
F-0.688;
F-0.671;
F-0.671;
R-7.5 for
12 in
R-7.5 for
12 in
R-15.0 for
24 in.
R-20 for
24 in.
R-20.0 for
48 in
R-20.0 for
48 in
R-25.0 for
48 in
R-25.0 for
48 in
Swinging
U-0.70
U-0.70
U-0.70
U-0.50
U-0.50
U-0.50
U-0.50
U-0.50
Non-swinging
U-1.45
U-1.45
U-1.45
U-0.50
U-0.50
U-0.50
U-0.50
U-0.50
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
0.25
cfm/ft2
Vertical Glazing Window to Wall Ratio < 20%
(WWR)
< 20%
< 20%
< 20%
< 20%
< 20%
< 20%
< 20%
Thermal
U-1.22
transmittance
(Assembly Maximum)
U-1.22
U-0.57
U-0.42
U-0.42
U-0.42
U-0.33
U-0.33
Solar heat gain
coefficient (SHGC)
0.25
0.25
0.37
0.39
0.39
0.39
NR (3)
NR (3)
South Overhangs
NR (3)
NR (3)
NR (3)
NR (3)
NR (3)
NR (3)
NR (3)
NR (3)
Percent Roof Area
≤4%
Walls
Floors Over
Unconditioned
Space
Slab-on-Grade
Unheated
Assembly Max F-value;
Heated
Doors
Air Tightness (4) Max Leakage at
±75Pa Blower Test
Pressures
Skylights
(Dining and
Servery)
≤4%
≤4%
≤4%
≤4%
≤4%
≤4%
None
Thermal
U-1.36
transmittance
(Assembly Maximum)
U-1.36
U-0.69
U-0.69
U-0.69
U-0.69
U-0.69
NR (3)
Solar heat gain
coefficient (SHGC)
0.19
0.19
0.34
0.39
0.49
0.64
NR (3)
0.19
14
Energy and Water Conservation Design Requirements for SRM Projects
Improved Lighting Design and Daylighting. Table 11 lists the interior lighting power densities (LPD)
for the baseline and the energy efficient model for each space. The final column in this table lists the
space type from Standard 90.1 Table 9.6.1. Daylighting controls were modeled in the servery and the
dining area as an energy conservation measure with a minimum illuminance level of 30 fc (300 lux).
Table 15 lists the energy savings by location for reduced LPD and for reduced LPD with daylighting.
The energy savings are best for the warmer climates. The energy performance in Fairbanks was better
without the skylights; therefore there are no skylights and no daylighting in the final energy efficient
model for Fairbanks. Occupancy sensors were not included in the simulations because the actual
occupancy patterns for the spaces were unknown during this analysis. However, they should be
included in all zones that are unoccupied for more than 20% of the building occupied period (3 a.m. to 8
p.m.). Zones that are possible candidates for occupancy sensors include restrooms, office, employee
break room, utility rooms, janitor’s closets, and storage rooms.
Table 11. Building Lighting Power.
Baseline
Zone
Efficient Model
90.1-2004 Space Type
W/ft2 (W/m2)
W
W/ft2 (W/m2)
W
Dining
0.9 (9.68)
7,183
0.8 (8.61)
6,383
Dining area
Storage/Receiving
0.8 (8.61)
2,098
0.8 (8.61)
2,098
Active Storage
Dishwashing
1.2 (12.91)
1,344
1.0 (10.76)
1,120
Food Preparation
Kitchen
1.2 (12.91)
3,315
1.1 (11.84)
3,039
Food Preparation
Servery
1.2 (12.91)
5,131
1.0 (10.76)
4,276
Food Preparation
Entry/Circulation
1.3 (13.99)
4,277
1.0 (10.76)
3,290
Lobby
Carryout
1.2 (12.91)
1,253
1.0 (10.76)
1,044
Food Preparation
Office
1.1 (11.84)
1,588
0.9 (9.68)
1,300
Office
Utility
1.5 (16.14)
1,580
1.0 (10.76)
1,053
Elec/Mech
Total
27,759
23,596
Ventilation. Table 12 lists the building infiltration, ventilation, and outside air requirements for the final
energy efficient model. Three ECMs were applied to the exhaust hoods: addition of end panels,
replacement of single island hoods with wall-mounted or back-shelf hoods, and application of demand
controlled ventilation (DCV). Table 13 lists the characteristics of the exhaust hoods with all the ECMs
applied. The first ECM was to add partial or full end panels to the kitchen hood and all wall-mounted
hoods in the servery and carryout zones. It was assumed that this ECM would reduce the flow
requirements for all affected hoods to the low end of the minimum flow range in Table 2 of the Kitchen
Ventilation chapter in the ASHRAE HVAC Applications Handbook (ASHRAE 2007). The second ECM
was to replace the single island hoods in the servery with wall-mounted, canopy hoods by adding full
back and partial side walls. The back walls can be transparent to allow visibility from the serving line.
The final ECM was to include DCV, which reduces the exhaust flow between heavy cooking periods. It
was assumed that the exhaust flow was reduced by half between the heavy cooking periods. A
schedule for the DCV operation was derived from analysis of the cooking loads. Actual savings from
DCV may vary depending on the effectiveness of the DCV controller and the amount of off peak
cooking time. Another ECM that affects the transfer air from the dining zone is the reduced infiltration
from a tighter building, which affects the make-up air requirements in the servery. Tables 16-6 and 1612 show the infiltration and the transfer air from the dining zone. The reduced infiltration leaves more of
the ventilation air in the dining zone available to be transferred to the servery.
The maximum outside air requirement in Tables 16-6 and 16-12 for the servery is higher than the
servery exhaust minus the dining transfer air. Each of the exhaust hoods in the servery and the dining
transfer air operate on different schedules. The maximum outside air requirement in the servery occurs
in the morning when some of the exhaust fans are on and before the dining outside air system is turned
15
Energy and Water Conservation Design Requirements for SRM Projects
on.
Table 12. Efficient Building Model Outside Air Requirements.
Zone
Infiltration
cfm (L/s)
62.1-2004
Ventilation
cfm (L/s)
Dining
480 (227)
5,187 (2,448)
Storage/Receiving
155 (73)
315 (149)
Transfer Air
cfm (L/s)
Exhaust Hood
cfm (L/s)
-4,755 (2,244)
Maximum Outside
Air
cfm (L/s)
5,187 (2,448)
315 (149)
Dishwashing
48 (23)
784 (370)
750 (354)
750 (354)
Kitchen
119 (56)
1,934 (913)
10,600 (5,003)
10,600 (5,003)
Servery
184 (87)
1,145 (540)
11,400 (5,380)
7,875 (3,717)
Entry/Circulation
184 (87)
372 (176)
Carryout
82 (39)
93 (44)
1,700 (802)
1,700 (802)
4,755 (2,244)
372 (176)
Office
98 (46)
117 (55)
117 (55)
Utility
82 (39)
63 (30)
63 (30)
Table 13. Energy Efficient Exhaust Hood Air Flows.
Zone
Hood
Duty
Dishwashing
Dishwasher
Light
Kitchen
Double Island
Medium
Length
ft (m)
Flow per
Length
cfm/ft (L/s/m)
Flow
cfm (L/s)
Static Press.
in w.g. (Pa)
Fan Power Total Fan
(kW)
Eff.
750 (354)
53.0 (16.2)
200 (310)
10,600 (5,003)
1.20 (298)
2.641
0.63
Carryout
Wall-Mounted
Medium
8.5 (2.6)
200 (310)
1,700 (802)
1.22 (304)
0.465
0.58
Servery
Wall-Mounted
Medium
5.5 (1.7)
200 (310)
1,100 (519)
0.85 (211)
0.222
0.57
Wall-Mounted
Medium
7.0 (2.1)
200 (310)
1,400 (661)
0.90 (223)
0.283
0.60
Wall-Mounted
Heavy
5.0 (1.5)
250 (387)
1,250 (590)
1.00 (249)
0.296
0.56
Wall-Mounted
Medium
7.0 (2.1)
200 (310)
1,400 (661)
0.90 (223)
0.309
0.55
Wall-Mounted
Medium
7.0 (2.1)
200 (310)
1,400 (661)
0.90 (223)
0.309
0.55
Wall-Mounted hood
over fryer
Medium
7.0 (2.1)
200 (310)
1,400 (661)
0.90 (223)
0.309
0.55
Wall-Mounted
Medium
9.0 (2.7)
200 (310)
1,800 (850)
0.84 (209)
0.347
0.60
Bake shop
Light
11.0 (3.4)
150 (232)
1,650 (779)
0.52 (129)
0.240
0.53
Servery Total
11,400 (5,380)
2.315
Building Total
23,700 (11,185)
5.422
Figure 10 shows (and Table 16 lists) the energy savings from reducing the hood exhaust rates. The
savings are higher in the colder climates because of the large temperature difference between the
outside air and the zone air temperatures. Installing end panels provides the largest energy savings for
climate zones 7 and 8. Replacing the single island hoods with wall-mounted hoods showed small
savings in the warm climates and larger savings in the cold climates. Including DCV on the hoods also
shows small savings in the warm climates and significant savings in the cold climates. If the singleisland hoods are not replaced, this ECM will have a larger effect in all climates. The savings associated
with this ECM strongly depend on the number of hours with reduced flow and the reduction in flow.
Further analysis should be completed if the operating conditions are different than those assumed in
this study.
The design exhaust rate for kitchen ventilation systems depends on the hood style along with subtle
construction features and enhancements (e.g., return flanges along the inside edge of the hood,
integral side skirts). Wall-mounted canopy hoods, island (single or double) canopy hoods, and proximity
(backshelf, pass-over, or eyebrow) hoods all have different capture areas and are mounted at different
heights and horizontal positions relative to the cooking equipment (Figure 11). Generally, for the
identical (thermal plume) challenge, a single-island canopy hood requires more exhaust than a wallmounted canopy hood, and a wall-mounted canopy hood requires more exhaust than a proximity
16
Energy and Water Conservation Design Requirements for SRM Projects
(backshelf) hood. The performance of a double-island canopy tends to emulate the performance of two
back-to-back wall-canopy hoods, although the lack of a physical barrier between the two hood sections
makes the configuration more susceptible to cross drafts. Where applicable, the following best-design
practices should be incorporated within the exhaust system design and specifications to ensure that
capture and containment performance of the hood is satisfactorily at the reduced exhaust rate:
1. Incorporate partial side panels or end walls (Figure 12a and 16-12b).
2. Maximize overhang and minimize clearance between appliance and rear wall (Figure 12c and 16-12d).
3. Position heavy duty equipment (e.g., broilers) in middle of the hood and light duty (e.g., ovens, kettles) at
the end of the cook line.
4. Specify wall-mounted canopy hoods instead of single-island canopies.
5. Specify back-shelf (i.e., proximity hoods) over short-order equipment such as griddles and fryers.
6. introduce low-velocity makeup air near hoods (e.g., no 4-way diffusers in kitchens).
7. Maximize transfer air.
8. Incorporate demand ventilation controls
High Efficiency HVAC. Three HVAC systems were modeled as improvements to the baseline system:
high efficiency PTAC, packaged variable air volume (VAV) with an air cooled chiller, and a packaged
VAV with a water cooled chiller. All three improved systems showed similar performance. The high
efficiency PTAC was included in the final models. Table 14 lists the four HVAC systems parameters.
This ECM shows significant energy savings in all climates. For climate zones 1 through 3 and 4B, it is
the single highest saving ECM.
Table 14. HVAC systems.
Baseline
PTAC
Parameter
High Eff. PTAC
Size range 1000Btu/h (kW)
135 – 240
(39 – 70)
135 – 240
(39 – 70)
EER
9.7
12
PVAV Air Cooled Chiller
PVAV Water Cooled
Chiller
COP
2.84
3.52
3.7
7.0
COP w/o supply fan
2.95
3.70
N/A
N/A
Total fan efficiency
0.2
0.45
0.45
0.45
Heating source
Gas furnace
Gas furnace
Gas boiler
Gas boiler
Heating efficiency
0.8
0.9
0.94
0.94
Pump efficiency
N/A
N/A
0.90
0.90
SHW gas boiler efficiency
0.8
0.94
0.94
0.94
Service Hot Water. Service hot water use is 15% to 20% of the total building energy consumption. The
SHW use in the food preparation and dish wash areas is a process load and not included in the energy
savings calculations. However, a 94% efficient boiler was included in the final energy efficient design
model. Another ECM for saving hot water is to install low flow prerinse nozzles with a flow rate of 1.2
gpm (0.076 L/s). This ECM was not included in the final model because the SHW for washing is
considered a process load.
17
Energy and Water Conservation Design Requirements for SRM Projects
CZ
City
Reduced LPD
Daylighting
Reduced LPD
Cool Roof
AEDG 30% SO
Fenestration
Envelope Air
Tightness
AEDG 30% SO
Opaque Envelope
Table 15. Annual Energy Savings for Individual ECMs (kBtu/ft2)
1A
Miami, FL
0.4 (1.4)
0.0 (0.0)
-0.6 (-2.1)
0.5 (1.7)
4.2 (14.5)
9.1 (31.5)
2A
Houston, TX
1.1 (3.8)
0.0 (0.0)
0.6 (2.1)
0.5 (1.7)
3.5 (12.1)
8.7 (30.1)
2B
Phoenix, AZ
0.7 (2.4)
0.0 (0.0)
0.4 (1.4)
1.1 (3.8)
3.5 (12.1)
8.4 (29.1)
3A
Memphis, TN
1.5 (5.2)
0.9 (3.1)
0.3 (1.0)
0.1 (0.3)
3.0 (10.4)
7.7 (26.7)
3B
El Paso, TX
0.8 (2.8)
1.0 (3.5)
0.3 (1.0)
-0.2 (-0.7)
3.4 (11.8)
8.4 (29.1)
3C
San Francisco, CA
1.1 (3.8)
1.3 (4.5)
0.9 (3.1)
-0.5 (-1.7)
2.4 (8.3)
6.7 (23.2)
4A
Baltimore, MD
2.0 (6.9)
2.3 (8.0)
0.6 (2.1)
-0.2 (-0.7)
2.4 (8.3)
6.3 (21.8)
4B
Albuquerque, NM
1.3 (4.5)
2.2 (7.6)
0.3 (1.0)
0.4 (1.4)
2.5 (8.7)
6.8 (23.5)
4C
Seattle, WA
2.0 (6.9)
2.5 (8.7)
0.5 (1.7)
-0.3 (-1.0)
1.8 (6.2)
4.7 (16.3)
5A
Chicago, IL
2.6 (9.0)
2.1 (7.3)
0.9 (3.1)
-0.4 (-1.4)
1.9 (6.6)
5.3 (18.3)
5B
Colo. Springs, CO
2.0 (6.9)
2.2 (7.6)
0.7 (2.4)
-0.6 (-2.1)
2.1 (7.3)
5.7 (19.7)
6A
Burlington, VT
3.2 (11.1)
2.6 (9.0)
1.2 (4.2)
-0.8 (-2.8)
1.7 (5.9)
4.8 (16.6)
6B
Helena, MT
3.0 (10.4)
3.1 (10.7)
1.2 (4.2)
-0.6 (-2.1)
1.6 (5.5)
4.3 (14.9)
7A
Duluth, MN
4.0 (13.8)
2.7 (9.3)
2.2 (7.6)
-1.1 (-3.8)
1.4 (4.8)
3.7 (12.8)
8A
Fairbanks, AK
5.9 (20.4)
7.2 (24.9)
1.7 (5.9)
-0.5 (-1.7)
1.2 (4.2)
2.2 (7.6)
Low-Flow Nozzles
High Eff. HVAC
First two hood ECMs
plus DCV on all Hoods
City
DCV Kitchen Hoods
on top of End Panels
CZ
DCV Hoods in Servery &
Carryout on top of End
Panels and Single
Island
End Panels on all
Hoods
Replace Single Island
Hoods in Servery
Table 16. Annual Energy Savings for Individual ECMs 1000Btu/ft2 (MJ/m2)
1A
Miami, FL
7.2 (24.9)
2.4 (8.3)
1.8 (6.2)
0.6 (2.1)
2.4 (8.3)
40.0 (138.5)
2.7 (9.3)
2A
Houston, TX
10.3 (35.7)
3.9 (13.5)
1.3 (4.5)
3.5 (12.1)
4.8 (16.6)
35.0 (121.1)
3.0 (10.4)
2.9 (10.0)
2B
Phoenix, AZ
8.7 (30.1)
2.8 (9.7)
0.4 (1.4)
3.4 (11.8)
3.8 (13.2)
34.0 (117.7)
3A
Memphis, TN
18.1 (62.6)
5.9 (20.4)
1.4 (4.8)
6.8 (23.5)
8.3 (28.7)
31.0 (107.3)
3.3 (11.4)
3B
El Paso, TX
11.0 (38.1)
3.4 (11.8)
-0.3 (-1.0)
4.6 (15.9)
4.3 (14.9)
32.0 (110.8)
3.2 (11.1)
3C
San Francisco, CA
15.0 (51.9)
3.7 (12.8)
-0.5 (-1.7)
6.7 (23.2)
6.2 (21.5)
19.0 (65.8)
3.4 (11.8)
4A
Baltimore, MD
25.8 (89.3)
8.9 (30.8)
2.9 (10.0)
10.8 (37.4)
13.6 (47.1)
30.0 (103.8)
3.6 (12.5)
4B
Albuquerque, NM
18.6 (64.4)
6.1 (21.1)
1.3 (4.5)
8.4 (29.1)
9.7 (33.6)
27.0 (93.5)
3.5 (12.1)
4C
Seattle, WA
24.8 (85.8)
8.0 (27.7)
1.3 (4.5)
10.9 (37.7)
12.2 (42.2)
21.0 (72.7)
3.6 (12.5)
5A
Chicago, IL
32.4 (112.1)
11.5 (39.8)
4.8 (16.6)
13.8 (47.8)
18.7 (64.7)
31.0 (107.3)
3.7 (12.8)
5B
Colo. Springs, CO
24.2 (83.8)
8.2 (28.4)
2.6 (9.0)
11.5 (39.8)
14.1 (48.8)
28.0 (96.9)
3.8 (13.2)
6A
Burlington, VT
38.7 (134.0)
13.8 (47.8)
7.0 (24.2)
16.9 (58.5)
23.9 (82.7)
32.0 (110.8)
3.9 (13.5)
6B
Helena, MT
34.2 (118.4)
12.1 (41.9)
5.5 (19.0)
15.7 (54.3)
21.2 (73.4)
28.0 (96.9)
3.9 (13.5)
7A
Duluth, MN
47.8 (165.4)
17.3 (59.9)
9.5 (32.9)
21.1 (73.0)
30.6 (105.9)
34.0 (117.7)
4.2 (14.5)
8A
Fairbanks, AK
69.7 (241.3)
25.5 (88.3)
17.3 (59.9)
30.4 (105.2)
47.7 (165.1)
45.0 (155.8)
4.6 (15.9)
18
Energy and Water Conservation Design Requirements for SRM Projects
Total Energy Savings with Recommended Technology Sets
The energy savings for the final energy efficient solutions are shown with and without the plug and
process loads in Tables 16-17 and 16-18. The energy savings ranges from 35% to 48%. Table 19 lists
the combinations of best performing solutions for each climate zone.
Table 17. Final Energy Efficient Design Solutions without Process Loads
CZ
1A
City
Baseline
1000Btu/ft2
(MJ/m2)
Final Energy Efficient
Solution
1000Btu/ft2
(MJ/m2)
Energy Savings
Miami, FL
153 (530)
100 (346)
35%
2A
Houston, TX
154 (533)
97 (336)
37%
2B
Phoenix, AZ
143 (495)
90 (312)
37%
3A
Memphis, TN
161 (557)
92 (318)
43%
3B
El Paso, TX
143 (495)
82 (284)
42%
3C
San Francisco, CA
112 (388)
60 (208)
46%
4A
Baltimore, MD
182 (630)
99 (343)
46%
4B
Albuquerque, NM
149 (516)
80 (277)
46%
4C
Seattle, WA
149 (516)
77 (267)
48%
5A
Chicago, IL
209 (723)
112 (388)
46%
5B
Colorado Springs, CO
168 (581)
88 (305)
48%
6A
Burlington, VT
236 (817)
124 (429)
47%
6B
Helena, MT
206 (713)
107 (370)
48%
7A
Duluth, MN
273 (945)
142 (492)
48%
8A
Fairbanks, AK
388 (1,343)
203 (703)
48%
Table 18. Final Energy Efficient Design Solutions with Process Loads
CZ
1A
City
Baseline
1000Btu/ft2
(MJ/m2)
Final Energy Efficient
Solution
1000Btu/ft2
(MJ/m2)
Energy Savings
Miami, FL
355 (1,229)
295 (1,021)
17%
2A
Houston, TX
363 (1,256)
297 (1,028)
18%
2B
Phoenix, AZ
348 (1,205)
287 (993)
17%
3A
Memphis, TN
375 (1,298)
297 (1,028)
21%
3B
El Paso, TX
355 (1,229)
286 (990)
19%
3C
San Francisco, CA
331 (1,146)
269 (931)
19%
4A
Baltimore, MD
402 (1,391)
309 (1,070)
23%
4B
Albuquerque, NM
368 (1,274)
290 (1,004)
21%
4C
Seattle, WA
372 (1,288)
290 (1,004)
22%
5A
Chicago, IL
433 (1,499)
326 (1,128)
25%
5B
Colorado Springs, CO
393 (1,360)
303 (1,049)
23%
6A
Burlington, VT
464 (1,606)
341 (1,180)
26%
6B
Helena, MT
435 (1,506)
324 (1,121)
25%
7A
Duluth, MN
508 (1,758)
365 (1,263)
28%
8A
Fairbanks, AK
630 (2,181)
432 (1,495)
31%
19
Energy and Water Conservation Design Requirements for SRM Projects
1A
High Eff. HVAC
Kitchen DCV Hoods
Servery DCV Hoods
Replace Single
Island Hoods
Hood End
Panels
Daylighting
Reduced LPD
Cool Roof
Skylights
AEDG 30% SO
Fenestration
City
AEDG 30% SO
Insulation
Zone
Envelope Air
Tightness
Table 19. Summary of ECMs in Final Models (grey shading indicates not recommended or investigate on a case by
case basis)
Miami, FL
2A
Houston, TX
2B
Phoenix, AZ
3A
Memphis, TN
3B
El Paso, TX
3C
San Francisco, CA
4A
Baltimore, MD
4B
Albuquerque, NM
4C
Seattle, WA
5A
Chicago, IL
5B
Colo. Springs, CO
6A
Burlington, VT
6B
Helena, MT
7A
Duluth, MN
8A
Fairbanks, AK
Energy savings associated with effectively reducing the average kitchen exhaust ventilation rate (and
the associated makeup air requirements) represent a very significant set of ECMs for Army dining
facilities. Installing partial end panels or skirts on all wall-canopy hoods in the kitchen and servery
shows significant energy savings in all climate zones, especially the cold climates. Similarly, replacing
single-island canopy hoods with wall-mounted canopy hoods (or proximity style back-shelf hoods on
short-order cooklines) generates significant savings in the cold climates. Overlaying demand controlled
ventilation on all ventilation hoods in the kitchen saves energy in all climate zones, particularly the hot
and cold climates. Applied to the servery hoods, there are cases where the reduction in average
ventilation rate did not generate savings in the mild climate zones.
Effectively, all three kitchen ventilation ECMs facilitate a reduction in the average exhaust and makeup
air flow rates and generate significant energy savings. In moderate climate zones, the benefits of
reduced makeup air heating and cooling may be offset by the “economizer” effect of having higher
exhaust rates during extended shoulder seasons.
Installing high efficiency HVAC (PTAC, 12.0 EER (3.52 COP); 0.9 Et gas heater; 0.94 Et gas boiler Vs
PTAC, 9.7 EER (2.84 COP); 0.8 Et gas heater; 0.8 Et gas boiler) in the baseline case per the ASHRAE
Standard 90.1-2004 requirements shows significant energy savings in all climates. It shows the highest
savings for climate zones 1 through 3 and 4B.
Installing Low-Flow Pre-Rinse Nozzles, 1.2 gpm, in each of the storage and receiving, dish wash, and
kitchen zones is very easy to implement and shows energy savings in all climates.
20
Energy and Water Conservation Design Requirements for SRM Projects
Summary and Discussion
EPAct 2005 sets energy performance requirements to reduce energy use in federal facilities. The
OACSIM and USACE are determined to meet these requirements for the large number of new buildings
to be constructed in the next few years by setting target energy budgets. USACE also wanted a
prescriptive path to meet or exceed these energy saving requirements, and also to use these
technologies to improve soldiers’ and workers’ productivity and wellbeing, as well as improving
buildings’ sustainability. With these objectives in mind, design guides for the most typical categories of
Army buildings were developed. This paper presents the results of developing target energy budgets
and energy design guide for Dining Facilities. The approach for other seven building types is similar to
that presented in this paper. Information on target energy budgets and design guidelines for
Unaccompanied Enlisted Personal Housing (UEPH) barracks and for TEMF are presented in two
companion papers (Herron et al. 2009 and Zhivov et al. 2009).
For the model DFAC building energy savings against the baseline vary between 35% and 48%
depending on the climate. The most effective energy conservation measures include strategies to
reduce the ventilation hood exhaust flows, high efficiency HVAC systems, improved lighting design, and
daylighting.
Results of this study were implemented through the Army’s standard Bid-Build process in late 2008 by
incorporation in RFP target energy budgets by climate zone and sets of technologies allowing to meet
these budgets. Designs and construction using RFP having new requirements began in 2008. They
allow either a custom design following target energy budgets and using required set of technologies
with a mandatory proof of compliance with energy targets, or contractors can use a complete set of
technologies included in the prescriptive path, which does not require a proof of compliance.
Actual and predicted energy savings strongly depend upon the climate, building orientation and (for
specific building design), will vary. However, implementation of developed energy budgets and a sets of
technologies included in the prescriptive path streamlines the facility design and construction process
and ensures that newly constructed facilities comply with the intent of the EPAct 2005 without
jeopardizing their functional quality.
Acknowledgement
This paper is based on the results of the project “Energy Benchmarks for Army Facilities” conducted for
the Office of the Assistant Chief of Staff of the Installations Management (OACSIM) and the
Headquarters, U.S. Army Corps of Engineers (HQUSACE). Information on the energy conservation
technologies analyzed in this project was based on research data resulted from the IEA-ECBCS
(International Energy Agency – Energy Conservation in Buildings and Community Systems) Annex 46
“Holistic Assessment Tool-kit on Energy Efficient Retrofit Measures for Government Buildings
(EnERGo) financially supported by the OACSIM and Headquarters, Installation Management Agency
(HQIMA). ASHRAE Technical Committee 7.6 Working Group members and the Annex 46 Subtask B
members contributed to the generation of the Energy Conservation Measures, their screening
conditions and the industrial model building parameters. The authors express their gratitude to MTG
group members.
21
Energy and Water Conservation Design Requirements for SRM Projects
References
ASHRAE 2004a. ANSI/ASHRAE/IESNA Standard 90.1-2004 Energy Standard for Buildings except
Low-Rise Residential Buildings. Atlanta, GA: American Society of Heating, Refrigerating and
Air-Conditioning Engineers, Inc.
ASHRAE 2004b. Advanced Energy Design Guide for Small Office Buildings. Atlanta, GA: American
Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
ASHRAE 2004c. ANSI/ASHRAE Standard 62.1-2004 Ventilation for Acceptable Indoor Air Quality.
Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
ASHRAE 2007. ASHRAE Handbook – HVAC Applications. Atlanta, GA: American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc.
Briggs, R.S., R.G. Lucas, and T. Taylor, 2003. Climate Classification for Building Energy Codes and
Standards: Part 2 - Zone Definitions, Maps and Comparisons, Technical and Symposium
Papers, ASHRAE Winter Meeting, Chicago, IL, January, 2003.
DOE 2007. 2007 Buildings Energy Data Book. http://buildingsdatabook.eere.energy.gov/. Washington,
DC: U.S. Department of Energy.
DOE 2008. EnergyPlus Energy Simulation Software. www.eere.energy.gov/buildings/energyplus/.
Washington, DC: U.S. Department of Energy.
EPA 2008. Website listing qualified Energy Star categories and modules of commercial foodservice
equipment.
http://www.energystar.gov/index.cfm?c=commercial_food_service.commercial_food_service.
Washington, DC: U.S. Environmental Protection Agency.
FEMP 2008. Federal Energy Management Program (FEMP) Energy Efficient Product
Recommendations. http://www1.eere.energy.gov/femp/procurement/eep_requirements.html.
Washington, DC: U.S. Department of Energy.
FSTC 2004a. Food Service Technology Center Design Guide Series on Commercial Kitchen
Ventilation. http://www.fishnick.com/equipment/ckv/designguides/. Pacific Gas & Electric
Company, San Ramon, CA.
FSTC 2004b. Food Service Technology Center Design Guide Series on Commercial Kitchen
Ventilation. http://www.fishnick.com/saveenergy/rebates/. Pacific Gas & Electric Company, San
Ramon, CA.
Herron, D, A. Zhivov, and M. Deru. 2009. Energy Design Guides for Army Barracks. ASHRAE
Transactions. ASHRAE Annual Meeting, Louisville, KY, June, 2009.
Marion, W. and Wilcox, S. 1995. Solar Radiation Data Manual for Buildings. TP-463-7904.
http://rredc.nrel.gov/solar/pubs/bluebook/. Golden, CO: National Renewable Energy Laboratory.
NARA 2006. Federal Register Vol. 71, No. 232. pp.70275-70284. Washington, D.C.: National Archives
and Records Administration.
22
Energy and Water Conservation Design Requirements for SRM Projects
Zhivov, A., D. Herron, and M. Deru. 2009. Achieving Energy Efficiency and Improving Indoor Air Quality
In Army Maintenance Facilities. ASHRAE Transactions. ASHRAE Annual Meeting, Louisville,
KY, June, 2009.
23
Energy and Water Conservation Design Requirements for SRM Projects
Figure 1. Sketch of a Proposed Army Dining Facility
Figure 2. Proposed DFAC floor plan from the Army
24
Energy and Water Conservation Design Requirements for SRM Projects
Carryout
Entry/
Circulation
Office
Servery
Dishwash
Utility
Kitchen
Storage
Dining
Figure 3. Thermal zoning for the DFAC energy model
Figure 4. Rendering of the energy simulation model for the DFAC
25
Energy and Water Conservation Design Requirements for SRM Projects
120
Kitchen
Servery
Dining
Carry Out
Bake Shop
Dishwashing
100
Electricity (kWh)
80
60
40
20
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
Figure 5. Daily process load electricity consumption profiles
200
180
Gas Consumption (kBtu)
160
Kitchen
Servery
Carry Out
Bake Shop
140
120
100
80
60
40
20
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
Figure 6. Daily process load gas consumption profiles
26
Energy and Water Conservation Design Requirements for SRM Projects
350
Total Gas (kBtu)
Total Elec (kWh)
Energy Consumption
300
250
200
150
100
50
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
Figure 7. Daily total process load consumption profiles of electricity and gas
Heating
Cooling
SWH
Pumps
Fans
Refrigeration
Interior Lighting
Interior Equipment Gas
Interior Equipment Elec
5,000
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
H
ia
m
i,
1A
ou
st
on
,2
A
Ph
oe
ni
x,
2B
M
em
ph
is
,3
A
El
P
Sa
as
o,
n
Fr
3B
an
cis
co
,3
Ba
C
l ti
m
or
Al
e,
bu
4A
qu
er
qu
e,
4B
Se
at
tle
,4
C
C
hi
ca
C
go
ol
,5
o.
A
Sp
ri n
gs
,5
Bu
B
rl i
ng
to
n,
6A
H
el
en
a,
6B
D
ul
ut
h,
Fa
7A
irb
an
ks
,8
A
0
M
Annual Total Site Energy (MWh)
4,500
Figure 8. Energy use by end use for the baseline building
27
Energy and Water Conservation Design Requirements for SRM Projects
3,500
Annual Site Energy (kWh)
3,000
2,500
2,000
Heating
Cooling
0.5% SHW
Pumps
Fans
Refrigeration
Interior Lighting
1,500
1,000
500
M
ia
m
Ho i, 1
A
us
to
Ph n , 2
A
oe
M nix,
em
2
ph B
is,
El
Sa
Pa 3A
n
so
Fr
,3
an
B
ci
sc
Ba
o,
lt
3
Al imo C
bu
re
,
qu
er 4A
qu
e,
Se
4B
at
tle
,4
C
C
Co h ic
a
go
lo
.S
,5
pr
A
in
Bu gs
,
rl i
ng 5B
to
n
He , 6
A
le
na
,6
Du
B
l
u
Fa
th
,
irb
7A
an
ks
,8
A
0
Figure 9. Energy use by end use for regulated loads in the baseline building
50%
400
35%
250
30%
25%
200
20%
150
15%
100
Percent Energy Savings
40%
300
Reduced hood flow
plus DCV on
kitchen, servery,
carryout
Hood end panels
Opaque Env.,
Reduced LPD, &
daylighting
Daylighting w/
reduced LPD
Reduced LPD
10%
Envelope
50
5%
Air Tightness
0%
m
ou i, 1A
st
P h o n,
oe 2A
M ni x
em , 2
ph B
i
Sa El s, 3
Pa
A
n
Fr
s
an o,
3
ci
B
Ba sco
,3
l
t
i
Al
m
bu o r C
q u e,
er 4A
qu
S e e, 4
B
at
C tle,
hi
C
4
c
C
ol
o. ago
Sp , 5
A
r
Bu ing
rli s, 5
ng
B
to
H n, 6
el
en A
a
D , 6B
u
Fa l u t
ir b h,
an 7A
ks
,8
A
0
H
M
ia
Energy Savings (million Btu/yr)
Reduced hood flow
plus DCV on
servery, carryout
45%
350
Figure 10. Annual energy savings for each ECM
28
Energy and Water Conservation Design Requirements for SRM Projects
Figure 11. Various canopy hoods for cooking equipment (source, ASHRAE Standard 154).
a.
b.
c.
d.
Figure 12. Example best-design practices within exhaust system design and specifications.
29