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Extremely Low Energy Design forArmy Buildings: Barracks

Richard Liesen, PhD Peter Ellis Alexander Zhivov, PhD Dale HerronMember ASHRAE Member ASHRAE Member ASHRAE Member ASHRAE

CH-12-008

ABSTRACT

The 2007 Energy Independence and Security Act (EISA)require that all new federal facilities be built fossil fuel free by2030. This raises the bar considerably from the 2005 EnergyPolicy Act, which required federal facilities be built to achieveat least 30% energy savings over ASHRAE Standard 90.1 –2004. On the trajectory towards the 2030 goal, buildings haveto meet 65% decrease of source energy from the CommercialBuilding Energy Consumption Survey (CBECS) survey for thebuilding type specified. The EISA requirement is not a compar-ison between a baseline and an energy efficient simulation, buta direct comparison with the actual results from the final simu-lation with the EISA target. This is not a delta percentagecomparison; it includes total source energy and all the buildingloads must be addressed and not left out of the calculation asan unregulated portion of the building load. The result of thestudy was guidance on how to reach a 60-80% energy usereduction from Commercial Building Energy ConsumptionStudy (CBECS).

The 2005 Energy Policy Act requires that federal facil-ities be built to achieve at least a 30% energy savings overthe 2004 ASHRAE Standard 90.1-2004. The ConstructionEngineering Research Laboratory (CERL) of the U.S. ArmyCorps of Engineers in collaboration with USACE HQ andCenters of Standardization for respective building types,subject matter expert (SME) contractors, and the DOENational Renewable Energy Laboratory (NREL) partici-pated in a study to recommend design guides to achieve theFederal requirements for new buildings to be constructedunder the Military Transformation Program. The buildingtypes included Unaccompanied Enlisted Personnel Housingor UEPH, administrative buildings (e.g., a brigade head-

quarters, and a company operation facility), a tactical equip-ment maintenance facility, and a dining facility. This paperpresents the results of the energy analysis for the soldierbarracks (UEPH). It provides the baseline building selectedfor the analysis and the modeling assumptions. As a result ofa computer analysis using EnergyPlus, the target energybudgets are defined for all DOE 15 Climate Zones. Finally,a recommended set of energy efficient solutions for eachclimate zone is presented that shows the buildings limit as itapproached net zero ready. It shows potential energy savingsboth on the building site and source energy when energy usereduction is considered on a building-by-building basis. Italso shows further energy use reduction opportunities whenenergy improvements are made with each building consid-ered as a part of the building cluster or community.

INTRODUCTION

Globally, buildings contribute to a large fraction of theworld’s energy usage. In the United States alone, buildingsconsume about 40% of total energy. The U.S. Army alonespends more than $1 billion annually in building-relatedenergy expenses. The U.S. Army Energy Security Implemen-tation Strategy sets the general direction for the U.S. Armyincluding elimination of energy waste in existing facilities,increase in energy efficiency in new construction and renova-tions, and reduced dependence on fossil fuels. The Army’slong-term goal is to foster Net Zero/Low Energy Installations.Through a combination of energy conservation, utilization ofwaste energy including use of co- and tri-generation, and thebalance of the energy needs using energy from renewablesources, we intend to produce as much as or more energy forinstallations than what we consume over the course of 1 year.

©2012 ASHRAE. THIS PREPRINT MAY NOT BE DISTRIBUTED IN PAPER OR DIGITAL FORM IN WHOLE OR IN PART. IT IS FOR DISCUSSION PURPOSES ONLYAT THE 2012 ASHRAE WINTER CONFERENCE. The archival version of this paper along with comments and author responses will be published in ASHRAETransactions, Volume 118, Part 1. ASHRAE must receive written questions or comments regarding this paper by February 10, 2012, for them to be included inTransactions.

Peter Ellis is president of Big Ladder Software, Denver, CO. Richard Liesen, Alexander Zhivov, and Dale Herron are senior engineers atthe U.S. Army Corps of Engineers Construction Energy Research Laboratory, Champaign, IL.

The U.S. 2005 Energy Policy Act (EPACT 2005) requiresthat federal facilities be built to achieve at least a 30% energysavings over the 2004 International Energy Code or ASHRAEStandard 90.1-2004 as appropriate, and that energy efficientdesigns must be life-cycle cost effective. In 2006-2008, theU.S. Army Corps of Engineers (USACE) collaborated withthe National Renewable Energy Laboratory (NREL), and theASHRAE Military Technology Group (MTG) to developbaseline and target energy budgets and design guides with aprescriptive path for achieving EPACT 2005 energy goals andthe results of this study were published in the Whole BuildingDesign Guide website and the ASHRAE papers (ASHRAE2009a, 2009b, 2009c).

The recently published USACE ECB-14-2010, whichrequires the reduction of building site energy consumptionwith new construction and major renovation projects by 40%compared to a facility designed in accordance with ASHRAE90.1-2007, is more stringent than (and thus supersedes)EPACT 2005. According to the U.S. Energy Independenceand Security Act (EISA 2007), new federal buildings andfederal buildings undergoing major renovations shall bedesigned to reduce energy consumption generated on- or off-site using fossil fuels by 55% in 2010, 80% by 2020, and 100%by 2030, as compared with such energy consumption by asimilar building in 2003.

The U.S. Army Engineer Research and DevelopmentCenter, Construction Engineering Research Laboratory of theUSACE, in collaboration with U.S. Department of Energy’s(DOE) National Renewable Energy Laboratory, academia,and private sector subject matter experts recently completedan energy analysis (USACE, 2011) that evaluates potential siteand source energy use reduction in new buildings to beconstructed. The building types studied included a soldierbarracks, a brigade headquarters (administrative building), acompany operation facility, a maintenance facility, and adining facility. As a reference, the study used recent buildingdesigns developed by USACE in collaboration with industryexperts and A&E firms. The study was conducted for repre-sentative locations in 15 DOE identified climate zones in theUnited States with building designs adapted to these climaticconditions. This paper presents the results of the energy anal-ysis for a typical Army barracks facility. It discusses energyefficiency measures and combinations used to reduce bothinternal and external loads on the building and overall energyuse. It shows potential energy savings both on the building siteand energy source when energy use reduction is considered ona building-by-building basis. It also shows further energy usereduction opportunities when energy improvements are madewith each building considered as a part of the building clusteror community.

While the main purpose of this study was to comply withthe Energy Independence and Security Act (EISA) of 2007target of a 65 percent fossil fuel reduction by 2015 achieved byreducing building energy consumption, the study simultane-ously determined compliance with the energy performance

option of the American Society of Heating, Refrigerating andAir-Conditioning (ASHRAE) Standard 189.1, which is basedon a 30 percent reduction of energy from ASHRAE 90.1-2007, including plug loads. This study was to determine if theEISA goals for 2015 could be met by energy efficiencymeasures (EEMs) alone without impacting the currentmission of the building.

APPROACH

The approaches used during the study included a prelim-inary meeting/charrettes with the COS (Center of Standard-ization) for the five building types as well as integratedschematic charrettes with COS representatives for eachprofessional discipline both before and after energy modelingwas completed. A lead Cost Estimator worked with the COSestimators and the U.S. Army Engineer Research and Devel-opment Center/Construction Engineering Research Labora-tory (ERDC/CERL) to assess what study findings may beincorporated under current project programming and howmuch additional funding will be necessary to incorporate allstudy findings into each facility type for the FY13 MILCONprogram. A webinar was held with representatives fromaffected installations in the FY13 MILCON program andlessons learned will be shared with COSs and Army Installa-tions staff. Operations and maintenance (O&M) impacts onstaff at the Installations level and long-term energy efficiencyof the buildings were also considered.

The energy efficient packages started with a base packageof low-energy features determined by CERL and NREL.These features focused specifically on a passive houseapproach, low infiltration rates, improved lighting strategies,reduced hot water usage and improved plug load levels thatcould then be modeled in combination with various HVACfeatures and technologies in an iterative process. By modelingthe various packages across different climate zones, energyusage and savings could be compared between the low-energyfeatures.

The energy use baseline, target energy budgets, andenergy savings were developed using different sets of technol-ogies, and were analyzed for the representative model of theUEPH barrack building used for this study is based on theinformation provided by the USACE Fort Worth District – thebarracks Center of Standardization. Energy efficiency tech-nology candidates were selected based on previous CERLstudies of Army barracks that outlined energy and IAQ (moldand mildew) related issues in existing facilities. EEMsselected based on previous studies and practical conditions atthe bases, recommendations of design teams, problems/issuesin existing facilities.

The goal of the integrated optimization process is to findthe optimum for the entire system. Hence, each elementrequires consideration. This process can be analyzed in severalsteps including a debate over whether to conserve energy firstor just generate energy with renewable alternatives. Figure 1shows the theoretical path and process for each individual

2 CH-12-008

building optimization. Point 1 is the base case buildingrequired to be built to the local code body requirements and theTotal Cash flow is the annual mortgage or financed cost plusthe energy cost. To get to Point 2, it is more cost effective toadd energy efficient technologies instead of renewables and isthe lowest annual cost (Point 2). One would not add renew-ables from Point 2 since many more energy efficiency tech-nologies that are more cost effective than adding renewablescan still be added. Point 3 is reached when the annual costequals the base-case building built to code, although at thatpoint, the building is now much more energy efficient and inmany cases much more comfortable. Continuing to add energyefficiency measures beyond Point 3 to the building, one even-tually reaches the crossover point, Point 4, where implement-ing energy generation systems, or supply technologies is morecost-effective than adding further energy efficiency options.By definition, this crossover (Point 4) marks the point wherethe building is “Net Zero Ready.” Point 4 is normally at 50%to 80% savings depending on building and location.

All energy simulations for the UEPH were carried outwith EnergyPlus. The first step in this whole building energysimulation project was to define the baseline building modelwhich is designed based on the Fort Worth District plans forthe Fort Leavenworth project. For this study, the GermanPassivhaus (passive house) standards were used to go beyondthe current ASHRAE standards and develop ultra-low energybuildings.

BUILDING DESCRIPTION

Unaccompanied Enlisted Personnel Housing (UEPH orbarracks) is a cross between an apartment building and college

dormitory. Within the Army, the different sizes of barracks arebased on the number of soldiers living in them. The represen-tative model of the UEPH barrack building used for this studyis based on the information provided by the USACE FortWorth District – the Barracks Center of Standardization. Themodel used for this study contained 56 double occupancyunits. Each apartment unit has two bedrooms with a storagearea, one shared bathroom, a kitchen, a mechanical room, anda storage area (Figure 2). The first floor has 18 units, a laundryroom, a common area, a mechanical room, and a storage area.The second and third floors have 19 units. Each floor is18,257 ft2 [1696 m2] and the building is 54,771 ft2 [5088.4m2], and Figure 3 shows an elevation view of the building anda rendering of the baseline computer model.

LOCATIONS

Fifteen locations were selected to represent 15 climatezones in the United States. EEMs were modeled for eachbuilding type across 15 locations. The 15 locations wereselected to represent 15 American Society of Heating, Refrig-erating and Air-Conditioning Engineers (ASHRAE) climatezones in the United States. The locations selected were repre-sentative cities for the climate zones. Colorado Springs wasselected for climate zone 5B instead of Boise, ID, to moreclosely align with the installations at Fort Carson, CO. Table 1lists the 15 climate zones and the cities used to represent them.

ENERGY MODELING

The energy simulations were completed using EnergyPlusversion 2.0 (DOE 2008). Table 2 lists the modeling assump-tions used in the baseline and energy efficient models. Customsoftware developed by Big Ladder Software was used to para-metrically construct the EnergyPlus models and manage theruns, utilizing multi-core processors when available.

The approach to modeling the energy efficiency improve-ments was to add one improvement at a time, starting with theenvelope, then infiltration, and then HVAC. The followingsections describe the approach to modeling each of these areas.

IMPROVED BUILDING ENVELOPE

Significant energy use reduction by buildings can beachieved by minimizing the impact of the external environ-ment on the building heating and/or cooling loads. While thecurrent advanced buildings practice in the United States isbased on the ASHRAE Standards 90.1 (2010) and 189.1(2009), the highest levels of insulation, windows, and air infil-tration for building energy envelope efficiency for obtainingultra-low energy buildings are the German Passive House(Passivhaus) standard. The Passivehaus standard was devel-oped by professors Bo Adamson of Lund University, Sweden,and Wolfgang Feist of the Institut für Wohnen und Umwelt(Institute for Housing and the Environment, Germany)followed by the Swiss MINENERGY-P standard.

For this study, the Passive House standards were used togo beyond the current ASHRAE standards. The basic concept

Figure 1 Lowest cost path to a building configuration thatuses net zero energy.

CH-12-008 3

Figure 2 A Section of the first floor plan for the UEPH barracks.

Figure 3 Elevation view and rendering of the energy simulation model.

4 CH-12-008

behind the passive house approach is a well insulated and veryairtight building to reduce the amount of energy required toheat, ventilate, and cool it. Typical Passive House character-istics for central European locations include:

• Airtight building shell ≤0.6 ach @ 50 Pa pressure differ-ence (~0.11 cfm/ft2 [0.56 L/s/m2] of the building enve-lope area at 75 Pa pressure difference) measured byblower-door test

• Annual heat requirement ≤15 kWh/m2/year (≤4.75kBtu/ft2/year)

• Primary Energy ≤ 120 kWh/m2/year (38.1 kBtu/ft2/year)• Window U-value ≤ 0.8 W/m2/K (0.14 Btu/h/ft2/°F)• Ventilation system with heat recovery with ≥75% effi-

ciency and low electric consumption @ 0.45 Wh/m3

(0.043 Btu/ft3)• Thermal Bridge Free Construction ≤0.01 W/m·K

(≤0.0058 Btu/(ft·°F))

Since 1996, more than 20,000 buildings meeting thesestandards were built and retrofitted around the world, primar-ily in Germany, Austria, and Switzerland, and they includeresidential, office, schools, and supermarket buildings. A greatmany of these buildings have been extensively monitored by

the PassivHaus Institut in Darmstadt. European UnionCommission intends (EU Parliament resolution of 31 January2008 on an Action Plan for Energy Efficiency) to place a bind-ing requirement that all new buildings needing to be heatedand/or cooled be constructed to Passive House or equivalentnon-residential standards from 2011 onwards.

ERDC-CERL researchers in collaboration with GeorgZielke, Architekturburo Zielke Passivhauser and Dr. BertholdKauffman, Passivhaus Institut, Germany, have developed thefollowing interpretation of Passive House characteristics ofthe building envelope to be applied to U.S. constructionspecifics for all 15 DOE climate zones.

Air Tightness

According to the USACE ECB 29 2009, the air leakagerate of the building envelope shall not exceed 0.25 CFM/ft2

(1.27 L/s/m2) at a pressure differential of 0.3 inch w.c. (75 Pa)for new and renovation construction projects. In 2010, morethan 200 buildings on Army Installations were constructedand renovated to meet or exceed this requirement (achievingair tightness of 0.10 cfm/ft2 (0.51 L/s/m2) or better was notuncommon) at no or minimal additional cost. Based on thisexperience and on industry consensus, the new level for airtightness was proposed to be lowered to 0.15 CFM/ft2 (0.76 L/s/m2) at a pressure differential of 0.3 inch w.c. (75 Pa).

Insulation of Nontransparent Building Components

Types of insulation materials used depend on construc-tion practices, the climate, and other factors. Typical insulat-ing materials used in the United States include wood-fiberboards, cellulose, foam glass, mineral wool, fiberglass,extruded polystyrene, expanded polystyrene, polyurethaneboards, perlite, etc. The most commonly used materials arewood-fiber boards (λ = 0.045 W/mK), mineral wool (λ =0.035-0.040 W/mK) and expanded polystyrene (λ = 0.035-0.040 W/mK). These low-cost materials are well suited formost new construction and retrofit situations. Table 3 listsinsulation requirements (R-values) for walls and roof in differ-ent climate conditions resulted from this study compared tocurrent Army requirements as well as requirements from theASHRAE Std 90.1 (2010, 2007), ASHRAE Std 189.1 and theASHRAE Advanced Energy Guides.

In addition to energy conservation, improved buildinginsulation and air tightness result in a more stable roomtemperature between day and night, higher internal wallsurface temperature in winter, and lower component internalwall temperature in summer. Higher wall temperature inwinter reduces the risk that mold or mildew may occur on theinternal wall surfaces and improves therefore the quality of lifein a building.

Business As Usual provides the least first cost insulationlevel. ASHRAE determines the minimum insulation level thatwill be mandated by code using a Life Cycle Cost optimizationalgorithm. The current ASHRAE Optimization parametersused for the 2010 development were national average

Table 1. Climate Zones and Cities Usedfor Simulations

Climate Zone

CityHDD,

Base 65°F(18 °C)

CDD,Base 50°F

(10 °C)

1A Miami, FL 200 9474

2A Houston, TX 1599 6876

2B Phoenix, AZ 1350 8425

3A Memphis. TN 3082 5467

3B El Paso, TX 2708 5488

3C San Francisco, CA 3016 2883

4A Baltimore, MD 4707 3709

4B Albuquerque, NM 4425 3908

4C Seattle, WA 4908 1823

5A Chicago, IL 6536 2941

5B Colorado Springs, CO 6415 2312

6A Burlington, VT 7771 2228

6B Helena, MT 7699 1841

7A Duluth, MN 9818 1536

8A Fairbanks, AK 13940 1040

CDD = Cooling degree Days; HDD – Heating Degree Days

CH-12-008 5

combined heating fuel prices at $1.22/therm ($0.042/kWh), ablended cooling fuel price at $0.09/kWh, and a scalar ratio of20. But for energy security planning and risk analysis it isnecessary to look at increased fuel prices to see the recom-mended insulation levels at higher energy prices. Thisscenario assumed fuel prices were triple, or $3.50/therm($0.119/kWh) and $0.30/kWh. This is the energy securityscenario that we must plan for today since wall and roof insu-lation level cannot be cost effectively retrofitted to these levelsat a later date.

In this example (Figure 4), the ASHRAE life cycle costcurves recommended for Climate Zone 2 going from R-25 toR-50 (R-4.4 to R-8.8) for roof insulation entirely above deckand from R-13 + R-7.5ci to R-13 + R-28.1ci (R-2.29 + R-1.32cito R-2.29 + R-4.95ci). This level would exceed the Passive

House insulation levels that are listed in Table 3, indicating thatthe Passive House levels are justified when higher energyprices are considered as part of the risk analysis. Tables 3 and4 list the values that were used in this study.

INFILTRATION

It is difficult to obtain good data and develop detailedmodels of infiltration. Every building has different leakagecharacteristics, and the infiltration varies with operation of thebuilding and ambient conditions. Most often an averageconstant infiltration rate in the energy model is used. Severalassumptions still have to be made to go from these leakagerates to the simple infiltration model in the building simulationprogram. The infiltration at these leakage rates and pressures

Table 2. Model Assumptions

Building Component Baseline Building Model Efficient Building Model

Area 54,771 ft2 (5088.4 m2) Same as baseline

Floors 3 Same as baseline

Orientation Long axis running east and west Same as baseline

Aspect Ratio Same as baseline

Window to wall ratio 15% on north and south facades Same as baseline

Window type Standard 90.1-2004 See Table 4

Wall construction Steel frame Same as baseline

Wall insulation Standard 90.1-2004 See Table 3

Roof construction Sloped roof and attic with insulation at the roof level

Sloped metal roof and attic with insulation at the ceiling

level

Roof insulation

Standard 90.1-2004 equal to the “insulation entirely

above deck” See Table 3

Infiltration 0.25 cfm/ft2 @ 0.3 inch w.c. 0.15 cfm/ft2 @ 0.3 inch w.c.

Lighting

Rooms - 1.1 W/ft2 (10.8 W/m2)

Corridors: 0.5 W/ft2 (6.5 W/m2)

See Table 6

Rooms – 0.6 W/ft2 (10.8 W/m2)

Corridors: 0.5 W/ft2 (6.5 W/m2)

See Table 6

Plug loads 1.7 W/ft2 (18.3 W/m2) plus refrigerator and range 0.835 W/ft2 (8.99 W/m2) plus refrigerator and range

Temp set points70°F (21.1C) heating; 75°F (23.9 C) cooling, no set

backSame as baseline

HVAC

DOAS (2.87 COP), central natural gas boiler hot

water system (0.80 Et), 4-pipe Fan Coil Units (FCUs)

for zone temperature control.

Sys Base: DOAS with DX dehumidification (4.4 COP),

gas heating coil (0.95 Et), ERV (80% effectiveness), 4-

pipe FCUs for zone temperature control.

Sys Optional: DOAS with DX dehumidification, gas

heating coil (0.95 Et), ERV (80% effectiveness), radiant

heating and cooling for zone temperature control.

DHW Standard natural gas boiler (0.8 Et) Condensing natural gas boiler (0.95 Et)

6 CH-12-008

CH-12-008 7

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5R

-25

R-2

5R

-25

R-3

0R

-30

R-3

0R

-30

R-3

0R

-30

R-3

0R

-35

R-3

5

189.

1–20

09—

Roo

fs in

sula

tion

abov

e de

ckR

-20

R-2

5R

-25

R-2

5R

-25

R-2

5R

-25

R-2

5R

-25

R-2

5R

-25

R-3

0R

-30

R-3

5R

-35

ASH

RA

E A

ED

G—

Roo

fs in

sula

tion

abov

e de

ckR

-15

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

90.1

–200

7—R

oofs

insu

latio

n ab

ove

deck

R-1

5R

-15

R-1

5R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-2

0R

-20

R-3

0

8 CH-12-008

Tabl

e 4.

Win

dow

Val

ues

1A2A

2B3A

3B3C

4A4B

4C5A

5B6A

6B7A

8A

Mia

mi,

FL

Hou

ston

, T

XP

hoen

ix,

AZ

Mem

phis

, T

NE

l Pas

o,

TX

San

Fra

ncis

co,

CA

Bal

tim

ore,

M

DA

lbuq

uerq

ue,

NM

Seat

tle,

W

AC

hica

go,

IL

Col

orad

o Sp

ring

s,

CO

Bur

lingt

on,

VT

Hel

ena,

M

TD

ulut

h,

MN

Fai

rban

ks,

AK

Win

dow

s

Pas

sive

Hau

sW

indo

w S

peci

fica

tion

s

U-V

alue

(B

tu/h

/ft2 /°

F)0.

260.

260.

260.

260.

260.

260.

180.

180.

180.

180.

180.

180.

180.

180.

18

U-V

alue

(W

/m2 /K

)1.

481.

481.

481.

481.

481.

481.

021.

021.

021.

021.

021.

021.

021.

021.

02

SHG

C0.

250.

250.

250.

390.

390.

390.

390.

390.

390.

490.

490.

490.

490.

490.

49

VT

>0.

50>

0.50

>0.

50>

0.50

>0.

50>

0.50

>0.5

0>

0.50

>0.5

0>

0.50

>0.

50>

0.50

>0.

50>0

.50

>0.

50

WW

R<3

0%<

30%

<30

%<

30%

<30

%<3

0%<

30%

<30

%<3

0%<

30%

<30%

<30%

<30

%<3

0%<

30%

Arm

y W

BD

G—

Win

dow

Spe

cifi

cati

ons

U-V

alue

(B

tu/h

/ft2 /°

F)0.

450.

450.

450.

450.

450.

450.

420.

420.

420.

420.

420.

420.

420.

330.

33

U-V

alue

(W

/m2 /K

)2.

562.

562.

562.

562.

562.

562.

382.

382.

382.

382.

382.

382.

381.

871.

87

SHG

C0.

250.

250.

250.

370.

370.

370.

390.

390.

390.

390.

390.

390.

39N

RN

R

VT

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

ASH

RA

E 1

89.1

Win

dow

Spe

cifi

cati

ons

U-V

alue

(B

tu/h

/ft2 /°

F)1.

200.

750.

750.

550.

550.

550.

450.

450.

450.

450.

450.

450.

450.

350.

35

U-V

alue

(W

/m2 /K

)6.

814.

264.

263.

123.

123.

122.

562.

562.

562.

562.

562.

562.

561.

991.

99

SHG

C0.

250.

250.

250.

250.

250.

250.

350.

350.

350.

350.

350.

400.

400.

450.

45

VT

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

ASH

RA

E 9

0.1-

2007

W

indo

w S

peci

fica

tion

s

U-V

alue

(B

tu/h

/ft2 /°

F)1.

200.

750.

750.

650.

650.

650.

550.

550.

550.

550.

550.

550.

550.

450.

45

U-V

alue

(W

/m2 /K

)6.

814.

264.

263.

693.

693.

693.

123.

123.

123.

123.

123.

123.

122.

562.

56

SHG

C0.

250.

250.

250.

250.

250.

250.

400.

400.

400.

400.

400.

400.

40N

RN

R

VT

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

Arm

y Pr

opos

ed

Arm

y R

equi

red

were calculated based on the total wall and flat roof area of thebuilding, then converted to a pressure of 5 Pa from 75 Paassuming a flow coefficient of 0.65. We assumed that the aver-age pressure drop across the building envelop is 0.02 inch w.c.(5 Pa). Wind pressure and temperature differentials across thebuilding envelope drive the infiltration and these drivingforces vary throughout the year; however, these variations arenot modeled in the simulations. We assume that a constant airchanges per hour will model the average effects over the year.Table 5 lists the infiltration at these two leakage rates.

The mechanical ventilation system pressurizes the build-ing by providing outside air equal to the building exhaust, plusthe air leakage at 0.02 inch w.c. (5 Pa). Infiltration is oftenassumed to go to zero when buildings are pressurized. Thisassumption is usually made because there is a lack of evidenceto about what really happens and how to model it in an energysimulation. We have assumed that the average uncontrolledinfiltration when the building is pressurized is reduced to 10%of the value calculated at 0.02 inch w.c. (5 Pa). The differencein the leakage rates between the two air tightness levels wasaccounted for in the outdoor ventilation rates for the baselineand energy efficient models.

VENTILATION

The ventilation was set to provide 90 CFM (42.5 L/s) ofoutside air to each apartment unit to make up for the bathroomexhaust and control humidity, which is greater than the venti-lation requirements from ASHRAE Standard 62.1-2004(ASHRAE 2004b) for the baseline model. This level of venti-lation is based on experience with Army barracks. Additionaloutside air was added to the whole building to make up for theleakage rate at 0.02 inch w.c. (5 Pa) pressurization (Table 5).For the efficient model, the ventilation air was reduced to 65CFM (30.7 L/s) per living unit with excess ventilation air perTable 5. The 65 CFM (30.7 L/s) was based on the standarddesign provided by the COS (Center of Standardization).

LIGHTING

The lighting analysis was completed by Atelier Ten andthe focus was on efficient lighting design, and not just improv-ing the efficiency of existing fixtures. An example of thecontrol strategies is listed in Table 6.

Lighting efficiency measures including lighting powerdensity reductions with control strategies for each zone weremodeled.

Figure 4 Insulation life cycle cost for business as usual and passiv haus.

CH-12-008 9

DOMESTIC HOT WATER

Hot water use was assumed to be used at 110°F (43.3 C)with a peak draw of 40 gal/h (295.5 L/hr) per unit from a 140°F(60 C) storage tank. The peak washing machine use per flooris assumed to be four loads per hour or 80 gal/h (363.7 L/hr)of 120°F (48.9 C) hot water, which is approximately 53 gal/h(241 L/hr) from a 140°F (60 C) storage tank.

Domestic hot water usage is calculated at two showers/day/person at 20 gal/shower (75.7 L/shower); along with 3-4flushes/person. Therefore water usage is 60 gal/person/day(272.8 L/person/day) for all water use with ~50% for hotwater. The current use is 30-35 gal/person/day (136.4 – 159 L/person/day) for hot water use, with a subset of 20 gal/person/

day for shower with a 2.0 gpm (0.15 L/s) on shower heads forthe baseline and then at 1.5 gpm (0.11 L/s) shower heads forthe efficient case. In the UEPH, hot water-use reduction can beachieved through the use of water-conserving fixtures, espe-cially shower heads and high efficiency washing machines.

PLUG LOADS

The modeling supported the findings of the previousEPACT study for each of the building types that plug loads area major source of energy usage, particularly in the UEPH. Forexample, in UEPH, the fraction of the total power consumed byplug loads increased from 29 percent in the baseline model to 43percent in the low-energy model. This would be indicative of all

Table 5. Infiltration Leakage Rates

0.25 cfm/ft2 (1.27 L/s/m2) 0.15 cfm/ft2 (0.76 L/s/m2)

ach at 0.3 in. w.c. (75 Pa) 2.98 1.79

ach at 0.02 in. w.c. (5 Pa) 0.51 0.31

Excess ventilation flow at 0.02 in. w.c. (cfm @ 5 Pa) 5832 3499

Excess ventilation flow at 5 Pa (L/s) 2752 1651

Table 6. Lighting Design by Atelier Ten

Design Criteria

Control Strategies

Technologies ApproachLevels

Automatic Interface

Space

Tar

get

Illu

min

ance

Tas

k, f

c(D

esig

n G

oal)

Tar

get

Lig

htin

g P

ower

Den

sity

, W

/ft2

Allo

wab

le L

ight

ing

Pow

erD

ensi

ty, W

/ft2

Swit

chin

g—(b

lank

)M

ulti

-Lev

el—

M

V—

Vac

ancy

(M

anua

l ON

/au

to O

FF

)O

—O

ccup

ancy

(A

uto

ON

/A

uto

OF

F)

Day

light

(e.g

., P

hoto

sens

ors)

Sche

dule

(e.g

., A

stro

nom

ical

tim

e cl

ock)

Lin

ear

Flu

ores

cent

Com

pact

Flu

ores

cent

Cer

amic

Met

al H

alid

e

Lig

ht E

mit

ting

Dio

des

Ove

rhea

d G

ener

al L

ight

ing

Ove

rhea

d A

mbi

ent

Lig

htin

g

Tas

k L

ight

ing

Wal

lwas

h/P

erim

eter

Lig

htin

g

Adj

usta

ble

Acc

ent

Lig

htin

g

Corridor 10 0.50 0.5 O 4 • •

LivingQuarters

5–30 0.60 1.1 V 4 4 4 • • •

Mechanical/Electrical

30 0.70 1.5 V 4 •

Restroom/Shower

20 0.80 0.9 V 4 4 4 • •

Stair 10 0.50 0.6 M O 4 •

Storage(General)

10 0.50 0.8 V 4 • •

10 CH-12-008

buildings where the overall energy usage is reduced withoutreducing the plug loads. The potential EEMs are:

• Use high-efficiency LED computer monitors.• Replace all desktop computers (100 W each) with lap-

top computers (30 W each).• Change computer power settings to standby when idle

for 15 minutes.• Implement the use of standby switching devices.• Eliminate personal printers, copiers, fax machines, and

scanners. Replace them with one or two multi-functionprint stations.

• If vending machines are in the building, use a load-man-aging device and de-lamp them.

• Turn miscellaneous electronics off when they are notbeing used or during unoccupied hours.

• Investigate more efficient task lighting, such as LEDtask lighting per work station.

• All plug load appliances and equipment are not createdequal in terms of energy usage. A prioritized list shouldbe developed that results in the greatest energy savingsfor least cost increase.

In the UEPH, the bedroom has a computer, stereo, televi-sion, and other smaller electronic devices for a plug loaddensity of 1.7 W/ft2 (18.3 W/m2). Each kitchen contains arefrigerator and an electric range. The refrigerator wasassumed to be very efficient with an average power consump-tion of 76 W, and the range was assumed to have a peak powerof 1,500 W. There are 14 washing machines in the building(four on the first floor and five on the second and third floors).With a 90% occupancy rate for the building, there are 140 occu-pants. Three loads per occupant per week for 420 loads/weekor 60 loads/day were assumed. ENERGY STAR® commercialwashing machines use approximately 20 gal (75.7 L) of waterper load and 0.60 kWh of electricity per load. The dryers wereassumed to use 1.5 kWh of electricity per load. Table 7 lists theschedules for the loads.

HVAC AND HOT WATER BOILER

The UEPH baseline HVAC system uses a DOAS (Dedi-cated Outdoor Air System) with condenser reheat. The spaceloads are met with 4-pipe fan coil units connected to a centralchiller and boiler in the baseline model and with radiant heat-ing and cooling in one of the energy efficient models. Thedomestic water-heating system in the baseline buildingmodels uses an 80 percent efficient boiler and the energy effi-cient models use a 95 percent efficient condensing boiler.

The ventilation was set to provide 90 cfm (42.5 L/s) ofoutside air to each apartment unit to make up for the bathroomexhaust and control humidity, which is greater than the venti-lation requirements from ASHRAE 62.1-2004 for the baselinemodel. Additional outside air was added to the whole buildingto make up for the leakage rate at 0.02 inch w.c. (5 Pa) pres-surization as shown in Table 5. For the efficient model, the

ventilation air was reduced to 65 cfm (30.7 L/s) per living unitwith excess ventilation air as listed in Table 5. The 65 cfm(30.7 L/s) was based on the standard design provided by theCOS.

The baseline HVAC system uses packaged single zone airconditioning (PSZ-AC) units with a natural gas furnace ineach room or zone. A high efficiency version of the baselineand a dedicated outdoor air system (DOAS) with fan coil unitswere considered for the energy efficient cases. The first systemwas modeled with an increase in coefficient of performance(COP) to 3.5, increased gas furnace efficiency to 0.9, andimproved fan efficiency. In the second case, the DOASprovided the building ventilation air and zone level fan coilunits were used to control zone loads. The DOAS included apackaged direct expansion coil for cooling and humiditycontrol, hot water coil for heating energy, and an energy recov-ery ventilator (ERV). The ERV was modeled with sensibleheat recovery only at 75% to 70% effectiveness at 75% to100% air flow. Later simulations included latent heat recovery.Frost control for the ERV was handled with the exhaust onlymethod in EnergyPlus, which bypasses the supply air aroundthe ERV to avoid frost conditions. The system was operatedwith an outdoor air temperature (OAT) reset on supply airtemperature (SAT). The SAT set point schedule was colderwith higher OAT and warmer with colder OAT. The set pointat high OAT was lower in the humid climates for better humid-ity control and higher in the dry climates for more energysavings. The space loads are met with 4-pipe fan coil unitsconnected to a central chiller and boiler.

The general HVAC strategy for Army buildings was toprovide high-efficiency HVAC systems that offset the sensibleheating and cooling loads in the spaces and to provide separatehigh-efficiency dedicated outdoor air systems (DOAS), whichincludes a Total Energy Recovery (TER) exhaust air system tohandle the ventilation requirements and the latent (moisture)load in the spaces. The outdoor air ventilation quantityprovided by the DOAS should maintain the building, includ-ing the hallways, at a slightly positive pressure relative tooutside to eliminate uncontrolled infiltration into the building.High-efficiency, variable-speed pumps and fans should beused throughout the HVAC system. High-efficiency boilersand chillers should be used in all cases.

The HVAC strategies and contained in the following listof energy efficient options that were considered:

• DOAS with condenser reheat and individual room fancoils for soldier comfort

• advanced HVAC systems; DOAS for ventilation, pres-surization and make-up air, with condenser heat recov-ery and Energy Recovery Ventilators, both sensible andtotal

• central exhaust that is used for heat recovery to pre-con-dition the ventilation air with Energy Recovery, sensibleand total recovery at 80 percent

CH-12-008 11

• High Efficiency Air Cooled Chiller package, COP from2.87 to 4.4

• condensing boilers, 80 percent to 95 percent efficient

• variable and high-efficiency fans and pumps.

• radiant heating and cooling in the ceilings

• ground-source heat pump (GSHP).

• Indirect Evaporative Pre-Cooling, the Sensible heatrecovery coil in the exhaust air stream is sprayed withwater to pre-cool outside air in the DOAS

• radiant heating and cooling in the ceilings

SOLAR HOT WATER

The Sustainable Design and Development Policy Update,dated October 27, 2010 from the Assistant Secretary of theArmy – Installations, Energy, and Environment, mandatesthat, beginning in FY13, all new construction projects with anaverage daily non-industrial hot water requirement of 50 gal(189 L) or more, and located in an area receiving an annualaverage of 4 kWh/m2/day (147 kBtu/ft2/day) or more will bedesigned to provide a minimum of 30 percent of the facility’shot water demand by solar water heating. EISA 2007, Section523, has a similar requirement for all new Federal buildings in

Table 7. UEPH Apartment Unit Internal Load Schedules

Hr Occupancy Lighting Plug Loads Service Hot Water

Wk Sat Sun Wk Sat Sun Wk Sat Sun Wk Sat Sun

1 0.80 0.75 0.75 0.10 0.10 0.10 0.30 0.30 0.30 0.00 0.00 0.00

2 0.80 0.75 0.75 0.10 0.10 0.10 0.30 0.30 0.30 0.00 0.00 0.00

3 0.80 0.75 0.75 0.10 0.10 0.10 0.30 0.30 0.30 0.00 0.00 0.00

4 0.80 0.75 0.75 0.10 0.10 0.10 0.30 0.30 0.30 0.00 0.00 0.00

5 0.80 0.75 0.75 0.20 0.20 0.20 0.30 0.30 0.30 0.00 0.00 0.00

6 0.80 0.75 0.75 0.40 0.30 0.30 0.30 0.30 0.30 0.10 0.10 0.10

7 0.70 0.65 0.75 0.50 0.50 0.50 0.30 0.30 0.30 0.20 0.20 0.20

8 0.60 0.60 0.70 0.70 0.50 0.70 0.50 0.35 0.30 0.10 0.10 0.10

9 0.50 0.50 1.00 0.20 0.20 0.20 0.50 0.40 0.50 0.00 0.00 0.00

10 0.25 0.25 0.00 0.20 0.20 0.20 0.30 0.40 0.50 0.00 0.00 0.00

11 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

12 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

13 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

14 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

15 0.20 0.20 0.20 0.10 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

16 0.20 0.20 0.20 0.10 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

17 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.50 0.00 0.00 0.00

18 0.20 0.20 0.20 0.50 0.50 0.50 0.30 0.30 0.50 0.10 0.10 0.10

19 0.30 0.30 0.30 0.70 0.50 0.50 0.50 0.50 0.50 0.10 0.10 0.10

20 0.50 0.50 0.50 0.70 0.50 0.50 0.60 0.50 0.40 0.10 0.10 0.10

21 0.50 0.50 0.50 0.70 0.50 0.50 0.70 0.50 0.40 0.00 0.00 0.00

22 0.70 0.50 0.50 0.50 0.50 0.50 0.70 0.50 0.40 0.00 0.00 0.00

23 0.70 0.50 0.50 0.40 0.40 0.40 0.50 0.50 0.40 0.00 0.00 0.00

24 0.80 0.75 0.75 0.20 0.20 0.20 0.30 0.50 0.30 0.00 0.00 0.00

Peak 2 occ/unit 0.6 W/ft2 (6.5 W/m2) 0.835 W/ft2 (9 W/m2) 1.5 gpm/shower (0.11 L/s)

12 CH-12-008

all locations if cost-effective. In the United States, differenttypes of solar water heating systems are available for use instandalone buildings. For this study, solar hot water wasdeemed feasible for UEPH based on the 30 percent renewableenergy requirement; energy savings were modeled for thisbuilding type.

RESULTS

For the UEPH, the Dormitory/Fraternity/Sorority cate-gory was chosen from the CBECS, because it was determinedto be the closest match to the UEPH facility. As will be seenfrom the results in this section, CBECS building categoriesand their related EUIs are not directly comparable to Armybuilding types. This directly affects whether a building meetsor falls short of the EISA 2007 targets for 2015. Annual EUIfor each climate zone was determined from the CBECS dataand compared to the energy baseline for the designed building.The target EUI is 35 percent of the CBECS values, or a 65percent increase in efficiency, which is a very aggressive targetrequired by the EISA 2007 legislation.

Modeling was completed for each baseline building plusadditional EEM packages for all 15 climate zones. LowEnergy Packages for all building types included increasedexterior insulation, daylighting and daylighting controls,DOAS HVAC systems, improved pumps and fans, pressuriza-tion and make-up air, top-tier ENERGY STAR® appliancesand products, and solar hot water. The results are shown intables and figures below with the cumulative percent savingscompared to the baseline building. In the tables and figuresbelow, the Baseline Building is the base building model fromeach of the COS standard designs. Each EEM or Low EnergyVersion is applied cumulatively to the baseline, starting withV1 (e.g., lighting load and electric power load density reduc-tion for UEPH), then V2, V3, and finally V4. V4 is consideredthe baseline high-performance or low-energy package foreach building. Then EEMs V5–V13 are applied individuallyor in combination to V4 to compare the different HVAC alter-natives. Table 8 lists and Figure 5 shows the source resultsnecessary for EISA 2007 compliance for each building.

As shown in Figure 5, the initial EEMs show goodimprovement and then there are diminishing returns. Evenwith all of these technologies applied, the targets could not beachieved; only when internal loads (building mission) arereduced further do we start seeing further improvements.Another interesting result is that when source fuels are calcu-lated and not just site energy, the savings from Ground SourceHeat Pumps (GSHP) are not as good as expected since muchof the advantages are negated when the source fuels for elec-tricity energy production are considered.

Buildings built or retrofitted to “passive house” require-ments and using advanced “low exergy” systems to satisfyremaining heating and cooling needs eventually become inter-nal load dominated. The remaining energy requirements willbe dominated by electrical power needs for lighting, appli-ances and internal processes and by domestic hot water needs.

Figure 6 shows the improvements made toward the EISAgoals, and illustrates that, without considering further internalload reduction and the addition of solar hot water (buildingmission), the EISA targets cannot be met by EEMs alone.

Tables 9 and 10 list the baseline component energy for theUEPH by climate zone, and indicate that the mission (lights,plug loads, and hot water) make up from 50 to 86% of the loadvarying by climate zone.

Figure 6 shows that even after the improved lightingdesign, reducing hot water consumption with low flow showerheads and the improving plug loads by 50%, there is a signif-icant percentage of load that remains, ranging from 75 to 94%of the load. With EISA 2007, the total energy is now consid-ered and important. Unlike the EPAct 2005, in which the plugloads were considered unregulated, they are now a significantpart of the problem.

According to the Office of the Assistant Secretary of theArmy, installations must first implement aggressive conserva-tion and efficiency efforts while benchmarking energyconsumption to identify further opportunities. The next step isto utilize waste energy or to “re-purpose” energy. Boiler stackexhaust, building exhausts or other thermal energy streamscan all be utilized for a secondary purpose. Co-generationrecovers heat from the electricity generation process. Thebalance of energy needs then are reduced and can be met byrenewable energy projects.

Figure 7 shows Point 1 is the base case building, which iseither an existing building, or one that must be built to localcode body requirements. If you add renewables at this point,the total annual cost of the net zero energy building will be asshown in point 8. The normal path was explained in the“Approach” section above, where reaching Point 4 was theindividual building “Net Zero Ready” point. Depending on themix of buildings in the cluster, the combined fossil fuel basedenergy reduction in this cluster can reach 30 to 60%. Addingrenewables from point 4 characterizing building cluster willresult in total annual cost of the net zero energy cluster ofbuilding as shown in point 7. Alternatively, the cluster ofbuildings characterized from point 4 can be connected to a co-generation plant, which will require relatively minor invest-ments compared to the cost of decentralized boilers and chill-ers for single buildings, but results in a significant fossil fuelreduction due to utilization of waste heat accompanying elec-tricity generation. This heat can be used either to satisfy heat-ing, cooling and domestic hot water needs of the cluster ofbuildings under consideration, or be exported to another build-ing cluster. By connecting to CHP plant (Combined Heat andPower), fossil fuel usage by the building cluster (point 5) canbe further reduced by 15-20% in a cost effective way. Frompoint 5, adding renewable generation becomes the cost effec-tive supply option. This point, by definition, occurs when thebuilding “cluster” is “Net Zero Ready.” Figure 7 shows thisprocess.

From the building cluster process diagram (Figure 7), itcan be seen that using combined heat and power (CHP) or

CH-12-008 13

14 CH-12-008

Ta

ble

8. U

EP

H E

nerg

y E

ffic

ienc

y M

easu

res

Res

ults

(I-P

)

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

Weather Region

2003 CBECS Dormitory/Fraternity/SororityTotal Source Fuel

EISA 2007 Fossil FuelSource Energy Target

EISA 2007 Source TargetEnergy Budget

Baseline Energy Budget

Lighting Load and Electric Power LoadDensity Reduction EPD

from 1.67 W/ft2 to 0.835 W/ft2

Passive Haus Insulation Specification;Increased Insulation and Air Tightness,Reduce OA Pressurization Air to 65 cfm

Due to Air Tightness

Increase Chiller and Boiler Efficienciesand All Variable High Efficiency Pumps and Fans

Reduce HW with 1.5 GPM Shower Heads

Energy Recovery (ERV) with V4

Indirect Evap Pre-Cooling with V4

Radiant Heating and Cooling with V4

ERV and Radiant with V4

ERV and Indirect Evap Pre-Cooling with V4

ERV, IDEC, and Radiant with V4

GSHP and ERV with V4

Reduction in Equipment Loads with Premium Equipmentin Soldiers Rooms, Added to GSHP and ERV (V11) (0.5 W/ft2)

Reduction in Equipment Loads withPremium Equipment in Soldiers Rooms,

Added to ERV, IDEC, and Radiant (V10) (0.5W/ft2)

1A_M

iam

i_FL

208

180

7320

915

113

311

311

111

010

310

810

810

399

111

9987

2A_H

oust

on_T

X19

415

868

195

143

124

108

106

104

9910

210

198

9510

897

83

2B_P

hoen

ix_A

Z19

513

168

186

132

115

101

100

9689

9592

8884

101

8972

3A_M

emph

is_T

N17

613

062

188

138

120

106

103

9999

9996

9591

106

9580

3B_E

lPas

o_T

X17

212

660

171

119

107

9795

9290

9189

8884

100

8872

3C_S

anFr

anci

sco_

CA

150

116

5215

210

798

9188

8788

8584

8784

9585

73

4A_B

altim

ore_

MD

178

123

6218

313

811

710

510

296

9998

9393

9010

898

79

4B_A

lbuq

uerq

ue_N

M16

494

5717

012

110

899

9691

9292

8788

8410

492

73

4C_S

eattl

e_W

A15

990

5616

212

010

496

9388

9290

8588

8597

8774

5A_C

hica

go_I

L18

511

865

187

143

121

109

105

9610

310

193

9490

104

9480

5B_C

olor

adoS

prin

gs_

CO

167

114

5917

212

511

110

299

9196

9588

9086

106

9575

6A_B

urlin

gton

_VT

203

130

7118

614

412

110

910

595

104

102

9293

9011

110

180

6B_H

elen

a_M

T18

210

764

179

136

115

105

102

9210

098

8991

8710

897

77

7A_D

ulut

h_M

N20

611

672

193

153

126

114

110

9610

910

693

9592

116

106

82

8A_F

airb

anks

_AK

237

136

8321

517

814

212

712

310

212

211

910

010

299

117

107

90

CH-12-008 15

Tabl

e 8.

UE

PH

Ene

rgy

Eff

icie

ncy

Mea

sure

s R

esu

lts (S

I)

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

Weather Region

2003 CBECS Dormitory/Fraternity/SororityTotal Source Fuel

EISA 2007 Fossil FuelSource Energy Target

EISA 2007 Source TargetEnergy Budget

Baseline Energy Budget

Lighting Load and Electric Power LoadDensity Reduction EPD from 18 W/m2 to 9 W/m2

Passive Haus Insulation Specification;Increased Insulation and Air Tightness,

Reduce OA Pressurization Air to 30.7 L/s Due to Air Tightness

Increase Chiller and Boiler Efficienciesand All Variable High Efficiency Pumps and Fans

Reduce HW with 0.11 L/s Shower Heads

Energy Recovery (ERV) with V4

Indirect Evap Pre-Cooling with V4

Radiant Heating and Cooling with V4

ERV and Radiant with V4

ERV and Indirect Evap Pre-Cooling with V4

ERV, IDEC and Radiant with V4

GSHP and ERV with V4

Reduction in Equipment Loads with Premium Equipmentin Soldiers Rooms, Added to GSHP and ERV (V11)

Reduction in Equipment Loads with Premium Equipmentin Soldiers Rooms, Added to ERV, IDEC, and Radiant (V10)

1A_M

iam

i_FL

655

568

229

658

477

420

355

351

348

324

340

340

325

314

350

311

276

2A_H

oust

on_T

X61

149

821

461

545

239

133

933

332

731

332

131

831

029

834

130

526

3

2B_P

hoen

ix_A

Z61

541

321

558

841

836

231

931

430

327

929

929

227

726

431

828

122

6

3A_M

emph

is_T

N55

641

019

559

243

737

833

432

631

331

131

330

230

128

833

530

125

3

3B_E

lPas

o_T

X54

339

719

054

037

433

930

630

029

128

328

728

027

726

531

427

722

8

3C_S

anFr

anci

sco_

CA

472

366

165

479

338

308

288

279

275

277

269

266

274

264

300

267

231

4A_B

altim

ore_

MD

562

388

197

577

434

370

331

322

303

313

310

292

294

283

341

308

249

4B_A

lbuq

uerq

ue_N

M51

629

718

153

638

134

131

130

228

729

229

027

627

826

632

729

123

0

4C_S

eattl

e_W

A50

128

417

551

037

932

830

429

427

929

128

326

927

726

730

727

523

5

5A_C

hica

go_I

L58

437

220

558

945

038

134

233

230

332

531

929

229

728

532

829

625

3

5B_C

olor

adoS

prin

gs_

CO

528

360

185

543

395

351

321

311

288

304

299

278

283

272

336

301

237

6A_B

urlin

gton

_VT

639

410

224

587

455

380

344

332

299

328

320

289

295

284

350

319

252

6B_H

elen

a_M

T57

533

820

156

342

836

433

232

128

931

631

028

028

627

534

030

724

2

7A_D

ulut

h_M

N64

936

622

760

848

339

836

034

630

334

433

529

330

129

136

533

426

0

8A_F

airb

anks

_AK

746

429

261

678

561

449

401

387

323

385

376

315

323

313

368

338

283

16 CH-12-008

Tabl

e 8.

UE

PH

Ene

rgy

Eff

icie

ncy

Mea

sure

s C

umu

lativ

e %

Sav

ings

(I-P

and

SI)

V0

V1

V2

V3

V4

V5

V6

V7

V8

V9

V10

V11

V12

V13

Cum

ulat

ive

% S

avin

gs

V

1-V

0V

2-V

0V

3-V

0V

4-V

0V

5-V

0V

6-V

0V

7-V

0V

8-V

0V

9-V

0V

10-V

0V

11-V

0V

12-V

0V

13-V

0

1A–2

8%–3

6%–4

6%–4

7%–4

7%–5

1%–4

8%–4

8%–5

1%–5

2%–4

7%–5

3%–5

8%

2A–2

7%–3

6%–4

5%–4

6%–4

7%–4

9%–4

8%–4

8%–5

0%–5

1%–4

5%–5

0%–5

7%

2B–2

9%–3

8%–4

6%–4

7%–4

8%–5

2%–4

9%–5

0%–5

3%–5

5%–4

6%–5

2%–6

2%

3A–2

6%–3

6%–4

4%–4

5%–4

7%–4

7%–4

7%–4

9%–4

9%–5

1%–4

3%–4

9%–5

7%

3B–3

1%–3

7%–4

3%–4

4%–4

6%–4

8%–4

7%–4

8%–4

9%–5

1%–4

2%–4

9%–5

8%

3C–3

0%–3

6%–4

0%–4

2%–4

3%–4

2%–4

4%–4

4%–4

3%–4

5%–3

7%–4

4%–5

2%

4A–2

5%–3

6%–4

3%–4

4%–4

8%–4

6%–4

6%–4

9%–4

9%–5

1%–4

1%–4

7%–5

7%

4B–2

9%–3

7%–4

2%–4

4%–4

7%–4

6%–4

6%–4

9%–4

8%–5

0%–3

9%–4

6%–5

7%

4C–2

6%–3

6%–4

0%–4

2%–4

5%–4

3%–4

5%–4

7%–4

6%–4

8%–4

0%–4

6%–5

4%

5A–2

4%–3

5%–4

2%–4

4%–4

9%–4

5%–4

6%–5

0%–5

0%–5

2%–4

4%–5

0%–5

7%

5B–2

7%–3

5%–4

1%–4

3%–4

7%–4

4%–4

5%–4

9%–4

8%–5

0%–3

8%–4

5%–5

6%

6A–2

2%–3

5%–4

1%–4

3%–4

9%–4

4%–4

5%–5

1%–5

0%–5

2%–4

0%–4

6%–5

7%

6B–2

4%–3

5%–4

1%–4

3%–4

9%–4

4%–4

5%–5

0%–4

9%–5

1%–4

0%–4

6%–5

7%

7A–2

1%–3

4%–4

1%–4

3%–5

0%–4

3%–4

5%–5

2%–5

1%–5

2%–4

0%–4

5%–5

7%

8A–1

7%–3

4%–4

1%–4

3%–5

2%–4

3%–4

5%–5

4%–5

2%–5

4%–4

6%–5

0%–5

8%

Ave

rage

% S

avin

gs–2

6%–3

6%–4

2%–4

4%–4

8%–4

6%–4

6%–4

9%–4

9%–5

1%–4

2%–4

8%–5

7%

co-generation can lead to a more cost effective overall highperformance building solution. To get an idea of the magni-tude of the energy performance with CHP, a theoretical exer-cise was done to explore the limit of efficiency increase with100% electrical tracking. A moderate efficiency CHPmachine was chosen with an electrical efficiency of 36%and thermal efficiency of 44% to show the gains. Thisconcept can result in gains of another ~20 to 30%, whichprovide the means to meet the EISA requirements for 2015.Table 11 shows the results.

CONCLUSIONS

This study showed that the application of a Passive Housebuilding envelope concept (improved insulation package andair tightness specifications), advanced lighting strategies, andefficient HVAC systems can result in significant energysavings (site and source) in Army barracks in all climates. Thebarracks site energy can be reduced by 50 to 70% (dependingon climate) compared to the EPACT 2005 baseline. However,source energy use reduction goals of EISA 2007 (starting2015) cannot be achieved.

The application of the Passive House building envelopeconcept significantly reduces heating and cooling loads on theHVAC systems, and minimizes the size of different systemtypes selected. The HVAC system type can be selected usingmultiple criteria (e.g., greater energy efficiency, ease of oper-ation and maintenance, and ease of installation). Some heatingand cooling technologies that can reduce building site energy

use will result in increased use of source fuel. For example,while the use of ground-source heat pumps (GSHPs) mayappear to be an attractive choice to reduce building site energyconsumption, calculations made back to the source fuelsnegate many of the gains related to the use of GSHPs, and insome locations, show that GSHPs use more source fuel thanalternative technologies.

When buildings built or retrofitted to Passive Houserequirements with advanced lighting systems and highly effi-cient “low exergy” HVAC systems reach a theoretical mini-mum, the largest percentage of the remaining energy use in thebuilding will be related to its “mission”: lighting, plug loads,and domestic hot water usage. It is important to understandthese loads, to improve their efficiency, and to reduce their use.Additional savings may be achieved with measures related toimproved efficiency of power generation supplied to the build-ing (co- and tri-generation) and use of energy supplied fromrenewable energy sources. Connecting a building to aCombined Heat and Power (CHP) plant can further reduce thebuilding’s fossil fuel usage by 20-30% depending on the ther-mal-to-electric load ratio.

Results of this study will be incorporated in the Design-Build process under MILCON Transformation Program andthe suggested sets of energy conservation technologiesallowed for 44 to 58% energy savings in UEPH barracks. Therecommended HVAC requirements for the UnaccompaniedEnlisted Personnel Housing (UEPH) are:

Figure 5 UEPH energy efficiency measures (EEMs).

CH-12-008 17

• Dedicated Outside Air System (DOAS) for ventilation• energy recovery from building exhaust• improved chiller and boiler efficiencies• all variable high efficiency pumps and fans• pressurization and make-up air• condenser heat recovery for DOAS• separate ventilation for living area and laundry facilities

Note that predicted energy savings strongly depend on theclimate; building orientation and site specific building designwill vary. However implementation of developed energybudgets and sets of technologies included in prescriptive path,will streamline the facility design and construction processand reduce cost, thereby ensuring that newly constructed facil-ities will comply with the intent of the EPAct 2005 withoutjeopardizing their functional quality.

ACKNOWLEDGMENTS

This study was conducted by the U.S. Army Corps ofEngineers Headquarters under leadership of Daniel Carpioand in collaboration with the USACE Construction Engineer-ing Research Laboratory, and the National Renewable EnergyLaboratory. We would like to acknowledge the help of theprivate sector subject matter experts who participated on thisproject, as well as the Fort Worth District, who providedspecific input on building design, equipment and operation toaid in the modeling efforts presented in this report.

REFERENCES

The Energy Policy Act of 2005: http://thomas.loc.gov/cgi-bin/bdquery/z?d109:h.r.00006. U.S. Congress (2005).Energy Policy Act of 2005, Pub. L. No. 109-58, 119Stat. 594 (2005). Washington, DC.

The Energy Independence and Security Act of 2007: http://thomas.loc.gov/cgi-bin/bdquery/z?d110:h.r.00006.Energy Independence and Security Act of 2007 (EISA2007), Public Law 110-140 (December 19, 2007) Sec-tion 433 Federal Building Energy Efficiency Perfor-mance Standards.

ASHRAE Standard 90.1 – 2004, Energy Standard for Build-ings Except Low-Rise Residential Buildings, AmericanSociety of Heating Refrigeration and Air ConditioningEngineers, Inc., Atlanta, GA.

ASHRAE (2004a). Energy Standard for Buildings ExceptLow-Rise Residential Buildings. ANSI/ ASHRAE/IESNA Standard 90.1-2004. Atlanta, GA: AmericanSociety of Heating, Refrigerating and Air-ConditioningEngineers.

ASHRAE (2004b). Ventilation for Acceptable Indoor AirQuality. ANSI/ASHRAE Standard 62.1-2004. Atlanta,GA: American Society of Heating, Refrigerating andAir-Conditioning Engineers.

ASHRAE (2008). Advanced Energy Design Guides. Atlanta,GA: American Society of Heating, Refrigerating and

Figure 6 UEPH % savings with comparison to EISA targets.

18 CH-12-008

Air-Conditioning Engineers. www.ashrae.org/publica-tions/page/1604.

Zhivov, A., D. Herron, and M. Deru. 2009. AchievingEnergy Efficiency and Improving Indoor Air Quality inArmy Maintenance Facilities. ASHRAE Transactions.ASHRAE Annual Meeting, Louisville, KY, June 2009.

Herron, D., A. Zhivov, and M. Deru. 2009. Energy DesignGuides for Army Barracks. ASHRAE Transactions.ASHRAE Annual Meeting, Louisville, KY, June 2009.

Deru M., A. Zhivov, D. Herron, D. Fisher and V. Smith.2009. Improving Energy Performance of Army DiningFacilities. ASHRAE Transactions. ASHRAE AnnualMeeting, Louisville, KY, June 2009.

Briggs, R.S., Lucas, R.G., and Taylor, T. (2003). ClimateClassification for Building Energy Codes and Stan-dards: Part 2 - Zone Definitions, Maps and Compari-sons, Technical and Symposium Papers, ASHRAEWinter Meeting, Chicago, IL, January, 2003. Atlanta,

GA: American Society of Heating Refrigerating, andAir-Conditioning Engineers.

DOE (2008). EnergyPlus, Building Energy Simulation Soft-ware web site. Washington, DC: U.S. Department ofEnergy. www.EnergyPlus.gov.

FEMP (2005). Heat Recovery from Wastewater Using aGravity-Film Heat Exchanger. DOE/EE-0247 Revised,Federal Energy Management Program, Washington,D.C.: U.S. Department of Energy.

Army vision for Net Zero. Net Zero is a force multiplier. 15December 2010. Office of the Assistant Secretary of theArmy (Installations, Energy & Environment), Washing-ton, DC.

Army MILCON Energy Efficiency and Sustainability Studyof Five Types of Army Buildings, USACE, ERDC-CERL, NREL, and PNNL, U.S. Army Corps of Engi-neers Summary Report, April 2011.

Table 9. Baseline UEPH (Site Energy)

Wea

ther

Reg

ion

Ele

c H

eati

ng, k

Btu

/ft2

Ele

c C

oolin

g, k

Btu

/ft2

Ele

c In

t. L

ight

s, k

Btu

/ft2

Ele

c In

teri

or E

quip

, kB

tu/f

t2

Ele

c F

ans,

kB

tu/f

t2

Ele

c P

umps

, kB

tu/f

t2

Ele

c H

eat

Rec

over

y, k

Btu

/ft2

Nat

Gas

Hea

ting

, kB

tu/f

t2

Nat

Gas

Hot

Wat

er, k

Btu

/ft2

Tot

al, k

Btu

/ft2

Tot

al E

lect

ric,

kB

tu/f

t2

Tot

al N

at G

as, k

Btu

/ft2

1A_Miami_FL 0 23 11 22 2.2 0.9 0.00 0.1 9 69 60 9

2A_Houston_TX 0 17 11 22 2.2 0.7 0.00 3.2 12 69 54 15

2B_Phoenix_AZ 0 15 11 22 2.4 0.6 0.00 1.3 10 64 52 12

3A_Memphis_TN 0 13 11 22 2.3 0.6 0.00 8.5 14 72 49 23

3B_ElPaso_TX 0 9 11 22 2.2 0.5 0.00 4.2 14 63 46 18

3C_SanFrancisco_CA

0 3 11 22 2.1 0.3 0.00 2.4 17 59 39 19

4A_Baltimore_MD 0 8 11 22 2.2 0.5 0.00 14.9 17 77 45 32

4B_Albuquerque_NM

0 6 11 22 2.4 0.4 0.00 9.5 17 69 43 26

4C_Seattle_WA 0 3 11 22 2.1 0.3 0.00 11.3 18 69 39 30

5A_Chicago_IL 0 7 11 22 2.2 0.4 0.00 22 19 84 43 41

5B_ColoradoSprings_CO

0 4 11 22 2.4 0.4 0.00 15 20 75 41 35

6A_Burlington_VT 0 5 11 22 2.1 0.4 0.00 27 21 88 41 48

6B_Helena_MT 0 3 11 22 2.3 0.3 0.00 23 21 84 40 44

7A_Duluth_MN 0 3 11 22 2.1 0.3 0.00 35 24 98 39 59

8A_Fairbanks_AK 0 2.0 11 22 2.2 0.3 0.00 57 27 122 38 84

CH-12-008 19

Deru, M, Langner, R., Zhivov, A., Liesen, R., Herron, D.,Smith, V., Extremely Low Energy Design for ArmyBuildings: Dining Facility, ASHRAE Winter Meeting,Chicago, IL, January, 2012, Atlanta, GA: AmericanSociety of Heating Refrigerating, and Air-ConditioningEngineers.

Langner, R., Deru, M, Zhivov, A., Liesen, R., Herron, D.,Extremely Low Energy Design for Army Buildings: Tac-tical Equipment Maintenance Facility, ASHRAE Winter

Meeting, Chicago, IL, January, 2012, Atlanta, GA:American Society of Heating Refrigerating, and Air-Conditioning Engineers.

Ellis, P., Liesen, R., Zhivov, A., Herron, D., Extremely LowEnergy Design for Army Buildings: Brigade Headquar-ters, ASHRAE Winter Meeting, Chicago, IL, January,2012, Atlanta, GA: American Society of HeatingRefrigerating, and Air-Conditioning Engineers.

Table 10. Energy Efficient UEPH (Site Energy) (I-P)

Wea

ther

Reg

ion

Ele

c H

eati

ng, k

Btu

/ft2

Ele

c C

oolin

g, k

Btu

/ft2

Ele

c In

t. L

ight

s, k

Btu

/ft2

Ele

c In

teri

or E

quip

, kB

tu/f

t2

Ele

c F

ans,

kB

tu/f

t2

Ele

c P

umps

, kB

tu/f

t2

Ele

c H

eat

Rec

over

y, k

Btu

/ft2

Nat

Gas

Hea

ting

, kB

tu/f

t2

Nat

Gas

Hot

Wat

er, k

Btu

/ft2

Tot

al, k

Btu

/ft2

Tot

al E

lect

ric,

kB

tu/f

t2

Tot

al N

at G

as, k

Btu

/ft2

1A_Miami_FL 0 7 5 14 0.7 0.5 0.10 0.0 6 34 28 6

2A_Houston_TX 0 5 5 14 0.7 0.4 0.09 0.1 8 34 26 8

2B_Phoenix_AZ 0 2 5 14 0.7 0.3 0.02 0.0 7 30 23 7

3A_Memphis_TN 0 3 5 14 0.7 0.3 0.09 0.7 9 34 24 10

3B_ElPaso_TX 0 2 5 14 0.7 0.2 0.05 0.1 9 31 22 9

3C_SanFrancisco_CA 0 1 5 14 0.7 0.2 0.05 0.2 11 33 22 11

4A_Baltimore_MD 0 2 5 14 0.7 0.3 0.09 1.0 11 35 23 12

4B_Albuquerque_NM 0 1 5 14 0.7 0.2 0.06 0.2 11 33 22 11

4C_Seattle_WA 0 1 5 14 0.7 0.2 0.08 0.7 12 34 21 13

5A_Chicago_IL 0 2 5 14 0.7 0.3 0.09 2 13 37 22 15

5B_ColoradoSprings_CO 0 1 5 14 0.7 0.2 0.08 1 13 35 22 14

6A_Burlington_VT 0 1 5 14 0.7 0.2 0.09 2 14 38 22 16

6B_Helena_MT 0 1 5 14 0.8 0.2 0.09 1 14 37 21 15

7A_Duluth_MN 0 1 5 14 0.7 0.2 0.10 4 16 41 22 19

8A_Fairbanks_AK 0 0.5 5 14 0.8 0.2 0.11 9 18 49 21 27

20 CH-12-008

CH-12-008 21

Table 10. Energy Efficient UEPH (Site Energy) (SI)W

eath

er R

egio

n

Ele

c H

eati

ng, k

Wh/

m2

Ele

c C

oolin

g, k

Wh/

m2

Ele

c In

t. L

ight

s, k

Wh/

m2

Ele

c In

teri

or E

quip

, kW

h/m

2

Ele

c F

ans,

kW

h/m

2

Ele

c P

umps

, kW

h/m

2

Ele

c H

eat

Rec

over

y, k

Wh/

m2

Nat

Gas

Hea

ting

, kW

h/m

2

Nat

Gas

Hot

Wat

er, k

Wh/

m2

Tot

al, k

Wh/

m2

Tot

al E

lect

ric,

kW

h/m

2

Tot

al N

at G

as, k

Wh/

m2

1A_Miami_FL 0 22 17 45 2 2 0.3 0.0 19 107 88 19

2A_Houston_TX 0 16 17 45 2 1 0.3 0.4 25 107 81 26

2B_Phoenix_AZ 0 7 17 45 2 1 0.1 0.1 22 94 72 22

3A_Memphis_TN 0 11 17 45 2 1 0.3 2.1 30 108 76 32

3B_ElPaso_TX 0 5 17 45 2 1 0.1 0.2 28 99 70 29

3C_SanFrancisco_CA 0 3 17 45 2 1 0.1 0.6 35 104 68 36

4A_Baltimore_MD 0 7 17 45 2 1 0.3 3.2 36 111 72 39

4B_Albuquerque_NM 0 4 17 45 2 1 0.2 0.5 35 104 69 35

4C_Seattle_WA 0 2 17 45 2 1 0.3 2.2 38 108 67 40

5A_Chicago_IL 0 6 17 45 2 1 0.3 6.5 40 117 71 46

5B_ColoradoSprings_CO 0 3 17 45 2 1 0.3 2.0 41 111 68 43

6A_Burlington_VT 0 4 17 45 2 1 0.3 7.5 44 120 69 51

6B_Helena_MT 0 2 17 45 2 1 0.3 4.3 44 116 67 48

7A_Duluth_MN 0 3 17 45 2 1 0.3 11.9 49 129 68 61

8A_Fairbanks_AK 0 1 17 45 2 1 0.3 29.9 57 153 67 86

Figure 7 Building cluster fossil fuel reduction optimizationprocess.

22 CH-12-008

Tabl

e 11

. T

heo

retic

al C

HP

Lim

it E

lect

ric

Trac

kin

g (I-

P)

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

kBtu

/ft2

Wea

ther

Reg

ion

Site 2003 CBECSDormitory/Fraternity/Sorority

Site Energy Budget

Source 2003 CBECSDormitory/Fraternity/Sorority

EISA 2007 Source Target Energy Budget

Ele

ctri

c T

rack

ing

of D

HW

; A

ssum

e Sa

le o

fT

herm

al t

o A

djoi

ning

Bui

ldin

g or

the

The

oret

ical

Lim

it o

f C

HP

;C

onve

rsio

n to

Sou

rce

Usi

ng G

as E

ff. o

f 1.

05

Ass

ume

100%

Sol

ar-T

herm

al fo

r D

HW

;T

heor

etic

al S

olar

The

rmal

Lim

it

Site

P

urch

E

lec

CoG

en

Pur

ch N

at

Gas

Exc

ess

The

rmal

or

Hea

t

Tot

Sit

e E

UI

Tot

So

urce

E

UI

% S

ourc

e E

nerg

y R

educ

tion

Site

Pur

ch

Ele

cSi

te P

urch

N

at G

asT

ot S

ite

EU

IT

ot S

ourc

e E

UI

1A_M

iam

i_FL

6824

208

730

6724

4446

78%

240

2481

2A_H

oust

on_T

X69

2419

468

062

1943

4577

%22

023

75

2B_P

hoen

ix_A

Z67

2319

568

053

1737

3980

%19

019

64

3A_M

emph

is_T

N68

2417

662

057

1543

4574

%21

122

70

3B_E

lPas

o_T

X64

2217

260

052

1438

4077

%19

019

63

3C_S

anFr

anci

sco_

CA

5820

150

520

5111

4042

72%

181

1962

4A_B

altim

ore_

MD

7526

178

620

5411

4446

74%

202

2167

4B_A

lbuq

uerq

ue_N

M66

2316

457

051

1140

4274

%18

019

61

4C_S

eattl

e_W

A68

2415

956

050

842

4472

%18

120

62

5A_C

hica

go_I

L84

2918

565

053

845

4874

%19

322

67

5B_C

olor

adoS

prin

gs_C

O73

2616

759

050

842

4474

%18

119

61

6A_B

urlin

gton

_VT

9734

203

710

525

4648

76%

193

2265

6B_H

elen

a_M

T86

3018

264

050

644

4675

%18

220

62

7A_D

ulut

h_M

N10

537

206

720

512

4951

75%

185

2366

8A_F

airb

anks

_AK

135

4723

783

049

–757

5975

%18

1129

71

CH-12-008 23

Tabl

e 11

. T

heo

retic

al C

HP

Lim

it E

lect

ric

Trac

kin

g (S

I)

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

kW·h

/m2

Wea

ther

Reg

ion

Site 2003 CBECSDormitory/Fraternity/Sorority

Site Energy Budget

Source 2003 CBECSDormitory/Fraternity/Sorority

EISA 2007 SourceTarget Energy Budget

Ele

ctri

c T

rack

ing

of D

HW

; A

ssum

e Sa

le o

f T

herm

al t

o A

djoi

ning

B

uild

ing

or t

he T

heor

etic

al L

imit

of

CH

P;

Con

vers

ion

to S

ourc

e us

ing

Gas

Eff

. Of

1.05

Ass

ume

100%

Sol

ar-T

herm

al fo

r D

HW

;T

heor

etic

al S

olar

The

rmal

Lim

it

Site

Pur

ch

Ele

c

CoG

en

Pur

ch N

at

Gas

Exc

ess

The

rmal

or

Hea

t

Tot

Sit

e E

UI

Tot

So

urce

E

UI

% S

ourc

e E

nerg

y R

educ

tion

Site

Pur

ch

Ele

cSi

te P

urch

N

at G

asT

ot S

ite

EU

IT

ot S

ourc

e E

UI

1A_M

iam

i_FL

216

7665

522

90

213

7513

814

578

%77

077

256

2A_H

oust

on_T

X21

676

611

214

019

560

136

143

77%

701

7223

6

2B_P

hoen

ix_A

Z21

174

615

215

016

952

117

122

80%

610

6120

3

3A_M

emph

is_T

N21

375

556

195

018

146

135

142

74%

654

6922

2

3B_E

lPas

o_T

X20

170

543

190

016

443

121

127

77%

591

6019

8

3C_S

anFr

anci

sco_

CA

182

6447

216

50

160

3312

613

372

%58

259

194

4A_B

altim

ore_

MD

236

8356

219

70

171

3413

714

474

%62

567

212

4B_A

lbuq

uerq

ue_N

M20

973

516

181

016

034

126

132

74%

581

5919

4

4C_S

eattl

e_W

A21

375

501

175

015

827

131

138

72%

575

6219

5

5A_C

hica

go_I

L26

492

584

205

016

724

143

150

74%

609

7021

1

5B_C

olor

adoS

prin

gs_C

O23

181

528

185

015

825

133

140

74%

573

6019

4

6A_B

urlin

gton

_VT

304

107

639

224

016

317

145

153

76%

5911

6920

7

6B_H

elen

a_M

T27

094

575

201

015

718

139

146

75%

567

6319

6

7A_D

ulut

h_M

N33

111

664

922

70

159

515

416

275

%57

1573

208

8A_F

airb

anks

_AK

425

149

746

261

015

6-2

317

918

875

%56

3591

224