Conference Paper

NREL/CP-550-48125

August 2010

Practical Integration Approach 

and Whole Building Energy 

Simulation of Three Energy 

Efficient Building Technologies 

Preprint 

James P. Miller, Alexander Zhivov, and 

Dale Heron

U.S. Army

Michael Deru and Kyle Benne

National Renewable Energy Laboratory

Presented at ASME 2010 4th International Conference on Energy 

Sustainability (ES2010)

Phoenix, Arizona

May 17–22, 2010
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Proceedings of the ASME 2010 4th International Conference of Energy Sustainability

ES2010

May 17-22, 2010, Phoenix, Arizona, USA

ES2010-90480

A PRACTICAL INTEGRATION APPROACH AND WHOLE BUILDING ENERGY 

SIMULATION OF THREE ENERGY EFFICIENT BUILDING TECHNOLOGIES

James P. Miller

U.S. Army ERDC-CERL

Champaign, Illinois, USA

james.p.miller@usace.army.mil

Michael Deru

National Renewable Energy Laboratory

Golden, Colorado, USA

michael.deru@nrel.gov

Kyle Benne

National Renewable Energy 

Laboratory

Golden, Colorado, USA

kyle.benne@nrel.gov

Alexander Zhivov

U.S. Army ERDC-CERL

Champaign, Illinois, USA

alexander.m.zhivov@usace.army.mil

Dale Herron

U.S. Army ERDC-CERL

Champaign, Illinois, USA

dale.l.herron@usace.army.mil

ABSTRACT

Rising energy costs and the desire to reduce 

energy consumption dictates a need for significantly 

improved building energy performance. Three 

technologies that have potential to save energy and 

improve sustainability of buildings are dedicated 

outdoor air systems (DOAS), radiant heating and 

cooling systems and tighter building envelopes. 

Although individually applying innovative 

technologies may incrementally improve building 

energy performance, more significant payoffs are

realized when compatible technologies are integrated

into an optimized system. Fortunately, DOAS, radiant 

heating and cooling systems and improved building 

envelopes are highly compatible. 

To investigate the energy savings potential of 

these three technologies, whole building energy 

simulations were performed for a barracks facility and 

an administration facility in 15 U.S. climate zones and 

16 international locations. The baseline facilities were 

assumed to be existing buildings with VAV HVAC 

systems (admin facilities) and packaged HVAC 

systems (barracks facilities). The energy simulations 

were adjusted for each location for optimal energy and 

humidity control performance. The results show that 

the upgraded facilities realized total building energy 

savings between 20% and 40% and improved humidity 

control when compared to baseline building 

performance.

INTRODUCTION

Building owners and designers are increasingly 

interested in building energy systems that cost 

effectively reduce energy consumption and energy 

costs while maintaining comfort and acceptable indoor 

air quality. Three technologies that have potential for 

significant energy savings are dedicated outdoor air 

systems (DOAS), radiant heating/cooling systems, and 

tighter building envelopes. While each of these 

technologies, applied individually, can realize energy 

savings, it is important to think in terms of a systems 

approach rather than just applying these technologies 

individually. For example, radiant cooling systems 

have the potential to save a great deal of energy when 

compared to all-air heating/cooling systems, primarily 

due to a major reduction in fan energy. Unfortunately, 

major moisture and condensation problems can occur if 

the space dew point temperature (DPT) is not 

maintained below the surface temperature of the 

radiant cooling system components. Tighter building 

envelopes reduce the heating, cooling and 

dehumidification energy required to overcome the 

effects of uncontrolled infiltration of outdoor air. They 

also reduce the amount of makeup air required to 

maintain positive pressurization of the building. 

BASELINE BUILDING DESCRIPTIONS

To better understand the energy impacts of these 

technologies, we modeled two building types (an 

administrative facility and a barracks facility) in fifteen 

1
U.S. climate zones and sixteen international locations

using EnergyPlus. Administration and barracks 

facilities are the two most common building types in 

the U.S. Army. Admin facilities are similar in many 

respects to private sector office buildings and barracks 

facilities bear similarities to many apartment buildings 

and hotel buildings with interior corridors. For this 

study, we developed each baseline facility model in 

compliance with the requirements of ASHRAE 

Standard 90.1-1989 (ASHRAE 1989) since the Army 

has a large inventory of existing admin and barracks 

facilities which were designed and constructed in 

accordance with this standard and are current 

candidates for major renovation and upgrade. For each 

facility type, we developed “improved” facility models 

which included DOAS and radiant heating/cooling 

systems and a “further improved” facility model which 

included DOAS, radiant heating/cooling and a tighter 

building envelope. Renderings of the baseline facilities 

are shown in Figs. 1 and 2 below. Technical 

specifications are provided in Tables 1 and 2. 

Figure 1. Rendering of modeled administration 

facility

credit: Kyle Benne/NREL

Figure 2. Rendering of modeled barracks facility

credit: Michael Deru/NREL

Table 1. Baseline administrative facility

Building 

Component Component Description

Area (total) 23,250 ft2 (2,160 m2

) 

Floors 4 

Foot print 

shape Rectangle 

Fenestration 

type Standard 90.1-1989 

Wall 

construction Steel frame with brick exterior 

Wall insulation Standard 90.1-1989, mass wall 

Roof 

construction 

Sloped metal roof with insulation at roof 

level 

Roof insulation Standard 90.1-1989, with attic 

Infiltration 1 cfm/ft2

 (5.08 L/s-m2) of shell area at 0.3 

iwg (75 Pa) 

Window-to-wall 

ratio 

Total – 23.44%; North – 30.00%; East – 

12.51%; South – 30.00%; West – 12.51% 

Temperature 

set points 

75  ̊F (23.9  ̊C) cooling and 70  ̊F (21.1  ̊C) 

heating with night setback to 86  ̊F (30  ̊C) 

cooling and 60  ̊F (15.6  ̊C) heating

Ventilation 20 cfm (9.44 L/s) per person

HVAC VAV system with central chiller (4.5 COP) 

and natural gas boiler (0.8 Et ) 

DHW Natural gas boiler (0.8 Et ) 

Table 2. Baseline barracks facility

Building 

Component Component Description

Area (total) 28,965 ft2

 (2,691 m2) 

Floors 3 

Foot print shape Rectangle 

Fenestration 

type Standard 90.1-1989 

Wall 

construction Wood frame with brick exterior 

Wall insulation Standard 90.1-1989, mass wall 

Roof 

construction 

Sloped metal roof with Insulation at roof 

Level 

Roof insulation Standard 90.1-1989, with attic 

Infiltration 1 cfm/ft2

 (5.08 L/s-m2) of shell area at 0.3 

iwg (75 Pa) 

Window-to-wall 

ratio 

Total – 6.88%; North – 8.91%; East – 

0.00%; South – 9.38%; West – 0.00% 

Temperature set 

points 

75  ̊F (23.9  ̊C) cooling and 70  ̊F (21.1 

 ̊C) heating 

Ventilation 75 cfm (35.4 L/s) continuous per unit

HVAC PSZ with DX-AC (2.6 COP) and gas 

furnace (0.8 Et ) 

DHW Natural gas boiler (0.8 Et ) 

The models assumed that the administrative 

facility was occupied during typical business hours, 

five days per week. During unoccupied hours, the 

system enters night cycle mode where outside 

ventilation air is shut off and zone temperature controls 

are set back (set up). The barracks facility models 

2
assumed that the heating, cooling and ventilating 

systems were in occupied mode 24 hours per day, 365 

days per year.

The baseline administrative facility used chilled 

water from an air-cooled chiller and hot water reheat at 

the VAV terminal units supplied by a central gas 

boiler. 

The floor plan of the barracks facility is similar to 

an apartment building with each unit designed for 

occupancy by two soldiers. Temperature control in 

each baseline barracks unit is handled by a single zone 

constant speed air system cooled by DX and heated by 

a natural gas furnace. 

IMPROVED BUILDING DESCRIPTIONS

The “improved” admin facility uses radiant 

heating/cooling panels served by chilled water from an 

air-cooled chiller and hot water from a gas boiler. A 

constant volume DOAS provides conditioned 

ventilation air only during occupied hours. The DOAS 

supply air temperature is governed by an outside air 

temperature reset schedule. The DOAS provides 

minimal sensible heating/cooling through water coils 

supplied by a gas boiler and a chilled water coil 

supplied by a second air-cooled chiller. The water 

loops feeding the DOAS are separate from the radiant 

system. The primary space sensible load is designed to 

be met by the radiant heating/cooling system. 

The HVAC system for the “improved” barracks 

facility is essentially the same as for the “improved” 

administrative facility. The major difference is that the 

“improved” barracks facility is assumed to be 

constantly occupied, thus the DOAS system runs 

continuously. The DOAS system models for both the 

administrative facility and barracks facility include 

total energy recovery (TER) to extract energy from the 

buildings’ exhaust air streams.

The “further improved” models for both the 

administrative facility and the barracks facility 

incorporate tighter building envelopes in addition to the 

DOAS system and radiant heating/cooling system in 

the “improved” models. Tighter building envelopes 

reduce infiltration from 1.0 cfm/ft2 (5.08 L/s-m

2

) at a 

reference pressure difference of 75 Pa between the 

building interior and the outdoor ambient conditions in 

the baseline facilities to 0.25 cfm/ft2 (1.27 L/s-m

2

) at a 

75 Pa pressure difference in the “further improved” 

models. 

SELECTED SIMULATION LOCATIONS AND 

CORRESPONDING ENERGY COSTS

Fifteen locations were selected to represent fifteen 

climate zones in the United States. The U.S. locations 

were selected as representative cities for the climate 

zones by the Pacific Northwest National Laboratory 

(Briggs et al. 2003). In addition, 16 locations were 

selected outside of the U.S. in Canada and Europe. 

The 15 U.S. and 16 non U.S. locations are shown in 

Tables 3 and 4. Both tables include the ASHRAE 

Standard 90.1-1989 table numbers for the locations that 

were used to select the envelope thermal criteria. The 

90.1-1989 tables for the non U.S. locations were 

selected based on the heating degree days (HDD) and 

cooling degree days (CDD). 

Table 3. U.S. Climate Zones and Cities used for 

Simulations

Climate 

Zone

ASHRAE

90.1 – 

1989 

Table

City 

HDD,

65oF 

(18.3 

oC)

CDD,

50oF 

(10 oC)

1A 5 Miami, FL 

200

(111)

9474

(5263)

2A 10 Houston, TX 

1599

(888)

6876

(3820)

2B 12 Phoenix, AZ 

1350

(750)

8425

(4681)

3A 15 Memphis, TN 

3082

(1712)

5467

(3037)

3B 18 El Paso, TX 

2708

(1504)

5488

(3049)

3C 19

San Francisco, 

CA 

3016

(1676)

2883

(1602)

4A 23 Baltimore, MD 

4707

(2615)

3709

(2061)

4B 24

Albuquerque, 

NM 

4425

(2458)

3908

(2171)

4C 25 Seattle, WA 

4908

(2727)

1823

(1013)

5A 26 Chicago, IL 

6536

(3631)

2941

(1634)

5B 28 Boise, ID 

5882

(3231)

2716

(1509)

6A 32 Burlington, VT 

7771

(4317)

2228

(1238)

6B 33 Helena, MT 

7699

(4277)

1841

(1023)

7A 36 Duluth, MN 

9818

(5454)

1536

(853)

8A 38 Fairbanks, AK 

13940

(7744)

1040

(578)

Flat utility tariffs were assumed for each location (i.e. 

no energy demand charges are included). The U.S. 

energy costs are based on flat rates at the average for 

commercial rates in each state and may not reflect the 

utility rates at a specific location. A fixed price was 

assumed for all non U.S. cities as shown in Table 5.

3
Table 4. Non U.S. Climate Zones and Cities used 

for Simulations

Climate 

Zone

ASHRAE

90.1 – 

1989 

Table 

City 

HDD,

65oF 

(18.3 

oC) 

CDD,

50oF 

(10 oC)

7 36 Edmonton, CAN

10049

(5583)

1042

(579)

6 33 Ottawa, CAN

8395

(4664)

2014

(1119)

5 19 Vancouver, CAN

5436

(3020)

1451

(806)

5 28 Stuttgart, DEU

6008

(3338)

2340

(1300)

5 28

Copenhagen, 

DNK 

6413

(3563)

1283

(713)

7 33 Helsinki, FIN

8482

(4712)

1039

(577)

7 33 Tampere, FIN

9036

(5020)

950

(528)

4 20 Lyon, FRA

4570

(2539)

2669

(1483)

4 3 Marseille, FRA

3123

(1735)

3789

(2105)

4 4 Nantes, FRA

4057

(2254)

2360

(1311)

4 19 Paris, FRA

4759

(2644)

2176

(1209)

4 19 London, GBR

5159

(2866)

1555

(864)

4 25 Milan, ITA

4750

(2639)

2947

(1637)

4 9 Naples, ITA

2455

(1364)

4473

(2485)

2 9 Palermo, ITA

1303

(724)

5805

(3225)

4 24 Rome, ITA

2599

(1444)

4199

(2333)

Table 5. Energy rates used in simulations

City 

Electricity 

Cost 

$/kWh

Natural Gas Cost 

($/Million Btu)

Miami, FL $0.0761 $11.44

Houston, TX $0.0787 $8.42

Phoenix, AZ $0.0724 $8.71

Memphis, TN $0.0706 $9.63

El Paso, TX $0.0787 $8.42

San Francisco, CA $0.1160 $8.50

Baltimore, MD $0.0753 $9.23

Albuquerque, NM $0.0738 $8.19

Seattle, WA $0.0620 $9.40

Chicago, IL $0.0752 $9.82

Boise, ID $0.0537 $8.54

Burlington, VT $0.1142 $8.76

Helena, MT $0.0740 $9.64

Duluth, MN $0.0630 $8.36

Fairbanks, AK $0.1100 $4.08

All non U.S. cities $0.0929 $10.67

U.S. MODELING RESULTS – ADMIN FACILITY

Figures 3 through 5 show the electrical, gas and 

total energy consumption results for the baseline and 

“improved” administration facility. In all cases, except 

San Francisco, the addition of DOAS and radiant 

heating/cooling resulted in decreased electrical 

consumption. The reduced electrical consumption was 

most evident in hot or hot/humid locations (i.e., Miami, 

Houston, Phoenix and El Paso). 

Figure 4 shows significant gas energy savings in 

the cooler and cold locations. This would appear to be 

a result of the greater efficiency of radiant heating 

systems than all-air systems.

Figure 3. Admin - electrical consumption

Figure 4. Admin - gas energy consumption

Figure 5. Admin - total energy consumption

4
Figure 5 indicates that the DOAS + Radiant 

systems save energy in most climate locations. In El 

Paso, San Francisco, and Albuquerque the “improved” 

system appears to consume more energy than the 

baseline system. This is further illustrated in Fig. 6 

where these locations have negative energy savings. 

Other locations in Fig. 6 show substantial energy 

savings, especially in the cooler/cold locations.

Figure 6. Admin - percent energy savings

Figure 7 illustrates the difference in air flow 

required by the baseline admin facilities as compared 

to the “improved” facilities using DOAS + radiant 

heating/cooling systems. The baseline facilities deliver 

conditioned air to not only ventilate the building but 

also to control space temperature. By handling space 

temperature control through the radiant systems, 

considerable reduction in air flow rates is possible.

Figures 8 through 12 show modeled results for the 

barracks facility, including both the “improved” case 

(i.e., DOAS and radiant heating/cooling) and the 

“further improved” case (i.e., DOAS plus radiant 

heating/cooling plus tighter building envelope). In Fig. 

8, one can see that both improved systems showed 

significant electrical energy reductions in most U.S. 

locations. This is especially interesting when 

comparing the barracks facility results in Fig. 8 with 

the administration facility results in Fig. 3. 

Very significant gas energy savings are shown in 

Fig. 9, especially in cooler/cold locations. There is 

also a significant reduction in gas energy consumption 

in the buildings with improved envelopes as compared 

to the buildings with DOAS and radiant only. This 

would seem to be due to decreased heating loads 

resulting from diminished infiltration of cold air as a 

result of improved building envelopes.

Figure 10 shows the total energy consumption 

performance of the baseline, “improved” and “further 

improved” barracks facilities.

Figure 7. Admin - maximum air flow (cfm)

Figure 8. Barracks – electrical energy consumption

Figure 9. Barracks – gas energy consumption

Figure 10. Barracks – total energy consumption

In Fig. 11 one can see that the “improved” and 

“further improved” barracks facilities save 

considerable energy over the baseline facilities. 

5
Figure 11. Barracks – percent energy savings

Figure 12 illustrates the difference in air flow 

required by the baseline barracks facilities as compared 

to the “improved” and “further improved” facilities. 

As with the administration facilities, the baseline 

barracks facilities deliver conditioned air to not only 

ventilate the building but also to control space 

temperature. By handling space temperature control 

through the radiant systems, considerable reduction in 

air flow rates (and related fan energy) is achieved. 

Figure 12. Barracks – maximum fan air flow (cfm)

.

INTERNATIONAL MODELING RESULTS

Similar simulations were performed for the 

administration building in sixteen international 

locations. In Fig. 13, one can see that the “improved” 

administration facility had significantly reduced 

electrical energy consumption in all locations when 

compared to the baseline facility. However, the 

electrical savings appeared to be achieved at the 

expense of an increase of gas usage in most locations 

as shown in Fig. 14. Nevertheless, when electrical and 

gas energy consumption was calculated, the total 

energy of the “improved” administration facilities was 

less than for the baseline facility at all locations as 

shown in Fig. 15. Figure 16 shows that the “improved” 

systems realized significant energy savings, ranging 

from a low of 8% (Paris) to 48% (Stuttgart).

Figure 13. Admin – electrical energy consumption 

Figure 14. Admin – gas energy consumption 

Figure 15. Admin – total energy consumption 

Figure 16. Admin – percent energy savings 

Figures 17 and 18 show the annual energy cost 

savings for U.S. and non U.S. locations. 

6
Figure 17. Annual energy cost savings – US 

locations 

Figure 18. Annual energy cost savings – Non US 

locations 

ECONOMIC CONSIDERATIONS

In most instances, it would be hard to justify the 

costs of performing a major facility renovation if one’s

primary motivation for the project was energy 

conservation. However, in the case of a major facility 

renovation project, enhanced efficiency features can 

make good economic sense.

The U.S. Army recently conducted a study at Fort 

Irwin, CA, to identify possibilities of transitioning the 

Army towards Net Zero Energy installations. A group 

of five barracks facilities (each about 25 years old and

similar in size and configuration to the barracks facility 

modeled in this study) were included in the Fort Irwin 

study. These buildings were studied to determine 

optional approaches to upgrading the facilities to 

significantly improve their energy performance.

Under the Army’s Barracks Upgrade Program 

(BUP), barracks facilities typically become eligible for 

major upgrades at about 25 years of age. A typical 

upgrade project would normally include complete 

interior renovation and improving the building 

envelope with tighter fitting, better insulated doors and 

more energy efficient windows. Lighting, mechanical 

systems and appliances are also replaced. Typically, a 

newly upgraded barracks facility will realize about 8% 

electrical energy savings and 7% heating energy 

savings. Although not insignificant, this is not very 

satisfactory when one considers the amount of money 

invested in the barracks upgrade project, particularly 

when one’s ultimate goal is to move towards a Net 

Zero Energy installation.

In a typical barracks upgrade project, existing twopipe fan coil units and makeup air units are replaced in 

kind. In the Fort Irwin study, four optional approaches 

to upgrading the mechanical systems were explored. 

These optional systems include:

o Option 1 - VAV DOAS with Direct 

Evaporative Cooling

o Option 2 – VAV DOAS system with Radiant 

Heating/Cooling (including direct and indirect 

evaporative cooling)

o Option 3 – VAV DOAS system with Fan 

Coils (including direct and indirect 

evaporative cooling)

o Option 4 - VAV DOAS with Direct and 

Indirect Evaporative Cooling

Cost estimates for the baseline mechanical system 

and each of the optional mechanical systems were 

prepared. Of the four optional approaches investigated 

in the Fort Irwin study, Option 2 is most similar to the 

“improved” system discussed in this study. As a result, 

the estimated costs of a typical mechanical system 

upgrade and a DOAS system with radiant 

heating/cooling (including direct and indirect

evaporative cooling) are compared in Table 6 below. 

In Table 7, other work elements common to a typical 

barracks upgrade project and an upgrade project 

performed in accordance with Option 2 are compared.

Table 6. Comparison of estimated retrofit costs

Typical 

Upgrade 

Project

Option 2

Approach Mechanical System Elements

$10,000 DOAS-VAV AHU with Direct Evap 

cooling 

$20,000 Indirect evaporative coolers

$35,000 Pad/Equipment enclosure for external 

equipment

$10,000 Duct riser from equipment enclosure 

into building

$15,000 Electrical power to equipment pad

$35,000 $35,000 CHW Piping to AHU dynamic 2 pipe 

switchover 

$18,000 $18,000 Ductwork for toilet exhaust system

$5,000 $5,000 Electrical for exhaust fan system

$30,000 $45,000 

3 Fan Coil Units for other spaces (game 

room, laundry, misc) (Larger for RHC 

system due to 60°F CHWS temps)

$12,000 Indirect evap cooler related 

controls/monitoring

$18,000 $18,000 Heating/cooling switchover controls -

dynamic - load based

$30,000 $30,000 Exhaust system modifications in rooms 

- add manual dampers

$6,000 $6,000 Exhaust system modifications at roof -

1 EF/controls

$64,800 Insulate existing make-up air duct – reuse for DOAS distribution

7
$30,000 $30,000 Ducting in rooms for DOAS – Radiant 

to diffuser

$50,400 Create closets for Fan Coil Units

$86,400 Install Fan Coil Unit access doors

$40,000 DOAS AHU Controls/monitoring 

equipment 

$17,000 $17,000 Automatic Heating/Cooling switchover 

valves and controls

$4,320 $4,320 New room supply air diffusers

$25,000 Toilet exhaust system heat recovery

$24,000

Radiant heating/cooling (RHC) room 

controls/DDC thermostat heating and 

cooling – switchover

$8,000 RHC water temp mixing controls

$20,000 RHC circulating pump system and 

VFD/controls 

$94,400 RHC panels system

$38,800 RHC attachment to ceiling (provide

ceiling for third floor)

$400,000 RHC piping to each unit (larger than 

existing piping)

$458,200

144 two-pipe FCUs (nominal 1/2 ton 

each, derated to use 50°F/68°F 

CHWS/CHWR temperatures)

$400,000 Piping to FCUs

$338,400 DDC controls for FCUs 

$1,526,720 $1,025,320 Subtotal

$152,672 $102,532 Mech Contractor Overhead @10%

$152,672 $102,532 Mech Contractor Profit @10%

$152,672 $102,532 General Contractor Fee @10%

$1,984,736 $1,332,916 Subtotal, hard costs

$317,558 $213,267 COE Admin @ 16%

$198,474 $133,292 Mech Engineering @10%

$59,542 $39,987 Elec Engineering @ 3%

$59,542 $39,987 Controls Engineering @ 3%

$19,847 $13,329 Struct Engineering @ 1%

$99,237 $66,646 Constr Management @ 5%

$99,237 $66,646 Proj Management @ 5%

$59,542 $39,987 Travel related expenses, all disciplines 

@ 3%

$138,932 $93,304 Commissioning (all onsite, no remote) 

@ 7%

$1,051,910 $706,445 Subtotal, soft costs

$3,036,646 $2,039,361 Project Subtotal

$455,497 $305,904 Unseen conditions multiplier @ 15%

$455,497 $305,904 Project escalation due to future 

installation date @ 15%

$455,497 $305,904 Remote site multiplier @ 15%

$4,403,137 $2,957,074 System Total

Perhaps surprisingly, the Fort Irwin Option 2 

system (DOAS, radiant heating/cooling, direct/indirect 

evaporative cooling) is estimated to be significantly 

less expensive to install than the conventional HVAC 

system using fan coil units and makeup air units. 

Although this Option 2 system is not identical to the 

system simulated in our modeled barracks facility, it is 

sufficiently similar to suggest that the “improved” 

version of the modeled facility (DOAS with radiant 

heating and cooling) should be a less costly alternative 

than the conventional HVAC system it replaced. That 

being the case, the “improved” system is the obvious 

choice for the modeled barracks facility since it not 

only has a lower first cost but also superior energy 

performance.

Table 7. Comparison of estimated retrofit costs 

common to both systems

Typical 

Upgrade 

Project

Option 2

Approach Other Common Work Elements

$91,000 $200,000 R-40 roof insulation

$79,000 $79,000 R-18 Wall insulation

$107,000 $107,000 Double Pane, Low E, Operable windows

$277,000 $386,000 Subtotal

$27,700 $38,600 General Contractor Fee - Army @ 10%

$304,700 $424,600 Subtotal, hard costs

$48,752 $67,936 COE Administration @ 16%

$3,047 $4,246 Mechanical Engineering @ 1%

$15,235 $21,230 Electrical Engineering @ 5%

$9,141 $12,738 Controls Engineering @ 3%

$9,141 $12,738 Structural Engineering @ 3%

$15,235 $21,230 Construction Management @ 5%

$15,235 $21,230 Project Management @ 5%

$9,141 $12,738 Travel related expenses, all disciplines @ 

3%

$15,235 $21,230 Commissioning (all onsite, no remote) @ 

5%

$140,162 $195,316 Subtotal, soft costs

$444,862 $619,916 Project Subtotal

$66,729 $92,987 Unseen conditions multiplier @ 15%

$66,729 $92,987 Project escalation due to future 

installation date @ 15%

$66,729 $92,987 Remote site multiplier @ 15%

$645,050 $898,878 System Total

Base 

Case $253,828 Incremental Cost Difference for Net-Zero Energy Facility Modifications

Having established that, for a major barracks

upgrade project, replacing the conventional HVAC 

system with an “improved” system is a better 

investment than replacing the existing conventional 

HVAC system with a similar system, one should 

consider whether to “further improve” the facility with 

an enhanced building envelope. 

After completion of a Barracks Upgrade project, 

barracks facilities have an envelope air leakage rate of 

approximately 0.4 CFM/ft2

at 0.3 iwg (75 Pa). From 

our experience, we have found that further reducing the 

leakage rate to 0.25 CFM/ft2

at 0.3 iwg (75 Pa) can be 

accomplished for about $0.50/ft2 ($5.38/m

2

). For the 

barracks facilities, this would add about $12,000 to the 

project costs which is about 0.37% of the total project 

cost.

By studying Fig. 17, one can compare the $12,000 

additional cost of “further improving” the building 

envelope to 0.25 CFM/ft2

at 0.3 iwg (75 Pa) with the 

additional simulated annual energy savings of making 

this improvement. For Fairbanks, AK, for example, 

the additional annual energy savings of further 

tightening the building envelope of a barracks facility 

is about $5000, yielding a simple payback of this 

further improvement to be less than 2.5 years. Warmer 

climate locations are not expected to yield such short 

payback periods. 

8
Similar cost estimates were not performed for the 

simulated administration facility, so no effort will be 

made to provide a detailed discussion of the economic 

payback of a project to “improve” or “further improve” 

such facilities. Nevertheless, given that the cost 

estimate for upgrading the barracks facilities indicates 

that the DOAS with radiant heating/cooling and 

direct/indirect evaporative cooling should be less 

expensive than the traditional barracks upgrade project, 

it seems reasonable to expect that this may also be true 

for a major upgrade of an administration facility.

CONCLUSIONS 

Retrofit of existing buildings with innovative 

technologies may not be economically viable if one is 

contemplating a project primarily for the sake of 

energy conservation. However, if a major renovation 

project is being planned, one should compare the delta 

(premium) costs of advanced technologies against the 

additional energy efficiency realized by the advanced 

technologies versus the costs and energy performance 

of conventional retrofit technologies. In many cases, 

this analysis will demonstrate the wisdom of investing 

a bit more money in more advanced technologies in 

order to realize substantial energy cost savings. 

In this study, incorporating innovative 

technologies into major facility upgrade projects was 

shown to have potential for significant energy 

performance improvements and may actually cost less 

than conventional “tried and true” approaches. For 

example, DOAS systems, when combined with radiant 

heating/cooling systems and tight building envelopes 

have significant potential to economically save energy 

while maintaining comfort. Depending on location, 

additional sealing of the building envelope may also be 

cost effective.

REFERENCES

[1] ASHRAE (1989). ANSI/ASHRAE/IESNA 

Standard 90.1-1989 Energy Efficient Design of New 

Buildings except Low-Rise Residential Buildings. Atlanta, 

GA: American Society of Heating, Refrigerating and AirConditioning Engineers, Inc.

[2] Briggs, R.S., Lucas, R.G., and Taylor, T.; 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.

[3] ASHRAE (2007). ANSI/ASHRAE Standard 62.1-

2007, Ventilation for Acceptable Indoor Air Quality, 

Atlanta, GA: American Society of Heating, Refrigerating 

and Air-Conditioning Engineers, Inc.

[4] Jeong, J-W., Mumma, S.A. “Designing a 

Dedicated Outdoor Air System with Ceiling Radiant Cooling 

Panels”, ASHRAE Journal, pp. 56-66, October 2006.

[5] Mumma, S.A. “Chilled Ceilings in Parallel with

Dedicated Outdoor Air Systems: Addressing the Concerns of

Condensation, Capacity, and Cost”, ASHRAE Transactions 

2002, Vol 108, Part 2, pp. 220-231. 

[6] Underwood, David M., Zhivov, A., Duncan, S., 

Woody, A., Björk, C., Richter, S., Neth, D., Pinault, D., Jank, 

R. “Working Towards Net Zero Energy at Fort Irwin”, draft 

ERDC-CERL technical report.

9
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Practical Integration Approach and Whole Building Energy 

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Three technologies that have potential to save energy and improve sustainability of buildings are dedicated outdoor 

air systems, radiant heating and cooling systems and tighter building envelopes. To investigate the energy savings 

potential of these three technologies, whole building energy simulations were performed for a barracks facility and an 

administration facility in 15 U.S. climate zones and 16 international locations. 

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dedicated outdoor air system; radiant heating; radiant cooling; building envelope 

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