Advanced Energy Design Guide for Small Hospitals and Healthcare

Reprinted from

Journal of

Healthcare

Engineering

Vol. 1 · No. 2 · 2010

Multi-Science Publishing

ISSN 1756-8250

Advanced Energy Design Guide for

Small Hospitals and Healthcare

Facilities

Eric Bonnema, Shanti Pless, Ian Doebber

NREL/JA-550-47013.

Posted with permission.

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010 Page 277–296

277

Advanced Energy Design Guide for Small

Hospitals and Healthcare Facilities

Eric Bonnema

*, Shanti Pless

, Ian Doebber

National Renewable Energy Laboratory, 1617 Cole Boulevard,

Golden, Colorado, 80401, USA

ABSTRACT

The Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities (AEDG-SHC)

was recently completed. It is the sixth document in a series of guides designed to achieve 30%

savings over the minimum code requirements of ANSI/ASHRAE/IESNA Standard 90.1-1999.

The guide [1] is available for print purchase or as a free download from http://www.ashrae.org/aedg

and provides user-friendly assistance and recommendations for the building design, construction,

and owner communities to achieve energy savings. Included in the guide are prescriptive

recommendations for quality assurance and commissioning; design of the building envelope;

fenestration; lighting systems (including electric lighting and daylighting); heating, ventilation,

and air-conditioning (HVAC) systems; building automation and controls; outside air (OA)

treatment; and service water heating (SWH). The guide educates, provides practical

recommendations for exceeding code minimums, and provides leadership to help design teams

and owners produce higher efficiency commercial buildings.

Keywords: 30% energy savings, high performance buildings, energy efficiency, Advanced

Energy Design Guide, small healthcare facilities

1. INTRODUCTION

The Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

(AEDG-SHC) is targeted to help small- to medium-sized acute care, outpatient, and

inpatient buildings achieve site energy savings of at least 30% compared to the

minimum requirements of ANSI/ASHRAE/IES Standard 90.1-1999 [2]. The 30%

energy savings target is the first step toward achieving a net-zero energy building—a

building that draws from outside sources less or equal energy than it generates on site

from renewable energy sources annually [3]. The guide was developed in collaboration

with these partnering organizations: the American Society of Heating, Refrigerating and

Air-Conditioning Engineers (ASHRAE), the American Institute of Architects (AIA),

the U.S. Green Building Council (USGBC), the Illuminating Engineering Society

Corresponding author. Email: [email protected]; Tel: +1 303 384-6185

This article was prepared by the National Renewable Energy Laboratory, operated by the Alliance for

Sustainable Energy LLC, under the funding of the U.S. Department of Energy.”

(IES), the U.S. Department of Energy (DOE), and the American Society for Healthcare

Engineering (ASHE). The healthcare facilities covered in the scope of the guide are

smaller than 90,000 ft

(8,360 m

), defined as:

• Small acute care hospitals

• Small inpatient community hospitals

• Critical access hospitals with 25 or fewer beds

• Outpatient surgical facilities

• Freestanding birthing centers (similar to outpatient surgical centers)

• Gastrointestinal endoscopy facilities (similar to outpatient surgical centers)

• Renal dialysis centers (similar to medical office buildings)

• Primary care outpatient centers

• Small primary (neighborhood) outpatient facilities

• Freestanding outpatient diagnostic and treatment facilities

• Freestanding urgent care facilities

• Medical office buildings (larger than 20,000 ft

[1,858 m

])

Three major objectives drove the development of the guide: (1) to achieve a 30%

energy savings over Standard 90.1-1999 [4]; (2) to produce a reference document for

contractors, owners, and designers of small hospitals and healthcare facilities; and (3)

to provide how-to assistance to contractors and designers [5]. The guide is intended to

show that achieving the 30% target is not only possible, but easily achievable. Case

studies show facilities around the country that have achieved and surpassed the 30%

energy savings target. Best practices and cautions are also provided to demonstrate how

to successfully implement the recommendations.

By specifying a target and identifying paths for different climate zones, the guide

provides one example of how to meet the 30% savings target and how to build facilities

that use substantially less energy than those built to meet the minimum Standard 90.1-

1999 energy code requirements. There may be other means of achieving the target, and

it is hoped that the guide generates ideas for innovation.

2. LAYOUT AND CONTENT

The introduction of the guide contains information about its goal and scope, as well

as instructions for its use. Next the guide provides resources for those who want to

understand and adopt an overall, integrated process for designing, constructing, and

operating energy-efficient small hospitals and healthcare facilities. The guide presents

an integrated process for achieving energy savings. It is valuable for designers and

builders who want to augment and improve their practices so energy efficiency is

deliberately considered at each stage of the development process, from project

conception through building operation. This section concludes by addressing the

details of an integrated design process. It discusses the benefits and features of

integrated design, specifics about the process, and step-by-step details about the

four phases of the process: predesign, design, construction, and acceptance/

occupancy/operation.

278 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

The third section contains the climate-specific recommendation tables, a unique set

of energy efficiency recommendations for each of the eight DOE climate zones in the

United States. Efficiency recommendations are organized by several categories:

envelope; electric lighting; daylighting; heating, ventilating, and air-conditioning

(HVAC); and service water heating (SWH). The recommendations are simply one path

to reach the 30% energy savings target over Standard 90.1-1999. Other approaches may

also save energy, but identifying all possible solutions is not in the scope of this guide;

assurance of the savings with other approaches is left to the user. To achieve 30% energy

savings, this guide assumes compliance with the more stringent of either the applicable

edition of Standard 90.1 or the local code requirements in all areas not addressed in

the climate-specific recommendation tables. Future editions of energy codes may have

more stringent values. In these cases, the more stringent values are recommended.

Next the guide presents seven detailed case studies that illustrate techniques and

methods discussed. Energy numbers are provided to benchmark these buildings against

future buildings. All these case studies use some of the recommendations in the tables,

but predate the publication of the guide and were not developed explicitly using those

tables. Readers are encouraged to view more case studies at http://www.ashrae.org/aedg,

and to submit their own. Case studies provide the motivation and the examples for

others to follow.

The final section provides guidance about good practices for implementing the

recommendations, as well as cautions to avoid known problems in energy-efficient

construction. The section is divided into quality assurance and commissioning,

envelope, lighting, daylighting, HVAC, SWH, and bonus savings. The bonus savings

subsection includes areas for additional good practice items that, if implemented

properly, should achieve savings beyond the 30% level.

The quality assurance and commissioning subsection contains specific details about

commissioning and its importance in every step of the design process. The envelope

subsection contains climate zone-specific information about explicit types of walls,

roofs, floors, doors, insulation, infiltration, and vertical fenestration. The lighting

subsection details best practices for interior finishes, specific lamp and ballast types,

lighting layouts, and control strategies for specific space types. The daylighting

subsection provides tips on general principles, using daylighting analysis tools,

daylighting space types and layouts, building shape and orientation with respect to

daylighting, window-to-wall ratios, sidelighting, toplighting, skylight construction,

shading devices, photosensor specification, and photocell placement.

The HVAC subsection includes best practices for multiple-zone variable-air volume

(VAV) air-handling systems, water-source (including ground-source) heat pumps,

dedicated outdoor air (OA) systems, HVAC load calculations, equipment efficiencies,

economizers, exhaust air energy recovery, ductwork design, duct insulation, duct

sealing, exhaust air systems, system-level control strategies, filters, chilled water

systems, heating water systems, and zone-level controls.

The bonus savings subsection includes good practices for lighting (exterior lighting,

lamp types), process loads (medical equipment, high-performance kitchen and laundry

equipment), renewable energy (photovoltaic and solar hot water systems, wind turbines),

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

279

combined heat and power, additional HVAC systems (condenser water heat recovery,

ground-source heat pumps, displacement ventilation, demand-controlled ventilation,

thermal storage, desiccant-based dehumidification, evaporative condensing), and

electrical distribution systems (transformer efficiencies, metering) [1].

3. DEVELOPMENT PROCESS

The SHC-AEDG was developed by a project committee (PC) that represents a diverse

group of professionals. ASHRAE, AIA, IES, USGBC, ASHE, and DOE collaborated to

provide guidance and support. Members of the PC came from these partner organizations,

the ASHRAE Standing Standards Project Committee 90.1, and the ASHRAE Technical

Committee 9.6, Healthcare Facilities. A steering committee (SC) made up of representatives

of ASHRAE, AIA, IES, USGBC, ASHE, and DOE oversaw the PC as the guide was

developed. The SC assigned a timeline for the task, an energy savings goal, a target

audience, space types to include, and possible topics to incorporate.

Following SC guidance, the PC developed a one-year plan for completing the

document. The PC used a schedule to plan for two peer review periods that

corresponded with a 65% completion draft (technical refinement review) and a 90%

completion draft (final review for errors). A focus group reviewed the conceptual 35%

draft. Many meetings and conference calls were also held with the full PC during the

development of the guide.

4. EVALUATION APPROACH

The guide contains a set of energy efficiency recommendations for each of the eight

DOE climate zones across the United States. The following steps describe how the

energy savings potential of the guide’s recommendations was determined.

4.1. Develop “Typical” Small Hospital and Healthcare Facility Prototypes

For building characteristics that are not specified by Standard 90.1 but that are needed

to develop code-compliant baseline models, the PC chose two recently constructed

healthcare facilities (a surgery center and a community hospital) as the foundation for

the prototypes. Information from the construction drawings for these facilities, along

with publications data, was used to determine “typical” small hospital and healthcare

facility characteristics. The publications surveyed include:

• The 2003 Commercial Buildings Energy Consumption Survey (CBECS) [6]

• Additional data sets from the PC, including actual floor plates and space

programming requirements for the community hospital and the surgery center

• The DOE Buildings Database (http://eere.buildinggreen.com)

• McGraw Hill Dodge construction data

• The Green Guide for Healthcare [7]

• DOE Commercial Buildings Benchmark Models [8]

• ASHRAE Standard 62.1-2004 [9]

• 2006 AIA Guidelines for Design and Construction of Health Care Facilities [10]

280 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

281

These documents were used to develop the prototype model characteristics,

including form and floor plate, plug/process loads, ventilation rates, and operating

schedules. These characteristics are the same for the baseline and low-energy models,

and are documented in Table 1.

Table 1. Prototype Characteristics [11]

Building

Prototype Models

Characteristic Community Hospital Surgery Center

Size 65,000 ft

41,000 ft

Number of floors 1 3

Peak number of 675 414

occupants

Constructions Steel-framed wall Steel-framed wall

Roof with insulation Roof with insulation

entirely above deck entirely above deck

WWR 26% 20%

Occupancy Fully occupied during the day Fully occupied during the day

Partially occupied at night Vacant at night

Whole-building 2.1 W/ft

1.8 W/ft

weighted average

peak plug loads

Percent conditioned Fully heated and cooled Fully heated and cooled

HVAC system types Baseline: Packaged variable air Baseline: PVAV with DX cooling,

volume system (PVAV) with water boiler heating

direct expansion (DX) cooling,

water boiler heating

Low-energy: PVAV with Low-energy: PVAV with DX

DX cooling or air-cooled cooling or air-cooled chiller

chiller or water-cooled chiller, or water-cooled chiller,

water boiler heating water boiler heating

4.2. Create Baseline Models from the Prototypes that are Minimally Code

Compliant for Standard 90.1-1999

The baseline models for the small hospital and healthcare facility were developed by

applying the applicable criteria in Standard 90.1-1999 to the prototype models. The

baseline small hospital and healthcare facility energy modeling assumptions obtained

from Standard 90.1-1999 include the envelope characteristics, building lighting loads,

HVAC equipment efficiency, operation, control, sizing, fan power assumptions, and

SWH efficiency.

4.3. Create the Low-Energy Models Based on the Recommended Energy

Efficiency Technologies in the Guide

The final recommendations were determined based on an iterative process using the

PC’s expertise and results from modeling the recommendations. To quantify the potential

energy savings from the final recommended energy efficiency measures, the low-energy

building models were simulated by implementing the following energy efficiency

technologies. The energy efficiency measures that were applied to all climate zones and

included in the energy saving calculation are:

• Enhanced building opaque envelope insulation

• Enhanced window glazing with overhangs

• Reduced lighting power density (LPD) and occupancy control

• Daylighting in staff areas (exam rooms, nurse stations, offices, corridors) and

public spaces (waiting, reception)

• Higher efficiency HVAC equipment

• High-efficiency SWH

4.4. Verify 30% Energy Savings Across the Various HVAC System Types Over the

Eight U.S. Climate Zones

EnergyPlus

was used to perform building energy simulation analysis to assess and

quantify the energy savings potential of the guide’s recommendations. Two sets of

simulations were run for each prototype: the first meets the minimum requirements of

Standard 90.1-1999; the second uses the recommendations in the guide to achieve 30%

energy savings. For each low-energy design, three cooling equipment types were

modeled: a package rooftop system with direct expansion (DX) cooling, a packaged

rooftop system with a central air-cooled chiller, and a packaged rooftop system with a

central water-cooled chiller. The recommendations result in greater than 30% energy

savings in all climate zones for each prototype within the range of cooling system types.

The flowchart in Figure 1 shows the evaluation approach.

5. MODELING METHODS

5.1. Climate Zones

The guide contains a unique set of energy efficiency recommendations for a range of

climate zones. The common set of climate zones includes eight zones covering the

entire United States (see Figure 2). Climate zones are categorized by heating degree

days and cooling degree days, and range from the very hot zone 1 to the very cold

zone 8. Some climate zones are divided into subzones based on humidity levels. Humid

subzones are “A” zones, dry subzones are “B” zones, and marine subzones are “C”

zones. The combination of climate zones 1 through 8, along with their respective

subzones “A,” “B,” and “C,” create 15 unique climate zones.

Fifteen specific climate locations (cities) were selected as being most representative

of each subzone, as shown in the list. To determine energy savings, Typical

Meteorological Year 2 weather files for each location were used to simulate the baseline

and low-energy models.

282 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

283

• Zone 1: Miami, Florida (hot, humid)

• Zone 2A: Houston, Texas (hot, humid)

• Zone 2B: Phoenix, Arizona (hot, dry)

• Zone 3A: Memphis, Tennessee (hot, humid)

• Zone 3B: El Paso, Texas (hot, dry)

• Zone 3C: San Francisco, California (marine)

• Zone 4A: Baltimore, Maryland (mild, humid)

• Zone 4B: Albuquerque, New Mexico (mild, dry)

90.1-1999 Sweep

Apply climate-specific

parameters to the

prototypes to create

the baseline models in

15 cities

SHC AEDG Sweep

Apply climate-specific

parameters to the

prototypes to create

the low-energy models

in15 cities

Other data

sources

Prototype 1 (P1)

community

hospital

Prototype 2 (P2)

surgery

center

Drawings

2006 AIA

Guidelines

for Health

Care

Green Guide

for Health

Care

Project

committee

Prototype models

Three different low-energy model cooling equipment types

15 baseline

EnergyPlus

simulations

Percent savings comparisons

15 DX low-energy

model EnergyPlus

simulations

15 air-cooled

chiller low-energy

model EnergyPlus

simulations

15 water-cooled

chiller low-energy

model EnergyPlus

simulations

Figure 1. Evaluation Approach Flowchart [11].

284 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

• Zone 4C: Seattle, Washington (marine)

• Zone 5A: Chicago, Illinois (cold, humid)

• Zone 5B: Boise, Idaho (cold, dry)

• Zone 6A: Burlington, Vermont (cold, humid)

• Zone 6B: Helena, Montana (cold, dry)

• Zone 7: Duluth, Minnesota (very cold)

• Zone 8: Fairbanks, Alaska (extremely cold)

5.2. Analysis Platform

EnergyPlus version 3.1 was used to complete the energy simulations [12]. EnergyPlus

is the contemporary DOE tool that accounts for the complicated interactions between

climate, internal gains, building form and fabric, HVAC systems, and renewable energy

systems. Alongside EnergyPlus, Opt-E-Plus [13], a software research tool that

integrates with EnergyPlus, was used to aid in this analysis. Opt-E-Plus was developed

by the commercial buildings research group at NREL and was used to create and

manage the EnergyPlus input files.

The main analysis started with 8 “seed” EnergyPlus input files (1 baseline and 3 low-

energy models for the 2 prototypes). Opt-E-Plus was then used to sweep these input

files across the 15 climate zones, generating 120 input files. Interim analysis included

sweeping 16 other “seed” EnergyPlus input files across the 15 climate zones to create

240 separate input files, for a total of 360 individual EnergyPlus input files. During this

Moist (A)

Dry (B)Marine (C)

All of Alaska in Zone 7

except for the following

Boroughs in Zone 8:

Bethel

Dellingham

Fairbanks N. Star

Nome

North Slope

Northwest Arctic

Southeast Fairbanks

Wade Hampton

Yukon-Koyukuk

Zone 1 includes

Hawaii. Guam,

Puerto Rico.

and the Virgin Islands

Figure 2. Climate Zones and Representative Cities [11].

sweep, Opt-E-Plus applied climate zone-specific AEDG-SHC recommendations (such

as roof insulation values) to each input file. When interfaced with a Linux

supercomputer, Opt-E-Plus was able to complete approximately 1,440 linear simulation

hours in only 12 clock hours.

The results were then analyzed to determine the energy savings over the code-

compliant baseline. If the 30% savings target was not met for each simulation, changes

were made to the recommendations and the analysis restarted from the beginning.

These “seed” input files were continuously updated based on the results of the previous

simulation iteration as the project progressed and were reswept numerous times. The

automation of certain portions of this iterative process with Opt-E-Plus made this

project possible in the allotted time frame. Ultimately, the 30% savings goal was

achieved for each climate zone.

6. RECOMMENDATIONS

The guide makes recommendations for enhanced efficiency in several building systems to

meet the 30% savings target. To further illustrate the impacts of these recommendations,

Table 2 shows the comparison between Standard 90.1-1999 and the climate-specific

recommendations for climate zone 5A (Chicago). The recommendations presented are

either minimum or maximum values. Minimum values include:

• R-values (continuous insulation [c.i] where noted)

• Mean lumens/watt (MLPW)

• Solar Reflectance Index (SRI)

• Energy efficiency ratio (EER)

• Integrated energy efficiency ratio (IEER)

• Integrated part-load value (IPLV)

• Coefficient of performance (COP)

•Effectiveness

• Combustion efficiency (E

)

• Thermal efficiency (E

)

• Energy factor (EF)

• Duct or pipe insulation thickness

Maximum values include:

• Fenestration insulation (U-factors)

• Fenestration solar heat gain coefficient (SHGC)

•Total fenestration to gross wall area ratio (WWR)

• Lighting power density (LPD)

• Fan brake horsepower (bhp)

• Fan input power per cfm of supply airflow (W/cfm)

Table 2 highlights some recommendations; although examples from only one

climate zone are shown here, the guide contains recommendations for all eight

climate zones.

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

285

286 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Table 2. Standard 90.1-1999 v. AEDG for Climate Zone 5 [11]

Item Component

Standard 90.1-1999

(Bin 17)

SHC AEDG

(Climate Zone 5)

.i.c 03-R .i.c 51-R kced evoba yleritne noitalusnI

Roofs

1.09 dradnatS htiw ylpmoC enoN IRS

Mass (HC > 7 Btu/ft

.i.c 3.31-R .i.c 6.7-R )

Steel framed R-13 + R-3.8 c.i. R-13 + R-15.6 c.i.

Walls

.i.c 5.7-R enoN sllaw edarg woleB

.i.c 7.61-R .i.c 3.8-R ssaM

Floors

83-R 91-R demarf leetS

.ni 42 rof 51-R enoN detaehnU sbalS

05.0-U 07.0-U gnigniwS

Doors

05.0-U 54.1-U gnigniwsnoN

xam %04 %04-1.03 RWW ot noitartsenef latoT

92.0 75.0 ecnattimsnart lamrehT

43.0 93.0 CGHS

96.0 enoN ecnattimsnart elbisiV

Vertical

fenestration

Exterior sun control None Projection factor > 0.5

%3 %5-1.2 )foor fo tnecrep( aerA

06.0 01.1 ecnattimsnart lamrehT

Envelope

Skylights

04.0 26.0 CGHS

Diagnostic and treatment block: shape

the building footprint such that the area

within 15 ft of the perimeter exceeds

40% of the floorplate

Daylighting

Design the building to maximize access

to natural light through sidelighting:

- Staff areas (exam rooms, nurse

stations, offices, corridors)

- Public spaces (waiting, reception)

None

Inpatient units: ensure that 75% of the

occupied space (not including patient

rooms) lies within 20 ft of the perimeter

Interior finishes

Daylit room interior surface average

reflectance

None

88% on ceilings and walls above 7 ft

50% on walls below 7 ft

Lighting/Daylighting

continued over

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

287

tf/W 6.1 DPL

tf/W 0.1

Light source system efficacy

(linear fluorescent and high-intensity

discharge)

None 90 MLPW minimum

Light source system efficacy

(all other sources)

None 50 MLPW minimum

Lighting controls - general None

Manual on, auto-off in all zones except

24-hour patient care areas

Lighting/Daylighting

Interior lighting

Dimming controls daylight harvesting None

Dim fixtures within 15 ft of sidelighting

edge and within 10 ft of toplighting edge

DX air conditioner

(packaged or split system)

8.5 EER 7.5 IPLV

10.0 EER

9.7 IPLV

Air-cooled chiller efficiency 9.2 EER 9.6 IPLV

9.6 EER

11.5 IPLV

Water-cooled chiller efficiency 3.8 COP 3.9 IPLV Comply with Standard 90.1

Chilled water pumps None

Variable-frequency drive (VFD) and

National Electrical Manufacturers

Association (NEMA) premium

efficiency

snaf rewot dna DFV enoN rewot gnilooC

E %08 reliob saG

90% E

at peak design heating water

temperature

HVAC

Critical care access

Single-duct

VAV air

handling

system

(indoor or

outdoor)

with DX

cooling and

water

boilers

seY enoN rezimonocE

Item Component

Standard 90.1-1999

(Bin 17)

SHC AEDG

(Climate Zone 5)

mfc 0001/ph 1.1 snaF

bhp ≤ supply cfm × 0.0013+A, NEMA

premium efficiency motors

seY enoN kcabtes wolfria enoZ

SHC AEDG

continued over

288 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Item Component

Standard 90.1-1999

(Bin 17)

SHC AEDG

(Climate Zone 5)

DX air conditioner

(packaged or split system)

8.5 EER 7.5 IPLV

10.0 EER

9.7 IPLV

Air-cooled chiller efficiency 9.2 EER 9.6 IPLV

9.6 EER

11.5 IPLV

Water-cooled chiller efficiency 3.8 COP 3.9 IPLV Comply with Standard 90.1

Chilled water pumps None VFD and NEMA premium efficiency

snaf rewot dna DFV enoN rewot gnilooC

E %08 reliob saG

90% E

at peak design heating water

temperature

seY enoN rezimonocE

Fans

1.1 hp per

1,000 cfm

bhp ≤ supply cfm × 0.0013+A, NEMA

premium efficiency motors

Single-duct

VAV air

handling

system

seY enoN kcabtes erutarepmet ecapS

Water-source heat pump < 65 kBtu/h

Cooling: 9.3 EER at 85°F

Heating: 3.8 COP at 70°F

Cooling: 12 EER at 86°F

Heating: 4.5 COP at 68°F

Water-source heat pump ≥ 65 kBtu/h

Cooling: 10.5 EER at

85°F

Heating: 3.8 COP at

70°F

Cooling: 12 EER at 86°F

Heating: 4.2 COP at 68°F

ycneiciffe muimerp AMEN dna DFV enoN spmup retaW

snaf no DFV enoN relooc diulf/srewot gnilooC

E %08 reliob saG

90% E

at peak design heating water

temperature

1.09 dradnatS htiw ylpmoC enoN rezimonocE

Exhaust air energy recovery in dedicated

OA system

None

Zone A: 50% total effectiveness

Zone B: 50% sensible effectiveness

Zone C: 50% total effectiveness

mfc/W 4.0 enoN snaf PHSW

Other fans

(dedicated OA system, exhaust)

None

bhp ≤ supply cfm × 0.0013+A, NEMA

premium efficiency motors

WSHP

system

seY enoN kcabtes erutarepmet ecapS

Noncritical Care Access

HVAC

continued over

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

289

DX air conditioner

(packaged or split system)

8.5 EER 7.5 IPLV

10.0 EER

9.7 IPLV

Air-cooled chiller efficiency 9.2 EER 9.6 IPLV

9.6 EER

11.5 IPLV

Water-cooled chiller efficiency 3.8 COP 3.9 IPLV Comply with Standard 90.1

Chilled water pumps None VFD and NEMA premium efficiency

snaf rewot dna DFV enoN rewot gnilooC

E %08 reliob saG

90% E

at peak design heating water

temperature

seY enoN rezimonocE

Exhaust air energy recovery in dedicated

OA system

None

Zone A: 50% total effectiveness

Zone B: 50% sensible effectiveness

Zone C: 50% total effectiveness

mfc/W 4.0 enoN stinu lioc naF

Other fans

(dedicated OA system, exhaust)

None

bhp supply cfm 0.0013+A, NEMA

premium efficiency motors

Fan coil and

chiller

system

seY enoN kcabtes erutarepmet ecapS

dezirotoM enoN repmad AO

Duct seal class

Supply: seal class B

Exhaust: seal class B

Return: seal class C

Supply: seal class A

Exhaust: seal class B

Return: seal class B

Ducts and dampers

6-R 6-R level noitalusnI

Gas storage (>75 kBtu/h) 80% E

E %09

Gas instantaneous 0.81 E

or 81% E

0.81 EF or 81% E

Electric (storage or instantaneous)

EF = 0.93-0.00132

Volume

EF > 0.99-0.0012 Volume

SWH

Pipe insulation (d < 1.5 in./d .ni 5.1/.1 in .ni 1/.ni 5.0 ).ni 5.1

Noncritical Care Access

HVAC

Item Component

Standard 90.1-1999

(Bin 17)

SHC AEDG

(Climate Zone 5)

A review of the recommendations for all climate zones indicates how climate affects

specific differences between low-energy and baseline models. For example, the

recommended increase in roof insulation is greater in cold climates than in hot climates,

reflecting the greater potential for extra insulation to save energy in colder regions.

Mass wall insulation nearly doubles in hot and cold climates compared to Standard

90.1-1999; steel-framed walls add continuous insulation in hot climates and

significantly increase in R-value in cold climates. Slab insulation increases over

Standard 90.1-1999 in cold climates only, again reflecting the greater impact of

insulation in cold climates. Vertical glazing thermal transmittance changes fairly

substantially in hot climates because it switches from single to double glazing, but the

value changes less dramatically in cold climates. SHGCs change slightly in hot and cold

climates. Adding window overhangs with a projection factor greater than 0.5 was

recommended for all climate zones.

The concept for improving the building envelope was based around the fact that

most small healthcare facilities use constant-volume reheat systems to handle the space

conditioning needs. These systems have traditionally been common in such facilities

because they can independently control temperature and humidity and maintain space

pressurization requirements. The roof, wall insulation, and window performance was

increased, which reduced the constant-volume airflow needs and associated reheat. The

envelope thermal performance was increased to the point that the reduced airflow

needs meet the code-required minimum values. This saves on fan power and reheat

energy, and smaller constant-volume systems can save capital costs with smaller air

systems and reduced cooling capacity.

The daylighting recommendations include designing the building to maximize

access to natural light through sidelighting in staff areas (exam rooms, nurse stations,

offices, corridors) and public spaces (waiting, reception), along with daylighting

controls. General LPDs were reduced 37.5% in this guide compared to Standard 90.1-

1999, representing a large proportion of the total energy savings.

HVAC cooling efficiencies improved 15% in this guide compared to Standard 90.1-

1999 in all climates zones except 6, 7, and 8, where they remained unchanged from

Standard 90.1-1999 because the cooling energy represented a small portion of the

whole-building energy use. Because high air change rates and humidity control are required

in many space types, the constant-volume reheat HVAC systems that have traditionally

been used in these facilities use a lot of energy for reheat. The baseline energy modeling

shows that reheat represents more than 20% of the total energy use in all climate zones.

Thus, high-efficiency condensing boilers are recommended for all climate zones

because of the significant reheat energy required to maintain airflow requirements and

humidity control in all locations. The SWH recommendations indicate the value of

using either high-efficiency or point-of-use water heaters to reduce water heating

energy use.

7. ENERGY SAVINGS RESULTS

Annual hourly simulations of two prototype buildings established the energy savings

results from the application of the guide. One prototype building was the 65,000 ft

290 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

(6,040 m

) community hospital; the other was a 41,000 ft

(3,810 m

) surgery center.

Both prototypes were simulated in all 15 climate locations, representing humidity

subzones for the eight climate zones depicted in the guide and the standard.

The results of the simulations are indicated in Figure 3, showing the energy savings

compared to the baseline for the community hospital and the surgery center.

All locations achieved the 30% savings for the community hospital and the surgery

center. In general, the community hospital outperformed the surgery center in most

climate locations because of its continuous (24-hour) operation. With lower lighting

levels, additional heating energy was necessary to compensate for the heating typically

gained from lighting power sources. However, this was more than offset by the cooling

load reduction associated with lower lighting levels.

Complete results of the prototype facility simulations are presented in the Technical

Support Document: Development of the Advanced Energy Design Guide for Small

Hospitals and Healthcare Facilities, available at http://www.nrel.gov/docs/fy10osti/

46314.pdf [11].

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291

1A-Miami

2A-Houston

2B-Phoenix

3B-El Paso

3C-San Francisco

3A-Memphis

4A-Baltimore

5A-Chicago

6A-Burlington

6B-Helena

7A-Duluth

8A-Fairbanks

5B-Boise

4B-Albuquerque

4c-Seattle

Percent energy savings over standard 90.1-1999

10%

15%

20%

25%

30%

35%

40%

45%

50%

Community hospital Surgery center

Figure 3. Percent Savings for the PVAV with DX Cooling Models.

8. BUNDLED ENERGY EFFICIENCY MEASURE ANALYSIS

During the modeling process, a baseline model and a low-energy model were created

and compared to provide the percent savings numbers. The low-energy model was

created by starting with the prototype model and applying as many guide recommendations

as possible. However, it is difficult to determine which recommendations provide the most

energy savings because they are all applied to the prototype model in a single operation.

To better understand how each recommendation affects energy performance, a study

was performed in which each guide recommendation was incrementally and

aggregately applied until the low-energy model was achieved. This study was termed a

bundled energy efficiency measure analysis and consisted of seven steps: (1) apply the

envelope efficiency measures, which included adding overhangs to the south windows,

adding skylights to the surgery center, and upgrading the building materials in

accordance with the guide recommendations; (2) reduce space-by-space LPD; (3) add

daylighting controls to applicable zones; (4) reduce fan pressure drop and increase fan

efficiencies; (5) improve boiler and SWH efficiencies; (6) improve DX cooling

efficiencies; and (7) implement a zone airflow setback strategy in which the HVAC

terminal boxes mimicked constant air volume boxes during occupied times and VAV

292 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Baseline

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

100

150

Annual energy end use intensity (kBtu/ft

)

200

250

300

350

3C-San Francisco 4A-Baltimore 4B-Albuquerque 4C-Seattle 5A-Chicago

Humidification (elec)

Pumps (elec)

Water systems (gas)

fans (elec)

Cooling (elec)

Heating (gas)

Interior lighting (elec)

Interior equipment (gas)

Interior equipment (elec)

Step 1 : Apply the AEDG

specific envelope criteria

to the baseline model.

Step 2 : Apply the AEDG

lighting power density

recommendations to the

model from Step 1.

Step 3 : Apply the AEDG

daylighting

recommendations to the

model from Step 2.

Step 4 : Apply the AEDG

fan efficiency

recommendations to the

model from Step 3.

Step 5 : Apply the AEDG

boiler efficiency

recommendations to the

model from Step 4.

Step 6 : Apply the AEDG

compressor efficiencies

to the model from Step 5.

Step 7 : Apply the AEDG

zone airflow setback to

the model from Step 6.

Figure 4. Community Hospital Bundled Energy Efficiency Measure Analysis

Results for Climate Zones 1A through 3B.

boxes during unoccupied times. The bundled energy efficiency analysis energy results

by end use for the community hospital are shown in Figure 4 (climate zones 1A

through 3B), Figure 5 (climate zones 3C through 5A), and Figure 6 (climate zones 5B

through 8A).

The results of this analysis show the biggest energy savers are the LPD reductions

and the implementation of a zone airflow setback. Colder climates benefited more from

the improved boiler efficiencies; hotter climates benefited more from improved cooling

efficiencies.

9. SUMMARY

As with the previous guides in the series, the SHC-AEDG provides a simple, easy-to-

use guide to help the building designer, contractor, and owner identify a clear

prescriptive path to 30% energy savings over Standard 90.1-1999. In many ways, the

SHC-AEDG is a simple interface to a complex analysis performed using EnergyPlus.

The combination of a set of recommendations contained on a single page, along with

numerous how-to tips to help the construction team complete the project successfully,

should result in increased energy efficiency in new buildings. Case studies of actual

small healthcare applications add to the comprehension of energy efficiency

Journal of Healthcare Engineering · Vol. 1 · No. 2 · 2010

293

aseline

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

100

150

Annual energy end use intensity (kBtu/ft

)

200

250

300

350

5B-Boise 6A-Burlington 6B-Helena 7A-Duluth 8A-Fairbanks

Humidification (elec)

Pumps (elec)

Water systems (gas)

Fans (elec)

Cooling (elec)

Heating (gas)

Interior lighting (elec)

Interior equipment (gas)

Interior equipment (elec)

Step 1 : Apply the AEDG

specific envelope criteria

to the baseline model.

Step 2 : Apply the AEDG

lighting power density

recommendations to the

model from Step 1.

Step 3 : Apply the AEDG

daylighting

recommendations to the

model from Step 2.

Step 4 : Apply the AEDG

fan efficiency

recommendations to the

model from Step 3.

Step 5 : Apply the AEDG

boiler efficiency

recommendations to the

model from Step 4.

Step 6 : Apply the AEDG

compressor efficiencies

to the model from Step 5.

Step 7 : Apply the AEDG

zone airflow setback to

the model from Step 6.

Figure 5. Community Hospital Bundled Energy Efficiency Measure Analysis

Results for Climate Zones 3C through 5A.

opportunities. The SHC-AEDG is available for print purchase or as a free download

from http://www.ashrae.org/aedg.

The ultimate goal of the Advanced Energy Design Guide partner organizations is to

achieve net-zero energy buildings, and the 30% savings guides represent the first step

in reaching this goal. The SHC-AEDG marks the last in the series of 30% savings

design guides. This guide has furthered similar work in the healthcare energy efficiency

field, as it set the stage for developing a large hospital best practices guide and is used

in planning the next series of 50% savings Advanced Energy Design Guides. Also, U.S.

government healthcare facilities are starting to use the guide to meet EPAct 2005 energy

efficiency requirements.

ACKNOWLEDGEMENTS

The authors would like to thank all the members of the PC for their diligence, creativity,

and willingness to support the creation of the guide. This project would not have been

possible without financial contributions from DOE, through Drury Crawley and Pat

LeDonne of the Building Technologies Program. Additional thanks to the ASHRAE

staff, whose direction, guidance, organizational skills, and dedication enabled timely

completion of the guide.

294 Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities

Baseline

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

100

150

Annual energy end use intensity (kBtu/ft

)

200

250

300

350

5B-Boise 6A-Burlington 6B-Helena 7A-Duluth 8A-Fairbanks

Humidification (elec)

Pumps (elec)

Water systems (gas)

Fans (elec)

Cooling (elec)

Heating (gas)

Interior lighting (elec)

Interior equipment (gas)

Interior equipment (elec)

Step 1 : Apply the AEDG

specific envelope criteria

to the baseline model.

Step 2 : Apply the AEDG

lighting power density

recommendations to the

model from Step 1.

Step 3 : Apply the AEDG

daylighting

recommendations to the

model from Step 2.

Step 4 : Apply the AEDG

fan efficiency

recommendations to the

model from Step 3.

Step 5 : Apply the AEDG

boiler efficiency

recommendations to the

model from Step 4.

Step 6 : Apply the AEDG

compressor efficiencies

to the model from Step 5.

Step 7 : Apply the AEDG

zone airflow setback to

the model from Step 6.

Figure 6. Community Hospital Bundled Energy Efficiency Measure Analysis

Results for Climate Zones 5B through 8A.

REFERENCES

[1] ASHRAE, AIA, IES, USGBC, DOE, Advanced Energy Design Guide for Small Hospitals and

Healthcare Facilities, American Society of Heating, Refrigerating and Air-Conditioning Engineers,

Atlanta, 2009.

[2] ANSI/ASHRAE/IESNA, Standard 90.1-1999 Energy Standard for Buildings except Low-Rise

Residential Buildings, American Society of Heating, Refrigerating and Air-Conditioning Engineers,

Atlanta, 1999.

[3] Torcellini, P., Pless, S., Deru, M., Crawley, D., Zero Energy Buildings: A Critical Look at the

Definition, ACEEE Summer Study on Energy Efficiency in Buildings, Golden, National Renewable

Energy Laboratory, 2006.

[4] ASHRAE, AIA, IESNA, NBI, DOE, Advanced Energy Design Guide for Small Office Buildings,

American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 2000.

[5] Colliver, D.G. and Jarnagin, R.E., Savings 30% Over Standard 90.1-1999: Advanced Energy Design

Guide for Small Office Buildings, ASHRAE Journal, 2005, 47 (3), 22–27.

[6] EIA, 2003 Commercial Buildings Energy Consumption Survey, EIA, Washington D.C., 2003,

Available from http://eia.doe.gov/emeu/cbecs/cbecs2003/introduction.html.

[7] GGHC, Green Guide for Health Care: Best Practices for Creating High Performance Healing

Environments, Version 2.2, http://www.gghc.org, August 2009.

[8] Torcellini et al., DOE Commercial Building Benchmark Models: Preprint, National Renewable Energy

Laboratory, Golden, NREL Report No. CP-550-43291, 2008.

[9] ASHRAE, Standard 62.1-2004 Ventilation for Acceptable Indoor Air Quality, American Society of

Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 2004.

[10] AIA, Guidelines for Design and Construction of Health Care Facilities, American Institute of

Architects, Washington D.C., 2006.

[11] Pless, S., Torcellini, P., Doebber, I., Bonnema, E., Technical Support Document: Development of the

Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities–30% Energy Savings.

National Renewable Energy Laboratory, Golden, NREL Report No. TP-550-46314, 2010.

[12] DOE, EnergyPlus Simulation Software, Version 3.1, U.S. Department of Energy, Washington D.C.,

http://www.energyplus.gov, 2009.

[13] “Opt-E-Plus Software for Commercial Building Optimization,” NREL/FS-550-45620. Golden, CO:

National Renewable Energy Laboratory. http://www.nrel.gov/docs/fy10osti/45620.pdf, 2010.

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