FEDERAL ENERGY MANAGEMENT PROGRAM

materials can be a more efficient process

to remove moisture than conventional

technologies that rely on overcooling

and reheating ventilation air.

Application

A careful and rigorous analysis using hourly

temperatures and loads is necessary in order to

identify attractive applications of integrated

systems. Circumstances can be favorable where

there are high electric rates and low gas rates;

special gas summertime or air-conditioning

rates or rebates for installing gas air-conditioning

equipment are helpful in achieving life-cycle

cost savings.

There are several building types that can be

attractive for integrated systems. These include

buildings with high ventilation rates such as movie

theaters and supermarkets because they have a

much higher latent cooling load than most buildings and benefit more from desiccant dehumidification. Buildings with balanced electrical and

thermal loads are attractive for on-site power generation or hybrid chiller plants because waste heat

can be used for heating or hot water. Hospitals and

hotels are good examples of these applications.

Life-cycle cost analysis should include

site-specific installation costs and

system performance using local

weather and building loads. The

efficiency and capacity of on-site

power generation may degrade

significantly with ambient temperature and altitude (some types

of generators are much more sensitive

to conditions than others); expectations

and predictions based on design conditions can be extremely misleading.

Desiccant systems must be carefully

engineered, installed, and commissioned to avoid significant energy losses

through increased fan and blower power

and motors for wheel rotation.

Integrated systems bring together gas-fired and

electrically driven equipment to provide heating,

cooling, dehumidification, and electrical service

to commercial and public buildings. The three

principal configurations are (1) hybrid chiller

plants incorporating gas-fired and electrically

driven chillers, (2) desiccant dehumidifiers using

waste heat from combustion of natural gas to

regenerate the desiccant, and (3) combined heating, cooling, and power systems that include

on-site electrical power generation with heating

and cooling space conditioning and potable hot

water production.

Energy-Saving Mechanism

Principal energy savings are achieved through

the use of waste heat from a combustion process

to provide hot water or steam for other purposes. Additional benefits derive from reducing

or eliminating use and costs of peak load electricity. On-site power generation can provide an

overall energy savings through the elimination

of transmission and distribution losses; primary

benefit of on-site power generation remains elimination of utility peak demand charges and user

control over power availability and reliability.

Desiccant dehumidification using hydroscopic

Integrated Systems

Building high-efficiency heating, cooling, and power-generating facilities

from gas-fired and electrically driven subsystems

Internet: http://www.eren.doe.gov/femp

Federal

Technology

Alert

A publication series

designed to speed the

adoption of energyefficient and renewable

technologies in the

Federal sector

Prepared by the

New Technology

Demonstration

Program

DOE/EE-0234

Integrated systems offer improved building services

and comfort.

No portion of this publication may be altered

in any form without prior

written consent from the

U.S. Department of Energy

and the authoring national

laboratory.
Technology Performance

There is very little performance history

available to judge integrated systems.

Hybrid chillers have been very successful as means of reducing summertime

air-conditioning costs; most, however,

are not run as truly integrated systems

where both electric and gas chillers run

simultaneously. Theoretically additional

savings could be made by operating the

chillers in a synergistic manner. Desiccant dehumidifiers are becoming a commercial success; regenerating desiccants

using waste heat is rare and there is no

performance history to report. On-site

power generation is growing in popularity as electric demand charges rise and

the electric grid becomes less dependable

in the summer. Traditionally, waste heat

has been recovered for space heating or

hot water; there is very little history of

waste heat use to drive absorption chillers

or to regenerate desiccant dehumidifiers.

There is also very little history concerning connecting on-site power generation

with the utility grid; interconnection is a

major issue and standards are needed to

expedite licensing and power industry

acceptance. New power generation

technologies are being commercialized

that could change the economics of

on-site power generation. These include

microturbines and fuel cells. There is no

performance history of these technologies in integrated systems.

Case Study

A case study is presented for a hybrid

chiller plant comparing two 400-ton

centrifugal chillers with one 400-ton

centrifugal and one 400-ton absorption

chiller. The life-cycle cost of the hybrid

chiller plant can be higher or lower than

the electric chiller plant depending on gas

utility incentives such as air-conditioning

gas rates and equipment rebates.

Technology in Perspective

Developments in the integration of onsite power generation, heating, cooling,

and dehumidification are moving rapidly as a result of the changing economics of commercial building electric rates.

Many combinations of integrated systems will be demonstrated in the 2000 to

2003 time frame. Until then, applications

other than hybrid chiller plants are on

the leading edge of energy technology

and have a high risk factor. Among the

near-term developments will be wider

commercialization of skid-mounted

integrated systems built-up from preengineered modules, leading to significantly lower equipment costs, faster

licensing of standardized systems, and

reduced risks.

FEDERAL ENERGY MANAGEMENT PROGRAM

Disclaimer

This report was sponsored by the United States Department of Energy, Office of Federal Energy Management

Programs. Neither the United States Government nor any agency or contractor thereof, nor any of their employees,

makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not

infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade

name, mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency or contractor thereof. The views and opinions of

authors expressed herein do not necessarily state or reflect those of the United States Government or any agency or

contractor thereof.
dehumidifier). Cost savings are

possible by reducing electrical

demand charges. Integrated

systems are best suited to buildings with large cooling loads

or buildings with balanced

and simultaneous electrical

and thermal loads. Equipment

costs for integrated systems have

been prohibitive for small applications, but reductions in the costs

for microturbines or fuel cells and

changing electric rate structures

could make small-scale integrated

systems more attractive.

The combinations of technologies (e.g.,

power generation, absorption chillers, natural

gas engines, desiccant dehumidifiers) generally

require additional training and experience of

building engineering and maintenance personnel. Subsystems are introduced that are fundamentally different than conventional HVAC

technologies; maintaining each individual component and balancing overall system operation

requires new knowledge and skills

Many combinations of gas-fired and electrically

driven heating, cooling, and power generation

equipment are possible that provide higher

system efficiencies, lower utility costs, or both.

Dramatic energy savings occur in systems which

take advantage of waste heat from power generation or engine-driven chillers. Hybrid chillers

are an established technology for reducing operating costs that are becoming increasingly attractive under electrical deregulation. Integrated

systems with desiccant dehumidification are

fairly recent innovations and are proving attractive in some applications. Combined power generation, heating, and cooling is a new technology

without an established performance record.

Abstract

Integrated systems employ gas-fired and electrically-driven equipment to provide heating and

cooling for space-conditioning and hot water,

dehumidification, and possibly on-site power

generation. While similar systems can be used

in industrial applications employing waste

heat from manufacturing processes, they are

not discussed in this report. There are at least

three major aspects of integrated systems:

(1) hybrid chilled water plants incorporating

gas-fired and electric-driven chillers, (2) desiccant dehumidification systems using process

waste heat to regenerate the desiccant, and

(3) on-site power generation using waste heat

for space conditioning, water heating, or heat

actuated cooling. System energy efficiency is

increased significantly in these applications

when waste heat from one component of the

integrated system is used by a second component (e.g., waste heat from power generation

used to provide hot water for laundry facilities

or for space heating, heat from engine-driven

chiller used to regenerate desiccant in desiccant

Integrated Systems

Building high-efficiency heating, cooling, and power-generating facilities from gas-fired and

electrically driven subsystems

Federal

Technology

Alert

1

FEDERAL ENERGY MANAGEMENT PROGRAM

Micro-Turbine Generator, Desiccant Dehumidifier,

and Absorption Chiller
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FEDERAL ENERGY MANAGEMENT PROGRAM

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FEDERAL ENERGY MANAGEMENT PROGRAM

Contents

Abstract ........................................................................................................................... 1

About the Technology .................................................................................................... 5

Application Domain

Energy-Saving Mechanism

Other Benefits

Variations

Federal Sector Potential .................................................................................................. 11

Technology Screening Process

Estimated Savings and Market Potential

Laboratory Perspective

Application ..................................................................................................................... 11

Application Screening

Where to Apply

What to Avoid

Equipment Integration

Maintenance Impact

Costs

Utility Incentives and Support

Technology Performance................................................................................................ 16

Field Experience

Case Study: Hybrid Chiller Plant................................................................................... 16

Facility Description

Existing Technology Description

New Technology Equipment Selection

Saving Potential

Life-Cycle Cost

The Technology In Perspective ...................................................................................... 18

The Technology’s Development .................................................................................... 19

Technology Outlook ....................................................................................................... 19

Manufacturers ................................................................................................................ 19

Who is Using the Technology......................................................................................... 22

 Federal Sites

 Non-Federal Sites

For Further Information ................................................................................................. 23

Appendix A: Glossary ................................................................................................ 27

Appendix B: Federal Life-Cycle Costing Procedures and the BLCC Software ....... 28
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FEDERAL ENERGY MANAGEMENT PROGRAM

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FEDERAL ENERGY MANAGEMENT PROGRAM

About the Technology

“Integrated systems” combine electric

and gas-fired equipment for building

services in a synergistic manner to reduce

overall system energy input or operating

costs. Building services can include comfort space conditioning (both heating

and cooling), water heating, dehumidification, and electrical power generation.

Similar systems employing waste heat

from manufacturing processes can be

used in industrial applications, but they

are not discussed in this report. The

equipment to provide these services

can be quite common and conventional

(e.g., electric chillers, IC engine-generator sets) or new and innovative (e.g., fuel

cells, microturbine generators). A partial

list of equipment that can be used in

integrated systems includes gas boilers,

gas-fired absorption or engine-driven

chillers, desiccant dehumidifiers, and

electrically driven chillers as well as

conventional engine-driven generators,

microturbines, and fuel cells for on-site

electrical power generation.

System energy efficiency can be increased

significantly in applications where waste

heat from one component of the system

can be used by a second piece of equipment. Additional benefits are possible

by reducing electrical demand charges.

Buildings with balanced, simultaneous

electrical and thermal loads are good

candidates for integrated systems as

are buildings with large water heating

loads. Equipment costs for integrated

systems are generally prohibitive for

small applications but may be advantageous in special circumstances or where

waste heat is available.

The concept of integrated systems can

be illustrated with a couple of examples.

First, consider an office building cooled

by a natural gas-fired absorption chiller

with a desiccant dehumidifier. Moisture

is removed from the air by using a desiccant wheel. The absorption chiller then

provides sensible cooling and leftover

waste heat from the combustion of natural gas used to power the chiller is used

to “regenerate” the desiccant. Waste heat

recovery and desiccant systems can also

be combined with engine-driven chillers

or on-site power generation to provide

similar savings.

A second configuration for an integrated

system would combine an absorption

chiller with an electrically driven centrifugal chiller for air conditioning a large

building. Traditionally one or two large,

electrically driven chillers would be used

in this application. Splitting the cooling

load between two chillers, one using

natural gas and the other using electricity, gives the building operator an additional tool in managing utility costs

depending on the rate schedules for gas

and electricity. Cooling plant operation

is tailored to minimize costs considering

demand charges, fuel costs, and system

efficiencies. Either the gas chiller can be

used, the electric chiller, or the two in

tandem to provide the required cooling

at the lowest cost. This configuration

may or may not provide an overall

reduction in energy consumption. An

engine-driven chiller could also be used

in tandem with an electrical chiller in

this configuration.

Finally, a third configuration of an integrated system could combine on-site

power generation with a hot water heat

recovery system and an electrically

driven centrifugal chiller. The overall

system efficiency is improved dramatically by the heat recovery for potable

hot water or building space heating.

Depending on equipment requirements

it may be possible to use waste heat

from power generation to regenerate a

desiccant for dehumidification or power

an absorption chiller for additional airconditioning capacity. The amount and

temperature of waste heat available

needs to be matched with the requirements of the desiccant or absorption

equipment. In each instance, an integrated system consists of matching

gas and electrically driven equipment

to work together to provide building

services.

Application Domain

The high initial cost of integrated systems has resulted in relatively few

installations, but systems are being

installed with increasing frequency to

reduce electrical costs. There are hundreds of installations of hybrid chiller

plants using absorption or enginedriven chillers in conjunction with

electric chillers. While there are a great

many installations of desiccant dehumidifiers with evaporative or compression cooling, there are few that employ

waste heat to regenerate the desiccant.

Finally, there are probably fewer than

five installations of on-site power generation with waste heat actuated cooling operating in the United States. All

known building combined cooling,

heating, and power systems in the

United States began operation in 1998

Some of the types of equipment that

can be used in integrated systems may

be unfamiliar to the reader:

• desiccant dehumidifiers use a rotating

wheel or liquid spray to chemically

remove water vapor from ventilation

air and then subsequently use heated

building exhaust air to remove moisture from the desiccant wheel or liquid.

• absorption chillers produce chilled

water for air conditioning by a reversible chemical process of absorbing

refrigerant vapor into a chemical

solution at low temperature and

using heat to desorb it at high temperature and pressure.

• fuel cells produce electricity through

a chemical reaction of hydrogen and

oxygen instead of the conventional

combustion of fossil fuels.

• microturbine generators are small

versions (25 to 300 kW) of turbinegenerators on a scale suitable for producing electricity for single-building

applications; multiple units can be

used to achieve higher capacities for

larger buildings.
6

FEDERAL ENERGY MANAGEMENT PROGRAM

or later. There are a great number of

Federal buildings where integrated systems could be employed in one configuration or another. Specific applications

of what can be done depend on what

equipment is commercially available.

Integrated systems have been built from

custom designs using commercially

available, independent “subsystems”

rather than being marketed from standardized designs from an individual

manufacturer or supplier. The list of possible subsystems include conventional

electric-driven air-to-air vapor compression air conditioners and electric-driven

chillers, gas-engine driven chillers, direct

and indirect-fired absorption chillers,

solid and liquid desiccant dehumidifiers,

engine-generators, microturbine generators, and natural gas fuel cells. There are

many well established manufacturers of

the conventional electric air conditioners

and chillers spanning the range of less

than one ton to several thousand tons of

cooling capacity.

There are at least nine manufacturers of

desiccant dehumidification systems with

drying capabilities covering the range

from 3 to 670 lbs of water per hour and

air flows of 300 to 84,000 cfm. This

equipment spans the range of small to

reasonably large building cooling loads;

desiccant dehumidification has been

used with success in quick service restaurants, movie theaters, supermarkets,

and hospitals.

Combinations of equipment for hybrid

chiller plants depend on the availability of absorption, engine-driven, and

electric-driven chillers. Double-effect

absorption chillers are available commercially from at least six manufacturers in the U.S. The cooling capacity of

this equipment ranges in size from

20 to 1700 tons (70 to 6000 kW). Enginedriven chillers are available from at

least seven manufacturers and range

in capacity from 15 to 4000 tons (53 to

14,000 kW). HVAC manufacturers produce electric chillers in capacities from

2 to 10,000 tons ( 7 to 35,000 kW).

the less efficient the cooling process is.

Instead of blowing air across a cold heat

exchanger to remove moisture, desiccant

dehumidifiers blow across surfaces or

through liquid sprays containing chemical compounds with lower vapor pressures than the supply air. The difference

in vapor pressure causes water molecules

to be adsorbed onto the surface of the

desiccant or chemically combined with it.

Practical applications of desiccants in

HVAC systems require that the moisture

be removed from the desiccant so it can

be reused. Some, but not all, desiccant

materials can be regenerated at the temperatures of waste heat streams from

on-site power generation or absorption

and engine-driven chillers; other desiccant materials require electric or gas

heaters to achieve the necessary regeneration temperatures. Figure 1 shows one

configuration for incorporating a desiccant wheel into an integrated system.

Comparing the “traditional” dehumidification with desiccant systems,

less energy is required to regenerate the

desiccant to satisfy the latent cooling

load (moisture removal) than is needed

by a conventional air conditioner to chill

the air stream below the dew point so

water condenses on the evaporator.

Desiccant dehumidifiers are particularly

attractive in applications where there is

a source of waste heat that is available

to regenerate the desiccant.

While the chemical process described

above requires less energy to dehumidify

the air than the mechanical one, there

are two factors that reduce the energy

savings. First, as water is removed from

the air using a desiccant, the air is heated

in the process. Approximately 1000 Btu

are added to the air for every pound of

water removed. An additional cooling

process has to be added to create a

dehumidification/cooling system that

provides the same level of comfort as

the conventional mechanical systems.

The cooling can be provided by a vapor

compression system chilling the air just

Integrated systems for combined cooling, heat, and power depend on the

availability of conventional enginegenerator sets, microturbines, or fuel

cells for electric power generation. There

are only two known manufacturers of

microturbine electrical generators in the

United States although several other

companies are preparing products that

will be available in 2000. There is only one

commercial manufacturer of small capacity (200 kW) fuel cells. There are at least

two manufacturers of pre-engineered

skid-mounted integrated systems incorporating power generation with heat

recovery and hot water, chilled water, or

steam services.

Energy-Saving Mechanism

Energy savings from integrated systems

is primarily the result of replacing purchased energy with recovered waste

heat for potable hot water, comfort heating or cooling, or desiccant regeneration.

Hybrid chiller plants generally provide

significant savings in energy costs by

replacing electricity use at peak load

periods with natural gas, but they do

not necessarily reduce overall energy

consumption. Some reductions may

be possible when the electric chiller is

used concurrently with a gas absorption

chiller in such a way as to maximize the

gas chiller efficiency.

Desiccant dehumidification can yield

direct energy savings as a more efficient

means of providing sensible cooling

than electric compression equipment.

Desiccant dehumidifiers use a chemical

process to remove moisture from the air

that can require much less energy than

conventional air conditioning systems.

The “traditional” method of dehumidification relies on chilling the supply air

below the dew point temperature so

moisture condenses on the outside of

heat exchanger tubes or fins. This process requires cooling the air below the

level needed for comfort and subsequently reheating the air; the colder

the air needs to be for dehumidification,
7

FEDERAL ENERGY MANAGEMENT PROGRAM

down to the temperature necessary for

comfort or by an indirect evaporative

cooling system. Evaporative cooling is

the reverse of desiccant dehumidification; it cools air by adding water to it.

An indirect system is used so that water

is added to the building exhaust air

and a heat exchanger is used to cool the

building supply air.

There is also an increase in “peripheral”

energy consumption for desiccant systems relative to conventional HVAC

systems. Liquid desiccant dehumidifiers

require energy for pumps that are not

a part of conventional systems. Solid

desiccant dehumidifiers employ honeycombed wheels that rotate through the

supply air flow. The pressure drop across

the desiccant wheel can be much greater

than it is across the evaporator in a conventional system requiring higher blower

power. The electric motor used to rotate

the desiccant wheel also uses energy as

may additional components added to the

desiccant system to boost its efficiency.

The principal benefit in using chiller

plants containing both gas and

electrically driven equipment is to

reduce electrical consumption, particularly at peak load periods. This can lead

to large cost savings, but not necessarily

energy savings. The hybrid chiller plant

can be designed in a manner such that

the electric chiller pre-cools the inlet

water for the absorption chiller (or vice

versa). This trades off the operation of

one machine at less than optimal conditions in order to run the second machine

at higher efficiency. There may be an

overall net increase in efficiency for the

combined machines as a result.

The energy savings in combined cooling, heating, and power are seen when

looking at the entire “power cycle.”

Normally, the generation of electricity

is done at a remote location and large

amounts of heat are rejected to the air

or nearby rivers, streams, or lakes. If the

power plant is 35% efficient, then 65% of

the energy content of the fuels is being

rejected to the environment.

If a building requires electricity, heating,

cooling, or hot water at the same time,

energy is provided for each of these

services separately. Combined cooling,

heating, and power systems use enginegenerator sets, microturbines, or fuel

cells to generate power on-site. The primary energy savings come from recovery

and use of waste heat from the power

generating process (there can also be

savings on the hottest days and highest

cooling loads depending on the efficiency of the utility generators used at

those times and electrical transmission

losses). Hot water can be produced by

the waste heat for space heating or

domestic hot water uses (e.g., laundry,

dish washing, bathing). Steam can be

produced for space heating or to power

absorption chillers for air conditioning

or to regenerate a desiccant. Making use

of the waste heat reduces the amount of

energy that would have been required

to provide these services and boosts

system efficiencies to as high as 80%.

Other Benefits

All three major types of integrated

systems provide additional benefits.

Hybrid chiller systems provide the

potential for significant cost savings by

reducing electric demand charges. They

give the building operators a capability

of changing their source of energy during the day or through a season using

the least expensive fuel as operating

load and energy costs vary. While the

“baseline” system may operate on

electricity, the gas-fired system can be

brought on line during peak loads to

keep utility load charges at a minimum.

Engine-driven chillers have the additional advantage of being able to modulate their cooling capacities by varying

engine speed which increases part-load

efficiency and follows the building load

more closely without cycling on and off.

Desiccant systems are recognized as providing intangible benefits by improving

indoor air quality and comfort. Also, by

operating strictly in the vapor phase of

water, there is no opportunity for water

to condense in the duct work providing

Figure 1. Two-wheeled desiccant dehumidifier.
8

FEDERAL ENERGY MANAGEMENT PROGRAM

an environment for mold and bacterial

growth. In many remodel situations or

retrofit applications, desiccant dehumidification or gas cooling can eliminate

large expenses necessary to upgrade

the building’s electrical service. On-site

power generation allows building

operators to maintain electrical service

during brownouts, rotating outages, or

transmission failures on hot summer

days when the regional electrical grid

is overloaded.

Variations

By nomenclature alone, integrated

systems include any combination of

dissimilar subsystems designed or

assembled in such a manner that they

work in conjunction with each other

at a higher efficiency or lower cost than

they would operate individually. There

are many variations within the subsystems themselves that can be used,

so naturally there are a great many

variations within integrated systems.

Desiccant dehumidification can be performed using solid or liquid desiccants,

with evaporative or compression cooling

systems, or with thermal wheels to transfer heat between supply and exhaust air

streams. On-site power can be generated

using conventional IC engine-driven

generators, microturbine generators,

combustion gas turbine generators, fuel

cells, wind-turbines, or photovoltaic

generators. Gas-fired water chillers can

be engine-driven or direct or indirect

fired absorption cycles; they can be used

alone or arranged with electric-driven

chillers in hybrid plants in series, parallel, or side-stream configurations.

Data on on-site generating technologies

is listed in Tables 1 and 2. Traditionally,

reciprocating IC and diesel enginegenerator sets have been used for emergency back-up power and on-site power

generation. Combustion gas-turbines

are also available for large installations,

while microturbines are coming onto

the market for small to medium sized

applications. Fuel cells are being developed and capacities could be available

covering the range from very small to

large installations.

Microturbines are very promising equipment for on-site power generation, and

they are attracting a lot of attention.

Their use should be considered very

carefully to avoid unwarranted expectations. First, microturbines employ internal heat recovery using recuperators to

preheat the combustion air, as illustrated

in Figure 2, which reduces the available

thermal energy for an integrated application. Eliminating the recuperator to

have exhaust heat for other uses reduces

the generating efficiency by about 50%.

Microturbine generating capacity is also

sensitive to inlet air temperature and

altitude; economic analyses must be

performed using actual operating

conditions rather than being based on

microturbine design capacity. Among

their advantages, microturbines have

extremely low NOx

 emissions and noise

levels. They also have fewer moving

parts, lower weight and smaller equipment footprint than conventional generation technologies and do not require

cooling towers or radiators. They do

require high pressure natural gas or a

gas compressor; they are not able to start

under large loads or follow large transients. Microturbines are well suited for

base load applications but cycling mode

will degrade component lifetimes; economic analyses in those applications

need to factor in higher parts and maintenance costs resulting from frequent

starts and stops. Further development

work is being performed to improve the

power electronics and gas compressors;

Table 1. Capacity, efficiency, and cost data for power generation systems.

Power System Capacity Range

Electrical

E y fficiency

( ) HHV

Capital Cost

( ) $/kW

Operating &

M t aintenance Cost

( ) $/kWh)

R W eciprocating Engine 2 % 0 kW to 20 M 2 0 8% to 45 $ 2 500 to $140 $0.007 to $0.0

M W icroturbine ~ % 25 to 300 k ~ 0 20% to 33 $ 1 600 to $100 $0.003 to $0.0

G W as Turbine 5 % 00 kW to 150 M 2 0 1% to 40 $ 8 600 to $90 $0.003 to $0.00

F W uel Cell 5 % kW to 3 M 3 0 6% to 60 $ 0 1900 to $350 $0.005 to $0.1

S W tirling Engine ~ % 200 W to 100 k 2 0 0% to 36 $ e 100 not availabl

R p otary Engine ~ % 5 kW and u 2 e 0% to 30 n e ot availabl not availabl

P W hotovoltaic 1 % kW to 1 M 6 0 % to 19 $ 4 660 $0.001 to $0.00

W W ind Turbine 1 % 0 kW to 1 M 2 0 5 $ 1 100 $0.0
9

FEDERAL ENERGY MANAGEMENT PROGRAM

there may be life-cycle problems with

the recuperators.

Electric and gas-fired absorption or

engine-driven chillers can be configured

in several different manners in order to

take best advantage of the characteristics

of each machine. There is a very good,

concise description of four common

arrangements in Cool Times (1997):

• “Series: a series of connected chillers,

as shown in Figure 3, can be used in

high ∆T chiller plants. They are especially popular because this arrangement is capable of taking advantage of

the high temperature preferences of

absorption chillers and the low temperature capabilities of vapor compression chillers. The disadvantage

Table 2. Advantages and disadvantages of technologies for on-site power generation.

Figure 2. Schematic diagram of a microturbine generator.

Generating

Technology

Advantages Disadvantages/Problems

Microturbine

Generators

• high reliability

• compact and modular design

• low maintenance and operating costs

• low emissions and noise

• ease of operation

• requires high pressure gas or gas compressor

• not able to start under large load or follow

large transients

• power electronics need further development

• may be life cycle problems with recuperator

• performance sensitive to temperature

and altitude

Reciprocating

Engine-generator

Sets

• runs well on part loads

• suitable for start/stop operation

• can be sized for lower electrical loads

• follow electrical and thermal loads

• insensitive to temperature and altitude

• emissions

• noise

• efficiency

Combustion

Gas Turbine

Generators

• reliable technology

• high efficiency

• low maintenance requirement

• high quality heat: 20,000-25,000 lb/h

125 psig steam (5 MW plant)

• need to be run on constant load

• not suitable for start/stop operation

F y uel Cells • high efficienc

• high output power quality

• no moving parts

• very low emissions

• low noise

• poor ability for multiple starts

• poor ability to follow large, rapid transients

• high capital cost

• availability

• not a firmly established technology

Photovoltaic and

Wind Generators

• pollution free • dependent on availability of environmental

resources
10

FEDERAL ENERGY MANAGEMENT PROGRAM

of this arrangement is the potential for

high pressure drop in the system, resulting in higher pumping energy.

• Parallel: the parallel arrangement

in Figure 4 is probably the most common arrangement in chilled water

plants with two or more chillers. This

arrangement is simple and reduces

pressure drops and pumping power,

but does not always have the flexibility to preferentially load

a specific chiller to manage utility costs.

• Sidestream: the sidestream arrangement in Figure 5 is becoming more popular in hybrid chiller plants, especially plants

with multiple electric chillers and a single peak shaving

absorption or engine-driven chiller. This system provides the

advantages of a series arrangement without the disadvantages

of high pressure drops. The absorption (or engine-driven)

chiller can operate in parallel with the electric chillers using

the bypass line or it can operate in series to prechill the return

water to the electric chillers and reduce their electrical load.

• Ice: hybrid chiller plants can also be used for ice or chilled

water storage. The electric machine is used to produce ice

during off-peak times while the absorber and ice storage

system operate during peak electric demand periods.

Engine-driven chillers can be used as back-up to make

the ice at off-peak times because they can achieve the low

temperatures required by ice storage systems.

The advantages and disadvantages of each configuration are

discussed in more detail in publications by the American Gas

Cooling Center (Technology Transfer Workshop Workbook for

Integrated System Design and Technology Transfer Workshop (TTW):

Integrated Systems Design).

Combined cooling, heating, and power systems integrate power

generation with chillers or compression air conditioners, desiccant dehumidification and cooling systems, and/or waste heat

utilization for space conditioning or hot water generation. Such

a system is illustrated in Figure 6. This shows a microturbine

that generates electricity to power an electrically driven centrifugal chiller and to meet the other electrical loads of the building

(e.g., fans and blowers, lighting). Steam or hot water from a heat

recovery heat exchanger in the exhaust from the microturbine is

used to power an indirect-fired absorption chiller, heat the building exhaust air to regenerate a desiccant wheel, and to provide

building space heating. Chilled water from the chillers is also

used to cool the ventilation air after it is dried by the desiccant

wheel. Typically an integrated system would not include all of

these subsystems, and in fact waste heat temperatures may be

too low for many of them to be used effectively.

Figure 3. Series configuration of gas and electric chillers.

Figure 4. Parallel configuration of gas and electric chillers.

Figure 5. Sidestream configuration of gas and electric chillers.
11

FEDERAL ENERGY MANAGEMENT PROGRAM

Federal Sector Potential

Federal Technology Alerts target technologies that appear to have significant

untapped Federal-sector potential and

for which some installation experience

exists. Integrated systems are recognized for their potential in reducing energy consumption, costs, and emissions.

Technology Screening Process

The new technologies presented in the

Federal Technology Alert are identified

primarily through direct submitals

from Federal agencies to the Program’s

Interlaboratory Council (ILC). The ILC

also identifies new technologies through

trade journals, product expositions, trade

associations, other research programs,

and other interested parties. Based on

these responses, the technologies are

evaluated by the ILC in terms of Federalsector potential energy savings, procurement, installation and maintenance costs.

They are also categorized as either just

coming to market or as technologies for

which field data and experience exist.

Integrated systems were judged to have

notable potential and to be life-cycle

cost-effective in the proper applications.

Integrated systems were selected for

the New Technology Demonstration

Program by the ILC. Several other technologies are slated for future Federal

Technology Alerts.

Estimated Savings

and Market Potential

No estimate of nationwide energy savings is available for integrated systems.

Discussions within the industry focus

on the potential market for combined

cooling, heating, and on-site power

generation where an estimated 75 GW

of capacity is economically justified.

This potential market is divided primarily between buildings for education

(27%), health care (24%), office buildings

(21%), food sales and service (10%), and

lodging (7%). The extent of cost-effective

heat recovery and energy savings potential in these markets is not known.

Laboratory Perspective

Integrated systems have existed in the

form of hybrid chiller plants since the

1970s, but they attracted increased attention in the 1990s because of deregulation of the electric industry. Increased

demand charges, time-of-day rates, and

real-time pricing of electricity change

the economics of hybrid chiller plants

significantly and make them attractive

as a means of managing building energy

costs. These systems have been demonstrated to be cost-effective in some gas

and electric rate structures.

Integrated systems incorporating on-site

power generation and desiccant dehumidification are relatively new technologies. Interest in using these systems is

due to both electric utility deregulation

and to technology advances in microturbine generators and desiccant materials. Concerns about “sick building

syndrome” and indoor air quality are

also leading to higher standards for

ventilation rates resulting in increased

latent cooling loads. Increased latent

loads improve the economics of desiccant dehumidification and incorporation of desiccant dehumidification in

integrated systems. Demonstration

projects employing microturbines,

advanced desiccant materials, and integrated systems employing these technologies together or in conjunction with

gas-fired chillers were initiated in 1998

and 1999.

Application

Application Screening

Unfortunately there are no rules of

thumb that help simplify the determination of where integrated gas and electric systems are practical. The decision

is fundamentally the result of long-term

gas and electric rates, electric demand

charges, equipment costs, and building

space conditioning loads. Summer air

Figure 6. Combined cooling, heating, and power system.
12

FEDERAL ENERGY MANAGEMENT PROGRAM

conditioning gas rates and/or utility

rebates are virtually essential to achieve

cost savings; discounts and rebates

from equipment manufacturers help.

Economics are probably unfavorable

if none of these conditions exist.

Where to Apply

Integrated systems normally have higher

initial costs and maintenance costs than

conventional HVAC systems, by their

very nature, and consequently are of

interest primarily where there can be

significant reductions in operating

energy costs. Cost savings occur because

of favorable gas to electrical price ratios,

avoided electrical demand charges, onetime gas utility rebates or incentives

to install gas-cooling equipment, and

reductions in purchased energy through

the use of waste heat from one of the

components in the integrated system by

another. The types of subsystems that

are combined to form an integrated system will depend on the advantages and

disadvantages of each as they pertain to

the particular application.

Desiccant dehumidification systems

may be cost-effective in several general

instances depending on indoor requirements, building usage and occupancy,

and ventilation or fresh air intake. Some

of these are enumerated in the FTA TwoWheel Desiccant Dehumidification Systems

and include:

• level of indoor humidity; dehumidification cannot be achieved below

40°F dew point using conventional

vapor compression equipment; this

is rare in commercial and office building applications,

• high latent load fraction (>25%); latent

loads are normally below 25% in

office buildings but may be higher

in supermarkets, movie theaters,

schools, and auditoriums,

• fresh air intake; buildings with unusually high fresh air intake (>20%) such

as those listed above, particularly in

humid climates,

• demand and energy costs; high summertime demand charges and electrical rates coupled with low gas rates,

and

• availability of free or inexpensive

regeneration energy; sources of waste

heat such as boilers, refrigeration condensers, engine-driven or absorption

cooling systems, or fuel cells capable of

providing air heated to 180° to 220°F.

Desiccant dehumidification can also be

attractive in retrofit applications where

additional cooling capacity is needed

and site specific factors (e.g. upgrading

building electrical service, available

space) make increased electric chillers

capacity expensive.

The advantages of hybrid chiller plants

lie primarily in reductions of electrical

demand charges, though there can be

gains in chiller plant efficiencies through

substitution of multiple smaller capacity

chillers for a single large chiller with poor

part load performance. Combinations

of gas-fired absorption or engine-driven

chillers with electrically driven chillers

should be considered in equal or unequal

capacities in applications where electrical peak rates and demand charges are

high and gas prices are low. Special consideration should be given where low

summertime gas rates or special air conditioning gas rates are available. Hybrid

chiller plants can also be very attractive

in retrofit applications where additional

cooling capacity is required and use of

electrically driven chillers by themselves

would require an expensive upgrade of

electrical service to the building.

Combined cooling, heating, and power

can be cost-effective where electrical

use rates and demand charges are high

relative to gas rates. On-site power generation may be cost-effective through

reduction in demand charges or peak

rates for electrical consumption alone.

It may not be cost-effective without the

use of waste heat for space and/or

water heating and “free” cooling from

desiccant dehumidification systems or

absorption chillers. The data in Table 3

can be used with information from preceding tables to scope out the components

Table 3. Approximate sizing of electrical load and building types.

Magnitude of Electrical Load Type of Application

• s >1 MW • large high-rise office building

• largest hospitals

• largest hotels

• large shopping malls

• ) 200 kW to 1 MW • hospitals (200 to 300 beds

• large hotels (750 rooms)

• office buildings (200,000 ft

2

)

• schools (125,000 ft

2

)

• large retail buildings

• t 50 to 200 kW • office buildings (50,000 f 2)

• average hotel (75,000 ft

2

, 125 rooms)

• multi-family residences (100 units)

• t 10 to 50 kW • fast food restaurant (4,000 f 2

)

• small office building (10,000 ft

2

)

• multi-family residences (<25 units)

• ~10 kW peak load

• 0.50 to 1.5 kW average load

• 0.10 kW base load common

• little coincidence of electrical

and thermal loads

• single-family residence
13

FEDERAL ENERGY MANAGEMENT PROGRAM

of an integrated system for a particular

building as a step in generating some cost

estimates. A detailed, hourly simulation

of electrical and thermal loads using actual building data and utility rates with

typical weather data is necessary to evaluate the savings generated through waste

heat recovery. Waste heat is valuable for

space heating or cooling purposes only

if it is available when heating or cooling

is required.

What to Avoid

Careful design and matching of components is required for integrated systems,

particularly combined cooling, heating,

and power. Microturbines and fuel cells

are more appropriate for on-site power

generation than other engine-driven generators because of their low emissions

and projected low maintenance costs.

Communication and planning with electric utilities and government air quality

agencies may be necessary to avoid

delays or obstacles to installing and

licensing an integrated system. Stringent

state or local regulations may restrict the

use of some gas-fired chillers. Licensing

delays may arise for systems employing

on-site power generation because of air

quality standards that were written to

regulate emissions of nitrogen and sulphur compounds from large utility operated power plants based on emissions

per unit electrical production (g/kWe

).

Regulations may not directly recognize

the benefits of on-site power generation

with waste heat recovery where emissions can be viewed in terms of mass per

unit useful energy (g/kWe+kWt). Good

preparation and communication with

the governing authorities can reduce or

eliminate licensing problems. It is also

necessary to coordinate with local utilities and electric distribution companies.

A significant amount of time and effort

may be required to resolve issues concerning interconnection with the local

utility grid. Electrical utilities may also

impose exit fees on users installing gasfired air conditioning or power generation equipment because of the costs

incurred by the utility from abandoned

capacity. Anticipation of future plans for

use of gas-fired equipment, and communication of those intentions to electrical utilities can be effective in reducing

or eliminating exit fees.

Equipment Integration

Desiccant dehumidifiers can be

integrated into conventional vapor

compression air conditioning systems

in order to handle the latent cooling load,

but they have greater potential when

teamed with gas-fired cooling equipment or with on-site power generators.

Desiccant wheels or liquid desiccants

need to be regenerated with heat which

removes or desorbs the moisture from

the desiccant so it can be vented to the

outside air. Typically electric heaters,

heat reclaim coils, steam coils, or gas

burners are used to provide the heat of

regeneration. Each of these processes

incur a fuel cost. Waste heat may be a

source of “free” energy to perform this

job. Regeneration temperatures vary

depending on desiccant materials, airflow velocities, and rotational speeds of

the desiccant wheel. While some materials can be regenerated at about 140°F

(E-Source p. 6.5.2) most require temperatures of 190° to 230°F. Waste heat from a

power generator or from an absorption

or engine-driven chiller may be able to

provide the heat of regeneration without any additional energy cost. Temperature and heat requirements need to be

matched between the desiccant equipment and the source of waste heat; waste

heat “availability” is summarized in

Table 4, and waste heat requirements

Table 4. Heat recovery, maintenance schedule, and emission data for electric generating systems.

Maximum Heat Expected Time

Recovery Temperature Heat Recovery Between Overhaul NOx

 Emissions

Power System (°F) (Btu/h per kW) (operating hours) (ppm)

Reciprocating Engine ~4000 to 10,000 25,000+ 20

Microturbine ~4000 to 12,000 40,000+ <1

Gas Turbine not available not available not available

Fuel Cell ~3500 to 4000 40,000+ ~1

Stirling Engine ~6000 to 12,000 up to ~60,000+ not available

Rotary Engine not available not available not available

PEM: proton exchange membrane fuel cell, PAFC: phosphoric acid fuel cell, SOFC: solid oxide fuel cell,

MCFC: molten carbonate fuel cell

~200°F water jacket

750° to 930°F exhaust

~500°F

930° to 1100°F

140° to 180°F (PEM)

390°F (PAFC)

1100° to 1400°F (SOFC)

~1100°F (MCFxC)

~160°F to 200°F

~300°F water jacket

~1600°F exhaust
14

FEDERAL ENERGY MANAGEMENT PROGRAM

an absorption chiller, or regenerating a

desiccant. Waste heat temperatures

from microturbines appear well suited

for use with indirect-fired absorption

equipment, but these numbers need to

be considered carefully in consultation

with microturbine manufacturers.

Microturbines use pressurized natural

gas, air compressors, and recuperators

in order to achieve high operating efficiencies. As illustrated in Figure 2, inlet

air is compressed, preheated in the

recuperator cooling the exhaust gases,

and then mixed with natural gas in the

burner. This process boosts the power

conversion efficiency of the microturbine

from 15 to 17% to an overall efficiency as

high as 33% (Kreider 2000), but reduces

the temperature of the exhaust air and

amount of waste heat available for use

with an absorption chiller or desiccant

dehumidifier.

Maintenance Impact

Solid desiccant dehumidification systems require periodic maintenance to

ensure that the desiccant and thermal

wheels are clean and rotating smoothly.

Dirt and dust reduce the effectiveness of

the desiccant and worn seals allow hot

air and moisture to leak from the exit

air stream to the supply air, reducing

system effectiveness. Periodic maintenance includes:

• changing filters and vacuuming the

desiccant wheel every two months,

• inspecting and repairing contact seals,

wheel drive assemblies, wheel support

bearings, fans, and fan belts regularly.

The desiccant wheel itself needs very

little maintenance if the filters are cleaned

and replaced on schedule; wheel life

should be 10,000 to 100,000 hours (10 to

15 years) under normal use. Contact

seals have an expected life of five years

(FTA 1997, p. 16).

Figure 7. Recoverable waste heat from engine-driven chillers.

for absorption and desiccant systems

are listed in Table 5.

Engine-driven chillers can be integrated

with desiccant dehumidifiers or absorption chillers. Waste heat can be recovered

from the cooling water or the exhaust

gases from engine-driven chillers as hot

water at temperatures of up to 230°F or

as low-pressure steam. The heat can be

used to regenerate desiccant wheels or

to drive indirect-fired absorption chillers. Temperatures are a closer match for

desiccant regeneration or single-effect

absorption chillers than they are for

double-effect absorption chillers. Enduse temperature requirements may

limit the use of waste heat to preheating to reduce some of the energy input

required by desiccants or absorption

chillers. Figure 7 shows data for recoverable waste heat from commercially

available engine-driven chillers as

1000’s of Btu/h per ton of chiller capacity. While there is broad scatter in the

data for small capacity chillers, the

recoverable waste heat is fairly constant at approximately 2750 Btu/h per

ton for chillers above 500 tons capacity

(E-Source 1997, Table 10-5, p. 10.4.2).

Finally, waste heat from a microturbine,

generator, or a fuel cell can be used for

hot water or space heating, powering

Table 5. Waste heat energy requirements.

Equipment Requirements Effect

Single-Effect Absorption 240-270°F steam, one ton cooling per

Chiller 9-12 psig 17,000-18,500 Btu/h input

Double-Effect Absorption 370°F steam, one ton cooling per

Chiller 115 psig 10,000 Btu/h input

Desiccant Dehumidifier 180-230°F hot air one lb H2O removed per

3700 Btu input

8

7

6

5

4

3

2

1

0 500 1,000 1,500 2,000 2,500 3,000 3,500

Chiller Capacity (tons)

Recovered Heat (kBtu/h/ton)
15

FEDERAL ENERGY MANAGEMENT PROGRAM

Absorption chillers may require maintenance procedures that are unfamiliar to

chiller plant personnel. This schedule

includes:

• daily check of burner and controls,

flue pressure, fuel leaks (direct-fired

chillers), chilled water loop and cooling tower operation,

• seasonal maintenance includes checking for vacuum leaks, checking the

purge pump, the electrical systems,

controls, and burner (indirect-fired

chillers).

Solution and refrigerant pump motors,

bearings, and seals require periodic

repair or replacement (E Source 1997).

Samples of refrigerant solution should

be drawn according to manufacturer

schedules and procedures and sent to

an outside laboratory to be checked for

the presence of non-condensibles and

concentration of corrosion inhibitors.

Engine-driven chillers require regular

maintenance of the engine in addition

to the normal maintenance required by

electric motor driven chillers. These

include:

• daily check of oil level, oil filter ∆P,

discharge temperature, condenser and

cooler tube ∆Ts, inlet and outlet temperatures, and operating pressures,

• a weekly check of the refrigerant

charge,

• quarterly tests of the oil and checks

of the mounting screws,

• semi-annual replacement of the oil

filter and oil return system, and

• an annual oil change, pressure test of

the refrigeration system, and cleaning of condenser tubes and water

strainers.

Engine top-end overhauls by trained

personnel are recommended somewhere

between 12,000 and 30,000 operating

hours and complete engine overhauls

anywhere between 15,000 and 60,000

operating hours, depending on operating conditions.

Microturbine electrical generators were

introduced as commercial products in the

United States in the fall of 1999, so there is

not a great deal of operating experience

with them. One manufacturer requires

regular service at prescribed intervals

to maintain their product warrantee.

These include:

• every 8000 hours of operation replace

the engine air filter, clean the electronics air filter, inspect the internal

fuel filter, and replace the external

fuel filter,

• every 16,000 hours, also replace the

turbine exhaust thermocouple, ignitor, and the fuel injectors.

The gas compressor also requires service

every 3000 to 16,000 hours, depending

on the gas supply pressure.

Finally, the controls of integrated systems

are more complicated than are those of

HVAC systems without combined and

inter-related operation of components.

Initial system commissioning is necessary to ensure that system performance

is up to design specifications; periodic

recommissioning and adjustment is

required to keep equipment operating

at that level.

Costs

Desiccant dehumidification systems

are sized on their air flow requirements,

cubic feet per minute or cfm; costs are

typically given in terms of dollars per cfm.

Equipment costs range from $5/cfm for

large commercial units down to $8/cfm

for units of less than 1000 cfm for residential applications (FTA 1997). Installation

costs depend heavily on site specific factors and are not generalized here.

Equipment costs for chiller plants varies with type of chiller (i.e. electricallydriven, absorption, engine-driven) and

chiller capacity. Approximate equipment

costs are listed in Table 6 (Arnold 1998,

Garland 1999). These data do not include

the cost of cooling towers and installation; cooling tower costs vary depending

on site specific conditions and range

from $50 to $100 per ton of heat rejected

(E-Source 1999). The gas-fired absorption and engine-driven chillers will

require larger cooling tower capacities

than electrically-driven chillers, because

of the higher peak load heat rejection

requirements.

Conventional engine-generators, turbine

generators, fuel cells, and recently introduced microturbine generators can be

used for power generation in combined

cooling, heating, and power systems.

Equipment parameters for enginegenerators, turbine generators, and fuel

cells are listed in Table 1. Microturbines

were introduced by one manufacturer

in October 1999 and are scheduled for

introduction by another in late 1999 or

early 2000. Cost data on these systems

are preliminary; projected future prices

of $300/kW may be possible because

of the economies of scale in mass

production. These costs also do not

include installation expenses, which vary

with local factors and can be significant.

Table 6. Approximate cost of water chillers (1998 $/ton capacity).

Chiller Type

Small

( ) <500 tons)

Medium

( ) 500-1000 tons)

Large

( ) 1000-1500 tons)

E 0 lectrically Driven $ 8 30 $ 8 27 <$27

E 0 ngine-Driven $ 0 600-$65 $ 0 525-$55 $46

S 5 ingle-Effect Absorption $ 0 28 $ 5 21 $19

D 0 ouble-Effect Absorption $ 0 60 $ 0 525-$55 $46
16

FEDERAL ENERGY MANAGEMENT PROGRAM

Utility Incentives and Support

Natural gas utilities frequently sponsor

customer incentive programs including

rebates for installing gas cooling equipment and summertime gas air conditioning rates. The availability of these

programs changes over time and it is

necessary to contact local gas suppliers

to identify the availability of utility incentive programs for natural gas air conditioning and on-site power generation.

Technology Performance

Field Experience

Maritz Inc. operates a multi-building

campus in suburban St. Louis, Missouri,

including 1.3 million ft2

 of office and

warehouse space spread over 300 acres.

Each building houses its own equipment room, generally with two chillers

individually sized to handle the design

cooling load. Maritz has opted for dual

chillers in order to provide redundancy

to ensure uninterrupted building services. They have been changing over

to hybrid plants combining absorption

and electric driven chillers to reduce

peak electric demand charges. Leonard

Bilheimer explains that in 1988 Maritz

chose to replace an electric chiller during

the process of remodeling a building

with a 200-ton direct-fired double-effect

absorption chiller, in part to avoid a costly

upgrade of building electrical service.

He had to overcome his initial feelings

left over from some unpleasant experiences with old single-effect absorption

chillers, but he’s become an enthusiastic

proponent of modern direct-fired absorption chiller/heaters. Since 1988 Maritz

has installed double-effect absorption

chillers in two additional buildings and

Bilheimer looks forward to more conversions to gas/electric chiller plants

as opportunities arise. Maritz has been

very successful at leveling their gas load

year-round and at shaving electrical

peak demand. Chiller plant operation

and routine testing and maintenance

of both electric and gas chillers are performed by an in-house staff with only

rare need for contracted replacement of

heat exchanger tubes by outside firms.

Maritz rarely operates the gas and electric chillers simultaneously, though they

do have limited experience in doing so.

While they monitor operating costs, they

have not tracked energy savings per se.

Both combined cooling, heating, and

power systems and desiccant regeneration with waste heat are such new applications that there is no field experience

to report on these systems.

Case Study: Hybrid Chiller

Plant

Facility Description

In order to compare conventional electricdriven chiller plants and hybrid chiller

plants, consider a nine story office building in Atlanta, Georgia. The exterior walls

are primarily glass, there is 370,000 ft2

of floor space, the lighting load averages

1.5 W/ft2 and electrical plug loads

1.0 W/ft2. The building is occupied by

up to 190 people on a schedule with

high occupancy between 8:00 a.m.

and 5:00 p.m. on weekdays with low

occupancy on evenings and weekends.

Computer simulations using the Gas

Cooling Guide from the Gas Research

Institute are used with chiller equipment

manufacturer’s data to calculate monthly

electrical demand and consumption.

Existing Technology Description

The baseline technology for heating

and air conditioning is two 400-ton

electrically driven centrifugal chillers

with a small boiler to provide space

heating. The cost of each of the chillers

is $132,000 and the cost of the cooling

tower is $71,092; annual maintenance

and operating costs (e.g., cooling water

chemical treatment, makeup water) are

estimated to be $36,000. The expected

equipment lifetime is 25 years. The cost

assumptions are listed in Table 7.

New Technology Equipment

Selection

The alternative technology considered in

this application is a 400-ton electrically

driven centrifugal chiller operated in

parallel with a 400-ton direct-fired,

double-effect absorption chiller. The

absorption chiller is the lead chiller in

peak and mid-peak periods with the

electrical chiller being used as necessary

to meet the load. The cost of the electrical chiller is $132,000 and the absorption

chiller $240,000; the cost of the cooling

tower is $88,046 (larger than electrically

driven baseline because of higher reject

heat requirement). Annual operating

and maintenance costs are $39,600. The

expected lifetime is 25 years.

Table 7. All-electrical and hybrid chiller plant cost comparison.

Cost Item

All-Electric

B r aseline Chiller

P t lan

Hybrid Gas &

E t lectric Chiller Plant

Equipment

a. Electric Chiller(s)

b. Absorption Chiller

c. Cooling Tower

Total

$264,000

$71,092

$335,092

$132,000

$240,000

$88,046

$460,046

Non-Energy O&M Costs

a. Electric Chiller(s)

b. Absorption Chiller

Total

$36,000 per year

$0 per year

$36,000 per year

$18,000 per year

$21,600 per year

$39,600 per year
17

FEDERAL ENERGY MANAGEMENT PROGRAM

Saving Potential

Information about changes in peak electrical demand is needed to evaluate the

cost savings of integrated systems as well

as data for gas and electrical consumption. Computer simulations are necessary to estimate these values. In this

case, the Gas Cooling Guide calculated

the annual energy consumption for the

baseline all-electric chiller plant in Atlanta as 4,446,900 kWh electricity and

19,970 therms of natural gas. The average energy consumption for the hybrid

plant is 4,081,104 kWh of electricity and

102,960 therms of natural gas. The peak

electrical demand is reduced approximately 16% each month; monthly peak

demand and monthly demand charges

are shown in Table 8. Over the lifetime

of the equipment, the hybrid chiller

plant would have electrical consumption 9,145,504 kWh lower than that of

the all-electric plant, while natural gas

use would be 2,074,750 therms higher.

Life-Cycle Cost

The life-cycle cost analysis depends

heavily on energy costs and any utility

rebates that are available for gas air conditioning or for improved electrical load

factors. Commercial electric rates schedules of 3.65¢ per kWh and demand

charges of $15.12 per kW in summer

and $9.31 per kW in winter are used

for this analysis. Natural gas rates are

$0.488 per therm in the summer and

$0.513 per therm in the winter; these

correspond to an annual average rate

of $0.511 per therm. Demand charges

are $172,550 per year for the all-electric

chiller plant and $143,420 for the hybrid

chiller plant, for a net savings of $29,131

per year. The initial and recurring costs

for these two chiller plants are summarized in Table 9. These data show that

the hybrid chiller plant has significantly

higher equipment costs than the baseline

all-electric chiller plant with slightly

higher non-energy operating and maintenance costs.

A life-cycle cost comparison of the hybrid

and electric chiller plants is also shown in

Table 9 for four different sets of assumptions for utility rate structures. The second and third columns of Table 9 contain

the costs for the baseline electric chiller

plant and the hybrid plant using equal

capacity electrically driven and absorption chillers and the rate structure

described in the preceding paragraph.

Table 8. Electricity demand and demand charges for electric and hybrid chiller plants.

Month

Peak Electric Demand (kW) Demand Charges

Electric

C t hiller Plant

Hybrid Chiller

P t lan

Demand

R s eductions

Electric

C t hiller Plant

Hybrid

C t s hiller Plant Net Saving

J 7 anuary 1 0 ,28 1 7 ,08 2 9 0 $ 4 12,74 $ 5 10,51 $2,23

F 4 ebruary 1 7 ,30 1 7 ,09 2 7 0 $ 2 12,93 $ 5 10,70 $2,23

M 7 arch 1 7 ,33 1 0 ,10 2 6 3 $ 2 13,28 $ 4 10,80 $2,48

A 0 pril 1 3 ,46 1 7 ,24 2 8 1 $ 8 14,61 $ 0 12,27 $2,34

M 2 ay 1 0 ,53 1 2 ,28 2 7 5 $ 4 15,39 $ 3 12,67 $2,72

J 7 une 1 7 ,56 1 0 ,31 2 3 5 $ 0 15,77 $ 3 13,07 $2,70

J 8 uly 1 0 ,62 1 8 ,36 2 8 6 $ 8 16,42 $ 0 13,53 $2,89

A 0 ugust 1 0 ,60 1 0 ,34 2 0 6 $ 6 16,13 $ 8 12,74 $2,80

S 0 eptember 1 7 ,53 1 3 ,28 2 4 4 $ 6 15,37 $ 8 12,74 $2,62

O 7 ctober 1 7 ,51 1 0 ,27 2 0 4 $ 8 15,23 $ 2 12,63 $2,59

N 3 ovember 1 0 ,29 1 3 ,09 2 8 0 $ 2 12,81 $ 6 10,62 $2,19

D 0 ecember 1 0 ,20 1 0 ,08 1 0 2 $ 4 11,81 $ 6 10,51 $1,29

Total $ 0 172,551 $ 1 143,42 $29,13
18

FEDERAL ENERGY MANAGEMENT PROGRAM

The fourth, fifth, and sixth columns

contain cost data for the hybrid chiller

plant assuming a special gas air conditioning rate (24.9¢ per therm), a gas

utility rebate of $250 per ton, and the

gas air-conditioning rate and the rebate.

This data shows negative savings for

the equipment costs, operating and

maintenance costs, and also for the

energy costs between the base case and

the hybrid chiller plant. The utility

rebate and gas air conditioning rate

decrease the life-cycle costs of the hybrid

systems significantly and can yield two

to seven year paybacks, as shown in the

columns on the right of Table 9.

The Technology In

Perspective

There are at least three different sides to

integrated systems. Those employing

hybrid gas-fired and electrically driven

chiller plants represent demonstrated

combinations of proven technologies.

Further development of system controls

will occur in order to manage energy

costs more effectively as utilities are

deregulated, but hybrid systems are

already proven effective means of controlling peak electrical demand charges.

Desiccant dehumidification systems are

commercially available, but there is not

much experience in incorporating waste

heat utilization to regenerate the desiccant. The U.S. Department of Energy is

currently sponsoring field tests of dual

wheel desiccant systems that are providing valuable insights on system performance, and design and installation

problems. Lessons learned from these

projects will benefit both stand-alone

desiccant systems and the use of desiccant wheels in integrated systems. Combined cooling, heating, and power is a

fairly young technology with extremely

few installations nationwide in 1999. It

is a major area of interest for building

Table 9. Life-cycle costs for hybrid chiller plants.

Cost Item

B e aseline

E c lectric

C t hiller Plant

H d ybri

C t hiller Plant

Hybrid Chiller

P s lant with Gas

A e /C Rate

Hybrid Chiller

P h lant with

U e tility Rebate

Hybrid Chiller

P h lant with

R d ebate and

G e as A/C Rate

Equipment

electric chiller(s)

absorption chiller

cooling tower

Total

$264,000

—

$71,092

$335,092

$132,000

$240,000

$88,046

$460,046

$132,000

$240,000

$88,046

$460,046

$132,000

$140,000

$88,046

$360,04

$132,000

$140,000

$88,046

$360,046

O 1 perating and Maintenance $ 1 567,79 $ 1 624,57 $ 1 624,57 $ 1 624,57 $624,57

Energy Costs

electricity (use)

electricity (demand)

gas

Total

$2,339,753

$2,487,319

$156,916

$4,983,988

$2,147,281

$2,067,393

$809,014

$5,023,688

$2,147,281

$2,067,393

$394,216

$4,608,890

$2,147,281

$2,067,393

$809,014

$5,023,688

$2,147,281

$2,067,393

$394,216

$4,608,890

Savings/Investments

p.v. non-investment savings

increased total investment

net savings

—

—

—

-$96,480

$124,954

-$221,434

$318,318

$124,954

$193,364

-$96,480

$24,954

-$121,434

$318,318

$24,954

$293,364

Life-Cycle Cost

epuipment

O&M

energy

Total

$335,092

$567,791

$4,983,988

$5,886,871

$460,046

$624,571

$5,023,688

$6,108,305

$460,046

$624,571

$4,608,890

$5,693,507

$360,046

$624,571

$5,023,688

$6,008,305

$360,046

$624,571

$4,608,890

$5,593,507

S —A avings-to-Investment Ratio N 5 / 2 A .5 N 6 / 12.7

A —A djusted Internal Rate of Return N % / 8 A .07 N % / 15.26

Payback

simple

discounted

—

—

never

never

6 years

7 years

never

never

2 years

2 years
19

FEDERAL ENERGY MANAGEMENT PROGRAM

energy R&D, and while it promises great

rewards, projects in this area should be

approached carefully with attention to

system controls, component synergisms,

energy costs, and local utility and air

quality regulations and standards.

The Technology’s

Development

Integrated systems, to date, have been

custom designed on a case-by-case basis

by engineers familiar with components

(e.g., chillers, power generators, dehumidifiers) from separate manufacturers.

While such special attention allows the

designers to take best advantage of

unique factors for each application

(e.g., latent cooling load, utility rates or

rebates), it also kept costs high. Chillers,

desiccant wheels, and electric generators have been developed separate from

their use in integrated systems. Doubleeffect absorption chillers were introduced

in the 1980s representing a quantum step

up in efficiency and reliability from the

old single-effect chillers. Electrically

driven centrifugal, screw, and reciprocating chillers changed dramatically in

the 1990s as manufacturers took the

opportunity to redesign machines as

CFCs were phased out so that new

machines have significantly higher efficiencies and lower refrigerant emissions

than old models. IC and diesel engine

generators were developed to mature,

efficient products. Desiccant systems

were also developed and were becoming widely used in niche applications

(e.g., supermarkets, theaters, hospitals)

in the 1990s. Microturbines with high

efficiency, low emissions and maintenance costs, and low noise are becoming

available. Rarely, though, were these

components put together into an integrated gas and electric system.

Technology Outlook

Look for developments in “packaged”

integrated systems from a single vendor

that incorporate multiple functions

on a single skid so that architects and

designers only need to be concerned

about matching the building’s requirements with a piece of equipment that

provides the necessary services. Making

pre-engineered, “off-the-shelf” systems

will reduce design and installation costs

to the point that integrated systems will

be considered by more people in more

instances.

There will be some further development

of components for integrated systems.

Much of the equipment needed for integrated systems comes from mature technologies. These include:

• IC and diesel engine-driven

generators,

• electrically driven and engine-driven

chillers, and

• single- and double-effect absorption

chillers.

While dual-wheel desiccant dehumidifiers are commercially available,

the technology is also undergoing significant developments to improve performance and reduce operating costs.

Small gas-turbine driven generators

appropriate for single building applications, particularly 30 and 75 kW microturbines, are new products and future

developments may increase performance or reduce costs. Major developments may come in the areas of controls

for integrated systems to manage energy

costs effectively.

Manufacturers

The number of manufacturers of components for integrated systems is extensive. The list provided below includes

manufacturers of chillers, desiccant

dehumidifiers, and on-site power generation equipment. Efforts were made to

identify all manufacturers of equipment

for integrated systems, but this listing

does not purport to be complete.

Absorption Equipment

American Yazaki Corp.

13740 Omega Road

Dallas, TX 75244

Ph: 972-385-8725

Fax: 972-385-1324

Broad

1 World Trade Center, Suite 7929

New York, NY 10048

Ph: 212-775-0665

Fax: 212-775-1936

Carrier Corp.

P.O. Box 4808

Syracuse, NY 13221

Contact: Doug Rector

Ph: 315-432-7152

Fax: 315-433-4985

Dunham-Bush Inc.

101 Burgess Road

Harrisonburg, VA 22801

Ph: 540-434-0711

Fax: 540-432-6486

e-mail: smassien@shentel.com

McQuay International

Chiller Products Group

P.O. Box 2510

Staunton, VA 24402

Contact: Dave Wiggins

Ph: 540-248-9557

Robur Corporation

2300 Lynch Road

Evansville, IN 47711-2951

Ph: 812-424-1800

Fax: 812-423-1847

The Trane Company

3600 Pammel Creek Road

La Crosse, WI 54601-7599

Ph: 608-787-3914

York International Corp.

P.O. Box 1592-361R

York, PA 17405-1592

Ph: 717-771-6359

Fax: 714-772-6820
20

FEDERAL ENERGY MANAGEMENT PROGRAM

Electric-Driven Chillers

Advantage Engineering, Inc.

525 East Stop 18 Road

Greenwood, IN 46142

Ph: 317-887-0729

fax: 317-881-1277

Carrier Corp.

P.O. Box 4808

Syracuse, NY 13221-4808

Contact: Jim Parsnow

Ph: 315-433-4376

Fax: 315-432-7836

e-mail: jim.parsnow@carrier.utc.com

Dunham-Bush

101 Burgess Road

Harrisonburg, VA 22801

Contact: Brian Davis

Ph: 540-434-0711

Fax: 540-434-4595

e-mail: dbmkt@shentel.net

McQuay International

P.O. Box 2510

Stanton, VA 24402

Contact: Jay Eldridge (water-cooled)

Ph: 540-248-9639

Fax: 540-248-9412

e-mail:

 eldridge.george@online.mcquay.com

or

Contact: Ric Tharp (air cooled)

Ph: 540-248-9684

Fax: 540-248-9412

e-mail:

 tharp.richard@online.mcquay.com

The Trane Company

3600 Pammel Creek Road

La Crosse, WI 54601-7599

Contact: Sher Peterson

Ph: 608-787-3084

Fax: 608-787-2204

e-mail: speterson@trane.com

York International Corp.

P.O. Box 1592-361P

York, PA 17405-1592

Contact: Bob Schmitt

Ph: 717-771-6356

Fax: 717-771-6820

Engine-Driven Chillers

Alterdyne Energy Systems

8050 Armour Street

San Diego, CA 92111

Contact: Joe Browning

Ph: 619-565-2131

Fax: 619-279-4296

Carrier Corporation

Carrier Parkway

P.O. Box 4808

Building TR-1

Syracuse, NY 13221

Ph: 315-432-7011

Fax: 315-433-4985

Chillco Inc.

1971 Abbott Road

P.O. Box 16

Buffalo, NY 14218

Ph: 716-822-0208

Fax: 716-822-0266

e-mail: chillcoinc@aol.com

GASAIR, Inc.

P.O. Box 5348

Kingwood, TX 77325

Ph: 713-360-0893

Fax: 713-360-7567

HEP, Inc.

2896 West Telegraph Road

Fillmore, CA 93015

Ph: 805-524-5880

Industrial Heat Recovery Equipment

(IHRE)

850 West Bradley Avenue

El Cajon, CA 92020

Contact: David Williams

Ph: 800-423-1333

Fax: 619-596-3080

Napps Technology Corporation

P.O. Box 1509

Longview, TX 75606

Ph: 903-984-2112

Fax: 903-984-1633

Powerchill

Cummins Southwest, Inc.

Power Systems Division

2222 N. 23rd Drive

P.O. Box 6688

Phoenix, AZ 85005-6688

Ph: 602-257-5984

Fax: 602-258-1010

Tecogen

45 First Avenue

P.O. Box 8995

Waltham, MA 02254-8995

Ph: 617-622-1400

Fax: 617-622-1025

Trane Company

3600 Pammel Creek Road

La Crosse, WI 54601-7599

Ph: 608-787-3914

Fax: 608-787-4100

Trico Energy Systems, Inc.

Two Appletree Square, Suite 335

Bloomington, MN 55425

Ph: 612-854-1690

Fax: 612-854-6657

York International Corp.

P.O. Box 1592-361R

York, PA 17405-1592

Ph: 717-771-7514

Fax: 717-771-6820

Desiccant Dehumidifiers

Advanced Thermal Technologies, Inc.

12900 Automobile Blvd.

Clearwater, FL 34622

Ph: 813-571-1888

Fax: 813-571-2242

Airflow Company

Dryomatic General Products Group

295 Bailes Lane

Frederick, MD 21701-3136

Contact: Richard M. Wolcott

Ph: 301-695-6500

Fax: 301-631-0396

Comfort Enterprises Co.

P.O. Box 11148

1812 Colonial Village Lane

Lancaster, PA 17605-1148

Ph: 717-394-8208 (ext. 206)

Fax: 717-394-0612

Engelhard/ICC

441 North Fifth Street

Philadelphia, PA 19123

Ph: 215-625-0700 (ext. 130)

Fax: 215-592-8299

Fresh Air Solutions

330 S. Warminster Rd.

Hatboro, PA 19040

(215) 740-0624
21

FEDERAL ENERGY MANAGEMENT PROGRAM

Kathabar Inc.

P.O. Box 791

New Brunswick, NJ 08903-0791

Ph: 908-356-6000

Fax: 908-356-0643

Munters Corporation

Cargocaire Division

79 Monroe Street

P.O. Box 640

Amesbury, MA 01913-0640

Ph: 508-388-0600 / 800-843-5360

Fax: 908-356-0643

e-mail: cargo@munters.com

Munters Corporation

DryCool Division

16900 Jordan Road

Selma, TX 78154

Ph: 210-651-5018 / 800-229-8557

Fax: 210-651-9085

Octagon Air Systems

1724 Koppers Road

Conley, GA 30017

Ph: 404-608-8881

Fax: 404-608-0880

Seasons ● 4 Inc.

4500 Industrial Access Road

Douglasville, GA 30134

Ph: 770-489-0716

Fax: 770-489-2938

Fuel Cells

Analytic Power Corporation

268 Summer Street

Boston, MA 02210

Contact: David Bloomfield

Ph: 617-542-6352

Fax: 617-695-3272

Ballard Power Systems, Inc.

980 West First Street, Unit 107

North Vancouver, BC V7P 3N4

Canada

Contact: Keith Prater

Ph: 604-986-9367

Fax: 604-986-3262

Energy Partners

Suite 102, Technology Center

West Palm Beach, FL 33407

Contact: Teresa Gomez

Ph: 407-688-0500

Fax: 407-688-9610

Fuel Cell Corporation of America

811 Route 51 South

Large, PA 15025

Contact: Charles Rose

Ph: 412-382-7124

Fax: 412-382-5509

H Power Corporation

60 Montgomery Street

Belleview, NJ 07109

Contact: Arthur Kaufman

Ph: 201-450-4400

Fax: 201-450-9850

e-mail: moreinfo@hpower.com

ONSI Corporation

195 Governor’s Highway

P.O. Box 1148

South Windsor, CT 06074

Contact: Greg Sandelli

Ph: 203-727-2348

Fax: 203-727-2319

Microturbine Generators

Allison Engine Company, Inc.

2001 S. Tibbs Avenue

Indianapolis, IN 46206-0420

Capstone Turbine Corporation

6430 Independence Avenue

Woodland Hills, California 91367

Ph: 877-282-8965

e-mail: info@capstoneturbine.com

Elliott Energy Systems

10485 Bush Drive North

Jacksonville, FL 32218-5601

Contact: Rich Sanders

Ph: 904-757-7600

Fax: 904-767-7604

Honeywell Power Systems.

8725 Pan American Freeway

Albuquerque, New Mexico 87113

Integrated Power Systems International

P.O. Box 92384

Rochester, New York 14692

Ph: 800-959-4724

Fax: 716-359-9061

e-mail: RCIPOWER@worldnet.att.net

Northern Research and Engineering

Corporation

39 Olympia Avenue

Woburn, MA 01801-2073

Ph: 781-935-9050

Fax 781-935-9052

SatCon Technology

161 First Street

Cambridge, MA 02142-1221

Contact: Ed Godere

Ph: 617-349-0884

Fax: 617-661-3373

Turbec AB,

Malmö, Sweden

TRD Corporation

7471 Tyler Boulevard

Mentor, OH 44060

Contact: Charles Heinrich

Ph: 216-946-2838

Fax: 216-946-2838

Reciprocating Engine-Generators

Caterpiller Inc. Information Center

P.O. Box 10097

Peoria, IL 61612

Cummins Southwest, Inc.

2222 North 23rd Drive

Phoenix, AZ 85009

Contact: Kirby Brown

Ph: 602-257-5984

Fax: 602-258-1010

Deutz MWM

33 Christa McAuliffe Boulevard

Plymouth, MA 02360

Contact: Eugene Morrill

Ph: 508-746-5500

Fax: 508-746-1630
22

FEDERAL ENERGY MANAGEMENT PROGRAM

Intelligen Energy Systems, Inc.

98 South Street

Hopkinton, MA 01748

Contact: Frank Fulton

Ph: 508-435-9007

Fax: 508-435-9160

Jenbacher Energiesysteme Ltd.

1502 Providence Highway, Suite #2

Norwood, MA 02062

Contact: Kimberley Cotter

Ph: 617-255-5886

Fax: 617-255-5887

Kohler Company Power Systems

Kohler Co. Generator Division

444 Highland Drive

Kohler, WI 53044

Ph: 414-565-3381

Fax: 414-459-1646

Onan Corporation

1400 73rd Avenue NE

Minneapolis, MN 55432

Ph: 612-574-5000

Fax: 612-574-8090

Tecogen, Inc.

P.O. Box 8995

Waltham, MA 02254-8995

Contact: Jeff Glick

Ph: 617-622-1400

Fax: 617-622-1252

Wärtsilä Diesel Inc.

201 Defense Highway, Suite 100

Annapolis, MD 21401

Contact: Mack Shelor

Ph: 410-573-2100

Fax: 410-573-2200

Waukesha Power Systems

Waukesha Engine Division

Dresser Industries, Inc.

1220 South Prairie Avenue

Waukesha, WI 53188

Ph: 414-549-2925

Fax: 414-549-2989

Stirling Engine-Generators

Stirling Technology Company

4208 West Clearwater Avenue

Kennewick, WA 99336

Contact: Maurice White

Ph: 509-735-4700 ext 105

Fax: 509-736-3660

Stirling Thermal Motors, Inc.

275 Metty Drive

Ann Arbor, MI 48103-9444

Contact: Lennart Johansonn

Ph: 313-995-1755

Fax: 313-995-0610

Sunpower, Inc.

6 Byard Street

Athens, OH 45701-2702

Contact: William Beale

Ph: 614-594-2221

Fax: 614-593-7531

Tamin Enterprises

311 Grove Street

Half Moon Bay, CA 94019-2005

Contact: Don Isaac, Jr.

Ph: 415-726-2338

Fax: 415-726-7342

e-mail: info@tamin.com

Rotary Engine-Generators

Alturdyne Power Systems

8050 Armout Street

San Diego, CA 92111

Ph: 619-565-2131

Moller International

1222 Research Park Drive

Davis, CA 95616

Contact: Ren Tubergen

Ph: 916-756-5086

Fax: 916-756-5179

Rotary Power International, Inc.

Industrial Products

P.O. Box 128

Woodridge, NJ 07075-0128

Contact: Jack Kasmer

Ph: 201-470-7095

Fax: 201-779-5595

Combustion Gas Turbine-Generators

ABB Alstom Power

P.O. Box 1

Waterside South

Lincoln LN5 7FD

United Kingdom

Ph: 01522 584000

Fax: 01522 584900

GE Power Systems

Evendale, Ohio

http://www.gepower.com

Solar Turbines Incorporated

Harbor Drive Facility

2200 Pacific Highway

San Diego, CA 92101

Ph: 619-544-5000

Fax: 619-544-2849

Combined Cooling, Heating,

and Power

Thermax Ltd. Novi Office

40440 Grand River Avenue

Novi, MI 48375

Ph: 248-474-3050

Fax: 248-474-5790

W‰rtsil‰ Diesel Inc.

201 Defense Highway, Suite 100

Annapolis, MD 21401

Contact: Mack Shelor

Ph: 410-573-2100

Fax: 410-573-2200

Who is Using the Technology

Federal Sites

Federal Energy Regulatory Commission

Union Center Plaza

Washington, DC

Non-Federal Sites

Hybrid Chiller Plants

Fairview Southdale Hospital

6401 France Avenue South

Minneapolis, MN

Ph: 612-924-5000

Hackensack University Medical Center

30 Prospect Avenue

Hackensack, NJ 07601

Contact: Wojciech Mickowski

Independent School District 622

Oakdale, Minnesota

Contact: John Brady

Armstrong, Torseth, Skold, and Rydeen

Maritz, Inc.

St. Louis, MO

Contact: Leonard Bilheimer

Ph: (314) 827-1311

Morton Plant Hospital

323 Jeffords St

Clearwater, FL 33756

Ph: 727-462-7000
23

FEDERAL ENERGY MANAGEMENT PROGRAM

Philadelphia Marriott

1201 Market Street

Philadelphia, PA 19107

Ph: 215-625-2900

Fax: 215-625-6000

Norfolk International Airport

2200 Norview Ave

Norfolk, VA

Ph: 757-857-3351

St. Elizabeth’s Hospital

1431 N Claremont Ave

Chicago, IL 60622

Ph: 773-278-2000

Contact: Richard Gilligan

Combined Cooling, Heating, Power

University of Maryland

CEEE

College Park, MD 20742-3035

Contact: Predrag Popovic

Ph: 301-403-4410

Fax: 301-403-4409

Desiccant Dehumidification with Waste

Heat Regeneration

Energy Resource Center

2250 Park Pl

El Segundo, CA

Ph: 310- 643-9016

For Further Information

AGCC 1996. Natural Gas Cooling

Equipment Guide, American Gas

Cooling Center, 1515 Wilson Boulevard,

Arlington, VA 22209, Fourth Edition,

April 1996.

AGCC 1999. Technology Transfer Workshop

Workbook for Integrated System Design,

American Gas Cooling Center, 400 N.

Capitol Street, N.W., Washington, DC

20001, 202-824-7141, March.

AGCC Technology Transfer Workshop

(TTW): Integrated Systems Design,

American Gas Cooling Center, 400 N.

Capitol Street, N.W., Washington, DC

20001, 202-824-7141.

Arnold, Roger and Bahnfleth, William

1996. Peak Shaving Using Natural Gas

Engine-Driven Chillers, Heating/Piping/

Air Conditioning, September 1998,

pp. 51-59.

Cool Times, November/December 1997,

Vol. 8, No. 6, News Digest of the

American Gas Cooling Center, Inc.,

1515 Wilson Boulevard, Arlington, VA

22209, pp. 2-4.

DPCA 1999. Distributed Power

Coalition of America website,

http://www.dpc.org/technologies.html

E-Source 1997. Commercial Space

Cooling and Air Handling Technology

Atlas, E Source, Inc. 1033 Walnut Street,

Boulder, Colorado 80302-5114.

FTA 1997. Federal Technology Alerts:

Two-Wheel Desiccant Dehumidification

System, http://www.pnl.gov/fta/

8_tdd.htm, April 1997

FTA 1995. Federal Technology Alerts:

Natural Gas Fuel Cells, http://

www.pnl.gov/fta/5_nat.htm#man,

November 1995.

Harriman, Lewis G., The Basics of

Commercial Desiccant Systems, Heating /

Piping / Air Conditioning, July 1994,

pp. 77-85.

Kreider, J. and Curtiss, P., 2000.

Distributed Electrical Generation

Technologies and Methods for Their

Economic Assessment, ASHRAE

Transactions 2000, V. 106, Pt. 1.

Teagan, P. 2000. “Fuel Cells for On-Site

Generation,” presented at ABST 2000,

June 5-8, 2000, Washington, DC.
24

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25

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendixes

Appendix A: Glossary

Appendix B: Federal Life-Cycle Costing Procedures and the BLCC Software
26

FEDERAL ENERGY MANAGEMENT PROGRAM

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27

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendix A

Glossary

absorption chiller water chiller based on absorption of refrigerant vapor into a liquid solution, pumping

of solution to elevated pressure, and desorption of refrigerant vapor through addition

of heat; direct-fired chillers employ natural gas burners, indirect-fired chillers use steam

or hot water from a boiler, heat recovery heat exchanger, or generator exhaust gas;

single-, double-, and triple-effect chillers employ multiple stages of desorption and

internal use of waste heat to boost efficiency

demand charge charges for the use of electricity based on the maximum power requirement, electrical

demand, during a specified period of time, typically a month ($/kW)

desiccant a solid or liquid material with an affinity for absorbing water molecules

engine-generator electrical generator using a reciprocating, Stirling, or rotary engine

enthalpy wheel heat exchanger rotating through building supply and exhaust air flows to transfer energy from one air stream to the other

evaporative cooling lowering the temperature of air through the evaporation from a water spray or wetted

membrane; direct evaporative cooling adds water to the supply air while indirect

evaporative cooling adds water to the exhaust air and incorporates a heat pipe or thermal wheel for indirect cooling of the supply air

fuel cell device for producing electricity using a chemical process rather than conventional

combustion processes with steam generators

heat wheel heat exchanger rotating through building supply and exhaust air flows to transfer heat

from one air stream to another

latent cooling load amount of cooling required to reduce humidity of air in conditioned space to specified

level for comfort

microturbine power generator turbine-engine driven electrical generator with output power of 25 to 300 kW

real time pricing charges for electrical demand and consumption based on instantaneous cost of production and distribution as opposed to fixed rates or fixed time-of-day rates

sensible cooling load amount of cooling required to reduce the temperature of air in the conditioned space

to a specified level for comfort

therm a unit of energy used to measure natural gas; 105

 Btus, 1.055 x 108 joules, approx.

97.5 ft3

thermal wheel heat exchanger rotating between two air flows to transfer heat from one to the other

ton or refrigeration ton quantity of cooling available from melting 2000 pounds of ice; 12,000 Btu/h or 3.1413 kW

vapor compression air conditioning cooling system based on mechanical compression of a gaseous refrigerant to a high

pressure, and heat transfer with changes of state (i.e., liquid and vapor) to produce

useful heating or cooling

waste heat portion of the energy input to a mechanical process which is rejected to the environment
28

FEDERAL ENERGY MANAGEMENT PROGRAM

Appendix B

Federal Life-Cycle Costing Procedures and the BLCC Software

Federal agencies are required to evaluate energy-related investments on the basis of minimum life-cycle costs (10 CFR Part 436).

A life-cycle cost evaluation computes the total long-run costs of a number of potential actions, and selects the action that minimizes the long-run costs. When considering retrofits, sticking with the existing equipment is one potential action, often called the

baseline condition. The life-cycle cost (LCC) of a potential investment is the present value of all of the costs associated with the

investment over time.

The first step in calculating the LCC is the identification of the costs. Installed Cost includes cost of materials purchased and the

labor required to install them (for example, the price of an energy-efficient lighting fixture, plus cost of labor to install it).

Energy Cost includes annual expenditures on energy to operate equipment. (For example, a lighting fixture that draws 100 watts

and operates 2,000 hours annually requires 200,000 watt-hours (200 kWh) annually. At an electricity price of $0.10 per kWh,

this fixture has an annual energy cost of $20.) Nonfuel Operations and Maintenance includes annual expenditures on parts and

activities required to operate equipment (for example, replacing burned out light bulbs). Replacement Costs include expenditures

to replace equipment upon failure (for example, replacing an oil furnace when it is no longer usable).

Because LCC includes the cost of money, periodic and aperiodic maintenance (O&M) and equipment replacement costs,

energy escalation rates, and salvage value, it is usually expressed as a present value, which is evaluated by

LCC = PV(IC) + PV(EC) + PV(OM) + PV(REP)

where PV(x) denotes “present value of cost stream x,”

IC is the installed cost,

EC is the annual energy cost,

OM is the annual nonenergy O&M cost, and

REP is the future replacement cost.

Net present value (NPV) is the difference between the LCCs of two investment alternatives, e.g., the LCC of an energy-saving

or energy-cost-reducing alternative and the LCC of the existing, or baseline, equipment. If the alternative’s LCC is less than the

baseline’s LCC, the alternative is said to have a positive NPV, i.e., it is cost-effective. NPV is thus given by

NPV = PV(EC0) – PV(EC1)) + PV(OM0) – PV(OM1)) + PV(REP0) – PV(REP1)) – PV(IC)

or

NPV = PV(ECS) + PV(OMS) + PV(REPS) – PV(IC)

where subscript 0 denotes the existing or baseline condition,

subscript 1 denotes the energy cost saving measure,

IC is the installation cost of the alternative (note that the IC of the baseline is assumed zero),

ECS is the annual energy cost savings,

OMS is the annual nonenergy O&M savings, and

REPS is the future replacement savings.

Levelized energy cost (LEC) is the break-even energy price (blended) at which a conservation, efficiency, renewable, or fuelswitching measure becomes cost-effective (NPV >= 0). Thus, a project’s LEC is given by

PV(LEC*EUS) = PV(OMS) + PV(REPS) – PV(IC)

where EUS is the annual energy use savings (energy units/yr). Savings-to-investment ratio (SIR) is the total (PV) savings of a measure divided by its installation cost:

SIR = (PV(ECS) + PV(OMS) + PV(REPS))/PV(IC).

Some of the tedious effort of life-cycle cost calculations can be avoided by using the Building Life-Cycle Cost software, BLCC,

developed by NIST. For copies of BLCC, call the FEMP Help Desk at (800) 363-3732.
FEDERAL ENERGY MANAGEMENT PROGRAM

About FEMP’s New Technology Demonstration Program

The Energy Policy Act of 1992, and subsequent Executive Orders, mandate that

energy consumption in Federal buildings be reduced by 35% from 1985 levels

by the year 2010. To achieve this goal,

the U.S. Department of Energy’s Federal

Energy Management Program (FEMP)

is sponsoring a series of programs to

reduce energy consumption at Federal

installations nationwide. One of these

programs, the New Technology Demonstration Program (NTDP), is tasked to

accelerate the introduction of energyefficient and renewable technologies

into the Federal sector and to improve

the rate of technology transfer.

As part of this effort FEMP is sponsoring a series of publications that are

designed to disemminate information

on new and emerging technologies.

New Technology Demonstration

Program publications comprise three

separate series:

Federal Technology Alerts—longer

summary reports that provide details

on energy-efficient, water-conserving,

and renewable-energy technologies

that have been selected for further

study for possible implementation in

the Federal sector. Additional information on Federal Technology Alerts (FTAs)

is provided in the next column.

Technology Installation Reviews—

concise reports describing a new technology and providing case study results,

typically from another demonstration

program or pilot project.

Technology Focuses—brief information

on new, energy-efficient, environmentally friendly technologies of potential

interest to the Federal sector.

More on FTAs

Federal Technology Alerts, our signature

reports, provide summary information

on candidate energy-saving technologies developed and manufactured in the

United States. The technologies featured

in the FTAs have already entered the

market and have some experience but are

not in general use in the Federal sector.

The goal of the FTAs is to improve the

rate of technology transfer of new

energy-saving technologies within the

Federal sector and to provide the right

people in the field with accurate, up-todate information on the new technologies so that they can make educated

judgments on whether the technologies

are suitable for their Federal sites.

The information in the FTAs typically

includes a description of the candidate

technology; the results of its screening

tests; a description of its performance,

applications and field experience to date;

a list of manufacturers; and important

contact information. Attached appendixes provide supplemental information and example worksheets on the

technology.

FEMP sponsors publication of the FTAs

to facilitate information-sharing between

manufacturers and government staff.

While the technology featured promises

significant Federal-sector savings, the

FTAs do not constitute FEMP’s endorsement of a particular product, as FEMP

has not independently verified performance data provided by manufacturers.

Nor do the FTAs attempt to chart market

activity vis-a-vis the technology featured.

Readers should note the publication date

on the back cover, and consider the FTAs

as an accurate picture of the technology

and its performance at the time of publication. Product innovations and the

entrance of new manufacturers or suppliers should be anticipated since the

date of publication. FEMP encourages

interested Federal energy and facility

managers to contact the manufacturers

and other Federal sites directly, and to

use the worksheets in the FTAs to aid

in their purchasing decisions.

Federal Energy Management Program

The Federal Government is the largest energy consumer in the nation. Annually, in its 500,000 buildings and 8,000 locations worldwide, it uses nearly two quadrillion Btu (quads) of energy, costing over $8 billion. This represents 2.5% of all

primary energy consumption in the United States. The Federal Energy Management Program was established in 1974 to

provide direction, guidance, and assistance to Federal agencies in planning and implementing energy management programs that will improve the energy efficiency and fuel flexibility of the Federal infrastructure.

Over the years several Federal laws and Executive Orders have shaped FEMP's mission. These include the Energy Policy

and Conservation Act of 1975; the National Energy Conservation and Policy Act of 1978; the Federal Energy Management

Improvement Act of 1988; and, most recently, Executive Order 12759 in 1991, the National Energy Policy Act of 1992

(EPACT), Executive Order 12902 in 1994, and Executive Order 13123 in 1999.

FEMP is currently involved in a wide range of energy-assessment activities, including conducting New Technology

Demonstrations, to hasten the penetration of energy-efficient technologies into the Federal marketplace.
FEDERAL ENERGY MANAGEMENT PROGRAM

For More Information

FEMP Help Desk

 (800) 363-3732

International callers please use

 (703) 287-8391

Web site: www.eren.doe.gov/femp

General Contacts

Ted Collins

New Technology Demonstration

 Program Manager

Federal Energy Management

 Program

U.S. Department of Energy

1000 Independence Ave., SW, EE-92

Washington, D.C. 20585

Phone: (202) 586-8017

Fax: (202) 586-3000

theodore.collins@ee.doe.gov

Steven A. Parker

Pacific Northwest National

 Laboratory

P.O. Box 999, MSIN: K5-08

Richland, WA 99352

Phone: (509) 375-6366

Fax: (509) 375-3614

steven.parker@pnl.gov

Technical Contact

Steve Fischer

Oak Ridge National Laboratory

P.O. Box 2008, MSIN: 6070

Oak Ridge, TN 37831-6070

Phone: (423) 574-2017

Fax: (423) 574-9329

fischersk@ornl.gov

Produced for the U.S. Department

of Energy by the Oak Ridge

National Laboratory

DOE/EE-0234

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% post consumer waste September 2000

Log on to FEMP’s New Technology Demonstration Program

Website

http://www.eren.doe.gov/femp/prodtech/newtechdemo.html

You will find links to

• An overview of the New Technology Demonstration Program

• Information on the program’s technology demonstrations

• Downloadable versions of program publications in Adobe Portable

Document Formats (pdf)

• A list of new technology projects underway

• Get on the program’s regular mailing list for new products when they

become available

• How Federal agencies may submit requests for the program to assess

new and emerging technologies