Subject: Re: Energy Ideas - HVAC-2

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

NEW TRICKS FOR AN OLD SYSTEM

Many inefficient cooling systems could be improved by proper
maintenance and design. The efficiency and performance of a
heating, ventilating and air conditioning (HVAC) system depends
upon the performance and interaction of each component. The
performance of an efficient HVAC system often degrades when scale
accumulates on heat exchanger surfaces, dirt causes bearings on
motors to stick or changes in the system load increases the
pressure within piping. These problems can be corrected without
the purchase of new equipment. 

Types of Cooling Systems

Because of the high heat capacity of water, water-cooled systems
are most commonly used for large-scale applications, i.e. large
buildings and district cooling systems. In these systems, a
cooling unit chills water to about 45o F. The cooling system then
circulates this water throughout a building or a district to
different air-handling systems. These systems take air from
conditioned space and pass it through a heat exchanger, where the
air loses heat to the cool water. The water is then returned to
the central chiller where it is again cooled. Smaller buildings
frequently use individual window air conditioning units.

Improved Efficiency With Proper Maintenance

In an article in the November, 1992 Energy User News ("Georgia
Tech Engineer Outlines HVAC Checklist," p. 4), Doug Moore, the
senior research engineer at Georgia Tech Research Institute,
outlined the steps necessary to maintain the efficiency of HVAC
equipment. For cooling systems, these steps include:

*    Checking the condition and tension of fan belts. A slipping
belt reduces air flow, can cause coil freeze-up and can result in
loss of cooling capacity.

*    Inspecting fan wheels for dirt or obstructions.

*    Cleaning the cooling and heating coils with factory-approved
coil cleaner.

*    Cleaning and inspecting condensate pans and drain piping.

*    Cleaning or replacing air filters (if you have standard
filters, replace them with high efficiency and high capacity
pleated filters).

*    Checking the operation of outside air and relief dampers,
and lubricating as required.

*    Draining and cleaning the cooling tower basin.

*    Cleaning the water distribution basin and clearing nozzles
of obstructions.

*    Checking the water treatment system and chemical level and
adjusting the bleed rate.

*    Checking the fan belts and gear boxes; adjusting or
lubricating them as required.

*    Cleaning pump strainers and verifying proper water flow
rates.

Economizer Installation

The use of equipment such as chillers can be minimized by
providing supplemental cooling with cold air, water or natural
ice during the fall and spring. When the outside air temperature
is sufficiently low and cooling is necessary to offset heat
generated by people, office equipment and lights, air can be
brought in from the outside. Ambient air can "precool" cooling
water, resulting in a lower cooling load for the chillers. Thus,
a smaller chiller can be used during this time of year, or a
chiller connected to an adjustable speed drive (see p. 9) can be
used to match the reduced load. Depending on the location, cool
water or even ice from nearby rivers can be brought to a facility
and used to precool or even completely chill water.

There are two types of economizer controls: dry-bulb control and
enthalpy control. The dry-bulb temperature is perceived
temperature without considering the latent heat of the water
vapor in the air. Dry-bulb control systems compare the outdoor to
indoor dry-bulb temperatures and use precooling when the outdoor
dry-bulb temperature is lower than the indoor dry-bulb
temperature. Enthalpy control systems use an economizer only when
the combined sensible and latent energy level (enthalpy) of
outdoor air is lower than the indoor air.

CASE STUDY:

Economizers at High School Campus
The Phoenix, Arizona Union High School District #210 installed
economizers and control systems in its buildings to permit the
use of outside air for cooling. When the outdoor air temperature
is lower than that of the inside air, the air handling system
precools the indoor air by passing both through a heat exchanger. 
(Contact: Kenneth E. Wissinger, Assistant to the Superintendent
for Business and Operations, Phoenix Union High School District
#210, 4502 North Central Avenue, Phoenix, AZ 85012, (602)
271-3301.)

Redesigning the Cooling System

When adding or removing a building or area from a district or
building cooling system, it is important to rescale the cooling
system accordingly. Off-line chillers and cooling towers should
be isolated, and the chilled and condenser water flow rates
correspondingly reduced. Unnecessary pumps should be shut off.
Since many existing cooling systems are oversized, a series of
small pumps or an adjustable speed pump should be installed to
prevent overuse.

CASE STUDIES:

District Cooling Resizing at University
The district cooling system at Yale University in New Haven,
Connecticut was wasting energy to overcome bottlenecks in its
piping system. Undersized pipes and an inefficient chilled water
distribution system increased the pumping pressure in the system
and introduced greater friction losses. The chillers were
modified from two-pass to single-pass units and the piping was
changed throughout the system to reduce friction losses. The
university spent $980,000 to redesign its hydronic loop. The new
design has increased the chiller plant~s output capacity by 2,500
tons and cut fuel bills by $309,000 during a five-month period in
1991, yielding an estimated 1.5 year payback period. In addition,
the increase in the efficiency of the system avoided the
expenditure of $2.5 million for a new chiller. (Contact: Mike
Kieley, Chief Engineer, Sterling Power Plant, 309 Congress
Avenue, New Haven, CT 06510, (203) 785-4414).

Pumping Reduction at Airport
The City of Phoenix, Arizona reduced the number of pumps required
to circulate chilled water at the Central Plant for Airport
Terminal 4 by reducing the pressure differential of the secondary
loop from 12 to 5 pounds per square inch (psi). At 12 psi and a
10o F difference between the supply and return water, three 150
horsepower (hp) pumps are required. Lowering the pressure to 5
psi enables one 150 hp adjustable speed drive pump operating at
80 percent capacity to maintain the same 10o F difference.
Savings are estimated at 6,000 kWh and $420 per day. (Contact:
Dimitrios Laloudakis, Energy Conservation Manager, 2631 S. 22nd
Avenue, Phoenix, AZ 85009, (602) 261-8813.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

SAVING MONEY BY SWITCHING TO GAS-DRIVEN ENGINES

Some facilities have managed to lower their energy costs by
switching from an electric to a natural gas-powered vapor
compression air chiller. Utilities have begun offering
Demand-Side Management rebates to facilities that install
gas-driven engines. While electric engines have a higher
coefficient of performance (the ratio of the cooling output to
the energy input), the inefficiency of electricity generation and
transmission makes the overall efficiency of gas and electric
engines nearly equal. 

CASE STUDY:

Chiller Installation at University
The State University of New York at Buffalo sought to air
condition portions of an old building which houses the chemistry
department. The three-floor, 220,000-square-foot building has
classrooms on the first floor and offices and laboratories, which
need air conditioning, on the second and third floors. The
facility manager estimated that the building required about 300
to 400 tons of cooling. The building did not have the existing
service to supply power to an electric chiller. Supplying that
service would have cost $210,000.

Instead, a gas-engine-powered, horizontal screw chiller was
installed in 1989. This chiller was chosen because it is easy to
maintain and because of the differences in fuel prices. Taking
efficiencies into account, electricity would cost $2.10 per therm
(100,000 British thermal units) while natural gas only cost 40
cents per therm. The cost of the gas-powered chiller was
$180,000, but with a gas utility rebate of $70,000, the chiller
cost only $30,000 more than an electric chiller. The annual
savings have been nearly $10,000. The chiller availability has
been almost 100 percent; the only shut-down occurred when the
lubricating pump needed to be repaired. Aside from the economic
benefits, the facility manager stressed the ease of maintenance
and the compact size of the chiller (4' x 12' x 7') which allowed
it to fit easily in the basement of the building. (Contact: Fred
Smeader, University Facility Engineer, SUNY Buffalo, 115 John
Beane Center, Buffalo, NY 14260, (716) 645-2612.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

HOW TO COOL WITH HEAT: ABSORPTION COOLING

Absorption cooling systems are as effective as conventional vapor
compression cooling systems, but require heat rather than
electricity. As a result, these systems can use a variety of
energy sources, including natural gas combustion, waste heat from
electricity generation or solar thermal power. More importantly,
these systems commonly use either ammonia or water as
refrigerants, neither of which contributes to the depletion of
the ozone layer or to global warming.

How They Work

Like vapor compression chillers (see "Electric Heat Pumps
Revisited," Energy Ideas, November, 1992, p. 6), absorption
chillers circulate a working fluid (the refrigerant) through an
expansion and condensation cycle. Heat from air in a building
causes a refrigerant to boil (see diagram below). Rather than
being compressed into a hot liquid, the gaseous refrigerant is
moved to a chamber where it is absorbed by another liquid
substance. The refrigerant-absorbent mixture is heated in a
boiler to separate the two fluids. Each is sent to its own
condensing chamber. The absorbent cools and condenses and is
returned to absorb more refrigerant. The refrigerant cools and
condenses and is returned to the evaporator where it will pick up
more heat from the indoor air. While earlier systems used ammonia
as the refrigerant and water as the absorbent, newer systems use
water as the refrigerant and a non-toxic lithium bromide salt
solution as the absorbent. The lithium bromide cycle occurs in a
vacuum, giving water a very low boiling temperature. 

Absorption cooling offers a few advantages over vapor-compression
systems. The first and foremost is the absence of a toxic and
ozone-depleting refrigerant. Since absorption cooling only
requires heat and small pumps for circulation of the water and
salt solution and the evacuation of the system, an absorption
chiller has very few moving parts. Consequently, these systems
are very reliable and easy to maintain. In addition, the systems
provide quiet, vibration-free operation. The greatest advantage
is the low cost of natural gas as compared to electricity costs
for large chillers (see life-cycle cost analysis, p. 7).

Site Efficiency and Source Efficiency

The greatest disadvantage of an absorption cooling system is its
low coefficient of performance (COP). The COP is the ratio of the
amount of energy that goes into a chiller to the amount of energy
removed by the chiller. Typically, an absorption chiller has a
site COP of 1; for every British thermal unit (Btu) of natural
gas burned on site, one Btu of energy is removed from the air.
Newer models are expected to attain a site COP of 1.5. Electric
vapor-compression chillers of intermediate size have a site COP
of 5, making them far more efficient. Since the generation of
electricity by fossil fuel combustion is only about 35 percent
efficient, the source, or overall, COP of an electric chiller is
only 1.75.

Cooling by Cogeneration

According to the Institute for Energy and Environmental Research
(IEER), of Takoma Park, Maryland, an absorption chiller-heater
which also produces electricity is the most efficient cooling and
heating system. The cogeneration of heat and electricity vastly
improves the energy efficiency of any combustion system by using
heat which would normally escape into the environment (see
"Cogeneration: Increased Efficiency without Increased Fuel,"
Energy Ideas, November, 1992, p. 4). In addition, the electricity
produced by a cogenerating chiller-heater could be sold to a
local electric utility pursuant to the Public Utility Regulatory
Policy Act (PURPA).

Developing such cogeneration units also contributes to smarter
energy planning for utilities. By installing cogeneration systems
to provide all energy - heating, cooling and electricity - to new
facilities, power generation increases only as demand increases.
This provides greater flexibility for electric utilities, which
usually forecast the long-term regional electricity demand and
build large central power stations, which may or may not be
needed in the future. In addition, the use of on-site natural gas
establishes a system which can be compatible with solar-produced
hydrogen fuel or biogas.

CASE STUDIES:

Absorption Chillers at Audubon Headquarters
When retrofitting their national headquarters in New York City,
the National Audubon Society installed rooftop absorption
chillers because these systems do not use CFCs, whereas
compression coolers do. The installation of a 180 ton natural
gas-fired chiller received a $72,000 rebate from the local
electric utility based on a $400 per ton rebate. (Contact: Dr.
Jan Beuea, Vice-President for Science, National Audubon Society,
700 Broadway, New York City, NY 10003, (212) 979-3000.)

Absorption Chiller at Junior High School
In 1987, the Northbrook, Illinois Junior High School installed a
200-ton absorption chiller-heater to provide air conditioning to
the 150,000-square-foot building. The school needed to maintain
its backup heating capability in addition to providing the air
conditioning. While an electric vapor compression chiller would
have required the expansion of the boiler room, the absorption
chiller-heater simply replaced one of the boilers and can provide
the necessary backup heat at any time. Although the
chiller-heater cost slightly more than an electric chiller, the
additional cost will be paid back. Natural gas is available at a
direct purchase price during the summer, only 17 cents per therm.
Electricity, at 7 cents per kilowatt hour, costs about $2.05 per
therm. 

While the system has operated reliably since its installation,
the building manager stressed the importance of the quality of
service received from the installer and the service company. They
took the time to fully train the building staff in the complete
operation of the chiller-heater and are readily available to
service the system. In addition, the school district was
impressed by the lack of ozone-depleting and toxic refrigerants
in the system. The building manager strongly suggests considering
these systems to anyone who is refitting a building. (Contact:
Tim Melting, Director of Buildings and Grounds, Northbrook School
District, 1475 Maple Avenue, Northbrook, IL 60062, (708)
498-7900.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

SELECTING A SAFE REFRIGERANT FOR COMPRESSION SYSTEMS

The combination of environmental and legislative pressures is
making the switch from chlorine- and bromine-containing
refrigerants to alternatives a necessity. By purchasing
alternatives to chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs), federal, state and local
governments can use taxpayer funds to benefit the public by
accelerating the introduction of alternatives into the market, a
crucial step to slowing and stopping the rate of depletion of the
ozone layer.

Benefits of CFCs and HCFCs Overstated

The supposed benefits of both CFCs and HCFCs have recently been
called into question. While CFCs have been known as effective
refrigerants, freon and other CFCs can cause fatalities at high
exposures. At medium levels of exposure, CFCs can cause lung
infections, kidney damage and tumors. At low exposures, they can
cause forgetfulness and dizziness. Manufacturers hid information
revealing their toxicity. As reported in the January-February,
1991 San Jose, California, Metro ("Breathing Uneasy," p. 12), "Du
Pont Co.~s own experiments in the early ~80s on CFC-113 [freon]
called attention to the danger but Du Pont obscured the ...
evidence, burying it at the back of a 1,700 page report." 

The reported success of HCFCs at reducing ozone depletion has
also been overstated. According to an article in the February 23,
1992 Washington Post ("Study Finds CFC Alternatives More Damaging
Than Believed"), the lower ozone-depleting potential of HCFCs was
incorrectly calculated. As the article states, "HCFCs are 95
percent less ozone-depleting than the original compounds only if
the analysis assumes that the alternatives release chlorine at
the same slow rate as CFCs. In fact ... they free chlorine much
faster; and because the coming years are critical for arresting
the chlorine buildup, the contributions of HCFCs will be ~far
higher~ than indicated by the earlier analysis of their
destructive power." HCFC-22 is only 75 percent less
ozone-depleting than CFCs, as opposed to the 95 percent figure
originally determined.

Legislation in Effect

In accordance with federal law, U.S. manufacturers will stop
making CFCs as of December 31, 1995. This deadline, established
by President Bush under the authority of the Clean Air Act
Amendments (CAA) of 1990, is earlier than the January 1, 2000
deadline established by the Montreal Protocol, an international
agreement. In addition, while the Montreal Protocol only calls
for voluntary phaseout of hydrochlorofluorocarbons (HCFCs), the
CAA calls for a mandatory total phaseout by 2030. 

According to an article in the March, 1992 Energy User News
("Users Worry About Price, Supply with Faster CFC Phaseout," p.
1), the U.S. Environmental Protection Agency (EPA) is seeking to
halt production of three HCFCs by the year 2005 in new equipment
and by 2015 in existing equipment. According to the article,
these three refrigerants have been targeted because of their
"high ozone depletion potentials relative to such other HCFCs as
[HCFC-]123."

The EPA also seeks to penalize the release of CFCs into the
atmosphere by systems which currently use them. Pursuant to
Section 608 of the CAA, the EPA has proposed that the release of
refrigerant while repairing an air conditioning system is subject
to a $25,000 fine. In addition, the EPA is calling for voluntary
certification of air conditioning service personnel.

Alternatives Have Been Developed

According to a 1992 report by the Institute for Energy and
Environmental Research (IEER), of Takoma Park, Maryland, certain
refrigerants and other technologies can successfully eliminate
the ozone depletion threat posed by air conditioning and
refrigeration systems. Chief among these are HFCs.

HFCs are close in their thermodynamic properties to CFC-11 and
CFC-12, but contain no chlorine or bromine. IEER reports that
HFC-134a is the "most promising candidate in the short-term for
use in existing vapor-compression systems using CFC-12 and in
stationary and mobile air-conditioning systems." HFC-134a is
non-toxic and non-flammable and performs about as well as CFC-12.
Research on compressor designs, lubricants and refrigeration have
indicated that HFC-134a can perform as well as, if not better
than, CFC-12. HFC-134a can be used in place of CFC-12 or R-500 in
water chillers, both as a "drop-in" substitute in existing
systems and in new designs.

As reported by Energy User News, manufacturers have not proposed
HFC-134a as a substitute, but rather focused on mixtures of other
HFCs, particularly HFC-152a, HFC-125 and HFC-32. IEER reports
that HFC-152a performs better than both HFC-134a and CFC-12 in
terms of energy efficiency and the necessary lubricants are not
as expensive. HFC-152a is highly flammable, though IEER reports
that its application in smaller systems should be entirely safe.
The HFCs should ultimately prove to be the safe alternatives to
CFCs.

CASE STUDY:

Recycling Refrigerants in School District
In accordance with federal law, Page, Arizona Unified School
District #8 has eliminated the venting of CFC~s into the
atmosphere by using a refrigerant recovery recharge unit. This
lightweight unit (weighing 27 pounds) may be carried to the
rooftop units and evacuates the refrigerant, storing it in a
container. A separate unit purifies the refrigerant prior to
replacing it in the air conditioner. The evacuator and purifier
cost a total of $3,100 and have saved $1,600 annually by
eliminating the purchase of additional refrigerant. The
maintenance staff reports that the unit has been extremely
reliable. While the school board initially considered purchasing
this system to save money, the 1990 Clean Air Act Amendments,
which may establish a $25,000 fine for releases of CFCs, made it
a priority. (Contact: Jack Gritton, Maintenance/Refrigeration,
Page Unified School District #8, Box 1927, Page, AZ 86040,
(602)645-8801.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

LIFE-CYCLE COST ANALYSIS

While the calculation of the life-cycle cost of an electric
vapor-compression or a natural gas absorption air conditioning
system is highly site-specific, the following generalized
calculation demonstrates the issues surrounding a selection. As
shown below, economics weigh heavily against absorption systems.
Even considering a very low purchase price for natural gas, the
payback period for an absorption chiller is over 15 years.
However, a Demand-Side Management rebate, such as the $70,000
rebate given to the State University of New York at Buffalo for
300 tons of gas cooling (see p. 5), can drastically reduce this
payback period; that rebate cuts the payback perit over
one year. 

This calculation probably underestimates the cost of electricity
for a chiller. Many electric utilities charge a high rate for
electricity to facilities with a high demand, especially during
the day when demand is highest.

Life-cycle cost analysis should, where possible, include
so-called "external"costs, including environmental and social
costs. A few states have estimated the cost of reducing carbon
dioxide and sulfur dioxide emissions and have used these figures
as the costs of pollution in least-cost planning for utilities. 

In this calculation, the low coeffecient of performance (COP) of
the absorption chiller as compared to the electric chiller
minimizes the difference between burning natural gas and burning
coal to generate electricity. Including the reduction of
pollution does not enhance the economic attractiveness of an
absorption cooler. Other factors which do not have estimated
costs, such as the elimination of the use of CFCs and HCFCs,
would give absorption cooling a stronger advantage.

                                        Electric       Nat. Gas
Size (tons) [1]                         300            300
Purchase Price [2]                      $75,000        $150,000
Site COP [2]2                           5              1
Heat Removed Annually (therms) [3]      20,000         20,000
Energy Consumed Annually                4,000          20,000
  (Heat Removed/COP (therms))
Cost of Energy ($/therm) [4]            2.05           0.17
Annual Energy Cost                      $8,200         $3,400
  (Consumption * Cost)
20-Yr. Economic LCC                     $239,000       $218,000

Source Energy Consumption (therm) [5]   11,425         20,000
Annual CO2 Emissions [6]                120            116
Annual SO2 Emissions [7]                1,400          0
Cost of CO2 ($/ton) [8]                 23             23
Cost of SO2 ($/ton) [9]                 1,500          1,500
Total Annual Pollution Cost             $3,180         $2,668

Total 20-Year LCC                       $315,200       $271,360

1 - Same size as gas-engine-driven chiller described on p. 5.
2 - Mike Byars, Trane Company
3 - Estimated from performance data for chiller described on p.5.
4 - Electric price = average listed in Energy User News
  Gas price = district purchase price as described on p. 6.
5 - Assuming 35 percent efficiency for electricity generation and
transmission; site and source energy for natural gas are equal.
6 - According to U.S. EPA, coal combustion emits about 210 lbs.
CO2 per MMBtu and natural gas combustion emits about 116 lbs. CO2
per MMBtu.
7 - According to U.S. EPA, coal combustion emits about 1.2 lbs.
SO2 per MMBtu and natural gas does not emit sulfur dioxide.
8 - Cost as determined for State of Massachusetts by Tellus
Institute.
9 - Cost as determined for State of Massachusetts by Tellus
Institute.

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

PUTTING YOUR COOLING SYSTEM ON ICE

Thermal Energy Storage (TES) systems make ice during off-peak
utility hours and then use that ice for cooling during peak
hours. While it is possible to design a TES system that is more
energy efficient than a conventional system, the main appeal of
these systems is economic. TES systems operate chillers at night
rather than during the day, lowering a facility~s (and therefore
the utility~s) daytime electric demand, generally allowing the
facity to pay a lower rate for electricity. By lowering peak
demand, these systems minimize a utility~s use of inefficient and
polluting boilers.

How TES Works

TES systems make ice at night when electricity rates are lower
and then pass chiller water through the ice during the day to
provide cooling. Instead of using pure water, the TES chiller
water is mixed with ethylene glycol (an antifreeze) at about a
three-to-one ratio. At night, the chiller (either
vapor-compression or absorption) chills the water to about 25o F,
rather than the usual 45o F. This supercooled solution is
circulated through a pipe (a mile or longer in length) which has
been tightly coiled and submersed in water within a storage tank.
The water in the tank loses heat to the solution and freezes (as
the water freezes it expands upwards). During the day, a control
system combines both the chiller and the ice as the cooling
system. The installation of this system allows a smaller chiller
(about 40 percent smaller) than the building would require, since
the chiller has all night to make ice which will supplement the
cooling load during the day.

Antifreeze Poses Danger to Animals

Because of its toxicity, care should be exercised in the handling
of ethylene glycol and other antifreeze agents. The danger does
not arise from the use of the antifreeze, but rather accidental
spills during transporting and handling the substance. According
to the U.S. Fish and Wildlife Service, ethylene glycol is a
colorless syrup alcohol which has a sweet flavor that attracts
animals. The antifreeze crystallizes in the kidneys, leading to
kidney failure. 

Energy Efficiency of TES

Typically, TES is less energy efficient than a conventional
system. The freezing and melting of ice has its own built-in
inefficiencies which do not exist in conventional systems.
However, the introduction of adjustable speed drives can reduce
the total energy used by the system. In addition, the ice can
provide colder chiller water than conventional systems, which
means that less water is necessary to cool the air in the air
handlers. This translates into less water which must be
circulated and a corresponding energy savings.

CASE STUDY:

TES System at Police Station
The City of Phoenix, Arizona replaced an inefficient 120-ton
chiller system with a 60-ton high efficiency chiller system and
ice storage at the Police Training Academy. The chiller will
operate at night, making ice to be used for cooling during the
day. In addition to the $38,250 equipment rebate for shifting 153
kilowatts to off-peak time, $6,130 and 94,300 kWh will be saved
annually. The city coordinated with the utility to determine the
best load and rate schedule for the project. (Contact: Dimitrios
Laloudakis, Energy Conservation Manager, 2631 South 22nd Ave.,
Phoenix, AZ 85009, (602) 261-8813.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

ENERGY IDEAS -- AIR CONDITIONING (Vol. 1, No. 4, December 1992)

Editor -- Jonathan Kleinman
Founder, Center for Study of Responsive Law -- Ralph Nader
Director, Government Purchasing Project -- Eleanor Lewis

This issue of "Energy Ideas" continues the discussion of heating,
ventilating and air conditioning (HVAC) systems.  In particular,
this issue considers increasing chiller efficiency, absorption
cooling systems, thermal energy storage and adjustable speed
drives.  One article covers an emerging technology -- fuel cells.

This issue also covers two environmental topics.  The first is
the selection of refrigerants for air conditioning systems.  As
the ozone hole continues to fade away, the selection of safe
fluids for use as refrigerants in air conditioning systems
becomes increasingly important.  HFCs and absorption cooling
systems provide the safest alternatives.  Also, end users have
begun to ask what they should do with their fluorescent lights
after the lights burn out.  They contain mercury, a toxic metal,
and the EPA has not stated whether end users will be held liable
for disposal of these lights into municipal landfills.

The last article of this issue contains a survey.  Please take
the time to answer the survey -- we would like to make this a
more effective resource for users of e-mail.  (please send
responses to ei (on EcoNet) or [email-masked] (on InterNet)).

To read an article, type <topic number>.<article number>

1.  Introduction
2.  Improving Cooling System Efficiency
3.  Switching from Electricity to Natural Gas
4.  Refrigerants: What are the Alternatives ?
5.  Life-Cycle Cost Analysis: Absorption vs. Vapor-Compression
6.  Thermal Energy Storage
7.  Adjustable Speed Drives
8.  On the Horizon: Fuel Cells
9.  Lighting Update: Mercury in Fluorescent Bulbs
10.  Resources
11.  Survey

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

INTRODUCTION

Concerted government purchases of energy-efficient and
non-ozone-depleting air conditioning systems can accomplish two
goals. First, these systems save money. Second, purchasing these
systems accelerates the diffusion of safe cooling systems into
the market, where they are desperately needed to minimize the
environmental impact of our energy use. 

According to an article in the October 30, 1992 Los Angeles
Times, the ozone hole over Antarctica stretches over nine million
record-breaking square miles (three times the size of the
continental United States), far enough to cover portions of
Chile. In the Northern hemisphere, the ozone layer has diminished
sharply over parts of Western Europe this year. In Oslo, Norway,
ozone measurements fell below 50 percent of normal levels.

The ozone layer blocks high-energy ultraviolet (UV) radiation
emitted by the sun. The thinning of the ozone layer over the
oceans can cause reduced reproductivity or death in several
surface-dwelling organisms, phytoplankton, zooplankton and fish
larvae, decimating the food chain. UV radiation has also been
linked to skin cancer and suppression of the human immune system.
According to the World Resources Institute, continued depletion
of stratospheric ozone can significantly increase the incidence
of skin cancer ~ perhaps as many as 12 million more cases in the
United States over the next 50 years ~ and adversely affect
agricultural production. 

Buildings and their air conditioning systems have been largely
responsible for the loss of ozone. Until recently, these systems
used chlorofluorocarbons (CFCs), chemicals whose thermodynamic
properties and supposed non-toxicity make them ideal
refrigerants. According to the National Audubon Society, nearly a
quarter of all emitted CFCs originate in building air
conditioning systems and the manufacturing processes used to make
building materials. Once emitted, a CFC molecule travels to the
atmosphere, where it can remain for over 100 years. Eventually,
sunlight breaks apart the molecule, freeing a chlorine atom which
destroys surrounding ozone molecules. Although industry has
touted newer refrigerants such as hydrochlorofluorcarbons (HCFCs)
as safer alternatives, these chemicals still release chlorine
into the atmosphere.

Air conditioning systems also affect the environment through
their energy consumption. Inefficient systems result in excessive
electricity consumption and contribute to the greenhouse effect,
acid rain, urban smog and the generation of low-level radioactive
waste. Inefficient systems also waste taxpayers~ money. The money
spent powering a school~s inefficient cooling system could be
spent instead on books.

This issue of Energy Ideas discusses ways to improve the energy
efficiency of air conditioning systems, from proper maintenance
to installation of adjustable speed drives. It also addresses the
alternatives to ozone-depleting cooling equipment.

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

ON THE HORIZON: FUEL CELLS

Fuel cells provide both heat and electric power without burning
fuel. Since they operate at relatively low temperatures and use
clean fuels, these cogenerators emit far less pollution than
conventional fossil fuel electricity sources. In addition, fuel
cells attain higher efficiencies than typical cogeneration
facilities (over 80 percent). 

Power from Electrochemical Reactions

Though a fuel cell does not burn fossil fuels, it consumes the
fuel in an electrochemical reaction which produces electricity
directly. A fuel cell consists of three parts: the fuel
processor, the power section and the power conditioner (see
diagram below). In a natural gas fuel cell, the fuel (methane) is
mixed with steam in the fuel processor. The chemical reaction
between the two gases yields a gas consisting of hydrogen, carbon
dioxide and trace amounts of nitrogen oxides. This gas is moved
to the power section, where an electrochemical reaction takes
place between the hydrogen and oxygen in air. This reaction
produces direct current (dc) electricity, steam and heat. The
steam is returned to the fuel processor to continue the cycle.
The power conditioner transforms the current into alternating
current (ac) which can be used on-site.

Types of Fuel Cells

Fuel cells are classified by the electrolyte they use. An
electrolyte is a non-metallic substance which can conduct
electricity. In the power section, the electrochemical reaction
occurs in the presence of an electrolyte, which conducts the
electrons yielded by the reaction toward the power conditioner.
The five types of fuel cells are: alkaline, which use potassium
hydroxide as the electrolyte; phosphoric acid; molten carbonate,
which use a liquid alkali carbonate; solid oxide, which use rare
metal oxides; and solid polymer, which use a polymer membrane as
the electrolyte. Currently, only phosphoric acid fuel cells have
been used commercially, because phosphoric acid is the only
common stable acid which will not react with either hydrogen or
oxygen.

Advantages of Fuel Cells

The main advantage of the fuel cell is the reduced emission of
air pollutants. According to an article in the May 22, 1992 Los
Angeles Times ("The Natural Gas-Powered Fuel Cell System," p.
D1), a natural gas fuel cell emits only 1,130 pounds of carbon
dioxide and 0.02 pounds of nitrogen oxide per megawatt-hour
(MWh), while a conventional power plant (presumably coal-fired)
emits 1,485 pounds of carbon dioxide and 5.74 pounds of nitrogen
oxide. The reduction in carbon dioxide emissions may be
attributed to both a slightly higher electricity generation
efficiency (42 percent as opposed to 34 percent for combustion)
and the use of natural gas instead of coal, which contains less
carbon per unit of energy. The reduction in nitrogen oxide
emissions may be attributed to the lower operating temperature of
the fuel cell as compared to a conventional power plant. In
addition, the use of natural gas eliminates emissions of volatile
organic compounds (VOCs) and sulfur dioxide, which lead to acid
rain.

Other advantages make the fuel cell a promising energy source.
According to the Southern California Gas Company, fuel cells
provide a constant, uninterrupted energy flow, since the cell
does not experience the power fluctuations typical of a utitlity
grid. The fuel cell is easy to operate and maintain, since it has
fewer moving parts, like turbine blades, than conventional power
systems. In addition, the fuel cell is modular, and its size can
be easily increased when growing demand requires more power.

CASE STUDY:

Fuel Cell Installation atop Office Building
In 1992, a 200-kW fuel cell was installed at the South Coast Air
Quality Management District (SCAQMD) headquarters in Diamond Bar,
California. This fuel cell is the first of ten which will be
installed, owned and operated by the Southern California Gas
Company. In this agreement, SCAQMD has agreed to purchase the
natural gas for the fuel cell; all of the electricity is used
on-site, and SCAQMD receives a 10 percent discount on its
electricity consumption. The fuel cell also provides all of the
building~s heat. Ranji George of SCAQMD stated that the agency
has a responsiblity to assist in the integration of technologies
which will lead to reductions in air pollution, and thus agreed
to test the fuel cell. He reported that the fuel cell has run
continuously without any problems since installed.(Contact:
Michelle Bagley, Southern California Gas Company, 555 W. Fifth
Street, Los Angeles, CA 90013, (213) 244-2544.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:55 PST

LIGHTING TECHNOLOGY UPDATE: DISPOSAL OF FLUORESCENT BULBS

While compact fluorescent (CFL) and long-tube fluorescent bulbs
save energy, they present disposal problems because they contain
mercury vapor. Fluorescent bulbs have always been discarded in
municipal landfills, but the question of what environmental
hazard is posed by the mercury contained within them has never
been addressed. With lighting retrofits in commercial buildings,
massive quantities of T-12 fluorescent bulbs are discarded.
Eventually, CFLs and other energy-efficient bulbs will burn out
and require disposal. These frequently contain a sufficient
amount of mercury to be classified as hazardous waste.

Toxicity of Mercury

Mercury is a heavy metal with a high toxicity and a strong
tendency to accumulate in the food chain. Worldwide, the major
source of mercury in humans is consumption of
mercury-contaminated food, especially fish. Long-term exposure,
or exposure during developmental stages, to either organic or
inorganic mercury can permanently damage the brain and kidneys.
Short-term exposure to high levels of inorganic or organic
mercury can cause similar health effects, which may be
reversible. Pregnant women, children and fetuses appear to be at
highest risk.

Mercury poisoning also damages the ecosystem. Mercury is unique
among the metals in that it consistently accumulates, rather than
diminishes, within the aquatic food chain. Organisms eating
mercury-contaminated fish, such as birds, wild mink and otter,
have been found to have mercury poisoning. In addition, several
countries have reported poisoning of birds through ingestion of
seeds treated with mercury compounds, and of predatory animals
through ingestion of contaminated birds.

Mercury in Landfills on the Rise

The use of fluorescent lights has increased the amount of mercury
in the municipal solid waste stream (MSWS). According to the U.S.
Environmental Protection Agency (EPA), the amount of mercury in
the MSWS from electric lighting is expected to rise dramatically
in the next decade. In 1970, well after the entry of the
fluorescent bulb into the market, 19.1 short tons of mercury
entered the MSWS; in 1980, 24.3 short tons; in 1989, 26.7 short
tons; and in 2000, an estimated 40.9 short tons of mercury is
expected. This increase is not likely to cause a switch to
another metal vapor, since no other metal performs as well as
mercury.

Energy-Efficiency May Offset Increase

Energy-efficient lighting will, however, reduce the amount of
mercury released into the air. According to a series of
independent studies, coal-fired power plants emit 80 to 90 tons
of mercury into the air every year in the United States. The EPA,
the Electric Power Research Institute and the Department of
Energy are currently conducting studies to measure more
accurately the amount of mercury emitted by coal plants, but
these results are not expected until after 1994.

The Question of Liability

As of yet, the EPA has not ruled on whether a facility that
discards fluorescent bulbs is liable for future cleanup costs. As
reported in the October, 1992 Energy User News ( "EPA: Spent
Fluorescent, HID Lamps May Be Hazardous Waste," p. 1), "end users
who discard spent fluorescent or high intensity discharge lamps
in municipal landfills may be violating federal hazardous waste
regulations and could be liable for fines or clean-up costs
[emphasis added]." 

Therefore, end users now must determine whether the lamps contain
a hazardous amount of mercury. According to David Layland of the
EPA~s Office of Solid Waste in Washington, DC, fluorescent bulbs
must undergo a "toxicity characteristic" test (TCLP) to classify
them as hazardous waste. This test mimics the conditions of a
landfill disposal and determines the mercury concentration of the
water which will leach from the landfill. If the mercury
concentration exceeds 0.2 milligrams per liter, the lamp fails
the toxicity test and must be disposed in a licensed hazardous
waste facility. 

States Enact Their Own Policies

The only federal legislation regulating the disposal of mercury
is the Resource Conservation and Recovery Act (RCRA). RCRA does
not require generators of small quantities of mercury (less than
100 kilograms per month) to dispose their waste in a licensed
hazardous waste landfill. This translates to roughly 350-400
bulbs per month. However, poor record keeping in a municipal
landfill may not identify who disposed of the bulbs in the
landfill, and any facility disposing of a large number of the
bulbs may be held liable for Superfund Cleanup. The EPA will not
clarify the fluorescent bulb question until 1993.

As a result, states have begun to address this issue. In
California, for example, the state EPA established a policy in
1988 under which end users may not dispose more than 25
fluorescent lamps per day in dumpsters bound for municipal
landfills. In Minnesota, the Minnesota Pollution Control Agency
(MPCA) strongly recommends that the lamps be recycled rather than
landfilled or incinerated. The October, 1992 Energy User News
reported that, in Minnesota, "a business or institution that
replaces the equivalent of more than 1,000 four-foot fluorescent
lamps per year must have a hazardous waste license and report to
the MPCA or appropriate metro-area county on what it does with
the used lamps. Smaller quantities need not be reported but must
still be managed properly as described in [an MPCA] fact sheet."

Recycling Processes Have Been Developed

Private firms have developed an enclosed recycling process which
crushes the fluorescent lamps in a vacuum and removes the mercury
vapor. A separating unit divides the remaining phosphor powder,
glass and metal. Mercury residuals, according to test data, are
well below legal limits. The glass and metal are recycled. The
phosphor powder is heated to volatilize and remove the mercury. 
The powder can be reused in another form, although these
additional uses require further investigation. According to one
of the firms, the mercury which is collected in this process
achieves 99.5 percent purity and can be reused in industry. 

Although recycling is currently the most expensive method of
disposal, it is the safest. The least expensive method,
incineration, will result in the emission of mercury into the
air. The second method of disposal, landfill in a licensed
hazardous waste facility, releases the end user of liability, but
nonetheless poses an environmental threat. The actual cost of
recycling, which may be 12 cents per bulb, does not prove to be
expensive relative to the total cost of a lighting retrofit.
According to a recycling firm, when including all of the costs
from using fluorescent lights for five years, recycling the
lights at the end of their useful life only accounts for 2
percent of the total cost.

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:55 PST

RESOURCES

Energy User News is a monthly publication concerning commercial
and industrial energy use. Four recent issues provide important
directories: November, 1992 contains a product guide of
chiller-heaters; October, 1992 contains a list of firms which
recycle spent fluorescent bulbs; April, 1992 contains a directory
of Demand-Side Management rebates offered by utilities across the
country; and February, 1992 contains a product guide for
reflectors and ballasts. Call 1-800-247-8080 for subscription
information.

The Electric Ideas Clearinghouse, a program of the Bonneville
Power Administration, offers a hotline to provide fast, free
information on commercial and industrial energy efficient
technologies, products and programs. They also have an electronic
bulletin board service with software libraries, training
calendar, referrals directory and discussion groups. Priority is
given to energy professionals in the Bonneville Power service
area (Washington, Oregon, Montana and Idaho). Within this area,
call (800) 872-3568; outside call (206) 586-8588.

The American Gas Cooling Center's (AGCC) new Natural Gas Cooling
Equipment Guide ($30 for members, $50 for non-members) introduces
three basic types of gas cooling equipment - absorption,
engine-driven and desiccant - and presents brief descriptions of
equipment that is commercially available today. Also included are
short descriptions of systems under development. The guide
provides information necessary to identify options and evaluate
their feasibility for specific applications. A manufacturer
contact for each gas cooling system is also identified. The AGCC
is a gas industry organization that directly supports technology
transfer and commercialization of advanced gas cooling equipment
to create a greater role for natural gas in the American energy
market. To order the Guide, contact Karima Davis, AGCC, 1515
Wilson Boulevard, Arlington, VA  22209, (703) 841-8410.

The Electric Power Research Institute (EPRI), founded in 1972,
manages technical research and development programs for the U.S.
electric utility industry to improve power production,
distribution and use. Some 700 utilities are members of the
institute. EPRI operates a customer assistance center, which
provides technical information to end-users of electric-powered
equipment. To reach the hotline, call 1-800-766-3774.

The Institute for Energy and Environmental Research (IEER) has
published a book which discusses the causes of ozone depletion,
the possible consequences and policies for the restoration of the
ozone layer.  Mending the Ozone Hole (250 pp.), by Arjun
Makhijani, Ph. D., and Kevin Gurney, is available for $25 from
IEER, 6935 Laurel Avenue, Takoma Park, MD 20912, (301) 270-5500.

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:54 PST

VARIABLE SPEED DRIVES PROVIDE FLEXIBLE POWER

One of the most energy-intensive activities of heating,
ventilating and air conditioning (HVAC) systems is the operation
of pumps and fans. Frequently, when a thermostat or other energy
management control device signals the HVAC system to increase or
decrease the temperature in a building, the HVAC system operates
at full power. This is seldom needed. Since frequent operation of
a pump or fan at a low rate consumes less energy than infrequent
operation of a pump or fan at a high flow rate, the installation
of a motor that varies its speed saves energy. These motors are
called adjustable speed drives (ASDs).
How They Work

The speed of a motor can be controlled by varying the amount and
frequency of the voltage applied to a motor, and by varying the
current passing through a motor. ASDs alter the speed of both
direct-current (dc - the type of current produced by a battery)
and alternating current (ac - the type of current produced by a
generator) motors by varying a fixed input voltage and current.

When used to drive dc motors, ASDs typically control both the
voltage and the current. At lower speeds, the current is
maintained at the value rated for the motor while the voltage is
increased to produce increased speed and torque (the force of the
twist provided by the motor). Above the rated speed, the voltage
is maintained at its rated value while the field current is
decreased to produce higher operation speeds.

ASDs control ac motors by controlling the magnitude of their
voltage as well as the frequency of the supply. An ac ASD
consists of three components: the rectifier, which converts an ac
signal to a fixed dc voltage or to an adjustable ac voltage; the
filter/dc link, which smooths the output of the rectifier; and
the inverter, which converts the dc output into an ac output of
adjustable frequency and adjustable voltage. 

Improved Efficiency and Other Benefits

According to an article in the September, 1992 Energy User News
("Graham Adds 300-Hp Unit to Its Series of Adjustable Speed
Motors," p. 18), installing an ASD can reduce energy consumption
by up to 60 percent. These motors can be used in chilled water
circulating systems, cooling towers, heat exchangers, exhaust and
make-up air systems, fume hoods, dust collecting systems,
domestic hot water and waste treatment systems. As shown in the
above diagram, the ASD compares the signals received from a
sensor and the setpoint and adjusts the motor speed to match the
two signals. 
Electronic speed control offers much more than just energy
savings. Less maintenance is one benefit, since electronic speed
controls often replace a mechanical transmission system. The
mechanical stresses on the machines, bearings and shafts are
lower, which prolongs the service life of the equipment. Because
of the low starting current, the thermal stress on the machine
itself and the electrical stress on the power supply are
substantially reduced.

A motor controlled by an ASD should not be operated at its
maximum output. The ASD
components use electricity to function and increase the electric
load. A 150 horsepower (hp) ASD motor operating at full power
consumes more energy than a constant 150 hp motor. The advantage
to the system is its variability; if you need a motor to operate
at a constant power level, do not purchase an ASD.

CASE STUDIES:

Installation at Police Station
The City of Phoenix installed a single ASD on a 20 hp tower fan
motor at the Police Training Academy. The ASD has saved about
30,000 kWh per year, resulting in annual savings of $2,172. The
installation of the ASD is also expected to reduce tower fan
maintenance. The cooling tower has a fan motor running at 100
percent speed intermittently to maintain a certain condenser
water temperature. The ASD varies the motor speed from 30 to 40
to 60 percent of full speed to maintain a constant cooling water
temperature. Since the energy consumption of the motor varies
with the cube of the speed, these speeds represent energy
reductions of 97 percent, 93 percent and 78 percent,
respectively. The expected payback period of the motor is 2.5 to
3.0 years. (Contact: Dimitrios Laloudakis, Energy Conservation
Manager, 2631 South 22nd Avenue, Phoenix, AZ 85009, (602)
261-8813.)

ASD Installation at School
Between 1988 and 1991, the Phoenix, Arizona, Union High School
District #210 added ASDs to the chilled/hot water systems on all
campuses. Each ASD cost about $180,000 and reduced the energy
consumption of each motor by approximately 60 percent. The pumps
were resized and some were replaced with higher efficiency pumps.
The district has not experienced any operating difficulties and
has an ongoing maintenance agreement with the manufacturer of the
ASDs. (Contact: Kenneth E. Wissinger, Assistant to the
Superintendent for Business and Operations, Phoenix Union High
School District #210, 4502 North Central Avenue, Phoenix, AZ
85012, (602) 271-3301.)

---

From: Essential Information <[email-masked]>
Date: 31 Dec 92 13:55 PST

ENERGY IDEAS SURVEY

We are interested in making this a more effective resource. 
Please take the time to respond to this survey and send a
hardcopy to: Energy Ideas Survey, P.O. Box 19367, Washington, DC 
20036, or fax to (202) 387-8034.  Thanks.

1.) Should each issue be shorter?  yes  no

2.) Are the articles too technical?     yes  no

3.) Are the articles too long?          yes  no

4.) Are the case studies helpful?       yes  no

5.) Do you want fewer or more case studies?
     fewer          more      same

6.) Do you want more information on life cycle cost analysis?    
               yes  no

7.) Do you want more information about financing?                
          yes  no

8.) Do you want more information about proper maintenance?       
          yes  no

9.) What other suggestions do you have for improving Energy
Ideas?

10.) Have you called any contact persons from the case studies to
ask for further information? If yes, who?

11.) What articles have been the most informative and helpful?
Why?

12.) What articles have been the least informative or helpful?
Why?

13.) What topics are of greatest interest to you? (i.e.,
financing, lighting, HVAC, solar power, maintenance, etc.) 

14.) What type of information is of greatest interest to you?
(i.e. technical descriptions, financial detail, problems with
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15.) If you want to receive Energy Ideas, please provide your
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