Solar
Heating and Cooling
www.SolarHeatingAndCooling.com
Our
Solar Heating and Cooling system will permanently reduce
your electric bills by up to 60% (or more) EVERY MONTH!
Add
our Solar Electric Power System and you can "cut the cord"
to your electric utility and eliminate your electric bills
forever!
With
our Solar Heating and Cooling System, you can Cool and Heat your Home,
School, Office Building, Hospital, or Just About any Other Building for
*free!
Cooling and heating your building (home, office, school,
hospital, etc.) costs you up to 60%, or more, every month you receive
your electric bill. You can eliminate the heating and cooling portion of
your electric bill forever, and cool and heat your home with the sun's
power with our Solar Heating and Cooling system!
Our Solar Heating and Cooling system is the cleanest,
greenest, and lowest cost method to cool and warm your home or
commercial office or other buildings. Our Solar Heating and
Cooling system will eliminate your energy costs for heating and cooling
your home, office, school, or any other commercial facility for *free:
Requires the purchase of our Solar Heating and Cooling system. Minimum
size is 10 tons. You must be located in a qualified geographic location,
which means our system must be located to receive direct sunlight.
For qualified customers, we will install the system with little to no
money down and you pay for the system with the savings our system
provides!
Solar Absorption Cooling. Solar heat can be used to
displace electricity used for cooling. Absorption chillers use a heat
source, such as natural gas or hot water from solar collectors, to
evaporate the already-pressurized refrigerant from an
absorbent/refrigerant mixture. Condensation of vapors provides the same
cooling effect as that provided by mechanical cooling systems. Although
absorption chillers require electricity for pumping the refrigerant, the
amount is very small compared to that consumed by a compressor in a
conventional electric air conditioner or refrigerator. Solar Absorption
Cooling systems are typically sized to carry the full air conditioning
load during sunny periods.
Let
Us Help You Design, Install and Buy Your
Solar Heating and Cooling System
Call us at 832-758-0027
We provide Demand Side Management
design and project development solutions that may provide a return on
investment in less than 12 months. We also offer energy-saving
technologies that may include; Absorption
Chillers, Adsorption Chillers, Automated
Demand Response, Cogeneration, Demand
Response Programs, Demand Side
Management, Energy Master
Planning, Engine Driven Chillers,
Trigeneration and Energy
Conservation Measures.
Our company provides turn-key
project solutions that include all or part of the following:
-
Engineering and Economic
Feasibility Studies
-
Project Design, Engineering
& Permitting
-
Project Construction
-
Project Funding &
Financing Options
-
Shared/Guaranteed Savings
program with no capital requirements.
-
Project Commissioning
-
Operations & Maintenance
For more information: call us at:
832-758-0027
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Solar electric power systems transform
sunlight into electricity. Sunlight is an abundant
resource. Every minute the sun bathes the Earth in as much
energy as the world consumes in an entire year.
Solar cells employ special materials called
semiconductors that create electricity when exposed to
light. Solar electric systems are quiet and easy to use,
and they require no fuel other than sunlight. Because they
contain no moving parts, they are durable, reliable, and
easy to maintain.
How It Works
Solar cells, also known as photovoltaic
(PV) cells, do the work of making electricity. Several
types of solar electric technology are under development,
but four—crystalline silicon (a form of refined beach
sand), thin films, concentrators, and thermophotovoltaics—are
illustrative of the range of technologies. Solar cells are
connected to a variety of other components to make a solar
electric power system.
Crystalline Silicon
Crystalline silicon solar cells are used
in more than half of all solar electric devices. Like most
semiconductor devices, they include a positive layer (on
the bottom) and a negative layer (on the top) that create
an electrical field inside the cell. When a photon of
light strikes a semiconductor, it releases electrons (see
animation). The free electrons flow through the solar
cell's bottom layer to a connecting wire as direct current
(DC) electricity.
Some solar cells are made from polycrystalline silicon,
which consists of several small silicon crystals.
Polycrystalline silicon solar cells are cheaper to produce
but somewhat less efficient than single-crystal silicon.
A simple silicon solar cell can power a watch or
calculator. However, it produces only a tiny amount of
electricity. Connected together, solar cells form modules
that can generate substantial amounts of power. Modules
are the building blocks of solar electric systems, which
can produce enough power for a house, a rural medical
clinic, or an entire village. Large arrays of solar
electric modules can power satellites or provide
electricity for utilities.
Solar Electric Power System Components
In addition to modules, several
components are needed to complete a solar electric power
system.
Many systems include batteries, battery chargers, a
backup generator, and a controller so that people in
solar-powered homes and buildings can turn on the lights
at night or run televisions or appliances on cloudy days.
Grid-connected systems don't require batteries or backup
generators because they use the grid for backup power.
Some remote system applications, such as those used to
pump water, do not require a backup power source.
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Components of a typical
standalone PV system using crystalline silicon
technology. (Source: Solar Electric Power
Association)
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Solar electric power systems can incorporate inverters
or power control units to transform the DC electricity
produced by the solar cells into alternating current (AC)
to run AC appliances or sell to a utility grid. Complete
systems usually include safety disconnects, fuses, and a
grounding circuit as well.
Thin Films
Solar electric thin films are lighter,
more resilient, and easier to manufacture than crystalline
silicon modules. The best-developed thin-film technology
uses amorphous silicon, in which the atoms are not
arranged in any particular order as they would be in a
crystal. An amorphous silicon film only one micron thick
can absorb 90% of the usable solar energy falling on it.
Other thin-film materials include cadmium telluride and
copper indium diselenide. Substantial cost savings are
possible with this technology because thin films require
relatively little semiconductor materials.
Thin films are produced as large, complete modules, not
as individual cells that must be mounted in frames and
wired together. They are manufactured by applying
extremely thin layers of semiconductor material to a
low-cost backing such as glass or plastic. Electrical
contacts, antireflective coatings, and protective layers
are also applied directly to the backing material. Thin
films conform to the shape of the backing, a feature that
allows them to be used in such innovative products as
flexible solar electric roofing shingles.
Concentrators
Concentrators use optical lenses (similar
to plastic magnifying glasses) or mirrors to concentrate
the sunlight that falls on a solar cell. With a
concentrator to magnify the light intensity, the solar
cell produces more electricity. Today, most solar cells in
concentrators are made from crystalline silicon. However,
materials such as gallium arsenide and gallium indium
phosphide are more efficient than silicon in solar
electric concentrators and will likely see more use in the
future. These materials are now used in communications
satellites and other space applications.
Concentrators produce more electricity using less of
the expensive semiconductor material than other solar
electric systems. A basic concentrator unit consists of a
lens to focus the light, a solar cell assembly, a housing
element, a secondary concentrator to reflect off-center
light rays onto the cell, a mechanism to dissipate excess
heat, and various contacts and adhesives. The basic unit
can be combined into modules of varying sizes and shapes.
Concentrators only work with direct sunlight and operate
most effectively in sunny, dry climates. They must be used
with tracking systems to keep them pointed toward the sun.
Thermophotovoltaics
Thermophotovoltaic (TPV) devices convert
heat into electricity in much the same way that other PV
devices convert light into electricity. The difference is
that TPV technology uses semiconductors "tuned"
to the longer-wavelength, invisible infrared radiation
emitted by warm objects. This technology is cleaner,
quieter, and simpler than conventional power generation
using steam turbines and generators.
TPV converters are relatively maintenance-free because
they contain no moving parts. In addition to using solar
energy, they can convert heat from any high-temperature
heat source, including combustion of a fuel such as
natural gas or propane, into electricity. TPV converters
produce virtually no carbon monoxide and few emissions.
They may be used in the future in gas furnaces that
generate their own electricity for self-ignition (during
power outages) and in portable generators and battery
chargers.
Advantages
Solar electric systems offer many
advantages. Standalone systems can eliminate the need to
build expensive new power lines to remote locations. For
rural and remote applications, solar electricity can cost
less than any other means of producing electricity. Solar
electric systems can also connect to existing power lines
to boost electricity output during times of high demand
such as on hot, sunny days when air conditioners are on.
Solar electric systems are flexible. Solar electric
modules can stand on the ground or be mounted on rooftops.
They can also be built into glass skylights and walls.
They can be made to look like roof shingles and can even
come equipped with devices to turn their DC output into
the same AC utilities deliver to wall sockets. These
advances mean individual homeowners and businesses can
relieve pressure on local utilities struggling to meet the
increasing demand for electricity.
More than 30 states offer grid-connected solar electric
system owners the chance to save money on their energy
bills by feeding any excess power their solar electric
system produces into the utility grid—an arrangement
called net metering.
Solar power systems require minimal maintenance. They
run quietly and efficiently without polluting. They are
easy to combine with other types of electric generators
such as wind, hydro, or natural gas turbines. They can
charge batteries to make solar electricity continuously
available.
For utilities, large-scale
solar electric power plants can help meet demand for
new power generation, especially in distributed
applications. A solar electric power plant is created from
multiple arrays that are interconnected electronically.
Solar electric plants are easier to site and are quicker
to build than conventional power plants. They are also
easy to expand incrementally—by adding more modules—as
power demand increases.
Solar electric power systems are good for the
environment. When solar electric technologies displace
fossil fuels for pumping water, lighting homes, or running
appliances, they reduce the greenhouse gases and
pollutants emitted into the atmosphere. The use of solar
electric systems is particularly important in developing
nations because it can help avert the expected increases
in emissions of greenhouse gases caused by the growing
demand for electricity in those countries.
Solar electric technologies also benefit the U.S.
economy by creating jobs in U.S. companies. Exporting
solar electric technologies to developing nations expands
U.S. markets while protecting the global environment.
Disadvantages
Although solar electric systems make
financial sense in remote areas that lack access to power
lines, they are usually more expensive than fossil fuels
for grid-connected applications.
This disadvantage is significant for utilities
considering large-scale solar electric power plants.
Although solar electricity costs considerably more than
electricity generated by conventional plants, regulatory
agencies often require utilities to supply electricity for
the lowest cash cost.
Utilities view solar electric power plants differently
than they view conventional power plants. Solar electric
modules produce electricity intermittently—only when the
sun shines. Their output varies with the weather and
disappears altogether at night. Integrating solar
electricity into a utility system requires creative
planning.
Applications
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A combination of solar electric
arrays and pool-heating solar collectors were used
to provide power and heat to the Georgia Tech
University Aquatic Center, site of the 1996
Olympic swimming competition. (Credit: Heliocol)
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Solar electricity has powered satellites
since the dawn of the space program. It has run remote
communications outposts high in the mountains and turned
on the lights, kept medicines cold, and pumped water in
rural areas for more than 30 years. Small solar cells are
used to power wristwatches, calculators, and other
electronic gadgets. More recently, solar electric systems
have been used to provide supplemental power to homes and
commercial buildings in cities.
Solar electric technology has important roles to play
in both the developing and developed worlds. From the
farmer irrigating his crops in rural Mexico to an
innovative lighting system for an Olympic sports arena,
solar electric solutions abound.
Electric utilities harness solar electricity for
distributed applications—near substations or at the end
of overloaded power lines, for example, to avoid or defer
costly line upgrades. They use solar electricity during
hot, sunny periods when the demand for air conditioning
stretches conventional power generation to its limit. The Sacramento
Municipal Utility District, for example, uses large
solar electric arrays as part of its power generation mix.
Utilities also rely on solar electricity to power remote,
standalone monitoring systems.
Consumers and builders are integrating solar electric
modules into their homes and offices. Innovative solar
electric technologies can replace conventional roofing and
facade materials in new buildings. Solar electric roofing
shingles, for example, are being used in some new
residences. In grid-connected applications, solar
electricity supplies some of a consumer's energy needs;
the local utility provides the rest.
Standalone solar electric systems power a variety of
applications far from the reaches of the power grid. These
applications include remote communications systems such as
television and radio transmitters and receivers, telephone
systems, and microwave repeaters. Standalone solar
electric power is also used to prevent corrosion of metal
pipes, tanks, bridges, and buildings.
Many remote residences worldwide use solar electricity
as their source of power. For instance, more than 100,000
vacation homes in Scandinavia rely solely on solar
electric technology to run lights and appliances.
Villages around the world are building solar electric
systems to bring electricity to their homes and local
industries, often for the first time. To make the maximum
use of available resources, village power is typically
produced by a hybrid power system that combines solar
electricity with diesel backup generators and sometimes
another renewable energy technology such wind power.
Villages also use standalone solar electric systems for
pumping water—an application shared by rural farmers and
ranchers in the United States.
For more information, visit the following Web sites:
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Our Solar Heating and Cooling
System - Uses the "free" Power of the Sun to Heat and Cool
your Commercial Business or Home for Free!
Cooling and heating your building (home, office, school,
hospital, etc.) costs you up to 60%, or more, every month you receive
your electric bill. You can eliminate the heating and cooling portion of
your electric bill forever, and cool and heat your home with the sun's
power with our Solar Heating and Cooling system!
Our Solar Heating and Cooling system is the cleanest,
greenest, and lowest cost method to cool and warm your home or
commercial office or other buildings. Our Solar Heating and
Cooling system will eliminate your energy costs for heating and cooling
your home, office, school, or any other commercial facility for *free:
Requires the purchase of our Solar Heating and Cooling system. Minimum
size is 10 tons. You must be located in a qualified geographic location,
which means our system must be located to receive direct sunlight.
For qualified customers, we will install the system with little to no
money down and you pay for the system with the savings our system
provides!
Solar Absorption Cooling. Solar heat can be used to
displace electricity used for cooling. Absorption chillers use a heat
source, such as natural gas or hot water from solar collectors, to
evaporate the already-pressurized refrigerant from an
absorbent/refrigerant mixture. Condensation of vapors provides the same
cooling effect as that provided by mechanical cooling systems. Although
absorption chillers require electricity for pumping the refrigerant, the
amount is very small compared to that consumed by a compressor in a
conventional electric air conditioner or refrigerator. Solar Absorption
Cooling systems are typically sized to carry the full air conditioning
load during sunny periods.
Let
Us Help You Design, Install and Buy Your Combination
Solar Electric Power and Heating & Cooling System System
We Exclusively Represent
Yazaki Energy's
Absorption Chillers and Chiller-Heaters
which offer superior performance and operating results
over any/all engine driven chiller
April 22, 2005:
Cogeneration Technologies and Yazaki
Energy enter into strategic sales and partnership agreement.
A Yazaki absorption chiller-heater, using water as the refrigerant, is
today’s best choice in air conditioning for protecting the environment
and reducing the cost of energy. Double-effect cycles and advanced
technology ensure high performance and long term reliability.
With over
100,000 units operating worldwide, Yazaki is a leading supplier of
non-CFC based space cooling.
Capacities of 30 through
100 RT are available to either cool or heat installations such as
schools, offices, hospitals, industrial facilities, and hotels.
Yazaki Energy's
Absorption
Chillers, Chiller-Heaters
significantly reduce
electric expenses and electric demand charges.
Yazaki Energy's absorption chillers can be run by solar, waste heat, hot
water,
exhaust heat &/or biofuels.
How Does
an Absorption Chiller Work?
What is an
Absorption Chiller?
Absorption
chillers use heat instead of mechanical energy to provide cooling. A
thermal compressor consists of an absorber, a generator, a pump, and a
throttling device, and replaces the mechanical vapor compressor.
In
the chiller, refrigerant vapor from the evaporator is absorbed by a
solution mixture in the absorber. This solution is then pumped to the
generator. There the refrigerant re-vaporizes using a waste steam heat
source. The refrigerant-depleted solution then returns to the absorber via
a throttling device. The two most common refrigerant/ absorbent mixtures
used in absorption chillers are water/lithium bromide and ammonia/water.
Compared
with mechanical chillers, absorption chillers have a low coefficient of
performance (COP = chiller load/heat input). However, absorption chillers
can substantially reduce operating costs because they are powered by
low-grade waste heat. Vapor compression chillers, by contrast, must be
motor- or engine-driven.
Low-pressure,
steam-driven absorption chillers are available in capacities ranging from
100 to 1,500 tons. Absorption chillers come in two commercially available
designs: single-effect and double-effect. Single-effect machines provide a
thermal COP of 0.7 and require about 18 pounds of
15-pound-per-square-inch-gauge (psig) steam per ton-hour of cooling.
Double-effect machines are about 40% more efficient, but require a higher
grade of thermal input, using about 10 pounds of 100- to 150-psig steam
per ton-hour.
A
single-effect absorption machine means all condensing heat cools and
condenses in the condenser. From there it is released to the cooling
water. A double-effect machine adopts a higher heat efficiency of
condensation and divides the generator into a high-temperature and a
low-temperature generator.
Is It Right for You?
Absorption cooling may be worth considering if your site requires cooling,
and if at least one of the following applies:
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You have a combined heat and power CHP)
unit and cannot use all of the available heat, or if you are
considering a new CHP plant
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Waste heat is available
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A low-cost source of fuels is available
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Your boiler efficiency is low due to a
poor load factor
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Your site has an electrical load limit
that will be expensive to upgrade
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Your site needs more cooling, but has an
electrical load limitation that is expensive to overcome, and you have
an adequate supply of heat.
In
short, absorption cooling may fit when a source of free or low-cost heat
is available, or if objections exist to using conventional refrigeration.
Essentially, the low-cost heat source displaces higher-cost electricity in
a conventional chiller.
In
Practice
In a plant where low-pressure steam is currently being vented to the
atmosphere, a mechanical chiller with a COP of 4.0 is used 4,000 hours a
year to produce an average 300 tons of refrigeration. The plant's cost of
electricity is $0.05 a kilowatt-hour.
An absorption unit requiring 5,400 lbs/hr of 15-psig steam could replace
the mechanical chiller, providing annual electrical cost savings of:
Annual Savings = 300 tons x (12,000 Btu/ton / 4.0) x 4,000 hrs/yr x
$0.05/kWh x kWh/3,413 Btu = $52,740
Actions You Can Take
Determine
the cost-effectiveness of displacing a portion of your cooling load with a
waste steam absorption chiller by taking the following steps:
-
Conduct a plant survey to identify
sources and availability of waste steam
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Determine cooling load requirements and
the cost of meeting those requirements with existing mechanical
chillers or new installations
-
Obtain installed cost quotes for a waste
steam absorption chiller
-
Conduct a life cycle cost analysis to
determine if the waste steam absorption chiller meets your company's
cost-effectiveness criteria.
Absorption Chiller
Refrigeration Cycle
The basic
cooling cycle is the same for the absorption and electric chillers. Both
systems use a low-temperature liquid refrigerant that absorbs heat from
the water to be cooled and converts to a vapor phase (in the evaporator
section). The refrigerant vapors are then compressed to a higher pressure
(by a compressor or a generator), converted back into a liquid by
rejecting heat to the external surroundings (in the condenser section),
and then expanded to a low- pressure mixture of liquid and vapor (in the
expander section) that goes back to the evaporator section and the cycle
is repeated.
The basic
difference between the electric chillers and absorption chillers is that
an electric chiller uses an electric motor for operating a compressor used
for raising the pressure of refrigerant vapors and an absorption chiller
uses heat for compressing refrigerant vapors to a high-pressure. The
rejected heat from the power-generation equipment (e.g. turbines,
microturbines, and engines) may be used with an absorption chiller to
provide the cooling in a CHP system.
The basic
absorption cycle employs two fluids, the absorbate or refrigerant, and the
absorbent. The most commonly fluids are water as the refrigerant and
lithium bromide as the absorbent. These fluids are separated and
recombined in the absorption cycle. In the absorption cycle the
low-pressure refrigerant vapor is absorbed into the absorbent releasing a
large amount of heat. The liquid refrigerant/absorbent solution is pumped
to a high-operating pressure generator using significantly less
electricity than that for compressing the refrigerant for an electric
chiller. Heat is added at the high-pressure generator from a gas burner,
steam, hot water or hot gases. The added heat causes the refrigerant to
desorb from the absorbent and vaporize. The vapors flow to a condenser,
where heat is rejected and condense to a high-pressure liquid. The liquid
is then throttled though an expansion valve to the lower pressure in the
evaporator where it evaporates by absorbing heat and provides useful
cooling. The remaining liquid absorbent, in the generator passes through a
valve, where its pressure is reduced, and then is recombined with the
low-pressure refrigerant vapors returning from the evaporator so the cycle
can be repeated.
Absorption
chillers are used to generate cold water (44°F) that is circulated to air
handlers in the distribution system for air conditioning.
"Indirect-fired"
absorption chillers use steam, hot water or hot gases steam from a boiler,
turbine or engine generator, or fuel cell as their primary power input.
Theses chillers can be well suited for integration into a CHP system for
buildings by utilizing the rejected heat from the electric generation
process, thereby providing high operating efficiencies through use of
otherwise wasted energy.
"Direct-fired"
systems contain natural gas burners; rejected heat from these chillers can
be used to regenerate desiccant dehumidifiers or provide hot water.
Commercially
absorption chillers can be single-effect or multiple-effect. The above
schematic refers to a single-effect absorption chiller. Multiple-effect
absorption chillers are more efficient and discussed below.
Multiple-Effect
Absorption Chillers
In a
single-effect absorption chiller, the heat released during the chemical
process of absorbing refrigerant vapor into the liquid stream, rich in
absorbent, is rejected to the environment. In a multiple-effect absorption
chiller, some of this energy is used as the driving force to generate more
refrigerant vapor. The more vapor generated per unit of heat or fuel
input, the greater the cooling capacity and the higher the overall
operating efficiency.
A
double-effect chiller uses two generators paired with a single condenser,
absorber, and evaporator. It requires a higher temperature heat input to
operate and therefore they are limited in the type of electrical
generation equipment they can be paired with when used in a CHP System.
Triple-effect
chillers can achieve even higher efficiencies than the double-effect
chillers. These chillers require still higher elevated operating
temperatures that can limit choices in materials and refrigerant/absorbent
pairs. Triple-effect chillers are under development by manufacturers
working in cooperation with the U.S. Department of Energy.
* Geothermal Energy... Power from the Depths
The Earth's crust is a bountiful source of energy—and
fossil fuels are only part of the story. Heat or thermal energy is by far
the more abundant resource. To put it in perspective, the thermal energy
in the uppermost six miles of the Earth's crust amounts to 50,000 times
the energy of all oil and gas resources in the world!
The word "geothermal" literally means
"Earth" plus "heat." The geothermal resource is the
world's largest energy resource and has been used by people for centuries.
In addition, it is environmentally friendly. It is a renewable resource
and can be used in ways that respect rather than upset our planet's
delicate environmental balance.
Geothermal power plants operating around the world are
proof that the Earth's thermal energy is readily converted to electricity
in geologically active areas. Many communities, commercial enterprises,
universities, and public facilities in the western United States are
heated directly with the water from underground reservoirs. For the
homeowner or building owner anywhere in the United States, the emergence
of geothermal heat pumps brings the benefits of geothermal energy to
everyone's doorstep.
The Basics
There's a relatively simple concept underlying all the
ways geothermal energy is used: The flow of thermal energy is available
from beneath the surface of the Earth and especially from subterranean
reservoirs of hot water. Over the years, technologies have evolved that
allow us to take advantage of this heat.
In fact, electric power plants driven by geothermal energy
provide over 44 billion kilowatt hours of electricity worldwide per year,
and world capacity is growing at approximately 9% per year. To produce
electric power from geothermal resources, underground reservoirs of steam
or hot water are tapped by wells and the steam rotates turbines that
generate electricity. Typically, water is then returned to the ground to
recharge the reservoir and complete the renewable energy cycle.
Underground reservoirs are also tapped for
"direct-use" applications. In these instances, hot water is
channeled to greenhouses, spas, fish farms, and homes to fill space
heating and hot water needs.
Geothermal energy use extends beyond underground
reservoirs. The soil and near-surface rocks, from 5 to 50 feet deep, have
a nearly constant temperature from geothermal heating. As a homeowner or
business owner, you can use the Earth as a heat source or heat sink with
geothermal heat pumps. According to the U.S. Environmental Protection
Agency (EPA), geothermal heat pumps are one of the nation's most
efficient—and therefore least polluting—heating, cooling, and
water-heating systems available. In winter, these systems draw on
"earth heat" to warm the house, and in summer they transfer heat
from the house to the earth, which ranges in temperature from 50° to 70°F
(10° to 21°C) depending on latitude.
A Clear Advantage
Geothermal energy delivers some powerful environmental and
economic benefits. If you live in an area that uses geothermal resources
for electricity production, you're quite fortunate. Consider Lake County,
California, which is home to many of the geothermal power plants at our
nation's best-developed geothermal resource, The Geysers. It's no
coincidence that the Lake County air basin is the first and only one in
compliance with all of California's stringent air quality regulations.
Perhaps you own a greenhouse and need to cut exorbitant
energy bills in order to stay in business. If you are located near a
geothermal resource, you should know that most greenhouse growers estimate
that direct use of geothermal resources instead of traditional energy
sources reduces heating costs by up to 80%. This can save about 5% to 8%
in total operating cost.
Assume you're a home or business owner who has installed a
geothermal heat pump. You're not only doing your part to help make the
world a cleaner place to live and breathe, you're rewarded with low
operating and maintenance costs, and, usually, lowest life-cycle costs.
(Life-cycle cost is the total cost of the equipment spread over the useful
life of the equipment.) In practical terms, your heat pump investment may
cost you $15 per month more in mortgage payments, but it may save you $30
per month on your electric bill.
In all three of these cases, domestic, not foreign,
resources are being used—a practice that has merits all its own. Nearly
half of our nation's annual trade deficit would be obliterated if we could
displace imported oil with domestic energy resources. A nation's trade
deficit represents a permanent loss of wealth for the citizens of that
nation. Keeping the wealth at home translates to more jobs and a robust
economy. And not only does our national economic and employment picture
improve, but a vital measure of national security is gained when we
control our own energy supplies.
Types of Geothermal Resources
The center of the Earth is 4000 miles (6400 kilometers)
deep. How hot is this region? Our best guess is 7200°F (4000°C) or
higher. Partially molten rock, at temperatures between 1200° and 2200°F
(650° to 1200°C), is believed to exist at depths of 50 to 60 miles (80
to 100 kilometers).
Heat is constantly flowing from the Earth's interior to
the surface. Most types of geothermal resources—hydrothermal,
geopressured, hot dry rock, and magma—result from concentration of
Earth's thermal energy within certain discrete regions of the subsurface.
Hydrothermal resources are reservoirs of steam or
hot water, which are formed by water seeping into the earth and collecting
in, and being heated by fractured or porous hot rock. These reservoirs are
tapped by drilling wells to deliver hot water to the surface for
generation of electricity or direct use. Hot water resources exist in
abundance around the world. In the United States, the hottest (and
currently most valuable) resources are located in the western states, and
Alaska and Hawaii. Technologies to tap hydrothermal resources are proven
commercial processes.
Geopressured resources are deeply buried waters at
moderate temperature that contain dissolved methane. While technologies
are available to tap geopressured resources, they are not currently
economically competitive. In the United States, this resource base is
located in the Gulf coast regions of Texas and Louisiana.
Hot dry rock resources occur at depths of 5 to 10
miles (8 to 16 kilometers) everywhere beneath the Earth's surface, and at
shallower depths in certain areas. Access to these resources involves
injecting cold water down one well, circulating it through hot fractured
rock, and drawing off the now hot water from another well. This promising
technology has been proven feasible, but no commercial applications are in
use at this time.
Magma (or molten rock) resources offer extremely
high-temperature geothermal opportunities, but existing technology does
not allow recovery of heat from these resources.
Earth energy is the heat contained in soil and
rocks at shallow depths. This resource is tapped by geothermal heat pumps.
Geothermal Power Plants—from Water to Light
Flip a switch and light up a room—what could be easier?
Push a button on the TV remote control and be entertained. It all seems so
simple that we are often unaware of the true environmental and social cost
of these conveniences—and who would want to give them up even if we had
to account for every penny?
But rather than thinking in terms of giving things up,
let's think positively: in the United States, right now, the installed
generating capacity for geothermal stands at about 2700 megawatts. That's
the equivalent of about 58 million barrels of oil, and provides enough
electricity for 3.7 million people. The cost of producing this power
ranges from 4¢ to 8¢ per kilowatt hour. The geothermal industry is
working to achieve a geothermal life-cycle energy cost of 3¢ per kilowatt
hour. And remember, this is clean energy produced from domestic resources.
How clean? In terms of air emissions, geothermal power
plants have an inherent advantage over fossil fuel plants because no
combustion takes place. Geothermal plants emit no nitrogen oxides and very
low amounts of sulfur dioxide—allowing them to easily meet the most
stringent clean air standards. The steam at some steam plants contains
hydrogen sulfide, but treatment processes remove more than 99.9% of those
emissions. Typical emissions of hydrogen sulfide from geothermal plants
are less than 1 part per billion—well below what people can smell. The
low levels of air emissions produced are mostly carbon dioxide, which many
people believe acts as a greenhouse gas to trap heat within Earth's
atmosphere. Even so, geothermal plants emit minimal amounts of carbon
dioxide—1/1000 to 1/2000 of the amount produced by fossil-fuel plants.
Geothermal water sometimes contains salts and dissolved
minerals. In the United States, the geothermal water is usually injected
back into the reservoir from where it came, at a depth well below
groundwater aquifers, after its heat energy has been extracted. This
recycles the geothermal water and replenishes the reservoir. However, some
geothermal plants also produce some solid materials, or sludges, that
require disposal in approved sites.
All U.S. geothermal power plants are located in the states
of California, Nevada, Utah, and Hawaii—home to some of the most
majestic scenery on Earth. It's fortunate, then, that these plants consume
only a small amount of land, and can coexist with numerous other land
uses, including agriculture, with minimal impact on the surrounding
beauty.
They're reliable and efficient, too. Taken as a group,
geothermal power plants are available to generate power 95% or more of the
time; they are seldom off-line for maintenance or repair. And, they have
the highest capacity factors of all types of power plants. Capacity factor
is the ratio of the amount of electricity a plant produces to how much
electricity it is capable of producing.
Dry Steam Power Plants were the first type of
geothermal power plant (in Italy in 1904). The Geysers in northern
California, which is the world's largest single source of geothermal
power, is also home to this type of plant. These plants use the steam as
it comes from wells in the ground, and direct it into the
turbine/generator unit to produce power.
Flash Steam Power Plants, which are the most
common, use water with temperatures greater than 360°F (182°C). This
very hot water is pumped under high pressure to equipment on the surface,
where the pressure is suddenly dropped, allowing some of the hot water to
"flash" into steam. The steam is then used to power the
turbine/generator. The remaining hot water and condensed steam are
injected back into the reservoir.
Binary Cycle Power Plants operate on the
lower-temperature waters, 225° to 360°F (107° to 182°C). These plants
use the heat of the hot water to boil a "working fluid," usually
an organic compound with a low boiling point. This working fluid is then
vaporized in a heat exchanger and used to turn a turbine. The geothermal
water and the working fluid are confined to separate closed loops, so
there are no emissions into the air.
Because these lower-temperature waters are much more
plentiful than high-temperature waters, binary cycle systems will be the
dominant geothermal power plants of the future.
Developing and commercializing geothermal power
technologies contributes not only to a cleaner environment, but to a
healthy U.S. industrial base, as well. Around the developing countries of
the world, demand for electric power is burgeoning—and nearly half of
these countries have geothermal resources. These markets have proven
particularly receptive to clean energy produced with indigenous resources,
creating attractive export options for geothermal technologies and
expertise. In fact, U.S. geothermal companies have signed contracts worth
more than $6 billion in the past few years to build geothermal power
plants in some of these developing countries.
Direct Use of Geothermal Energy
If you've ever soaked in water from a natural hot spring,
you're one of the millions of people around the world who has enjoyed the
direct use of geothermal energy. And while this naturally occurring hot
water may be the perfect tonic for frayed nerves and sore muscles, it's
capable of much more. In the United States alone, direct geothermal
applications (not including geothermal heat pumps) have an installed
capacity of 500 thermal megawatts, which is roughly equivalent to saving
half a million barrels of oil per year. This includes approximately 40
greenhouses, 30 fish farms, 190 resorts and spas, 125 space and district
heating projects, and 10 industrial projects.
The resource required for these applications is widespread
across the western third of the United States. This is water in an
underground reservoir, at low-to-moderate temperatures usually ranging
from 68° to 302°F (20° to 150°C). The consumer of direct-use
geothermal energy can count on savings in energy costs—as much as an 80%
reduction from traditional fuel costs, depending on the application and
the industry. Direct-use systems typically require a larger initial
investment, but have lower operating costs and no need for ongoing fuel
purchases, therefore reducing life-cycle costs.
In a typical application, a well brings heated water to
the surface; a mechanical system—piping, heat exchanger,
controls—delivers the heat to the space or process; and a disposal
system either injects the cooled geothermal fluid underground or disposes
of it on the surface.
The direct use of geothermal energy offers some heartening
possibilities. Imagine an entire community of people having their homes
heated geothermally. Sound like something way off in the future? Not at
all. In 1893, the citizens of Boise, Idaho, put their pioneering spirit to
work and built the world's first geothermal district heating system by
piping water from a nearby hot spring. Within a few years, the system was
providing heat to 200 homes and 40 downtown businesses—and the system
continues to flourish today.
There are now 18 district heating systems in the United
States (including one in Klamath Falls, Oregon, that melts snow from the
city's downtown sidewalks), and the potential for more is tremendous. A
recently updated resource inventory of 10 western states identified 271
communities located within 5 miles (8 kilometers) of a geothermal
resource.
Greenhouse operators are taking advantage of geothermal
direct use in growing numbers, with nearly 40 greenhouses (many of which
are several acres in size) producing vegetables, flowers, houseplants, and
tree seedlings in eight western states. Operators of fish farms are
profiting from the lower energy costs and improved fish growth rates that
geothermal energy delivers. Other industrial and commercial applications
that match well with geothermal direct use include food dehydration,
laundries, gold processing, milk pasteurizing, and swimming pools and
spas.
The Heat Pump Solution
The geothermal heat pump doesn't create electricity—but
it greatly reduces consumption of it. If you would like to reduce the cost
of heating and cooling your home, you might want to consider installing a
geothermal heat pump, an economical and energy-efficient technology for
space heating and cooling and water heating. Nationwide, more than 350,000
of these systems are in operation in homes, schools, and businesses. And
the geothermal heat pump industry expects to be installing 40,000 systems
per year by 2000.
In winter, heat pump systems draw thermal energy from the
ambient temperature of the shallow ground, which ranges between 50° and
70°F (10° to 21°C ) depending on latitude. In summer, the process is
reversed to a cooling mode, using the ground as a sink for the heat
contained within the building. The system does not convert electricity to
heat; rather, it uses electricity to move thermal energy between the
building and the ground and condition it to a higher or lower temperature
according to the heating or cooling requirements. Consumption of
electricity is reduced 30% to 60% compared to traditional heating and
cooling systems, allowing a payback of system installation in 2 to 10
years. And these low-maintenance systems have long lives of 30 years or
more. Some systems are also capable of producing domestic hot water at no
cost in summer and at small cost in winter.
An analysis by the EPA found these systems to be among the
most efficient space-conditioning technologies available—with the lowest
environmental cost of all that were analyzed. But this might be the most
compelling statistic: Surveys show that the number of satisfied geothermal
heat pump customers stands at 95% or higher.
About Solar Heating and Cooling
It is possible to use solar thermal energy or solar electricity to operate
or power an HVAC or heating and cooling system. The following is a
brief description of "active" solar cooling and refrigeration
technologies. Active solar energy systems use a mechanical or electrical
device to transfer solar energy absorbed in a solar collector to another
component in the "system." It is possible to also cool a
building or structure by using the natural processes of solar heat
transfer (conduction, convection, and radiation). This is often referred
to as "passive solar cooling," and is primarily an architectural
technique. This brief focuses on active solar cooling systems. The
American Solar Energy Society (ASES, see Source List below) is one source
of information on passive solar cooling techniques.
Absorption Cooling and Refrigeration
Absorption cooling is the first and oldest form of air conditioning and
refrigeration. An absorption air conditioner or refrigerator does not use
an electric compressor to mechanically pressurize the refrigerant.
Instead, the absorption device uses a heat source, such as natural gas or
a large solar collector, to evaporate the already-pressurized refrigerant
from an absorbent/refrigerant mixture. This takes place in a device called
the vapor generator. Although absorption coolers require electricity for
pumping the refrigerant, the amount is small compared to that consumed by
a compressor in a conventional electric air conditioner or refrigerator.
When used with solar thermal energy systems, absorption coolers must be
adapted to operate at the normal working temperatures for solar
collectors: 180° to 250°F (82° to 121°C). It is also possible to
produce ice with a solar powered absorption device, which can be used for
cooling or refrigeration.
How
Does an Engine Driven Chiller Work?
Packaged
natural gas engine-driven water chillers and direct expansion (DX) units
are now available. Commercially proven custom and packaged engine-driven
refrigeration units offer excellent reliability and economic advantages
for ice rinks, refrigerated warehouses and other applications. The
industry is also focusing on developing small, engine-driven heating and
cooling systems suitable for small commercial applications.
Operation:
Engine-driven cooling systems employ a conventional vapor compression
cycle. Their main components are the compressor, condenser, expansion
valve and evaporator.
Advantages: The main difference between a natural gas and
conventional electric system is the replacement of the electric motor with
a gas engine. This change results in variable-speed operation capability;
higher part-load efficiency; efficient high-temperature waste-heat
recovery for water heating, process heating, or steam generation; and an
overall reduction in operating expenses.
* Requires no
more room than conventional electric chillers
* Lowest
operating cost of any available chiller
* Depending on
electric rates and natural gas rates, an engine driven chiller may operate
at up to 1/2 of the cost of direct-fired absorption chillers
*
Like absorption chillers, engine driven chillers reduce on-peak
electric demand charges.
* Depending on
your electric and/or natural gas supplier, there may be rebates available
for purchasing a new absorption chiller or engine driven chiller from your
utility supplier.
*
Environmentally friendly.
For
more information on absorption chillers, call
us at: 832-758-0027
www.AbsorptionChillers.comTM
* Some of the above information from the Department
of Energy website with permission.
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