Geothermal Heating & Cooling
Did you know that you can heat and cool your home or business with dirt? Yep, dirt.
A geothermal heating and cooling system takes advantage of the Earth’s ability to store a vast amount of heat in the soil. This heat energy is maintained at a constant temperature in the soil and near-surface rocks. In New York, the soil maintains a temperature of 52°F beginning approximately five feet down. In the summer, the ground beneath us is cooler than the outside air. In the winter, the ground is warmer than the outside air. During the geothermal process no heat is created, it is simply transported to or from the ground. Most importantly, no fossil fuel is burned.
Geothermal heating systems “capture” this steady supply of heat energy and use it throughout your home or building. Once installed, your home or building will use much less energy, which can save money each month and reduce pollution produced by fossil fuel systems.
There are two pieces to the geothermal unit: the heat pump and the ground loop. The heat pump is the indoor unit and the ground loops are the underground pipes. During the winter the ground loop circulates water, absorbs the heat, and then sends it to the heat pump, which is then heats your home. During the summer, the heat pump reverses. It pulls heat out of your home and transports the heat into the ground, consequently cooling your home.
Horizontal Ground Loop
This type of loop is usually the most cost effective when trenches are easy to dig and the size of the yard is adequate. Polyethylene pipes are inserted, and the trenches are backfilled. A typical home requires 1/4 to 3/4 of an acre for the trenches.
Vertical Ground Loop
This type of loop is used where space is limited. Vertical holes are bored 150 to 450 feet deep, much like wells. A single loop of pipe with a U-bend at the bottom is inserted before the hole is backfilled. A typical home requires 3 to 5 bores with approximately 15ft of separation between the holes.
Pond Closed Loops
This type of loop design may be the most economical when a home is near water, such as a shallow pond or lake. In the loop, fluid circulates through polyethylene piping in a closed system, just as it does through ground loops. A 1/2-acre, 8-foot deep pond is sufficient for an average home.
Geothermal Heat Pumps
Water to Air Heat PumpThis heat pump outputs forced air, and are most commonly used to replace legacy forced-air furnaces and central air conditioning systems. There are variations that allow for split systems, high-velocity systems, and ductless systems.
Water to Water Heat Pump
This heat pump is for hydronic systems that use water to carry heating or cooling through the building. Systems such as radiant under-floor heating, baseboard radiators, and conventional cast iron radiators would use a liquid-to-water heat pump.
Combination Heat Pump
This heat pump can produce forced-air and circulating water simultaneously and individually. These systems are largely being used for houses that have a combination of air and liquid conditioning needs, such as central air-conditioning and a heated pool.
How safe are GSHPs?
GSHP systems are safe and protected. With no exposed equipment outdoors, children or pets cannot injure themselves or damage exterior units. GSHPs have no open flame, flammable fuel or potentially dangerous fuel storage tanks.
How much does a GSHP cost?
The initial investment for a GSHP system is greater than that of a conventional system. However, when you consider the operating costs of a geothermal heating, cooling, and water heating system, energy savings can quickly offset the initial difference in purchase price. For a ballpark estimate use the geothermal calculator.
How will I save money with a GSHP?
GSHPs can save money, both in operating costs and maintenance costs. Investments can be recouped in as little as three years. There is a positive cash flow, since the energy savings usually exceed payment on the system.
How long will my GSHP system last?
GSHPs are durable and highly reliable. The GSHP contains fewer mechanical components, and all components are either buried in the ground or located inside the home. The underground pipe carries up to a 50-year warranty.
Can one system provide both space heating and cooling for my home? What about heating hot water?
Yes. A GSHP (ground source heat pump), can be a combination heating/cooling and hot water heating system. You can change from one mode to another with a simple flick on your indoor thermostat. Some GSHPs can save you up to 50% on your water-heating bill by preheating tank water.
Can these systems be used for commercial, industrial, or apartment requirements?
Yes! Many GSHP systems are being installed using a multitude of systems hooked up to an array of buried vertical or horizontal loops. This simplifies zone control and internal load balancing.
Is it advisable to install a GSHP system large enough to handle my total heating needs?
GSHP systems are generally sized to meet all your cooling needs. Depending on heating needs, a GSHP system usually supplies 80-100 percent of your designed heating load. Sizing the system to handle your entire heating needs may result in slightly lower heating costs, but the savings may not offset the added total of the larger system. Special consideration should be given to systems in the north where multiple capacity units should be considered to handle the large variation between heating and cooling loads. Your dealer/installer should provide a heating and cooling load calculation to guide your equipment selection.
How does a ground source heat pump (GHSP) system heat water for my home?
Using what is called a desuperheater, GSHPs turn waste heat to the task of heating hot water. During the summer, when the system is in cooling mode, your hot water is produced as a byproduct of the thermal process. In winter, when the system is in heating mode, the desuperheater heats a portion of your water. Desuperheaters are standard on some units, optional on others. Stand-alone systems to heat water all year around can be purchased.
How much space does a GSHP unit require?
Most of a GSHP installation is underground. Inside the house, the heat pump units are about the same size as a traditional heating and cooling unit.
How noisy is the GSHP unit?
GSHPs are very quiet, providing a pleasant environment inside and outside the home. GSHPs have no noisy fan units to disturb outdoor activities.
What about comfort?
A GSHP system moves warm air (90-105°F) throughout your home or business via standard ductwork. An even comfort level is created because the warm air is moved in slightly higher volumes and saturates the building with warmth more evenly. This helps even out hot or colds spots and eliminates the cold air blasts common with fossil fuel furnaces.
How effective is this underground system?
The buried pipe, or ground loop, is the most recent technical advancement in heat pump technology. Recently, new heat pump designs and improved buried pipe materials have been combined to make GSHP systems the most efficient heating and cooling systems available.
Are GSHP systems guaranteed?
Nearly all GSHP system manufacturers offer a warranty for major components that is equivalent to the warranties for conventional heating and cooling systems. Manufacturers of plastic pipe used for ground loops warrant their products for 50 years.
What are the advantages to an HVAC dealer?
GSHP systems create a huge retrofit market not subject to wild fluctuations in housing construction. There is also ample opportunity for stable growth benefiting the dealer and employees. In addition, these systems are relatively maintenance-free, requiring only regular filter changes. This means fewer maintenance and support calls. There is no outside equipment, so wear and tear is less.
What other costs are there besides the GSHP system?
You can expect an installation charge for any electrical work, ductwork, water hook-up, and other provisions or adaptations to your home that are required. Your installer can estimate these costs in advance.
How would increased use of GSHP systems affect electricity cost and availability?
The reduced peak load requirements would allow utilities to serve more customers and to lower fixed costs per customer, thus offsetting some increased variable costs. This would result in less cost per kilowatt, since fixed investment for new capacity is high.
Are GSHP systems difficult to install?
Most units are easy to install, especially when they are replacing another forced-air system. This is known as a retrofit. GSHPs can be installed in areas unsuitable for fossil fuel furnaces because there is no combustion and thus no need to vent exhaust fumes. Ductwork must be installed in homes without an existing air distribution system. Your dealer or installer can assess the cost of installing ductwork.
Can I install a ground source heat exchanger myself?
It’s not recommended. Thermal fusion of the pipe, drilling and trenching are procedures best handled by licensed professionals. Nonprofessional installations may result in less than optimum performance, which could cancel out anticipated savings
How long does it take to install a horizontal system?
This depends on soil conditions, length and depth of pipe, and equipment required. A typical installation can be completed in one or two days.
How long does it take to install a vertical system?
With the vertical installation, time varies with conditions on the site such as type and depth of the overburden, type and hardness of the bedrock, and the presence of aquifers. Typical drilling times are one or two days; total installation can usually be accomplished in two days.
How do GSHPs protect the environment?
GSHP systems conserve natural resources by providing climate control very efficiently-thus also lowering emissions. GSHPs also minimize ozone layer destruction by using factory-sealed refrigeration systems, which will seldom or never have to be recharged.
What are the environmental benefits of GSHP systems?
Currently installed systems are making a huge difference in our environment! The systems are eliminating more than three million tons of carbon dioxide and is equivalent of taking 650,000 automobiles off the road. GSHP systems conserve energy and, because they move heat that already exists rather than burning something to create heat, they reduce the amount of toxic emissions in the atmosphere. They use renewable energy from the sun, and, because the system doesn’t rely on outside air, it keeps the air inside of buildings cleaner and free from pollens, outdoor pollutants, mold spores, and other allergens.
Does this mean that in extremely cold climates additional heat sources are necessary?
Systems come with an auxiliary heater built in. Geothermal Heat pumps can provide all the heat necessary even in the coldest weather, however you want to be sure your system is sized correctly. If it is undersized, the auxiliary heater (using electricity) will run too much and cause higher electric bills. An economic analysis by your contractor should dictate what portion of the heat should be provided by the heat pump and what portion by auxiliary means.
Will my existing ductwork function with this system?
Yes, in most cases. Capital Heat will be able to determine ductwork requirements and if any minor modifications are needed.
Will an underground loop affect my lawn or landscape?
No. Research has shown that loops have no adverse effects on grass, trees, or shrubs. Most horizontal installations require trenches about six inches wide. Temporary bare areas can be restored with grass seed or sod. Vertical loops require little space and do not damage lawns significantly.
My yard contains many shade trees. Will this affect ground temperature and my ability to use it as an energy source?
Not at all. The system is installed deep enough that it utilizes constant ground temperature.
Will I have to add insulation to my home if I install one of these systems?
Ground source heat pump systems will reduce your heating and cooling costs regardless of how well your home is insulated. However, insulating and weatherizing are key factors in gaining maximum savings from any type of heating and cooling system.
Reproduced from The International Ground Source Heat Pump Associations Frequently Asked Questions section. Permission pending.
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