Geothermal Heating & Cooling Systems, News and Info
Heat Pumps - Fundamentals
Heat naturally flows “downhill”, from higher to lower temperatures. A heat pump is a machine which causes the heat to flow in a direction opposite to its natural tendency or “uphill” in terms of temperature. Because work must be done (energy consumed) to accomplish this, the name heat “pump” is used to describe the device.
In reality, a heat pump is nothing more than a refrigeration unit. Any refrigeration device (window air conditioner, refrigerator, freezer, etc.) moves heat from a space (to keep it cool) and discharges that heat at higher temperatures. The only difference between a heat pump and a refrigeration unit is the desired effect--cooling for the refrigeration unit and heating for the heat pump. A second distinguishing factor of many heat pumps is that they are reversible and can provide either heating or cooling to the space.
One of the most important characteristics of heat pumps, particularly in the context of home heating/cooling, is that the efficiency of the unit and the energy required to operate it are directly related to the temperatures between which it operates. In heat pump terminology, the difference between the temperature where the heat is absorbed (the “source”) and the temperature where the heat is delivered (the “sink”) is called the “lift.” The larger the lift, the greater the power input required by the heat pump. This is important because it forms the basis for the efficiency advantage of the geothermal heat pumps over air-source heat pumps. An air-source heat pump, must remove heat from cold outside air in the winter and deliver heat to hot outside air in the summer. In contrast, the GHP retrieves heat from relatively warm soil (or groundwater) in the winter and delivers heat to the same relatively cool soil (or groundwater) in the summer.
As a result, geothermal heat pump, regardless of the season is always pumping the heat over a shorter temperature distance than the air-source heat pump. This leads to higher efficiency and lower energy use.
Benefits of Geothermal Heat Pump Systems
The biggest benefit of GHPs is that they use 25%–50% less electricity than conventional heating or cooling systems. This translates into a GHP using one unit of electricity to move three units of heat from the earth. According to the EPA, geothermal heat pumps can reduce energy consumption—and corresponding emissions—up to 44% compared to air-source heat pumps and up to 72% compared to electric resistance heating with standard air-conditioning equipment. GHPs also improve humidity control by maintaining about 50% relative indoor humidity, making GHPs very effective in humid areas.
Geothermal heat pump systems allow for design flexibility and can be installed in both new and retrofit situations. Because the hardware requires less space than that needed by conventional HVAC systems, the equipment rooms can be greatly scaled down in size, freeing space for productive use. GHP systems also provide excellent “zone” space conditioning, allowing different parts of your home to be heated or cooled to different temperatures.
Because GHP systems have relatively few moving parts, and because those parts are sheltered inside a building, they are durable and highly reliable. The underground piping often carries warranties of 25–50 years, and the heat pumps often last 20 years or more. Since they usually have no outdoor compressors, GHPs are not susceptible to vandalism. On the other hand, the components in the living space are easily accessible, which increases the convenience factor and helps ensure that the upkeep is done on a timely basis.
Because they have no outside condensing units like air conditioners, there’s no concern about noise outside the home. A two-speed GHP system is so quiet inside a house that users do not know it is operating: there are no tell-tale blasts of cold or hot air.
DIRTCHEAP
Geothermal Heating & Cooling Systems, News and Info
phone: 763.389.0376
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Massmann Geothermal & Mechanical, LLC
www.MassmannGeothermal.com