Geothermal Technologies - Basic Operating Overview
Mankind eventually discovered that they could neither create nor destroy the energy God had created, but they could change the energy from one form to another. Scientists now refer to this discovered principle as the first law of thermodynamics. ETA systems utilize basic heat pump principals, with innovative, advanced, and patented designs that take advantage of stable geothermal temperatures to provide the most advanced heating and cooling systems known to exist. A heat pump is an electrically operated machine that provides heat by compressing a vapor and raising its temperature. Cooling is provided by expanding a vapor and lowering its temperature. ETA utilizes these principals along with the first law of thermodynamics to provide the most efficient HVAC technologies known to exist.
For example, if one compresses 1 cubic yard, or 1 cubic meter, of a vapor that is 55° F (13° C) into only 1 cubic inch, or centimeter, the pressure of the vapor is greatly increased, and so is the temperature. All of the heat energy that was formerly in a large area is condensed into a much smaller area, so the temperature is much higher. Conversely, if one expands 1 cubic inch, or 1 cubic centimeter of vapor that is 55° F into a much larger areas such as 1 cubic yard, or meter, the pressure of the vapor is greatly decreased, and so is the temperature. All of the heat energy that was formally in a small area is expanded into a much larger area, so the temperature is much lower. Thus, a heat pump can raise the temperature of a 55° F (13° C) vapor up to 150° F (66° C) by simply compressing the vapor via the use of a compressor. Likewise, a heat pump can lower the temperature of a 55° F (13° C) vapor down to 20° F (-7° C) by expanding the vapor through an expansion device.
Heat pumps operate utilizing these basic principles of vapor compression and expansion, together with the factual law of physics that heat flows to cold (Fourier’s Law of conduction heat transfer). For example, if you hold a cold cup of water in your hand, the “cold” feeling will begin to dissipate as the “warmth” of your hand travels into the cold cup of water (actually raising the temperature of the water). Your hand feels cold because heat is flowing out of your hand. If heat were flowing into your hand from a hot cup of coffee, your hand would feel hot. It is these basic principals that allow a typical and constant 55° F (13° C) temperature beneath the surface of the earth to be used to heat and cool the air within your home or business. Applying the Principals to ETA Geothermal Technologies
In the winter, an expanded and cold vapor refrigerant circulated within highly heat conductive copper tubing and absorbs the approximate 55° F (13° C) heat naturally supplied by the earth. This 55° F (13° C) heated refrigerant vapor is compressed, and the resulting now hot vapor is circulated within an air handler, where the cold return air from your house or business is also circulated by means of an electric fan. An air handler is simply a box within with finned tubing and a fan. The cold interior “return” air from your home or business is blown across the finned tubing by the electric fan. In the heating mode, the finned copper tubing is hot, containing the refrigerant vapor that has been compressed by the system’s vapor compressor. The heat from the hot vapor circulating within the finned tubing inside the air handler is naturally absorbed by the colder air. (Remember the principal that heat will always travel to cold). The now warmed air is blown into your home or business through “supply” air ductwork via the electric fan within the air handler.Thus, the heat supplied for your interior air is supplied by the natural and renewable temperature of the earth’s crust, for free. Your only expense is the cost to operate a compressor to raise the temperature of the free heat, and the cost to operate a fan to transfer the heat into your interior air.
In the cooling mode, the refrigerant vapor is circulated in a reverse direction, with the hot compressed vapor being sent in the earth, where the excess heat is naturally absorbed and taken away by the much cooler sub-surface temperature. For example, you may have a hot vapor with a temperature of 120° F (49° C) leaving the compressor unit and traveling into the underground copper ground source heat exchanger. This 120° F (49° C) is much hotter than the 55° F (13° C) ground. If we again apply the principal that heat will always travel to cold, we can understand that the ground will remove the heat and begin to cool down the hot refrigerant vapor. With the excess heat in the refrigerant vapor removed by the earth, the cooled refrigerant actually condenses into a liquid. The cooled liquid refrigerant is then expanded, by means of an expansion device, into a lower pressure, which causes the temperature of the refrigerant to drop even lower. The now cold refrigerant is next circulated through the finned tubing within the air handler. The cold refrigerant absorbs the excessive heat from your interior air, as the heat in your air naturally travels to the colder refrigerant. Your now cooled air is circulated back into your home or business. The refrigerant that has absorbed the excessive heat from you interior air now expands back into a vapor. The warmed vapor, having absorbed the exceed heat from your interior air, is compressed by the vapor compressor, and the temperature of the refrigerant vapor is greatly increased. This resulting hot vapor is sent into the ground where the excess heat is removed and the process is repeated. Again, your home/business is cooled via the simple expenditure of energy that is only necessary to operate a compressor and the fan in your air handler.
Air-Source Heat Pump
An air-source heat pump basically operates in the same manner. However, there are several problems.
With an ETA system, the ground actually works for you, tirelessly and without charge, to provide your heating and cooling needs. Your bills are extremely low because you only pay for the small amount of power necessary to operate a compressor and a fan.Further, since there is no open flame, as with fossil fuel-based systems, there is no flue venting requirement, there is not danger of explosion, there is not danger of carbon monoxide poisoning, and the air is not uncomfortably dried out. The ETA system is very safe, and is environmentally friendly. The fact that ETA systems have only two primary moving parts (a compressor and a fan) result in the systems requiring minimal service requirements. ETA believes it has the most efficient and most comfortable heating/cooling system in the world, bar none. This belief is supported via both detailed laboratory tests and independently certified in-field results.