Frequently Asked Questions

Back to Contents

Geothermal Heat Pumps

What is a heat pump?

A heat pump is a refrigeration circuit that is used to move heat from one location to another. A heat source (air, water or earth) is used to evaporate the refrigerant, a compressor concentrates and moves it to another location and releases it. It’s like an air conditioner that can run in reverse to cool in summer and heat in winter.

What is a Geothermal Heat Pump (GHP)?

It’s a heat pump that uses the constant and favorable temperature of the earth as its heat source/heat sink. Up to 75% of the heat it delivers to the building is renewable energy; therefore the cost of operation is greatly reduced.

Do they deliver the same or greater comfort as a furnace or an air source heat pump?

Greater comfort . . . absolutely. Their heat source is warmer that ambient air in the winter and cooler than ambient air in summer. Because of the warmth of the earth, EarthLinked systems deliver greater warmth in the winter, without sudden blasts of heat like a furnace. In the summer, their longer run cycles and cooler evaporator coils deliver cooler air with greater dehumidification…thus greater comfort.

Can one system provide space heating and cooling for my home and water heating?

Yes. A GHP can deliver space heating/cooling and hot water heating. You can change from one mode to another with a simple flick of the indoor thermostat. Using a desuperheater on the air conditioning cycle, some GHPs can save up to 50% on your water-heating bill by preheating water.

How does a GHP system heat water for my home?

Using a desuperheater, GHPs use waste heat to heat hot water. During the summer, when the system is in the cooling mode, water heating is a free byproduct of the cooling process. In winter, the desuperheater heats a portion of your hot water. Desuperheaters are standard on some units, optional on others.

How much space does a GHP unit require?

The majority of any GHP system is underground. Inside the building, the heat pump unit is much smaller than traditional heating and cooling units. The EarthLinked system is one-half the size of a water based unit because it does not require a water circulating pump and an intermediate heat exchanger. It is one-half the size of an air-source heat pump because it does not have an outside fan coil.

How long will a GHP system last?

GHPs are durable and highly reliable. All components are either buried in the ground or can be located inside the home, which protects them from weather and temperature extremes. The industry considers the useful life of a GHP to be 20 years. Because of its fewer mechanical components, the EarthLinked system can reasonably be expected to exceed that.

How noisy is the GHP unit?

GHPs are very quiet and unobtrusive. They provide a pleasant environment inside and outside of the home. GHPs have no noisy outside fan units.

How safe are GHPs?

GHP systems are fully enclosed, safe and protected. They have no exposed equipment outdoors. GHPs have no flame, flammable fuel, noxious emissions or fuel storage tanks.

Can these systems be used for commercial, industrial, or apartment requirements?

Yes! Many GHP systems are installed using multiple systems. This simplifies zone control and internal thermal load balancing.

What are the advantages to an HVAC dealer?

GHP systems open access to a huge retrofit upgrade market not subject to wide fluctuations in the housing construction market. This creates an opportunity for stable growth. The systems are relatively maintenance-free, requiring only periodic filter changes. This means fewer maintenance and service calls. There is no need for exposed outside equipment, so wear and tear is less.

What types of geothermal heat pumps are available?

There are essentially two types:
Water based geothermal heat pump units, which include:
1) Open loop units that pump water from the earth or a pond, exchange heat and then dump the water.
2) Closed loop units that circulate a water and antifreeze mixture in a closed plastic loop, extract heat from the earth, exchange that heat into the refrigerant circuit through a heat exchanger, then distribute the heat using the refrigeration circuit.

Direct geoexchange systems, including the EarthLinked® brand, that directly exchange heat with the earth by placing the refrigerant circuit in direct contact with its heat source for heating and its heat sink for cooling.

Which type of technology can save the most operating cost?

Because the EarthLinked direct method does not consume energy to circulate water; does not have an intermediate heat exchanger from water to the refrigerant; exchanges heat through copper refrigeration tubing; and it uses proprietary EarthLinked refrigerant flow controls, it has proved to be 25% more efficient in field tests.

Which technology is the least obtrusive to install?

Because the direct method has a higher heat differential with the earth and higher efficiency, it uses approximately on-half the length and one-half the diameter bore hole as the closed loop water based unit; and the earth loops can be installed diagonally, so the footprint at the surface is very small and less drilling is needed.

What sets EarthLinked® systems apart from other GHPs?

EarthLinked’s proprietary modulating refrigerant flow controls add efficiency gains and earth loop options that are not possible with other systems. Utility field tests have shown EarthLinked to be up to 25% more efficient than water based units.

Is one type of GHP better suited to one type of building?

Yes. Because of their size and thermal capacity, EarthLinked systems are best suited for 1) heating and cooling residential and small commercial buildings, and 2) large hot water heating users including commercial and institutional applications. Because of their size and thermal capacity, water based units are better suited to large spaces.

Can the system be used to heat water?

Yes. The EarthLinked water heating options include desuperheating (providing "free" hot water in the cooling mode) and integrated "on-demand" for year-round domestic hot water. The unit can also provide hot water for radiant in-floor heating and swimming pools.

Is the EarthLinked system AHRI certified?

Yes. The EarthLinked system is rated according to AHRI (the Air Conditioning, Heating and Refrigeration Institute) Standard 870 for Direct GeoExchange Heat Pumps. The average heating COP is 3.9, with a cooling mode EER of 17. The system is ETL safety listed and qualified under the EPA EnergyStar® program standards.

Are the EarthLinked units that are sold in Europe different from those sold in the U.S.?

Yes. The compressors are suitable for 50 Hertz electrical supply and are compatible with Refrigerant R-407C. A larger percentage of the systems sold in Europe are for heating-only because of a cooler climate.

Back to Contents