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Geothermal Heat Pump Types

Posted by Taylor Hendricksen on Jan 16, 2012 in Design | 0 comments

Geothermal Heat Pump

There are basically 4 different types of geothermal heat pumps on the market today.

They all have different methods of connecting to heating distribution in your home or building. Some types are more efficient than others at delivering the heat to the room, but that is a property of the distribution system, not the heat pump.

All of these heat pump types still get their energy the same way. The energy from the ground loop is still transferred into the internal refrigerant loop, but what happens to it after that is what makes the difference.

The four different types of geothermal heat pumps are water to air, water to water, combo and split units.

Water to Air Geothermal Heat Pump

The first and probably most common geothermal heat pump is the water to air heat pump. This heat pump is used for houses with forced air systems, and basically replaces a furnace. The ground loop brings in the energy to the refrigerant loop (the water portion of “water to air”). That refrigerant then is compressed and cycled in front of a fan coil unit to be sent through duct work distribution to the house (the air portion of “water to air”).

One possible design issue is the sizing of the ductwork. Because geothermal heat pumps are considered a low temp heat source, a higher volume of air movement is needed to deliver the same amount of heat to the space. This will either require larger ductwork to accommodate for the increased air volume, or a specialized, small duct high velocity system like Unico.

Water to Water Geothermal Heat Pump

The second type of geothermal heat pump out there is a water to water heat pump, or hydronic. This type functions the same as the water to air on the ground loop side of the refrigerant, but instead of sending the compressed and heated refrigerant to a fan coil, it is transferred directly into another water supply that circulates through the heat pump, and into the hydronic distribution. This hydronic distribution is most commonly radiant heat, but it can also be used in conjunction with domestic hot water or a snow melt system.

Combo Geothermal Heat Pump

The third type of geothermal heat pump is a combo unit. This combines the previous two heat pumps, providing both forced air and hydronic distribution. This is perfect in homes or buildings where both types of distribution are needed. Some zones may be very high heat loss, such as rooms with big windows, or near an exit door that is constantly open, and will require more heat in the space than just radiant or just forced air could provide. This is where a combo unit delivering both could come in very handy.

Split Geothermal Heat Pump

The last type of geothermal heat pump on the market is known as a split heat pump. This type is basically the same as a regular heat pump on the water side, but it sends the refrigerant in a long loop to a remote air handler. This makes it easier in larger jobs to keep the heat pump in the mechanical room with all the loop field connections, and still have an air handler delivering heat to a hard to reach place, such as the second story of a large house. This allows for greater flexibility in the overall design of the heating distribution system.