Geothermal Systems Questions and Answers Pennsylvania Geothermal Heating Systems

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GeoThermal Energy - Geothermal Heat Pumps
Common Question and Answers

1. What is a geothermal heat pump?

A geothermal heat pump is an electrically-powered device that uses the
natural heat storage ability of the earth and/or the earth's groundwater
to heat and cool your home or business.

2.How does it work?

Like any type of heat pump, it simply moves heat energy from one place to another. Your refrigerator works using the same scientific principle. By using the refrigeration process, geothermal heat pumps remove heat energy stored in the earth and/or the earth's groundwater and transfer it to the home.

3.How is heat transferred between the earth and home?

The earth has the ability to absorb and store heat energy. To use that stored energy, heat is extracted from the earth through a liquid medium (groundwater or an anti-freeze solution) and is pumped to the heat pump or heat exchanger. The heat removed from the earth is then used to heat your home. In the summer, the process is reversed and the indoor heat is extracted from your home and transferred to the earth through the liquid.

4.You mentioned heating and cooling. Does it do both?

One of the things that makes a heat pump so versatile is its ability to be a heating and cooling system in one. You can change from one mode to another with a simple flick of a switch on your indoor thermostat. In the cooling mode, a geothermal heat pump takes the heat from the indoors and transfers it to the cooler earth through either a groundwater or an underground closed loop system.

5.Do I need separate ground loops for heating and cooling?

NO. The same loop works for both heating and cooling. All that happens between modes, is a reversal in the energy or heat flow.

6.What types of loops are available?

There are two main types of systems: open and closed systems.

7.Does the underground pipe system really work?

The buried pipe, or "ground loop", is the most recent technical advancement in heat pump technology. The idea to bury pipe in the ground to gather heat energy began in the 1940s. But it's only been in the last few years that new heat pump designs and improved pipe material have been combined to make geothermal heat pumps the most efficient heating and cooling systems available.

8.How much groundwater does an open-loop system need?

A geothermal heat pump using an open-loop system needs a different amount of water depending on the size of the unit and the manufacturer's specifications. The water requirement of a specific model is usually expressed in gallons per minute and is listed in the specifications for that unit. Your heating contractor should be able to provide this information. Generally, the average system will use 6 to 10 gpm while operating.

This selection process should include a discussion with a licensed well driller and geologist to determine if sufficient groundwater resources are available for your project need. In addition, open loop systems may require both a pumping well and a recharge/discharge well. The production well could be your domestic water well, but it is critical that the well capacity, pump size, piping, and plumbing are enlarged to handle the additional flow.

9. What problems can be caused by poor water quality?

Poor water quality can cause serious problems in open-loop systems. Your water should be tested for pH, hardness, total dissolved solids,
alkalinity, iron, manganese, conductivity, saturation index and other parameters depending on your location.

Mineral deposits can build-up inside the heat pump's heat exchanger. Sometimes a periodic cleaning with a mild acid solution is all that's needed to remove the mineral scale.

Impurities, such as: iron and manganese, can eventually clog a return well. If your water has a high iron or manganese content you should be sure that the discharge water is not excessively aerated before it's injected into a return well. In some cases, the water needs to be pretreated.

Finally, you should not consider using water from a spring, pond, river, or lake as the source for your heat pump system. If this option is selected, it would be advisable to evaluate the changes in the water quality and install a purification system to remove particles and organic material. If particles, organic material, and microbiological agents are not removed, they could clog a heat pump, decrease efficiency, and make the system inoperable in a shortened period of time.

10.Does an open-loop system cause environmental damage?

NO ! They are pollution free. The heat pump merely removes heat from or adds heat to the water. No pollutants are added whatsoever. The only change in the water returned to the environment is a slight increase or decrease in the temperature.

11.Are there any laws that apply to open loop installations?

In some localities, all or parts of the installation may be subject to local ordinances, codes, covenants, or licensing requirements. Check with your local authorities to determine if any restrictions apply in your area and be sure to hirer a professional.