Earth Energy

Geothermal Energy
In most cases, communities take advantage of naturally occurring geysers, hot springs, and steam vents (called fumaroles) to gather hot water and steam for heating. Geysers and fumaroles occur when ground water seeps through cracks and comes in contact with volcanically heated rocks. In Iceland for instance, wells are drilled into volcanic rocks to extract hot water and steam. The hot water or steam is carried to communities in insulated pipes and used to heat homes and businesses.

In some cases, the water is superheated (heated under pressure to temperatures greater than 100o C). Superheated water quickly turns to high-pressure steam, which can turn high-speed turbines that drive electrical generators. Geothermal power plants are in use in the US, Philippines, Iceland, Japan and elsewhere. New Brunswick is not close to active geological areas, but new geothermal technologies may allow this energy source to be used here in the future.

Ground Source Heat Pumps
The temperature of the soil below about 2 meters remains constant regardless of the weather or season. In most places throughout southern Canada, soil temperatures at this depth hover between 5 and 10o C. The difference between air and deep soil temperatures can be used for heating and cooling in a very efficient manner, with a ground source heat pump, also called a geothermal heat pump.

A ground source heat pump works the same way as a refrigerator. The heat pump uses a compressor, lengths of sealed tubing for gathering and dispersing heat (heat exchangers), and a gas called the refrigerant. The compressor motor, located inside the house, circulates refrigerant around the network of tubes. Heat from the surrounding soil warms the liquid refrigerant in the buried tubes, changing it to a gas. The refrigerant gas enters the compressor, which squeezes it, raising its pressure and temperature. The hot refrigerant circulates through radiators inside the house, releasing the heat collected from the soil to the inside of the house. This process changes the refrigerant back into a liquid and the process starts again.

By reversing the flow of the refrigerant, the heat pump system can cool the house in summertime. Heat collected from inside the house can be released back into the cool soil, resulting in a highly efficient air conditioning system for the home. A ground source heat pump requires some electricity to run the compressor. In an efficient, well-insulated home, this electricity could be easily supplied by a rooftop solar panel. An efficient ground source heat pump will create 3 units of hot/cool for each unit of electricity used to run it, making this a very effective energy source.