Geothermal Heat Pumps

Below 10 meters from the Earth the temperature remains nearly constant between 50° and 60°F (10°-16°C). Like the cave, this ground is warmer than the air above it during the winter and cooler air in summer.

Geothermal heat pumps harness this energy from beneath the earth and take advantage of this resource for heating and cooling of buildings.

Geothermal Heat pumps (sometimes referred to as Geoexchange, water source heat pumps), have been in use since 1940’s. Geothermal Heat pumps use the heat below the earth’s crust to heat homes and offices during winter rather, than the outdoor air temperature.

As a result, the system can achieve a relatively high yield (300%-600%) during the coldest winter nights, compared with 175%-250% for air-source heat pump to cool days.

During winter, the heat below the earth is used as the medium to heat homes, as heat is removed from the heat exchanger by the heat pump system and it is pumped into the indoor air delivery system.

During summer, the process is reversed as heat pump moves heat into the heat exchanger from the indoor air. Heat extracted by the heat pump can also be used to heat water, providing a source of hot water during summer.

In U.S., many areas experience varying temperature ranging from 45°C during summers to Sub-zero cold in winter. Few meters below the surface soil remains relatively constant temperature.

The ground temperature which normally maintains at 45°F(7°C) to 75°F(21°C) is warmer than the air above it during the winter and cooler air in summer.

The three main power plant designs which use geothermal as an energy source are: “dry steam”, “flash steam”, and “binary-cycle” power stations.

How Do Geothermal Heat pumps Work?

Geothermal heat pump doesn’t create heat by burning fuel. Instead, the collection of the world’s natural heat is extracted through a series of number of pipes during winter, called loops, installed below the surface of the ground.

The fluid circulates through the loop and transfer heat to the house. Electrically driven compressor and heat exchanger concentrate the Earth’s energy and release it at high temperature inside the home. Channels distribute the heat in different rooms.

In summer, the entire process works in opposite direction. Underground loop draws excess heat from the house and allows it to be absorbed by the Earth.

It cools your homes in the same way as a refrigerator keeps your food cool – drawing heat from the inside, but not blowing cold air.

Traditional heat pumps use more energy than the geothermal heat pumps which draw their energy from below the ground.

Geothermal heat pumps not only save energy and money but also help in reducing air pollution. They are also more efficient in cooling of the house.

Geothermal Disadvantages

1. The cost of installing the geothermal system can be costly though the additional costs are returned to energy savings during the years 5-10.

2. The area needed to set up pipes can be quite large and may not be suitable for smaller developments.

Learn more about the advantages and disadvantages of geothermal energy.

Life of the system is about 25 years and 50 + years of internal elements of earth loop. Approximately 40,000 installed geothermal heat pumps in the United States each year.

References:

http://en.wikipedia.org/wiki/Geothermal_heat_pump 

http://www.consumerenergycenter.org/home/heating_cooling/geothermal.html 

http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12640

Rinkesh

Rinkesh is passionate about clean and green energy. He is running this site since 2009 and writes on various environmental and renewable energy related topics. He lives a green lifestyle and is often looking for ways to improve the environment around him.