Most people use the energy that has been generated from fossil fuels (oil, natural gas, coal or uranium). Since beginning of the energy crisis, these fossil fuels are becoming more expensive.
The only way to alleviate the energy crisis is, on one hand, to conserve energy and, on the other hand, to use the energy that is not generated from fossil fuels. And that is the real purpose of using renewable energy.
Renewable energy is all around us and is free of charge (except biomass). The energy generated from geothermal sources, from the sun or wind can replace the use of primary energy generated from fossil fuels.
Geothermal heat pump works by taking heat from the earth to provide the useful energy for heating homes and provide hot water. Geothermal heat pumps offer excellent energy saving up to 75% of heating energy that can be extracted from the earth. Electricity is used to operate the compressor and the circulation of fluid that exchanges heat.
Closed loop pipes are placed in the ground and filled with glycol antifreeze fluid. The fluid is heated with heat from the ground to about 10-12°C. Then the fluid is transferred to a heat pump where the heat is handed to another medium. Heat pump, with the help of its compressor provides hot water for the heating system.
Geothermal energy is best used for under floor heating, which requires low temperature water for heating the house.
Electricity consumption of heat pump water/water, which includes geothermal heat pump depends on several factors.
- Capacity heat pump (heating and air cooling) which depends on the thermal properties of the heated / cooled building (house),
- Depths of geothermal probes and soil characteristics, especially soil moisture,
- Internal heating installations, temperature regime in which the heating system works
Geothermal heat pumps are the most expensive form of investment in heat pumps and therefore most often used for buildings with heat losses below 50W/m2 heated object which is achieved by insulating the house (walls min 10cm insulation, roof, windows ...).
Quality and reliability greatly depends on the manufacturer of geothermal heat pumps, but we can say that this is a clean and efficient renewable energy source.
An alternative to the earth-to-air heat exchanger is the water to earth heat exchanger. This is typically similar to geothermal heat pump tubing embedded horizontally in the soil to a similar depth of the earth-air heat exchanger. It uses approximately double the length of pipe of 35 mm diameter, e.g., around 80 m compared to an EAHX of 40 m. A heat exchanger coil is placed before the air inlet of the heat recovery ventilator. Typically a brine liquid (heavily salted water) is used as the heat exchanger fluid.
Many European installations are now using this setup due to the ease of installation. No fall or drainage point is required and it is safe because of the reduced risk from mold.
Even though the installation price of a geothermal system can be several times that of an air-source system of the same heating and cooling capacity, the additional costs are returned to you in energy savings in 5 to 10 years. However, it may start paying for itself immediately. If the cost of your geothermal heat pump is rolled into the mortgage for new house construction, the extra $30 a month on your mortgage payment will be offset by the greater savings on your heating and cooling bills. System life is estimated at 25 years for the inside components and 50+ years for the ground loop. While most of the energy improvement tax credits expired at the end of 2012, geothermal tax credits of 30% are still in play. There hasn’t been a better time to invest in a geothermal system. There are approximately 50,000 geothermal heat pumps installed in the United States each year.