Term geothermal heating refers to the direct use of heat stored in the Earth's core to heat our homes, offices, or for any other heating application. The popularity of geothermal heating systems continues to grow though on global scale it still accounts for only around 0.07% of global primary energy consumption.
Geothermal heating systems have lot more pros than cons but let me first explain the working principle of geothermal heating system. Geothermal heating systems use geothermal heat pumps to force the transfer of heat from the ground to the desired heating application. Each geothermal heat pump is equipped with an outdoor unit called condenser and an indoor unit that's called an evaporator coil. In order for heat to be successfully transferred we also need refrigerant, usually in form of highly pressured liquid. This refrigerant circulates underground, absorbs heat from the ground, and on its return, the now warmer fluid passes through the heat pump which uses electricity to extract the heat from the fluid, and the re-chilled fluid is sent back through the ground to continue this cycle. This extracted heat is then used to heat our homes and offices.
Pros of geothermal heating:
Energy conservation. Geothermal heating systems use 25% to 50% less electricity than conventional heating systems.
Geothermal heating has virtually no environmental impact, and is totally environmentally friendly
Low maintenance costs after installations.
Geothermal heating systems add extra value to your property.
Excellent option in humid conditions because they maintain around 50% relative indoor humidity.
Geothermal heating systems are ideal to use for under floor heating which is very popular these days.
Geothermal heating systems operate very silently which is not always the case with conventional heating systems.
Geothermal heating systems have significantly better efficiency compared to geothermal electricity generation because it doesn't require high temperatures like geothermal electricity generation does.
Geothermal heat pumps operate on almost the same working principle as the conventional heat pumps. The only real difference is that geothermal heat pumps extract heat from the earth's core instead from outdoor air like this is the case with conventional heat pumps.
Cons of geothermal heating:
High installation costs (sometimes several times that of a conventional air-source system of the same heating capacity).
Relatively complicated installation procedure.