GEOTHERMAL energy can be your solution!
The geothermal energy is stored as heat below the surface of the earth (rocks, soil and groundwater).
- Low enthalpy geothermal energy: ground temperature between 77ºF (25°C) and 212ºF (100°C) from hot springs or volcanic areas. Direct heating and heat pump.
- Geothermal medium and high enthalpy: Underground at great depths to over 212ºF (100°C) or 302ºF (150°C) for electricity generation in binary cycle in large facilities or direct use.
This post will analyze only the energy of the shallow subsurface, harvested with electric geothermal heat pump to heat a rural building.
Uptake of geothermal energy
The energy is captured from underground or transfer by means of pipes buried in different positions and depths, which passes water with glycol.
- Uptake vertical. – Holes from 50m to 200m with high temperature stability.
- Uptake horizontal. – Near to shallow (pe 1.5m), more economical but not for cooling.
- Uptake of lakes or rivers.- Exchange energy with water instead of soil.
In three cases, the gycol water circuit of the geothermal sensors exchanged energy with the heat exchangers of the heat pump.
How does a heat pump work?
First you must understand that a heat pump works like a refrigerator or circuit of an air conditioner. It is a circuit with a refrigerant fluid (eg freon), which changes from liquid to gaseous state as a function of pressure and temperature.
- Compressor. - A simple electric pump compresses the gas refrigerant. As a consequence, it is heated and the pressure increases (similar effect of inflating a tire).
- Condensation. - The hot refrigerant is condensed, passing to liquid state, and can transfer this heat to a heating circuit with a liquid exchanger.
- Expansion valve. - When a liquid under great pressure is allowed to expand suddenly, it cools very quickly and turns into gas (similar to the effect of opening the valve of a tire).
- Evaporation. - In this part of the circuit, the refrigerant is turning again into gas at very low temperatures. To get back to the compressor to restart the cycle.
Geothermal heat pump in HEATING mode.
- Circuit of the heat pump with a refrigerant passing from liquid to gas, with one part cold and one hot, and liquid / liquid exchangers .
- Circuit of the geothermal sensors where brine is heated (or cooled) progressively according to the temperature of the subsoil.
- Circuits of heating and cooling the building with individual exchangers in the heat pump.
In winter, the heat stored in the basement and taken up by geothermal probes, is transferred to the cold zone of the evaporator of the heat pump, which in turn will transfer to the heat zone (condensation). The second heat exchanger to the heating circuit will absorb some of this heat to heat the building, preferably with underfloor heating.
Geothermal heat pump in COOLING mode.
In summer it is to extract heat pump to transfer heat into the ground, so you get much more efficiency in obtaining cold air for air conditioning of buildings.
Any system of refrigeration (refrigerator, air conditioning) cools based on extracting heat. In summer, when hot outside, the underground, comparatively cold, can absorb excess of heat.
You need electricity, so it is not advisable in isolated rural buildings that have produced their own electricity.
But if you have electric line, geothermal heat pumps are extremely efficient since consumption of 1 kW compression pump, can provide the equivalent of 4 to 6 times the energy as heat or cold, due to temperature differences subsoil with respect to the outside. With the advantage of heating and cooling in one system and 365 days / 24h.
Did you know the geothermal heat pump? Do you see suitable for your rural home? Your opinions interest us.