how do engineers use the earth's heat to create geothermal energy?
they use geotheral plants to power it up and by this power plant they can easily direct steam to turbine and then the pressure will move the turbine. This is how we generate steam
Steam pushes a turbine attached to a generator.
The use the earth's heat to heat water which creates steam. This steam spins a turbine, and this turbine is connected to a generator which produces electricity.
Here in New Zealand we have two geothermal power stations operating.
a ground source heat pump is a classic example of using geothermal energy. In heating mode, the external fluid is pumped from the well at 8-16 degrees Celsius and passes through the heat exchange unit. Within the heat exchanger, the refrigerant expands and changes from liquid into gas. This absorbs heat (latent heat of vaporization) from the external fluid, thereby cooling the external fluid. Meanwhile the refrigerant is pumped to the compressor where it is pressurized thereby becoming superheated. This 'hot gas' releases the heat and warms the air of the house. At the same time, the refrigerant gas loses heat to the air and changes back to a liquid. The external loop again provides the heat necessary to change the refrigerant back into a gas thereby cooling the external fluid. The external fluid absorbs heat from the soil and the process is repeated. Note the external fluid only changes temperature while the internal refrigerant changes both temperature and phase. There are some residential heat pumps that use refrigerant in the external loop. The cooling cycle is very similar except a valve on the internal refrigerant loop reverses the direction of flow. Now the compressed refrigerant coming from the compressor heats the external fluid, before passing through the evaporator where it vaporizes taking up heat from the air in the house. The heated external fluid is pumped into the ground where it is cooled and recirculated. Alternatively, the superheated refrigerant may pass through a second heat exchanger allowing the water heater to absorb the waste heat. This means that in summer, the heat pump provides air conditioning and the hot water. The heat is being pumped from the air in the house to the water in the water heater.
