refrigeration_cycle[1]A thin tube loops back and forth inside and outside of your refrigerator. This tube is connected to a pump, which is powered by an electric motor and carries refrigerant inside the tube. The refrigerant starts out as a liquid.  The pump pushes the liquid through a lot of coils inside the freezer area. There the chemical turns to a vapor. So when the gas expands it becomes very cold and the principle of “HOT TRAVELS TO COLD” happens. The coils soak up some of the heat that is inside the freezer thus the refrigerator becomes colder.  The pump then forces the refrigerant through thinner pipes which are on the outside of the refrigerator. By compressing it, the refrigerant now turns back into a liquid. A fan will blow over the coils to help release the heat to the air outside of the refrigerator.  Once the refrigerant passes through the outside coils, the liquid is ready to go back through the refrigerator and repeat the process over and over again.  So basically, you are not putting cold air into the refrigerator, you are removing the hot air out of the refrigerator.


Now let’s look at how the refrigeration process is used in a geothermal heat pump.

How Does a Geothermal Heat Pump Work?

Looking at how a refrigerator works helps explain how a conventional, or air source heat pump works. An air conditioner works like a refrigerator, except that it extracts  heat from the air inside your house and transfers it to the air outside. A  conventional heat pump has a reversing capability, so in the winter it  reverses. It takes the heat from outside and delivers it inside the house. It sounds strange to think that we can gather heat from frigid winter air, but  remember the rule…”HOT TRAVELS TO COLD” so if the refrigerant is colder than the outside air, it will work. If however, the outside air gets extremely cold, then supplemental electric heating elements, or heat strips, will activate, similar to a toaster, to heat the house.

The cool thing about geothermal heat pumps is that they don’t depend on the temperature of the outdoor air as the heat exchanger. They use the relatively stable temperature of the earth as the transfer source. The greater the temperature difference between two areas, the easier and more efficient the heat transfer process.  So your yard can be compared to a rechargeable solar battery.

Think about it, in the summer when you are trying to remove heat from the  house, it may be 80 to 100 degrees outside whereas the earth in Georgia will probably be between 50 to 70 degrees. Remember the rule “HOT TRAVELS TO COLD“. This difference in temperature makes it much easier to transfer the heat from the house to the earth, than to the outside air.  Then again in the winter, when the outdoor temperature is 20 to 30 degrees, the earth will still probably be between 45 to 65 degrees making it easier to gather heat for the house.