How Refrigerators and Heat Pumps Work

We would like to include a basic explanation of how heat pumps (especially in refrigerators) work, and then relate it to the earth. Although not exhibits, the following websites have fairly simple explanations that can be useful:

http://www.energyquest.ca.gov/how_it_works/refrigerator.html

http://www.geojerry.com/heatmovesfromcoolertowarmer.html

We would use a similar diagram to the one in the first link, except that we would relate to inside of the fridge to the inside of your house, while mentioning that a geothermal system is more versatile, allowing cooling AND heating.