Every time I see a construction project being built, one that requires a large expanse of blacktop for a parking lot, I think of the possibility of using that space for geothermal heating and cooling.
The geothermal process makes use of the constant 50-60 degree temperature of the earth below 10 feet. By circulating water in pipes over an area, the temperature of the water can be utilized in the following manner. If the outside temperature is 90 degrees, the 50-60 degree-water can be used for cooling. The air conditioner must extract only 20 degrees from the water to reduce the temperature to 70 degrees. If the outside temperature is 20 degrees, the water can be sent to a heater which has to raise the temperature only 10-20 degrees to reach 70 degrees. The process works like a refrigerator, only on a much larger scale.