Large commercial buildings and schools often use vertical systems because the land area required for horizontal loops would be prohibitive. They are used in residential areas where the area of available land is not great enough, or in some cases where the vegetation covers too much of the open land. Vertical loops are also used where the soil is too shallow for trenching, and they minimize the disturbance to existing landscaping.
To install a vertical closed-loop system, a series of geothermal borings are drilled. The drillers then insert two lines of plastic pipe into each boring (fused together with a u-bend at the bottom). The plastic pipes are connected together at the top, filled with the mixture, and the pipe configuration is brought into the house where they are connected to a heat pump (furnace/air conditioner).
The principle of the system is simple: The potable antifreeze and water mixture is continuously circulated through the loop by a low wattage circulatory pump. In the winter, the earth’s energy is collected by the mixture in the piping and taken to the house, where it is absorbed by the heat pump’s gaseous refrigerant and converted to usable warm air for heating purposes. In the summer, the process is reversed. The warm air in the house is collected and then transferred back into the ground. This excess heat energy may also be used to preheat water for your water heater.