A Ground Loop is used as a heat sink. Two ground loop trenches are buried under different ends of the driveway. Each trench has three separate tubes, coupled to buried corrugated galvanized steel for heat transfer. Heat is exhanged with the house either via heat exchangers, or a water-to-water heat pump.

HEAT EXCAHNGE

High-efficiency light cooling during warm days is achieved by running the ground loop pump, and using a heat exchanger to cool water in the household heating/cooling system. No refrigeration cycle is used in this heat exchange, so cooling is obtained at the cost of running teh water pumps (perhaps 150 watts).

 HEAT PUMPING

Low-grade heat (e.g. 95F for floor heating) is efficiently produced during the fall and mild winter, when the heat pump's coefficient of performance is higher than 5. For every kWh of electricity used, over 5 kWh of usable heat is produced. Because the ground loop uses water, the temperature of the heat pump cold output cannot go below the freezing point (0 C).

Cooling is achieved during hot periods of the summer by running the heat pump as a chiller. Because the ground loop is water in pipes to the irrigation system, nightly irrigation will cool the ground loop making it more cooler for the next day. Plants will be irrigated with slightly warm water.

Heat Pump Plumbing