A History of Geothermal Heat Pump and Its Development

The first forms of geothermal heating started back in the first century A.D. when the Romans conquered Aquae Sulis and used the hot springs there to feed public baths and under floor heating. In 1852, Lord Kelvin had already invented the heat pump. But the idea of drawing heat from the ground was not patented until 1912, by a man named Heinrich Zoelly. Still the geothermal heat pump was not successfully implemented until the late 1940âlis.

Geothermal heating and cooling takes advantage of warmth stored in the earth ground. The earth ground temperature in around 55 degrees F. (13 degrees C.) at the depth of around ten feet. A geothermal heat pump uses many different systems of transferring heat into the ground. For example: standing column well, closed loop, vertical, horizontal, pond system, open loop, and also direct exchange systems. Most all of them are done by recirculation of fluids mostly water or water and antifreeze solutions. A standing column well system is a special type of open loop system. It works by drawing water from the bottom of a deep rock well running it through the heat pump then returning it to the top of the well. Then as the water travels downwards it transfers heat into the bedrock or draws heat from it. But the bad thing about this system is it cannot be used where the geology is mostly clay, silt, or sand. Closed loop systems contain two loops. One loop is contained in the appliance cabinet where it exchanges heat with the second loop that comes in from outside where it is buried. After leaving the exchanger, the second loop carries the water out to exchange the heat into the ground or pull heat from it.

A vertical system is a closed loop that runs pipes vertically to transfer heat. They run a pair of pipes in a bored hole between 75 to 500 feet deep. They fill the borehole with a bentonite grout to help the transfer of heat to the soil or rock. A horizontal system is also a closed loop system that the pipes run horizontally about 3.3 to 6.6 feet under the ground to exchange heat. A pond system is also a closed loop. It consists of coils of pipe attached to a frame and is located at the bottom of a pond. It uses the pond water to transfer heat. Open loop systems known as groundwater heat pumps pump natural water from a well or body of water to transfer heat. All these systems exchanges heat via forced air distribution or by the use of radiant floor systems for heating or cooling of a business or home. But direct exchange (the oldest type of geothermal) works by a single loop circulating refrigerant to transfer the heat instead of re-circulating water or water antifreeze solutions.

Geothermal heating and cooling systems are the most energy-efficient, environmentally safe and cost-effective space conditioning systems available. E.P.A has found out that geothermal can reduce energy consumption by over 40% compared to 70% from electric resistance heating. In addition, geothermal systems produce zero emissions making them green approved. You can also use the system to heat water in which could save the user money in the long run by saving on fuel or electric on a hot water heater.

In my research, I have found that geothermal might cost more based on where you live and what type of system you use but in the long run will save you money. Geothermal systems are safer for the environment than traditional systems that use fuel or electric. So why would you settle for 90% when you can have 500% to 600% with geothermal heating and cooling.