What Is Geothermal Energy?
NAHB Green Verification
April 6, 2020
Energy Star – Save Money and Energy
April 6, 2020
BACORP Building Group, Inc has been designing and installing geo-exchange systems for 35 years. We have more systems installed than all our competitors that use these systems, combined. The technology relies primarily on the Earth’s natural thermal energy, a renewable resource, to heat or cool a structure.
The only additional energy geo-exchange systems require is the small amount of electricity they employ to concentrate the natural energy and then to circulate high-quality heating and cooling throughout the home.
Clients that have used geo-exchange systems give them superior ratings because of their ability to deliver comfortably warm air, even on the coldest winter days, and because of their extraordinarily low operating costs.
As an additional benefit, geo-exchange systems can provide inexpensive hot water, either to supplement or replace entirely the output of a conventional, domestic water heater. Geo-exchange heating and cooling is cost effective because it uses energy so efficiently.
This makes it very environmentally friendly, too. For these reasons, federal agencies like the Environmental Protection Agency and the Department of Energy, as well as state agencies endorse it. Contact us for more details.
Geo-exchange systems work on a different principle than an ordinary furnace/air conditioning system, and they require little maintenance or attention. Conventional heating systems must create heat by burning a fuel, typically natural gas, propane, or fuel oil. With geo-exchange systems, there’s no need to create heat, hence no need for chemical combustion.
Instead, the Earth’s natural heat is collected in winter through a series of pipes, called a loop, installed below the surface of the ground or submersed in a pond or lake. Fluid circulating in the loop carries this heat to the structure.
An indoor geo-exchange system then uses electrically-driven compressors and heat exchangers in a vapor compression cycle–the same principle employed in a refrigerator–to concentrate the Earth’s energy and release it inside the structure at a higher temperature. In typical systems, duct fans distribute the heat to various rooms.
In summer, the process is reversed in order to cool the home. Excess heat is drawn from the structure, expelled to the loop, and absorbed by the Earth. Geo-exchange systems provide cooling in the same way that a refrigerator keeps its contents cool, by drawing heat from the interior, not by injecting cold air.
Geo-exchange systems do the work that ordinarily requires two appliances, a furnace, and an air conditioner. They can be located indoors because there’s no need to exchange heat with the outdoor air. They’re so quiet that occupants don’t even realize they’re on. They are also compact.
Typically, they are installed in a basement or attic, and some are small enough to fit on a closet shelf. The indoor location also means the equipment is protected from mechanical breakdowns that could result from exposure to harsh weather.
Geo-exchange works differently than conventional heat pumps that use the outdoor air as their heat source or heat sink. Geo-exchange systems don’t have to work as hard (which means they use less energy) because they draw heat from a source whose temperature is moderate.The temperature of the ground or groundwater a few feet beneath the Earth’s surface remains relatively constant throughout the year, even though the outdoor air temperature may fluctuate greatly with the change of seasons. At a depth of approximately 6 feet, for example, the temperature of soil in most of the world’s regions remains stable between 45 F and 70 F. This is why well water drawn from below ground feels so cool even on the hottest summer days.
In winter, it’s much easier to capture heat from the soil at a moderate 50 F. than from the atmosphere when the air temperature is below zero. This is also why geo-exchange systems encounter no difficulty blowing comfortably warm air through a home’s ventilation system, even when the outdoor air temperature is extremely cold. Conversely, in summer, the relatively cool ground absorbs a home’s waste heat more readily than the warm outdoor air.
Studies show that approximately 70% of the energy used in a geo-exchange heating and cooling system is renewable energy from the ground. The remainder is clean, electrical energy which is employed to concentrate heat and transport it from one location to another.
In winter, the ground soaks up solar energy and provides a barrier to cold air. In summer, the ground heats up more slowly than the outside air.
Once installed, the loop in a geo-exchange system remains out of sight beneath the Earth’s surface while it works unobtrusively to tap the heating and cooling the Earth provides. The loop is made of a material that is extraordinarily durable but which allows heat to pass through efficiently.
This is important so it doesn’t retard the exchange of heat between the Earth and the fluid in the loop. Loop manufacturers typically use high-density polyethylene, a tough plastic. When installers connect sections of pipe, they heat-fuse the joints. This makes the connections stronger than the pipe itself.
Some loop manufacturers offer up to 50-year warranties. The fluid in the loop is water or an environmentally safe antifreeze solution that circulates through the pipes in a closed system.
