Ground Source Heat Pumps Harness Earth Energy
May 7, 2008
Today’s tip is about ground source heat pumps, also known as geothermal heat pumps, which, when incorporated into the design of a new building, can trim a facility’s energy bill compared to buildings heated and cooled with traditional systems.
Ground source heat pumps harness the energy of the Earth – geothermal heat – to provide cheap, efficient cooling in the summer and heating in the winter. Because their initial expense is significantly greater than traditional HVAC, they have a payback period from 5 to 12 years, in most cases. But they can save as much as 60 percent on energy costs compared with a traditional HVAC system and the payback period shortens as energy costs continue to rise.
The most critical factor in determining whether a geothermal heat pump system is cost effective is the load. If there is a good balance between heating and cooling, the systems can operate cost effectively. A more cooling-dominated building can see even greater energy-cost savings.
There is two general categories of ground source heat pumps: Open loop and closed loop. Open loop systems are less common, usually deriving their energy from ground water sources. Closed loop systems are comprised of a continuous loop of vertical or horizontal pipes placed in the ground with a liquid circulating through them. In vertical closed-loop systems, holes of 300 feet or more are drilled into the earth.
Because geothermal heat pumps use renewable energy, some utilities or third-party organizations may offer incentives or rebates to help defray the higher first cost of the systems.
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