Heating and Cooling from the Earth’s Engine
Mar 29, 2015 01:24AM
● By Brian Oram
When people think of renewable energy, their first thought is typically solar power or wind energy. As snowbirds return to their cooler climates, one natural and reliable renewable energy system is a geothermal or a ground-source heating and cooling system. These systems come with a variety of configurations, and a single system can heat or cool a home without natural gas, coal, oil or biomass. However, some electric power is required to run the system. This relatively obscure technology is robust, proven and available now to those willing to understand the simple beauty of these systems.
A geothermal system moves and stores energy rather than producing energy through combustion or resistance. Geothermal systems work by exchanging hot or cold air from the home with the stable stored energy in the ground, rather than by converting chemical energy to heat. This is a renewable energy system that is very efficient and has enough flexibility to fit a variety of applications. Some added benefits in addition to efficiency are that geothermal energy creates no pollution to our air or water and, other than electricity, they eliminate the need to purchase highly processed petrochemical fuel from less than environmentally conscious producers.
While the air temperature in northern climates can vary from season to season, the Earth’s temperature a few feet under the surface is essentially the same in winter and summer. In the winter, the system can heat a home using the Earth’s relatively warm core energy. In the summer, the same system can cool the home with the Earth’s relatively cool mass. Year-round, geothermal systems can produce hot water.
Geothermal heat pumps have an efficiency of over 300 to 500 percent (meaning they get a payback of three to five times the energy used to run the system). This efficiency provides the heating/cooling needs at a cost that is 30 to 70 percent less expensive than conventional energy systems, without combustion, carbon dioxide, methane, water pollution or the waste generated by other energy systems.
Geothermal ground-source heating and cooling systems work during the night, when the sun is blocked by clouds and when the wind is not blowing. While electricity costs may vary, geothermal costs don’t fluctuate like natural firewood, gas, coal and heating oil. The ground-source system comes in a variety of configurations to easily fit new home construction or homes with a more conventional, existing duct-based heating and cooling system.
The geothermal system has three main components: connection to the Earth, delivery and distribution system and a geothermal heat pump. The Earth connection allows the system to pull or store heat in the Earth. In heating mode, the system uses the Earth connection to pull a small quantity of heat from the Earth to heat a person’s space. In cooling mode, the system does the reverse and transfers heat from the air back to the Earth. The distribution system can be a series of vertical connections or loops buried in the ground that transfer and help to distribute the energy.
The geothermal heat pump is very efficient energy transfer system that moves the energy from the building to the transfer fluid. The system does require an electrical source to run the heat pumps and circulation system, and it is critical that an existing home have a formal energy audit done prior to installing a system.
New construction should use green building and energy efficient insulating systems so the system can be properly sized.
Users can benefit from lower energy costs, elimination of water and air pollution and a significant reduction of the expensive and environmentally destructive infrastructure of fossil fuels by adapting geothermal systems as soon as possible.
Brian Oram is a Professional Geologist and owner of B. F. Environmental Consultants Inc.