Geo Thermal Heat Pumps

City of Wyandotte, Mich., creates a geothermal utility

WYANDOTTE, MICH. — The principle behind geothermal heating and cooling is a simple one: dig down toward the bedrock almost anywhere in the world and you reach a stable temperature zone that is somewhere between 52°F and 55°F year-round. By using water circulated in a deep enough ground well as an energy transfer medium, you get the ∆T between well temperature and surface temperature — cooling power on hot days, heating power on cold ones — practically for free.

The plan, made possible in part through a $560,000 Neighborhood Stabilization Grant from the federal government, is an ambitious one. The project has identified 48 installations in the planning phase, and work has been either started or completed on 10. Included in the plan are 25 new residential installations, 19 retrofit installations, three commercial installations and one new 20-unit multi-family development.

The city hired private contractors to drill ground source wells in utility easements and connect several homes to each well. Tentative plans call for the municipal services to cover the $8,000 cost for each well and charge home and building owners a monthly service fee and energy charge based on the capacity of the system installed. On the other side of the equation, homeowners can qualify for a 30% tax credit on the cost of purchasing and installing a geothermal system through 2016.

The job of installing those systems went to Jeff Caplan’s firm, Cappy Heating & Air Conditioning , based in Livonia, Mich. Caplan, the owner and president, has been in the trades for nearly 30 years and sees geothermal work as a natural outgrowth of his regular HVAC service. Cappy Heating & A/C is accredited by the International Ground Source Heat Pump Association (IGSHPA). The company has about 32 employees, with a service area covering most of southeast Michigan.

“The geothermal utility puts in the field portion, the drilling and the pipe,” Caplan said. “We pick it up from the geothermal utility stop box — it’s like a water box that’s out in the front yard — and pipe it into the home. And from there we supply and install the ground-source heat pump, then do all the sheet metal ductwork. We design and build all of that.”

Caplan decided to use the Envision series ground source heat pump from WaterFurnace . The appliance is available in seven single-speed sizes and five dual-capacity sizes to meet the needs of almost any application. It uses ozone-safe R-410A refrigerant, and features microprocessor controls. Correctly installed and maintained, it can deliver energy savings as high as 70% compared to more conventional heating and cooling systems, and can even supplement the domestic hot water supply.

EnLink Geoenergy: A Case for Geothermal Heat Pumps' Contribution ...

Much confusion surrounds how geothermal heating and cooling differs from geothermal electricity generation. Both forms have the capacity to reduce reliance on non-renewable, carbon-emitting energy sources by using thermal energy created and stored within the earth. Geothermal heat pumps (GHPs), which make use of underground pipes filled with water that exchanges temperatures, tout extreme efficiency and actually reduce the amount of electricity needed to maintain atmospheric comfort levels in a building. Considering current electricity prices, Oak Ridge National Lab estimates that the widespread use of ground source heat pumps would represent savings between $33 and $38 billion in retail utility bills within the United States, which exceeds current renewable energy contributions from solar photovoltaic, wind and geothermal power combined. By transferring a combination of stored solar energy and geothermal energy that is manifested as a constant temperature just below the earth’s surface, GHPs reduce energy consumption and correlated air pollution emissions up to 44% compared to air-source heat pumps and up to 72% compared to electric resistance heating with standard air-conditioning equipment. With 400% operating efficiencies in mind, it is hard to deny that GHPs are a sensible and ecologically advanced alternative to traditional HVAC methods. Combined with a desuperheater, GHPs can also serve as a water heater that does not require additional energy to operate, and—unlike natural gas furnaces—the magic that contributes to GHPs’ reduced electricity reliance is replenished daily. Essentially, geothermal heat pumps bypass the need to produce power by using a natural means to heat and cool. Oddly enough, though, GHPs are overlooked by many states’ Renewable Portfolio Standards (RPS), which are put into effect to increase renewable energy production. Only eight out of 32 states that require or recommend that utilities produce energy from renewable sources and/or promote efficient technologies list geothermal heat pumps as qualifying devices. Some would argue that the reason for this is because GHPs do not generate power, yet most RPSs only address renewable energy—not renewable power or renewable electricity. Heat is energy, and heat in the earth’s crust is renewable. Ergo, the heat that we are transferring to and from the earth is indeed renewable energy.

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