Heat Pump Project

Heat Pump Project

MGE installed a closed-loop Ground Source Heat Pump (GSHP) system to meet the heating and air-conditioning needs of the Lussier Community Education Center. The center is a multifunctional facility providing developmental programs for children and youth and helping to meet member needs on the west side of Madison.

The GSHP system is expected to reduce annual energy costs. MGE included a monitoring system to provide data to help verify if actual performance reflects the equipment manufacturer values and demonstrates lower energy use.

Our findings

Findings from monitoring data gathered for Summer 2012 and Winter 2012-2013 indicate the operation of a GSHP system will cost less than an equivalent HVAC system, however, the savings will not yield an economic payback in a reasonable time period if the installation cost of the bore field is included in the calculation. See our Lussier Geothermal Heat Pump System [217 kB PDF] fact sheet for more details and our analysis.

How the system works

Geothermal heat pumps use the earth's natural heat to assist with the heating and cooling of buildings.

  • A series of U-shaped pipes will be buried in 20 holes about 300 feet deep to reach a constant ground temperature of about 50 degrees.
  • Fluid (water with a small amount of environmentally friendly polypropylene glycol) circulates through the pipes and carries the heating or cooling to a series of heat pumps.
  • The heat pumps amplify the heating and cooling effect and release it inside the building.

Winter heating mode

Winter heating mode

Summer cooling mode

Cost

For a geothermal heat pump to reach its maximum performance, a building must be energy efficient. The Lussier Center was built to exceed state energy codes—with high-performance windows, insulation and other features.

The geothermal system costs about 20% more to install than conventional commercial heating and cooling units.

Project engineering consultation

  • Sustainable Engineering Group LLC (for the geothermal heat pumps)
  • KJWW Engineering Consultants (for the HVAC engineering)

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