Thanks to some financial assistance from Eugene Water & Electric Board, Southtowne Shoppes is now heated and cooled with a ground-coupled heat pump system, the most efficient mechanical system available.

According to EWEB Energy Management Engineer Brian Hawley, the new system will cut energy use by over 50 percent.

“We’ve looked at total facility energy use both before and after the upgrades,” says Hawley. “The energy use has been cut from over 2,500 kilowatt hours (kWh) to less than 1,250 kWh per day. In a single day, the savings are enough to provide the energy for a typical residence for a whole month.”

Most heat pumps blow outside air across a coil to extract or reject heat, but Southtowne Shoppes will use the earth for heat exchange. The ground-coupled heat exchanger uses water circulated in a closed loop with over 10,000 feet of buried pipe in the ground. The buried pipe is arranged in 20 holes, with each hole about 300 feet deep and spaced about 12 feet apart.

A few feet below the surface, the earth maintains a constant temperature of about 55 degrees. The circulated water exchanges energy with the earth, approaching ground temperature before it returns to the heat pumps.

“The stable loop temperature provides a better heat source in the winter and a better heat sink in the summer,” says Hawley. “It’s also easier to extract heat from relatively warm earth than cold winter air, and it’s easier to reject heat to relatively cool earth than hot summer air.”
In addition to efficient water source heat pumps, programmable electronic controls in each business space optimize energy efficiency while maintaining comfort.

A few of the major benefits of the ground-coupled heat pump system are energy efficiency, flexible zoning for comfort, easy maintenance and longer equipment life. To top it off, the new heating and cooling system at Southtowne Shoppes is also one of the most environmentally friendly systems available.