Environmental Education Institute Applies Its Own Expertise to Efficient Heating

• By Scott Aronowitz
• 10/15/09

The Chewonki Foundation, a non-profit institution in Wiscasset, ME, offering numerous educational programs focusing on the environment and the natural world, has applied its own knowledge to heating its largest facility, the Center for Environmental Education, using a geothermal heating unit (GHU).

The subsurface ground temperature throughout Maine is approximately 50 degrees F at all times, explained Tom Twist, sustainability educator for Chewonki. The GHU can warm the building's above-ground floors using the geothermal energy, or "earth heat," collected from a deepwater well.

"The geothermal system we installed is expected to be energy efficient," Twist said. "In fact, we've projected the system will function at one-third the cost of a traditional oil-heat system, and can be expected to pay for itself in 3-5 years."

Preferring not to leave it to chance, however, Chewonki has installed a HOBO U30-ETH Web-based energy logging system from data logger manufacturer Onset. Chewonki installed the system with funding from a grant from the Maine Public Utilities Commission (MPUC) in an effort to determine whether geothermal heating is a viable alternative to energy derived from fossil fuels, such as traditional heating oil.

Onset described the technical operation of the data logging system as follows:

The data logging unit, which measures, records and transmits system performance data to the Web, is configured with a number of sensors. Two flow meters are connected to the well pump, which measure BTUs the system is producing and flow rates. A kilowatt sensor measures the electric draw of all the system pumps, including a number of tiny circulating pumps and the larger heat pump itself. Temperature probes measure air temperatures inside and outside of the building, and well temperatures coming in and going out.

"The Web display of the data is a benefit to us for a number of reasons," explained Twist, who said that, not being a programmer, he doubts he could create an accessible yet compelling display. "Having it published by Onset using their secure and dedicated server makes it easy for us to see what we need to see. Second, it makes the data widely accessible, which is great for our students who can log in and see firsthand how the system is performing."

The foundation expects to have applicable data to present to the MPUC by spring 2010, though Twist said he expects to know by this fall whether the GHU is shrinking Chewonki's carbon footprint.