For more information:

www.geothermalconnecticut.org

Geothermal  Energy

CONNECTICUT

AGRICULTURAL GUIDE TO GEOTHERMAL IN CONNECTICUT

Contact UsCT FARM ENERGY PROGRAM

c/o CT RC&D 1066 Saybrook Rd. - PO Box 70

Haddam, CT 06438 amanda@ctfarmenergy.org

860.345.3977 x100 www.ctfarmenergy.org

THIS GUIDE IS A PROJECT OF:

through a REDA grant, CT Farm Energy Program(CFEP), a program of CT RC&D, seeks toimplement a two-year pilot project. CFEP will offereducation, outreach, workshops, and renewableenergy assessments specifically focused ongeothermal opportunities for farms and agriculturallybased rural small businesses in Connecticut. Thegoal of this project is to reduce barriers toalternative renewable energy resources byproviding eligible farms and businesses with a freegeothermal energy assessment and correspondingreport, with no obligation to implement.

With USDA Rural Development  support

Funding opportunities and technicalassistance are available. Contact CFEP

for more information.

An equal opportunity employer and providerPhoto Credit: Peter J. Tavino Jr.

www.igshpa.org/geothermal 

www.energizect.com/events-resources/energy-basics/geothermal www.epa.gov/rhc/geothermal-heating-and-cooling-technologies  www.energy.gov/energysaver/choosing-and-installing-geothermal-heat-pumps

There are several effective ways to moveheat in order to warm or cool a building.The diagram below illustrates theexchange process for both cooling andheating. The usual method in Connecticut is theclosed loop vertical borehole. These areabout 400' to 500' deep and 6" indiameter, like a commonly drilled waterwell. The same well drilling truck rigsperform the installation. Other methods are open-loop, where verypure abundant water is pumped into theheat pump from the well and returnedback down. In certain soil conditions, a 7' deephorizontal trench can be installed by anexcavator (track hoe). Sometimes therefrigerant is circulated underground.Pond loops are feasible, but not usual inConnecticut. Most loops installed have a 50 yearwarranty; however, loops are expected tolast up to 100 years.

Ground Loops

Connecticut is fortunate to have soilsand rock that are good for geothermalsystems. The ground is too cold to heatefficiently in Alaska, and warm ground isunnecessary in Florida, where heating isnot predominant. Connecticut’s bedrockhas high thermal conductivity, meaningthe heat moves rapidly. Heat pumps are either air-sourced orground-sourced or water-sourced to aboiler or cooling tower. A heat pumpuses less electricity if it is drawing heatfrom 50 degree ground temps instead ofthe 20 degree air temps for air-sourced.Ground-sourced heat pumps do not needpreheated water-source from fuelburning boilers. The many installedConnecticut geothermal heat pumpshave a great track record of performingwell, using little electricity because ofConnecticut’s great geological features.

A 400' deep borehole, sized for acertain building heat load would usean 800' long polyethylene U bendthat delivers the circulating waterdown to the bottom and back upagain at a different temperature.

Heat Pumps

Geothermal EnergyThe United States EnvironmentalProtection Agency promotes ground-source heating and cooling as arenewable technology. EPA notes that geothermal heat pumps: “take advantage of the naturallyoccurring difference between the aboveground air temperature and thesubsurface soil and bedrock temperatureto move heat…for space heating,cooling and water heating.” Agricultural and rural small businessowners can save operating costs byswitching from electric heat, fuel oil, orpropane to efficient geothermal heatingand cooling. In Connecticut, the deepearth temperature is approximately 50degrees Fahrenheit year-round. Moving a medium such as colder 40degree water into 50 degree soil or rockwarms the water to about 45 degrees.The 45 degree water then warmsrefrigerant in a heat pump that heats to120 degrees when compressed - to heatan entire building. This cools the waterback down to 40 degrees where it re-enters the earth to reach 45 degreeswarm again, in a constant cycle.

Image: Peter J. Tavino Jr.