Geothermal energy is a very cost-effective alternative technology for heating and cooling buildings. Not to be confused with hot rocks, geysers, or steam from deep under the Earth's surface which can be harnessed for electricity generation, it is also known widely as "GeoExchange" in some industry circles. GeoExchange takes advantage of heat from the Sun that is absorbed by the Earth. A few feet below the surface, the Earth is at a near-constant temperature (50 - 55 degrees). Using water as a transfer medium, it is pumped from a well or loop buried under the surface and then passed through heat pumps which use refrigeration technology (think of your refridgerator or A/C), to provide either heating or cooling to the building. The water is then returned to the well or loop. The only fuel used in geothermal heating and cooling is the electricity for the pumps, but it is much more efficient. For every Kwh of electricity used, 4 to 6 Kwh of heating or cooling energy is delivered to the building.
GeoExchange is particularly well-suited to the municipal building environment, because the additional capital investment required over a conventional system is compensated for by significantly lower operating costs. In general, municipal buildings are intended to be long-lived, facilitating consideration of up-front investments. More importantly, the most intense pressure on municipal finance is in the operating budgets. Many municipalities find it easier to secure taxpayer support for capital investments because they seem more like investments than spending and because tax increases to pay for them have a finite life. On the other side, the steeply increasing price of energy has squeezed operating budgets ever tighter, so an investment which offsets and reduces a rapidly growing operating expense is very attractive.
- Geothermal Notes - notes made while researching Geothermal systems for heating and cooling buildings. They have not (yet?) been organized for presentation or general use, but everyone is welcome to the information here.
- Homeowner Workshops - Water Energy Design/Distributors are the regional experts on geothermal. Their primary business is as a distributor of products used in geothermal systems, but the principals are widely acknowledged as go-to experts. The company hosts free monthly workshops for homeowners, contractors and others interested in geothermal.
- Newbridge on the Charles - This Continuing Care Retirement Community is now being built on Route 135 just across Route 128 in Dedham. The heating and cooling for the 1 million square feet of buildings will be provided by geothermal energy. Over 400 wells will make Newbridge the largest geothermal installations in the region.
- Newbridge on the Charles (with its headquarters offices in Needham) was one of two Needham award winners at the June Green Business Expo sponsored by the Newton Needham Chamber of Commerce. Green Needham participated in the Chamber subcommittee that put on the expo and was also an exhibitor at the event.
- Noble & Greenough School installs geothermal system - Boston Globe, September, 2007
- Hastings School - White Paper describing the first successful geothermal installation in a school at Hastings School in Westborough in 1997. Interestingly, this was not an installation during construction, but a retrofit.
-  - Wikipedia Article on Ground Source Heat Pumps that describes the different methods and benefits of GeoExchange (or geothermal) systems.
-  - CNBC Video Interview about geothermal Heat Pumps with Climatemaster's Dan Ellis.