Fort Hoosac Solar Hot Water

In late 2006, Williams installed a solar hot water system on Fort Hoosac, a dormitory that houses 13 graduate students from the History of Art Program. The system consists of evacuated tube solar collectors that absorb the sun’s energy and convert it to heat. That heat is then used to pre-heat cold water before it enters the building’s hot water boilers. At many times during the year they supply enough hot water to meet the needs of the buildings occupants. Even during the rest of the year, bringing the pre-heated water up to the proper temperature for use in the building requires less fuel than heating completely cold water. As a result, the solar hot water system saves fuel and reduces greenhouse gas emissions.

  • 1. Antifreeze circulates through the solar collectors and is heated by the sun. The collectors themselves don’t warm up very much; they very efficiently collect heat in the circulating fluid instead.
  • 2. The warm antifreeze from the solar collectors travels to the solar storage tank.
  • 3. A heat exchanger in the solar storage tank takes heat from the antifreeze circulating fluid and transfers it to the domestic hot water in the tank.
  • 4. The cooler antifreeze returns to the solar collector to be re-heated.
  • 5. Hot water from the solar storage tank is pumped to the back-up water heater. There are times when the solar collectors can’t provide enough hot water for the building (on cloudy days, for example), and in those cases, the back up water heater brings the water the rest of the way up to temperature. Even when they can’t provide all of the necessary heat, the solar collectors do provide part of the heat.
  • 6. If the water is not sufficiently hot when it reaches the back-up water heater, heat is transfered from the oil or natural gas fired boiler.
  • 7. Hot water is as needed to showers, sinks, and other household items that use it.