skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Saddle Hill Trust Lot 77, Medway, Massachusetts. Solar energy system performance evaluation, September 1979-August 1980

Technical Report ·
DOI:https://doi.org/10.2172/6658867· OSTI ID:6658867

The Saddle Hill Trust Lot 77 site is a single-family residence in Medway, Massachusetts that uses solar energy to preheat incoming city water. The solar energy system consists of an array of four Solaron DHW series 2000 flat-plate collectors having a total area of 78 square feet. The array faces south at a tilt of 38 degrees to the horizontal. Air is the medium used to transfer heat from the collectors to an air-to-liquid heat exchanger in the DHW subsystem. Solar energy is retained in a 120-gallon DHW preheat tank. Preheated city water is then supplied to a conventional gas-fired (auxiliary energy) 40-gallon DHW tank. The Saddle Hill Trust Lot 77 solar energy system supplied 38% of the DHW heating needs during the period from September 1979 through August 1980. There were 10.28 million BTU of energy collected by the system and 5.29 million BTU or 51% of this energy was used to help satisfy the DHW load. The collector array efficiency (based on the total solar radiation incident on the collector array) was 28%. The use of solar energy saved 8639 cubic feet of natural gas. The solar energy system functioned consistently throughout the reporting period, providing significant amounts of solar energy to the DHW subsystem. The measured system solar fraction of 38% was close to the 43% design solar fraction for the system. However, the net dollar savings for the year were minimal, as the cost of the electrical energy needed to operate the system was almost as great as the cost of the fossil fuel saved.

Research Organization:
Automation Industries, Inc., Silver Spring, MD (USA). Vitro Labs. Div.
DOE Contract Number:
AC01-79CS30027
OSTI ID:
6658867
Report Number(s):
SOLAR/1040-80/14
Country of Publication:
United States
Language:
English