Posted on: Saturday, September 1, 2001

Army solar project to reap big savings

By Jan TenBruggencate
Advertiser Science Writer

The Army will save $250,000 annually in electrical costs for water heating under a massive new solar water heating project that is a joint venture with Hawaiian Electric Co.

The utility says it is the nation's largest project involving the installation of solar water heating units.

The project will place 650 solar water heating units on the roofs of Helemano military housing units and on buildings at the Wai'anae Recreational Center.

Solar water heaters generally consist of a serpentine array of piping in a black box behind a glass surface. During the day, the sun heats the rooftop box and the water inside the pipes. The water is stored in an insulated water tank like the ones normally used in electric and gas water heating installations.

Properly sized units can generally meet all water heating requirements for families, except during extended periods of cloudy weather or periods of high use, such as when house guests add to the number of showers and laundry loads.

The overall project is expected to cost about $1.9 million, but Hawaiian Electric rebates will reduce the cost to the Army to about $1.7 million. Two models of solar water heaters will be used, one from Inter Island Solar Supply and the other from R&R Services.

Hawaiian Electric account manager Steve Luckett said construction is expected to begin soon and may be completed by the end of the year.

Water heating is usually the largest single cost item in an electric bill. The savings after installation of the units, which cost between $3,000 and $3,500 apiece before rebates, should pay for the entire project within about seven years.

The solar heating systems have life expectancies of 10 to 25 years, Hawaiian Electric said.