Solar energy to heat water for Southwestern fraternity house
When alumni of Phi Delta Theta fraternity return for homecoming this year, they are going to notice something very different about their former fraternity house.
An 8x10 solar collector is being placed on the roof as part of a new system that will enable the house to use solar energy to heat some of its water. The system is being installed by Jeff Bendall, a member of the fraternity who graduated in 2000 and now works for a solar energy company in Austin.
Bendall is a member of the Phi Delta House Corp., which is responsible for maintaining the fraternity house. Phi Delta Theta is one of two fraternities at Southwestern that maintain their own houses.
Bendall said the fraternity began discussing the solar thermal project last spring when one of the two hot water heaters in the house failed. Bendall is solar thermal project manager for Lighthouse Solar Austin, a locally owned arm of a company based in Boulder, Colo., that is called Lighthouse Solar. He said the solar thermal systems his company installs cost about $6,500 and should last 15 years. He estimates that the system will pay for itself in 12 years.
The new system has three components. The most obvious, of course, is the solar collector that was placed on the roof of the building facing south. This collector consists of 30 glass evacuator tubes that have a narrow copper tube running inside them. Heat will accumulate in these tubes and gather at the top end. The top end of each tube sticks into another tube running across the top of the collector. There, the tubes will heat a special fluid that is a combination of distilled water and propylene glycol.
This heated liquid will flow down to a solar storage tank, which was placed in an upstairs closet. Heat exchange coils in this tank will pre-heat hot water, which is delivered to the 120-gallon hot water heater.
Bendall estimates that the system should reduce the amount of energy required to heat water by 70 percent a year − 100 percent in the summer and 50 percent in the winter. The fraternity may be eligible for a federal tax credit to offset some of the cost of purchasing the system. A small pump is needed to circulate the water-based fluid, but Bendall said it uses a minimal amount of electricity.
The system also has an electrical back-up system in case there are extended periods without sun or there is simply more demand for hot water than the solar system can provide.
Bendall said the system should be fairly easy to maintain and not require any more maintenance than a regular hot water heater.
While members of the fraternity who live in the house are simply glad to have hot water again, they are also excited about the solar project.
“It’s been a great opportunity to work with some of our alumni,” said Nick Cox, a junior chemistry major who serves as house manager for the fraternity. Cox helped Bendall install the new system.
If the system works out, Cox said the fraternity may consider a similar system for their other hot water heater when it needs to be replaced.