Scanning for ideas: Solar help for home water heaters

Dec. 13, 2007
This closed-loop antifreeze-filled system from Butler Sun Solutions, Solana Beach, Calif. (butlersunsolutions.com), should supply half the hot-water needs of a family of four living in southwestern states or about 1,700 kW-hr annually.

It includes 40 sq ft of collectors and a solar-wand heat exchanger for about $2,500.

The solar wand is a double-walled copper-in-brass in-tank heat exchanger with about 2 sq ft of heat-transfer area. Inside of it, copper tubing runs side by side the brass outer tube, but plastic standoffs limit tube-to-tube contact. Tubes are also insulated with closed cell foam insulation from a collector-to-hot-water-tank umbilical, which also includes all electrical and fluid connections.

The system can be controlled with a conventional 115-Vac differential temperature controller or a photovoltaic-powered 12-Vdc pump. The working fluid is propylene glycol, a common antifreeze liquid.

Sponsored Recommendations

June 27, 2025
Ensure workplace safety and compliance with our comprehensive Lockout/Tagout (LOTO) Safety Training course. Learn critical procedures to prevent serious injuries.
June 27, 2025
Join our expert webinar to discover essential safety control measures and best practices for engineering a truly safe and compliant industrial environment.
June 25, 2025
An innovative aircraft with electric drives combines the best of both worlds. The cross between drone and helicopter could mean significantly faster and more efficient air emergency...
June 25, 2025
Effective when other materials fail, ceramics are particularly suitable for applications requiring wear and chemical resistance, sliding characteristics or biocompatibility. Discover...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!