Solar water heating improvements

Solar water was hot in the 1980s, but due to the inefficient performance of some of those early systems, it faded into relative obscurity. People didn’t want to deal with scalding water on hot days and cold showers at night. Today water heating accounts for 17 percent of the average home’s energy use, so it’s an easy target for savings. The mainstream water-heating conversation became tank versus tankless. Fortunately, engineers continued to work on solar technology. Today, solar hot water systems are quite different from those initial, unreliable systems.

“Net-zero” house in Seattle

In May 2018, the Genesee Park net-zero home made a splash as the first net-zero house in the Seattle area. The Dwell Development design-build project boasted many envelope-pushing energy-efficiency features. Among more obvious strategies, the home included a custom solar hot water generating system by Silk Road Environmental, a solar thermal solutions company based in Washington state.

The big difference in today’s solar water heating systems

Water-based solar water heating systems are still being utilized worldwide. Tempering valves have made them better at maintaining a constant water temperature throughout the house. But heating water directly is not always the best plan. The state of the art in solar water heating is thermal fluid. The rooftop panels on the Genesee Park net-zero home are filled with a non-toxic thermal gel instead of water. The silicone-based fluid can reach 700 degrees Fahrenheit before overheating and won’t freeze until it reaches -50 degrees. The passive system has no moving parts, so failures are rare and maintenance is negligible. The system uses nested vacuum-sealed tubes. The innermost tube is filled with thermal fluid, which absorbs heat from the sun helped by ultraviolet-sensitive coatings and metal tubing. When the fluid boils, vapor rises up the pipe, transferring heat to cold water, a heated manifold. Then the fluid condenses back down the tube to reheat. Panels containing the tubes can be mounted anywhere that receives enough sunlight on rooftops, walls, or the ground.

Cost and benefit of solar water heating

Like solar electricity, every solar hot water project is custom designed for the individual project, and costs can vary widely. Cost factors include the size and needs of the system, and whether you have the system installed for you or do it yourself.
Ray Lam, president of Silk Road Environmental, says he doesn’t like to talk about return on investment. “When you choose to buy a nicer car, you don’t do it because of ROI. You do it because it’s a better product and the technology or aesthetics appeal to you,” says Lam.
For environmentally-minded homeowners, eliminating nearly 20 percent of your home’s energy use with one design decision is an excellent return regardless of financial considerations.

Solar power is here to stay, and the sooner you explore how much you can save, the sooner you can enjoy the benefits of residential solar power. Go to HahaSmart.com and try our price checker tool. It tells you how much solar power you need, and how much you can save.

Please visit our solar blog to find out more about the benefits of going solar.