Sun will provide most of power for hot water

    Sixty people sat in a workshop listening to a talk about hot water heaters during the Valley Electric Association 2009 Energy Symposium on the Saturday morning of Labor Day weekend.

The catch was this was a promotion for a solar hot water system from a representative of Rheem, one of the more popular vendors at the symposium at the Pahrump Nugget Convention Center.

Almost 200 people at the weekend symposium signed up for an inspection of their home for installation of a solar hot water heater, VEA Marketing Manager Staci Behnke said. That makes about 350 VEA members so far who are interested in receiving the solar hot water heaters, she added.

Informational meetings on the program have been scheduled from 10 a.m. to 7 p.m., Sept. 22-24 at the Saddle West Hotel Hospitality Suite.

"Rheem used to have a very long history in the solar water heating business, particularly from 1978 through 1986. Through the first solar tax credit era, we had a number of systems," Jeff Mahoney said, the Rheem alternative energy market manager.

"Like most of the manufacturers, when the industry collapsed in 1986 we stopped making complete systems, but we continued to make tanks for the replacement market for the systems that were still out there in operation, and for other companies that survived the collapse and needed a tank to complete their system. Most recently, in the last year and a half, we have gotten back into the solar hot water business and we are offering a complete package."

The two major components to a solar hot water heater are the collector to gather the sun's energy and a tank to store that energy, Mahoney said.

The solar collector panels are covered in glass to prevent wind from blowing away the heat and also serve as a greenhouse effect, he said. The sun's energy is transferred to a solution, which can be water, but in Pahrump, Rheem will use propylene gylcol which provides freeze protection down to 30 degrees below zero, Mahoney said.

It's piped through copper tubing to the tank and called a "closed loop system."

"Closed loop basically means once you fill up the loop, the collector, the piping, the heat exchanger, then back to the collector, you fill it with this fluid, pressurize it, seal it up and you should never have to refill it up again. It's the same fluid being used for the life of the system to heat the water inside the solar tank," Mahoney said.

The system can heat the water up to 300 degrees in the summer, but a tempering valve mixes the hot and cold water to the desired temperature, he said.

A solar controller, what he described as "the brains of the outfit," tells the pump circulating fluid between the solar collectors and the tank when to kick on and off.

"A solar water heating system is not designed to provide 100 percent of your water. The only place that's going to happen is a tropical climate like Hawaii or the Caribbean. So over the course of the year, in Pahrump, probably about 70 to 80 percent of your hot water will be generated by the sun, the rest is going to have to be provided by that backup source," Mahoney said.

The water loses about five degrees per hour, he said.

One member of the audience noted the warranty is 10 years on the hot water tank and 10 years on the collector but it will take 15 years for VEA customers to pay it off. Mahoney said the solar collectors have a design life of 25 to 30 years. Their failure rate on the solar collectors is less than one-tenth of 1 percent, he said.

Mahoney told another listener the solar panels don't have to be placed on the roof, they can be placed on the ground but need to be facing south with no obstructions.

Another audience member asked whether homeowner's insurance would cover the solar collector panels, a question Mahoney couldn't answer.

What about cleaning?

Mahoney said homeowners can merely take a garden hose and wash off the solar panels if there's a lot of dust. He told another questioner the solar panels weigh from 80 to 106 pounds.

Mahoney said he's been asked about their durability in the Southeast, where there are hail storms. Mahoney said he walked across the solar panels to test their strength. But he admitted, "If somebody throws a fast ball with a five-pound rock, you're probably going to have some damage. But it's going to take something significant to break it, and if it breaks, it breaks just like automotive glass into little bitty pieces."