Bill Lowstuter’s had a dream for the past 35 years: Getting other people into hot water. Really hot water. It looks like his dream is about to come true.
Lowstuter is founder and chief operating officer of SunTrac Solar of Golden, Colorado.
Most of us think of photovoltaics – using the sun’s power to create electricity – when we think of solar power. But SunTrac manufactures four-by-eight-foot panels that concentrate the sun’s energy to create super-hot water – 140 to 250 degrees Fahrenheit – for commercial and industrial use.
It’s ideal, Lowstuter says, for companies that prepare and process food, hotels and hospitals that need 160-degree water for their laundries, breweries and other commercial and industrial operations that use very hot water.
“It will work really well on domestic hot water for your home,” Lowstuter adds, “but it’s overkill.”
He came up with his design for a solar-concentrating panel in 1975 and built a prototype in 1978. He still has it.
“I’ve carried it around for 30 years and nine houses in five states,” he says. “So, I just have to thank my wife for her patience and perseverance.”
She must like him a lot. “Some of our first dates were actually assembling some of the solar panels,” he says. “Who says engineers aren’t romantic?”
The prototype “was the same design, the same configuration we have now,” Lowstuter says, with some modifications along the way to make the panels more rugged and durable.
Ready to actively sell the product
Although he came up with the idea 35 years ago, Lowstuter says he got serious about developing the product about four years ago.
SunTrac’s ready to actively start selling, he says, “because I’m now really comfortable with the ruggedness, reliability and long-term viability of the product.” For example, a panel installed at Lowstuter’s house came through a one-inch hail storm “perfectly fine.” The same storm damaged the roof of his house and several cars and destroyed his garden. The panels are rated for a 30-year life, he says.
Another reason SunTrac is ready to begin selling its product, Lowstuter says, is the Cleantech Open – a business competition designed to help clean tech startup companies develop the business and marketing expertise they need to become successful.
“I entered the Cleantech Open because I’m an engineer, I’m a tinkerer, and I don’t have the skillsets from the standpoint of doing business planning, marketing and the sales piece of this,” he says.
The Cleantech Open was “a tremendous learning opportunity to be able to help us advance by several years in terms of our business acumen and our presentations and the quality of knowing the market, knowing how to get to the market, knowing how to go into the market and tell the story about why people should be interested in our product and our company,” he says. “It was an immense help.”
Elegant in its simplicity
SunTrac’s product is elegant in its simplicity.
Remember using a magnifying glass to concentrate sunlight to start a fire when you were a kid? SunTrac uses the same principal, except it uses parabola-shaped curved polished aluminum mirrors to focus sunlight on black copper tubes filled with liquid. The liquid, typically a propylene glycol solution, is then used to heat water for commercial and industrial use.
The heart of the SunTrac solar panel is a rectangular manifold – two one-inch metal pipes joined together with six half-inch copper tubes with a special black paint to absorb heat. The manifold serves as a frame that provides the panel’s shape and as a mounting mechanism for the mirrors. And the pipes and copper tubes carry the liquid heated by the mirrors.
The whole thing is enclosed in a metal case with a five-millimeter (3/16”) tempered glass front to protect the mirrors from the elements.
To maximize the amount of sunlight converted to heat, a small 12-volt DC brushless electric motor activated by a pair of light sensors moves the mirrors to track the sun as it moves across the sky. The motor is mounted on the outside of the case for easy replacement.
The panels are up to 76 percent energy efficient – they convert up to 76 percent of the solar energy hitting them into heat. That’s significantly better than evacuated glass tubes, the main competing technology. The average efficiency of the top 15 evacuated tubes on the market is 59 percent, according to a comparison on SunTrac’s website.
As an engineer with extensive manufacturing experience, Lowstuter also has simplified the manufacturing process.
“There’s only about two hours of work in (building) each panel,” Lowstuter says. “We can build probably 25 to 30 a day with a staff of 10 people and five work stations. So, we’re able to rapidly ramp up in terms of being able to meet any anticipated production requirements.”
“The entire panel is designed to be assembled really with two tools,” Lowstuter says. “One is a Number 8 hex head wrench and the other is a Number 10 hex head wrench. There are only two bolt sizes in this entire assembly.”
One SunTrac panel can deliver the same amount of energy (when converted to BTUs) as ten 205-watt photovoltaic panels, Lowstuter says. Up to eight panels can be connected for added heating capacity.