With California set to start doling out incentives for solar water heating systems on properties soon, you can expect to see more new companies crowding in this space. Startup Cogenra Solar is one of such new comer, and it has designed a hybrid system that uses mirrors and solar cells to generate electricity and useful heat.
The system, which comes with a single-axis tracker, relies on glass mirrors to concentrate the sunlight onto silicon solar cells to produce electricity, Cogenra CEO and founder, Gilad Almogy, told us in a recent interview. And in the same region where the cells reside is a fluid-containing tube that absorbs the heat produced from the process of electricity production.
The fluid, a glycol mixture that is freeze-resistant and commonly used to transfer heat in cars and liquid-cooled computers, is then piped to a holding tank for heating water (see diagram below). In settings that requires hot water around the clock, a boiler remains necessary for the final heating.
“It’s a system optimized for both highly efficient PV and heat generation,” said Almogy, who founded the company (previously called SkyWatch Energy) last year, has raised $10.5 million and counts Khosla Ventures as among its investors.
A panel filled with silicon solar cells typically can convert around 16 percent of the sunlight that falls on it into electricity. The rest of the solar energy becomes heat, which is dissipated but can threaten the performance of solar cells. A growing number of companies, like PVT Solar, Cool Energy and Conserval Engineering, are looking at ways to generate electricity while also making use of the heat. Cogenra’s system can turn 75 percent of the solar energy into useful electricity and heat, Almogy said.
Almogy said the system can dial up and down the desired temperatures of the water, from around 120-degree F for businesses such as hotels to around 180-degree F for industrial operations such as food processing.
Almogy’s first showcase installation will be a 272-kilowatt system at the Sonoma Wine Company in Graton, a town in Northern California, the company said Wednesday. The size of the installation is larger than the 80-kilowatt one that Cogenra had initially estimated when it applied for a grant from the California Public Utilities Commission, which has approved $1.47 million for the company to develop new features for its hybrid designs.
Cogenra plans to explore ways to automate the system so that it can, say, focus on generating more electricity and less heat at different times during the day when electricity rates and demand are high, said Almogy. Cogenra and Sonoma Wine Company will pony up $2.7 million total for the project and Cogenra plans to turn on the installation at the wine company in November.
Sonoma Wine won’t own the system, however. Cogenra will own and operate the installation and sell the electricity and thermal energy under a long-term agreement. Cogenra plans to make money from offering such heat and electricity sales agreements, as well as from selling equipment. The company can use its own money to support some initial energy contracts, but will need to raise project financing to sustain the business.
Cogenra’s emergence comes at a time when California is set to launch an incentive program for solar water heating systems installed for businesses and multifamily housings. The California Solar Initiative-Thermal launched the residential part of the program in May this year, and could start the commercial and multifamily portion by the end of this week.
The state has budgeted $350.8 million for the entire CSI-Thermal program and plans to run it until the end of 2017, or when the money is spent. Residential systems get a rebate based on the estimated amount of thermal energy (in therms) or electricity (in kilowatt hours) that the systems can displace in the first year.
Commercial, and multifamily systems of up to 250-kilowatt would follow the same rebate scheme, according to proposed rules. For systems larger than 250-kilowatt, the state will first pay 70 percent of the estimated displacement for the first year. The rest will depend on how much the systems actually generate after one year.
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