A dairy plant in northern California, US, has fired up a 50 kW solar system that will provide both electricity and hot water, meeting half its wastewater heating needs, says Cogenra Solar.

Cogenra and OneSun have installed a 140 m2 solar array at Clover Stornetta Farms Dairy Processing Plant in Petaluma designed to deliver 6000 gallons (23,000 litres) of solar hot water daily for the Clean-in-Place (CIP) process at the plant, said Cogenra.

Solar cogeneration modules pre-heat water up to 63°C. It is then injected with steam to reach the temperatures required for CIP.

The 20-module array has been integrated into Clover’s existing natural gas water heaters and electrical equipment. Remote monitoring and diagnostics provide real-time status on the system’s energy performance.

Cogenra claims solar cogeneration cuts greenhouse gas emissions almost three times more than standalone photovoltaics (PV) and almost twice as much as solar hot water (SHW) systems.

Dual production of electricity and hot water enables a payback of less than five years, much quicker than PV or SHW, said the company.

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