Imagine using the sun to cool buildings. Cogenra Solar’s added cooling as a new dimension of its hybrid photovoltaic thermal concentrating solar system.
The company announced this week that it has installed its first system capable of providing electric power, hot water, heating and cooling. The 50.2 kilowatt array was installed on the roof of the Southern California Gas Company's (SoCalGas) Energy Resource Center.
In addition to providing electricity for the building, the system captures the thermal energy of the sun in water. Cogenra said that by combining both forms of storage the system is able to capture over 75 percent of the sun’s incident energy. The systems store the hot water in tank, which provides hot water and heating onsite. But now the system is able to cool buildings as well.
The system at the center is connected to one of the building’s absorption chillers and serves as the heat source that powers the chiller’s reaction, according to Cogenra Senior Director Dr. Mani Thothadri. “The water come back to us colder from the absorption chiller. The absorption chiller takes heat from us and uses that as the energy source to create cool,” he said.
“There’s a good correlation between when the sun is shining and air conditioning. We also have storage,” Thothadri said. So even under cloudy conditions and into evening, the solar air conditioning will still work, depending on the storage and system design. “This is an automating system. It’s another solution that doesn’t augment your traditional chiller,” he said.
“Our system is optimized for the commercial market and those markets have massive cooling loads,” Thothadri said. In commercial buildings air conditioning is often needed even in the winter. That’s because of all the energy usage within the buildings, including lighting, electronics, computers and humans.
While the Cogenra systems will have additional costs, they add value by reducing additional energy needs onsite, thereby saving money. The systems have a less than 5-year payback period, according to Thothadri.
The company already has plans to install more systems with solar air conditioning. “We have two universities where we are about to do projects integrated into their heating and cooling units,” Thothadri said. The technology could be used for a variety of building types including hospitals, data centers and more.
Image courtesy of Cogenra