A team from the University of California, Merced, has unveiled a technology that they say will make harnessing solar thermal energy to power air conditioning units simpler, cheaper and more effective. The team, led by UC Merced Professor Roland Winston and mechanical engineering graduate student Heather Poiry, built a system called the External Compound Parabolic Concentrator (XCPC). The XCPC works by collecting thermal energy from the sun into specially made tubes. The heat is then transfered using existing heating, ventilation and air conditioning technology.
The XCPC functions at 60 percent efficiency at temperatures up to 400 F, a performance previously seen only in tracking solar thermal systems. And, unlike tracking systems, the UC Merced design does not use expensive moving parts, and collects both direct and indirect sunlight, making it cheaper to install and operate, and more efficient during cloudy or hazy conditions. To demonstrate the system, Winston’s team are using the technology to cool a mobile office trailer at the university’s Castle Science and Technology Center.
“We believe this is the first working system of its kind anywhere in the world,” Winston said. “For any application that requires process heat, the XCPC system is potentially a very cost-effective way to reduce conventional fuel consumption and greenhouse gases. Its nontracking design also enables it to be installed in any number of ways, including on rooftops and walls. You don’t have this type of architectural flexibility with tracking thermal systems.”
The work is being conducted under the supervision of the University of California Advanced Solar Technologies Institute, a multicampus research group headquartered at UC Merced that includes researchers from UC campuses at Berkeley, Santa Barbara, Davis and San Diego. Over the course of two years, more than thirty UC Merced students have participated in the project.