Solar Cogeneration of Electricity with High-Temperature Process Heat

Abstract

Summary: Side-by-side installations of flat plate photovoltaics and parabolic trough collectors consume significant space and have high system losses; by using an all-in-one, spectrum-splitting hybrid receiver, electricity and high-temperature heat can be generated with a single efficient system. Here, the performance of a transmissive concentrator photovoltaic/thermal (tCPV/T) system is demonstrated on-sun, with a total energy efficiency of 85.1% ± 3.3%, 138 W electric power at 304 suns (with average cell temperatures <110°C), 903 W hot water output (average 34°C and 1.7 bar, peak temperatures to 56°C), and 1,139 W high-temperature steam output (average 201°C and 45 bar, peak temperatures up to 248°C). The spectrum-splitting hybrid receiver uses a sparse array of III–V triple-junction solar cells on GaAs substrates contained within a transparent microchannel water cooling stack, followed by a structured flow path thermal receiver cooled with pressurized water. System economics based on a 2.72-m2 prototype performance is shown to be at or near market competitiveness to natural-gas-produced process heat for a variety of locations, with a levelized cost of heat of 0.03 $/kWth for an installation in San Diego, California.

Keywords

• hybrid solar system
• concentrating photovoltaic/thermal
• transmissive photovoltaics
• spectrum splitting