The prototype HCPVT system uses a large parabolic dish, made from many mirror facets, which are attached to a sun-tracking system. The tracking system positions the dish at the best angle to capture the sun’s rays, which then reflect off the mirrors onto several microchannel-liquid-cooled receivers with triple junction photovoltaic chips. Each chip can convert 200–250 watts, on average, over a typical eight hour day in a sunny region.
The entire receiver combines hundreds of chips and provides 25 kilowatts of electrical power. The photovoltaic chips are mounted on micro-structured layers that pipe liquid coolants within a few tens of micrometers off the chip to absorb the heat and draw it away 10 times more effectively than with passive air cooling.
The coolant maintains the chips almost at the same temperature for a solar concentration of 2,000 times and can keep them at safe temperatures up to a solar concentration of 5,000 times.
The direct cooling solution with very small pumping power is inspired by the hierarchical branched blood supply system of the human body and has been already tested by IBM scientists in high performance computers, including Aquasar.
“Microtechnology as known from computer chip manufacturing is crucial to enable such an efficient thermal transfer from the photovoltaic chip over to the cooling liquid,” said Andre Bernard, head of the MNT Institute at NTB Buchs. “And by using innovative ways to fabricate these heat transfer devices we aim at a cost-efficient production.”