(OilPrice) IBM researchers in Switzerland have designed a high concentration photovoltaic thermal system (HCPVT) that concentrates solar radiation by a factor of 2,000, and converts 75% into usable energy. A parabolic reflector tracks the sun and focuses its rays onto an array of triple-junction photovoltaic chips. To prevent them melting, the array uses microchannel water-cooling, a technique also used in high-performance computers, which circulates the coolant to within a few tens of micrometres of the chips.
The array holds hundreds of 1cm2 standard commercial chips, each generating 50W of electricity – a 30% solar energy conversion rate. (Without concentrated sunlight, each chip would generate just 25 milliwatts.) The system’s energy conversion rate is boosted to over 75% by using the coolant’s waste heat to power desalination or air-cooling units. Currently, the best conversion rate for concentration photovoltaic systems is around 60%.