Concentrated evacuated tubes for solar-thermal energy generation using stirling engine

In this study a commercial evacuated tube solar hot-water system was modified to be used as a thermal-power source for a thermodynamic engine. Commercial hot-water systems are meant to operate at temperatures that are close to the boiling point of water. Single-tube non-imaging concentrators were built in order to increase the input solar-radiation per tube and therefore supply thermal-power at temperatures of 180 – 220 °C. Simulations and experiments show that it is possible to use concentrators to increase the temperature range of thermal power extracted from a commercial evacuated tube system and use this modified system to increase the efficiency of solar-thermal energy generation.