Transient response of thermosyphon solar collectors

Abstract The response of thermosyphon solar water heaters to step changes of insolation is investigated. Measurements of the transient flow development in a thermosyphon circuit were obtained using a laser doppler anemometer and a mathematical model was developed to simulate the transient performance. The results show that although there are long time delays associated with the development of the thermosyphon flow the energy collection capability is not affected by thermosyphon time delays.