Investigation of evacuated-tube solar collectors performance using computational fluid dynamics

The present investigation deals with the numerical prediction of the overall performance of evacuated-tube solar collectors using computational fluid dynamics. A standard water-in-glass element, with its tank portion, is investigated and various design variations are checked. The results show that the standard evacuated-tube design can be greatly improved if minor changes are implemented. Among those enhancements, a slightly lowered tube-tank junction may results in a non-negligible boost of collector overall performance. Tailoring the length of the collector elements to the location in which the collector is used, i.e. the inclination angle of the collector, may also add a plus to the overall performance. However, this latter improvement may prove not worthy if looked at from a pure economical point of view.