A NEW DYNAMIC TEST METHOD OF THERMAL PERFORMANCE FOR EVACUATED TUBE SOLAR COLLECTOR

摘要

In the present paper, the thermal performance of evacuated tube solar collector is investigated. A new dynamic model for testing solar collector is analyzed. The model is derived from thermal energy balance and solved by transfer function. In the model the collector is like as a system, the outlet temperature ( Tfo ) is the system output, the other variables: the inlet temperature ( Tfi ), the ambient temperature ( Ta ) and the solar irradiance ( I ) on aperture plane per unit area are the system inputs. By the measurements of Tfo, Tfi, Ta and I the characteristic parameters of the transfer function can be obtained. And then the system output ( Tfo) can be calculated by the transfer function and the system inputs. The results on the basis of the new method are very close to actual measured values when the system inputs are highly variable.