Abstract:
Trough solar collector is one of the key components of trough solar collector system, therefore, it is very important to analyze its thermodynamic performance. In this paper, a one-dimensional steady-state model of the collector was constructed using the distributed parameter method. The influences of molten salt inlet mass flow rate, solar radiation, annular space pressure and other factors on the entransy dissipation rate, entropy production rate, exergy loss rate and heat loss rate of the collector were investigated. Results show that the exuvial dissipation rate and entropy production rate decrease with the increase of molten salt inlet flow rate and emissivity. It increases with increasing solar radiation. When the amount of solar radiation increases by 67%, the entransy dissipation rate and entropy production rate increase by 191.4% and 177.7%, respectively. The variation trend of exergy loss rate with each parameter is basically the same as that of entropy production rate. The heat loss rate decreases with the increase of molten salt inlet mass flow rate and ambient temperature, and increases with the increase of solar radiation, annular space pressure, ambient wind speed and emissivity. When the emissivity increases by 28.6%, the heat loss rate increases by 18.9%. To explore the dynamic characteristics of the heat collection system, the dynamic simulation models of the two-tank heat collection system and the single-tank system were constructed and the simulation calculation was carried out. Results show that the dynamic response time of the two-tank system is obviously longer than that of the single-tank system. The number and location of molten salt tanks will only affect the dynamic response of the system in the initial stage, and will not affect the outlet temperature of each working medium in the system during stablization stabilized. The system was analyzed from entransy dissipation rate and entropy production rate. Results show that the entransy dissipation rate and entropy production rate of heat exchanger first increase with time and then remain unchanged, the entransy dissipation rate and entropy production rate of the collector and the molten salt tank decrease with time and then remain unchanged.