Study on the thermodynamic characteristic matching property and limit design principle of general flat plate solar air collectors (FPSACs)
flat plate solar air collector (FPSAC), thermodynamic characteristic matching property, limit design principle, collector efficiency intercept
Based on a typical single pass flat plate solar air collector (FPSAC) model, the collector thermodynamic characteristic matching property between the air-side heat transfer and total heat losses is analyzed in terms of unified air-side heat transfer coefficient U b-f and total heat loss coefficient U L. Then the limit design principle of FPSACs is discussed in order to obtain high collector efficiency intercepts. The results show that, both lower and upper limit values of U L exist for obtaining an expected efficiency intercept (η0) which is lower than the maximum realizable intercept ((η0)max) with specific collector components. The case of maximum realizable intercept (η0)max can be obtained by the minimum realizable total heat loss coefficient (U L)min and a high convective heat transfer coefficient U b-f (U b-f = 200 W/(m2·K) is argued to be good collector air-side thermal performance and is considered in the present study), resulting in a minimum thermodynamic characteristic coefficient ζmin. And the maximum realizable intercepts for different component combination cases of FPSACs are obtained by numerical calculation. Besides, for FPSACs with specific airflow channels, the cases of minimum realizable (U L)min represent the limit design.
Tsinghua University Press
Jie Deng, Xudong Yang, Rongjiang Ma et al. Study on the thermodynamic characteristic matching property and limit design principle of general flat plate solar air collectors (FPSACs). Build Simul, 2016, 9(5): 529–540.