Experimentally determined correlations for solar collector/regenerator heat and mass transfer

Local and overall performance measurements were taken on a prototype (11 x 11 m) solar collector/regenerator component of an open-cycle absorption refrigeration system. The data taken included local solution temperatures and inlet and exit concentrations. An interative method was used to solve a series of energy balances, over small finite distances in the flow direction, for local concentrations and local heat and mass transfer coefficients. Experimental convection coefficients were compared to those predicted by established correlations used in previous collector performance models. Established correlations underpredict heat transfer coefficients by a factor of 1.3 to 2.5 and underpredict mass transfer coefficients by a factor of 1.5 to 3.5. Local combined heat and mass transfer correlations were derived from the data. The correlations express nondimensional heat and mass transfer coefficients as functions of parameters describing forced convection, free convection heat transfer and free convection mass transfer. These correlations were integrated into a collector/regenerator performance model. The present model is a significant improvement over previous models and accurately predicts experimentally measured performance for a wide range of solar/meteorological conditions.