On the Effectiveness of Baffles in Indirect Solar Storage Systems

Parameters that control heat transfer and mixing in energy extraction from indirect solar storage tanks that employ an immersed heat exchanger with a straight baffle beneath are identified and estimated. The analysis of flow in the baffle is based on boundary layer theory and provides insight into the effectiveness of a baffle in controlling growth of the thermal plume from the heat exchanger. The important physical mechanisms are the restricted entrainment and heat transfer to the storage fluid. For an adiabatic baffle as a base case, key design factors are the point of attachment of the plume on the baffle and the width of the baffle relative to that of the heat exchanger.