An innovative surface morphology for a solar air heater to augment its performance

It is generally observed that solar air heater has lower conversion efficiencies due to low density of the working substance i.e. air. Hence many researchers are working hard to improve the performance by various design changes for the absorber itself. However, there is scope for improving the performance by means of surface morphology of the duct such that the flow may be made to accelerate and decelerate in the duct. This will result in a momentum exchange among the heated air particles. In this paper the width-wise dimension is morphed such that the duct takes the shape of a converging as well as a diverging passage. Converging shapes of the absorber plate result in an improved enthalpy augmentation due to an increase in the kinetic energy of the medium. Several parametric configurations of the converging and diverging ducts corresponding to various convergence ratios and divergence ratios are studied under different mass flow rate considerations so as to bring out an optimum design of the morphed duct.