Thermal performance evaluation of a solar air heater integrated with helical tubes carrying phase change material

Abstract

Abstract In this present work, the efforts have been made to improve the efficiency of solar air heater (SAH). For this, total two models have been developed. There is one reference model SAH-A and one modified model SAH-B which is integrated with paraffin wax as a low cost energy storage material. Furthermore, model SAH-B is further modified into a new model SAH C which is integrated with a specific mixture of paraffin wax and Granular coarbon powder (GCP). For better heat storage capacity of the aforesaid energy materials, helical tube of copper made has been considered as a container. Both the models of air heater (SAH-B and SAH C) have been experimentally tested on natural and forced convection under the climatic conditions of Moradabad city, India. Results show that SAH- C is better over SAH-A and SAH-B in performance comparison. Thermal efficiency of SAH C is found to be 79.10%, whereas it is found around 57.41% for SAH-B and around 50% for SAH-A. The other major parameter is heat transfer coefficient and for SAH C it is found to be 411.05 W/m2K, whereas it is found around 389 W/m2K for SAH-B and around 249.19 W/m2K for SAH-A. The maximum exhaust temperature of SAH C is reported to be 52.5 °C, whereas it is observed around 46.9 °C for SAH-B and about to be 44.7 °C for SAH-A. The main parameters of the present work summarizes that the model SAH C is an economic and optimum model for space heating, timber seasoning, drying operations etc. The total cost of the best configured SAH C model is only $67.