Thermodynamic performance of forced convection solar air heaters using pin-fin absorber plate packed with latent heat storage materials

In this work, the thermodynamic performance of a forced convection solar air heater (FCSAH) was evaluated using two different absorber plate configurations, namely a flat absorber plate and a pin-fin absorber plate packed with latent heat storage material (paraffin wax). The experiments were carried out under the meteorological conditions of Coimbatore city in India. The parameters such as outlet air temperature, thermo-hydraulic efficiency and exergy efficiency were evaluated with reference to solar intensity, ambient temperature and ambient wind velocity. An artificial neural network (ANN) model was developed to simulate the thermodynamic performance of a FCSAH using flat absorber plate and pin-fin absorber plate packed with paraffin wax to have a realistic performance comparison. The ANN-predicted results are found to be closer to the experimental values with a maximum fraction of absolute variance, minimum root-mean-square errors and minimum coefficient of variance. The results showed that the pin-fin absorber plate packed with paraffin wax has additional heat storage for the period of 3 h with 2-5 degrees C enhanced outlet air temperature when compared to the flat absorber plate. The FCSAH using pin-fin absorber plate packed with paraffin wax has 3-35 % higher thermo-hydraulic efficiency with 2-15 % higher exergy efficiency when compared to the flat absorber plate. The results confirmed that pin-fin absorber plate packed with paraffin is a good option to enhance the thermodynamic performance of a FCSAH.