Performance analysis of optically semi-transparent material packed-bed solar air heater

Abstract

This paper deals with theoretical analysis of performance of solar air collector having its duct packed with optically semitransparent materials. The heat transfer equations for two dimensional fully developed fluid flows under quasisteady state conditions have been developed in order to analyze the thermal, thermo-hydraulic and exergy performance and to study the effect of system and operating parameters. A computer programme is developed in C ++ language to estimate the temperature rise of entering air for evaluation of performance by solving the governing equations numerically using relevant correlations for heat transfer coefficient for packed bed systems. Results of air temperature rise and thermal efficiency obtained from the analysis have been compared with available experimental results and results are found fairly in closed agreement. It has been found that there is considerable enhancement in thermal efficiency with packed bed collector. Effect of total bed depth on efficiency show that there is an upper limiting value of total bed depth beyond which the thermal efficiency begins to fall again and this type of characteristics behavior is observed at all mass flow rate. It is also noticed that there exists an optimal value of effective and exergy efficiencies for a given mass flow rate.

Efficiency Enhancement in Double-Pass Perforated Glazed Solar Air Heaters with Porous Beds: Taguchi-Artificial Neural Network Optimization and Cost–Benefit Analysis

“…Obviously, the exergy efficiencies show a minimum in non-optimized DPGSAHI and DPGSAHM (Figure 9a,b), 1.21% for DPGSAHI experimental and 1.45% for DPGSAHM at 0.033 kg/s whereas, ~3% and 2.4% exergy efficiencies were obtained for the hybrid optimized DPGSAHM and DPG-SAHI, respectively. Notably, the exergy efficiency became greater at a ṁ (7.1% for DPG-SAHI at 0.014 kg/s) and mitigated with increments in rate mass flow, compatible by the study of Velmurugan and Kalaivanan [32] and Chouksey and Sharma [31]. As indicated in Figure 6, the ∆T between the absorber plates and the current of air was greater at a lower mass flow rate of 0.014 kg/s.…”

“…The exergy analysis is based on the two laws of thermodynamics explained in details elsewhere [31], and the following assumptions were considered during the exergy analyses [32]:…”

“…As the thickness of the packing material and the gap between the internal and plexi glasses increased, the temperature difference decreased accordingly. The reason for this can be described as follows; as the thickness of the packing material increases, the rate of heat transfer to the flowing air decreases resulting in a decrease in convective heat transfer coefficient between the bed and the glasses and higher thermal losses [31].…”

“…Moreover, if the p-value is less than α = 0.05, the influence of that parameter on the response is significant [33]. transfer to the flowing air decreases resulting in a decrease in convective heat transfer coefficient between the bed and the glasses and higher thermal losses [31]. Variation due to each parameter influences the thermal efficiency and temperature difference.…”

Future Research Tendencies and Possibilities of Using Cogeneration Applications of Solar Air Heaters: A Bibliometric Analysis

“…The results obtained, the increase in thermal efficiency and temperature, were in line with the available results from the literature. There was also a considerable improvement in thermal efficiency [46]. Nems Magdalena of the University of Sciences and Technologies in Wroclaw, Poland, conducted a thermal analysis of a brick heat storage system.…”