Energy Analysis of a Novel Perforated Cross-flow Solar Air Heaters Integrated with Encapsulated Phase Change Material Units: An Experimental Study

Abstract

This study analyzes the thermal efficiency of a new perforated cross-flow solar air heater (SAH) integrated with encapsulated phase change material (PCM) by using an experimnetal approach. Since SAHs represent low thermal efficiencies, this study introduces a novel SAH that uses two methods to address this problem: the perforated absorber with cross-flow configuration and encapsulated latent heat storage (PCM) units. The perforated cross-flow configuration improves the turbulence and, consequently, the heat exchange rate in SAHs and improves instantaneous efficiency. PCM units store thermal energy, prolong the operating period, and increase long-term efficiency. To perform thermal analysis, a perforated SAH with encapsulated PCM units was fabricated and tested outdoors at mair = of 0.012 kg/s and 0.024 kg/s in autumn while ambient and operating parameters were monitored. The experimental data reveal that the outlet temperature reaches the peak value of 38 oC and 32 oC. At mair = 0.012 kg/s and 0.024 kg/s, the temperature readings were 12 oC and 6 oC higher than the ambient temperature respectively. During the day, the charge/discharge process occurs in the encapsulated PCM units, avoids sharp temperature gradients and flattens the outlet and absorber temperatures’ profiles. The fabricated SAH reaches the highest thermal efficiency of nearly 83.7% at mair = 0.024 kg/s, which is a suitable value compared to common SAHs.

Keywords

• heat storage unit
• perforated solar air heaters
• phase change materials
• thermal efficiency