Parametric analysis for exergetic optimisation of a solar shell-and-tube latent heat storage unit for agricultural applications

• Published in: Applied thermal engineering Vol. 233; p. 121029
• Main Authors: Munir, Zeeshan, Roman, Franz, Niazi, Badar Munir Khan, Mahmood, Naveed, Munir, Anjum, Hensel, Oliver
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: Decentralised agricultural application; Exergetic optimisation; Latent heat storage; Parametric study; Phase change material (PCM); RT70HC; Shell and tube tank; Solar thermal exergy storage; Phase change material (PCM); RT70HC; Solar thermal exergy storage; Parametric study; Shell and tube tank; Latent heat storage; Exergetic optimisation; Decentralised agricultural application
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2023.121029

•Adaption of PCM in Agriculture has been very limited despite great potential.•A novel latent heat storage unit is developed for various agricultural processes.•Thermal input and flow rate have an inverse effect on exergetic performance.•Flow rate significantly affects spatial exergy distribution in the tank.•Solar intensity and concentration ratio are crucial for exergetic efficiency. Thermal energy storage by employing phase change materials (PCMs) has gained huge attention in many fields but despite great potential, a broader implementation in agricultural processes is yet to be achieved. Therefore, a standalone system for solar thermal energy storage using a Scheffler concentrator was developed for variety of agricultural applications. This study is aimed at the exergetic optimisation of the system by assessing the impact of various intensities of solar thermal input and flow rates on the exergetic performance and exergetic distribution inside an inversely arranged shell and tube heat storage unit. The experimental setup consisted of a cylindrical heat receiver, an inversely arranged shell and tube PCM tank and a flat plate resistive electric heater for solar irradiation simulation. The tank filled with 4 kg of RT70HC PCM was subject to various charging cycles under 2.5 LPM, 5 LPM, 7.5 LPM and 10 LPM flow rates and 450 W/m2, 575 W/m2, 700 W/m2 and 825 W/m2 of simulated solar intensities. The results indicate that increasing the mass flow rate enhances the heating uniformity within the tank but also leads to higher total exergy losses. However, the difference in the rate of exergy stored in the PCM was mostly negligible. Conversely, increasing the exergetic thermal input had a significantly positive impact on the rate of exergy stored in the PCM.. The exergetic efficiency of the PCM tank varied from 17.5% to 9.2%, with its peak value recorded at a 2.5 LPM flow rate and 1070 W of exergetic input.