Abstract Present work is focused on the assessment of energy and exergy flow in a mixed-mode solar dryer during the drying of pineapple slices by utilizing first and second law of thermodynamics. Moreover, drying kinetics and effective moisture diffusivity with shrinkage correction were also investigated at natural convection (NC) and forced convection (FC). The initial moisture of pineapple slices (90%, wb) was reduced to 29.66, 23.06, 24.05 and 19.68% (wb) in 6.5 hours under NC, air mass flow rates of 0.006, 0.01 and 0.015 kg/s, respectively. Results revealed that diffusivity estimated assuming negligible shrinkage demonstrated 3.5-5.3 times overestimation than shrinkage consideration. Energy analysis exhibited that about 55-78% of total input solar energy constituted thermal losses from the absorber plate. Remarkably, an increase of air mass flow rate caused an augmentation in useful heat gain by air and a simultaneous reduction in thermal losses from collector along with its efficiency improvement. Exergetic investigation of dryer identified that the exergy efficiency of the solar collector and drying chamber was positively influenced by air velocity. Furthermore, exergy efficiency of the dryer for NC and drying air mass flow rate of 0.006, 0.01 kg/s was 85.45%, 46.15%, and 18.88% lesser than 0.015 kg/s, respectively.

中文翻译：

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在不同空气质量流量下菠萝切片混合模式太阳能干燥过程中的干燥特性、能量和能量研究

摘要 目前的工作重点是利用热力学第一和第二定律评估混合模式太阳能干燥器在菠萝片干燥过程中的能量和火用流。此外，还在自然对流 (NC) 和强制对流 (FC) 下研究了干燥动力学和具有收缩校正的有效水分扩散率。在 NC 和 0.006、0.01 和 0.015 kg/s 的空气质量流量下，菠萝片的初始水分（90%，wb）在 6.5 小时内分别降至 29.66、23.06、24.05 和 19.68%（wb）。结果表明，假设收缩可忽略不计估计的扩散率比收缩考虑高估了 3.5-5.3 倍。能量分析表明，总输入太阳能的约 55-78% 构成来自吸收板的热损失。值得注意的是，空气质量流量的增加导致空气有用热量增益的增加，同时减少了集热器的热损失，同时提高了其效率。对干燥器的火用调查发现，太阳能收集器和干燥室的火用效率受到空气速度的积极影响。此外，干燥机的 NC 和干燥空气质量流量为 0.006、0.01 kg/s 的火用效率分别比 0.015 kg/s 小 85.45%、46.15% 和 18.88%。