Influence of operational modes on the system performance and exergy efficiency of carbon fiber film heater-assisted heat pump drying systems

IF 5.1 3区工程技术 Q2 ENERGY & FUELS

Thermal Science and Engineering Progress Pub Date : 2025-04-13 DOI:10.1016/j.tsep.2025.103591

Ahmet Yüksel, Ümit İşkan, Cüneyt Tunçkal

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Abstract

This study investigated the drying performance of apple slices using a closed-circuit heat pump drying (HPD) system enhanced by a carbon fiber film heater (CFFH) integrated under the trays. The motivation behind this research was to improve the coefficient of performance (COP) and drying uniformity of the HPD system through innovative heating strategies. It was hypothesized that different operational strategies of the CFFH would significantly affect the system’s performance and exergy efficiency. To test this, three different CFFH operating strategies were implemented: continuous operation with the HPD system (Case-I), simultaneous intermittent operation with the external condenser (Case-II), and simultaneous intermittent operation with the external evaporator (Case-III). The experimental results revealed that Case-III achieved the highest coefficient of performance for the heat pump (COP_HP) at 4.44 and the highest coefficient of performance for the system (COP_SYS) values at 3.34, while Case-I demonstrated the lowest values at 4.08 for COP_HP and 2.98 for COP_SYS. Compared to the HPD system without CFFH, Case-I yielded higher moisture extraction rate (MER) and specific energy consumption (SEC) values by 0.005 kg/h and 0.935 kg/kWh, respectively, while specific moisture extraction rate (SMER) values were 0.007 kg/kWh lower. Furthermore, the highest exergy efficiency of 90.7 % was observed in the capillary tube during Case-II, whereas the compressor in Case-I exhibited the lowest efficiency at 60.6 %. In conclusion, integrating CFFHs with the HPD system not only facilitated more uniform drying of the apple slices but also enhanced COP_HP.

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运行方式对碳纤维膜加热器辅助热泵干燥系统性能及火用效率的影响

本研究调查了使用集成在托盘下的碳纤维膜加热器（CFFH）的闭路热泵干燥（HPD）系统对苹果片的干燥性能。这项研究的动机是通过创新的加热策略提高 HPD 系统的性能系数（COP）和干燥均匀性。假设 CFFH 的不同操作策略会显著影响系统的性能和能效。为了验证这一点，我们采用了三种不同的 CFFH 运行策略：与 HPD 系统连续运行（案例 I）、与外部冷凝器同时间歇运行（案例 II）以及与外部蒸发器同时间歇运行（案例 III）。实验结果表明，Case-III 的热泵性能系数（COPHP）最高，为 4.44，系统性能系数（COPSYS）最高，为 3.34，而 Case-I 的 COPHP 性能系数（COPHP）最低，为 4.08，COPSYS 性能系数（COPHP）最低，为 2.98。与不含 CFFH 的 HPD 系统相比，案例 I 的抽湿率（MER）和比能耗（SEC）值分别高出 0.005 千克/小时和 0.935 千克/千瓦时，而比抽湿率（SMER）值则低 0.007 千克/千瓦时。此外，在案例 II 中，毛细管的能效最高，为 90.7%，而案例 I 中压缩机的能效最低，为 60.6%。总之，将 CFFHs 与 HPD 系统集成在一起，不仅有助于更均匀地干燥苹果片，还能提高 COPHP。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Thermal Science and Engineering Progress Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

7.20

自引率

10.40%

发文量

327

审稿时长

41 days

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