Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples
The heat transfer during air cooling of postharvest produce tends to be heterogeneous using either room cooling or forced-air cooling due to airflow maldistribution. The heterogeneity is typically evaluated in terms of temperature. In this study, the thermodynamic indicators, including the rates and...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Elsevier
2021-04-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X20305748 |
| _version_ | 1831671062539010048 |
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| author | Guan-Bang Wang Xin-Rong Zhang |
| author_facet | Guan-Bang Wang Xin-Rong Zhang |
| author_sort | Guan-Bang Wang |
| collection | DOAJ |
| description | The heat transfer during air cooling of postharvest produce tends to be heterogeneous using either room cooling or forced-air cooling due to airflow maldistribution. The heterogeneity is typically evaluated in terms of temperature. In this study, the thermodynamic indicators, including the rates and the temporal cumulation of entropy generation and entransy dissipation, are proposed for heterogeneity analysis. Based on the experiments with postharvest apples, the heterogeneity is compared between air cooling methods using the proposed thermodynamic indicators. The temporal variation tendencies and spatial distribution characteristics of these thermodynamic indicators are further discussed. Higher heat transfer heterogeneity regarding to the rates of entropy generation and entransy dissipation is observed at the beginning stage and at the end of the process with lower temperature heterogeneity. In comparison with the entropy generation, the entransy dissipation is more appropriate for heterogeneity comparison because of the consistency. The cumulative entransy dissipation is generally higher at the locations with more airflow and higher heat transfer rate. When compared with room cooling, the consistent reduction of standard deviation and coefficient of variation for the cumulative entransy dissipation indicates overall lower heat transfer heterogeneity for forced-air cooling. |
| first_indexed | 2024-12-19T23:29:33Z |
| format | Article |
| id | doaj.art-159d2fbc11ac4ec4ae292191d04eea7f |
| institution | Directory Open Access Journal |
| issn | 2214-157X |
| language | English |
| last_indexed | 2024-12-19T23:29:33Z |
| publishDate | 2021-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Thermal Engineering |
| spelling | doaj.art-159d2fbc11ac4ec4ae292191d04eea7f2022-12-21T20:01:46ZengElsevierCase Studies in Thermal Engineering2214-157X2021-04-0124100832Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest applesGuan-Bang Wang0Xin-Rong Zhang1Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing, 100871, China; Beijing Engineering Research Center of City Heat, Beijing, 100871, ChinaDepartment of Energy and Resources Engineering, College of Engineering, Peking University, Beijing, 100871, China; Beijing Engineering Research Center of City Heat, Beijing, 100871, China; Corresponding author. Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing, 100871, China.The heat transfer during air cooling of postharvest produce tends to be heterogeneous using either room cooling or forced-air cooling due to airflow maldistribution. The heterogeneity is typically evaluated in terms of temperature. In this study, the thermodynamic indicators, including the rates and the temporal cumulation of entropy generation and entransy dissipation, are proposed for heterogeneity analysis. Based on the experiments with postharvest apples, the heterogeneity is compared between air cooling methods using the proposed thermodynamic indicators. The temporal variation tendencies and spatial distribution characteristics of these thermodynamic indicators are further discussed. Higher heat transfer heterogeneity regarding to the rates of entropy generation and entransy dissipation is observed at the beginning stage and at the end of the process with lower temperature heterogeneity. In comparison with the entropy generation, the entransy dissipation is more appropriate for heterogeneity comparison because of the consistency. The cumulative entransy dissipation is generally higher at the locations with more airflow and higher heat transfer rate. When compared with room cooling, the consistent reduction of standard deviation and coefficient of variation for the cumulative entransy dissipation indicates overall lower heat transfer heterogeneity for forced-air cooling.http://www.sciencedirect.com/science/article/pii/S2214157X20305748Entransy dissipationEntropy generationHeat transfer heterogeneityPostharvest precoolingThermodynamic analysis |
| spellingShingle | Guan-Bang Wang Xin-Rong Zhang Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples Case Studies in Thermal Engineering Entransy dissipation Entropy generation Heat transfer heterogeneity Postharvest precooling Thermodynamic analysis |
| title | Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples |
| title_full | Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples |
| title_fullStr | Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples |
| title_full_unstemmed | Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples |
| title_short | Thermodynamic evaluation of heat transfer heterogeneity: Comparative case studies on air cooling methods for postharvest apples |
| title_sort | thermodynamic evaluation of heat transfer heterogeneity comparative case studies on air cooling methods for postharvest apples |
| topic | Entransy dissipation Entropy generation Heat transfer heterogeneity Postharvest precooling Thermodynamic analysis |
| url | http://www.sciencedirect.com/science/article/pii/S2214157X20305748 |
| work_keys_str_mv | AT guanbangwang thermodynamicevaluationofheattransferheterogeneitycomparativecasestudiesonaircoolingmethodsforpostharvestapples AT xinrongzhang thermodynamicevaluationofheattransferheterogeneitycomparativecasestudiesonaircoolingmethodsforpostharvestapples |