This study presents the results of an experimental investigation of the influence of latent thermal heat storage elements (PCMs) on the power consumption as well as the temperature distribution inside the commercial household refrigerators. In order to design more energy-efficient refrigeration systems through means that have no or less impact on the environment and provides a better performance in prolonging the food preservation time, improving the performance, cooling time period, storage capability, maintaining the constant cooling effect for more time during the power off periods; the use of phase change materials (PCMs) coupled to the refrigeration systems has been chosen as it could be one of the most economically attractive and environmentally friendly solutions. In this study, two nearly similar refrigerator types were equipped with different phase change materials in different test configurations of sachets and tubes, and the performance was determined under standard conditions, to see any reduction in energy consumption and decrease in temperature fluctuations and consequently a better food preservation inside both cabinet-freezer parts of a refrigerator during on and off cycles of compressor. PCM-equipped refrigerator was also tested under open/close-door cycles. In the whole procedure effects of turning off the refrigerator on temperature fluctuations inside both cabinet-freezer parts were also investigated. This experimental analysis of both cabinet and freezer parts containing PCM, shows that the use of latent heat storage which is located inside the refrigerator, helps the storage of energy and prolongs food preservation time and uses the excessive stored energy to improve the fridge-freezer cooling cycle by its release at appropriate time. The energy stored in the PCM is yielded to the refrigerator cell during the off-cycle and allows several hours of continuous operation without power supply, also reduction of temperature fluctuations and increasing stability inside the refrigerator are very important achievements through using PCMs on refrigeration appliances.
Questo studio presenta i risultati di un'indagine sperimentale sull'influenza degli elementi latenti di accumulo di calore termico (PCM) sul consumo di energia e sulla distribuzione della temperatura all'interno dei frigoriferi domestici. Al fine di progettare sistemi di refrigerazione più efficienti dal punto di vista energetico attraverso mezzi che non hanno un impatto sull'ambiente o hanno un impatto minore, e forniscono prestazioni migliori nel prolungare il tempo di conservazione degli alimenti, migliorando le prestazioni, il periodo di raffreddamento, la capacità di conservazione, mantenendo l'effetto di raffreddamento costante per più tempo durante i periodi di spegnimento; è stato scelto l'uso di materiali a cambiamento di fase (PCM) accoppiati ai sistemi di refrigerazione in quanto potrebbe essere una delle soluzioni economicamente più allettanti e rispettose dell'ambiente. In questo studio, due tipi di frigorifero quasi simili sono stati equipaggiati con diversi materiali a cambiamento di fase (PCMs) in diverse configurazioni di prova di bustine e tubi e le prestazioni sono state determinate in condizioni standard, per vedere qualsiasi riduzione del consumo di energia e diminuzione delle fluttuazioni di temperatura e di conseguenza un migliore conservazione degli alimenti all'interno di entrambe le parti dell'armadio-congelatore di un frigorifero durante i cicli di accensione e spegnimento del compressore. Anche il frigorifero dotato di PCM è stato testato con cicli di apertura / chiusura. Nell'intera procedura sono stati anche studiati gli effetti dello spegnimento del frigorifero sulle fluttuazioni di temperatura all'interno di entrambe le parti dell'armadio-congelatore. Questa analisi sperimentale di entrambe le parti dell'armadio e del congelatore contenenti PCM, mostra che l'uso di accumulo di calore latente che si trova all'interno del frigorifero, aiuta lo stoccaggio di energia e prolunga i tempi di conservazione degli alimenti e utilizza l'energia eccessiva immagazzinata per migliorare il raffreddamento del frigorifero-congelatore ciclo dal suo rilascio al momento opportuno. L'energia immagazzinata nel PCM viene ceduta alla cella del frigorifero durante il ciclo di inattività e consente diverse ore di funzionamento continuo senza alimentazione elettrica, inoltre la riduzione delle fluttuazioni di temperatura e l'aumento della stabilità all'interno del frigorifero sono risultati molto importanti attraverso l'utilizzo di PCM su apparecchi di refrigerazione.
Study of an innovative technique aimed at a better food preservation and reduction of energy consumption in refrigeration appliances
SALIMI, MAHSA
2018/2019
Abstract
This study presents the results of an experimental investigation of the influence of latent thermal heat storage elements (PCMs) on the power consumption as well as the temperature distribution inside the commercial household refrigerators. In order to design more energy-efficient refrigeration systems through means that have no or less impact on the environment and provides a better performance in prolonging the food preservation time, improving the performance, cooling time period, storage capability, maintaining the constant cooling effect for more time during the power off periods; the use of phase change materials (PCMs) coupled to the refrigeration systems has been chosen as it could be one of the most economically attractive and environmentally friendly solutions. In this study, two nearly similar refrigerator types were equipped with different phase change materials in different test configurations of sachets and tubes, and the performance was determined under standard conditions, to see any reduction in energy consumption and decrease in temperature fluctuations and consequently a better food preservation inside both cabinet-freezer parts of a refrigerator during on and off cycles of compressor. PCM-equipped refrigerator was also tested under open/close-door cycles. In the whole procedure effects of turning off the refrigerator on temperature fluctuations inside both cabinet-freezer parts were also investigated. This experimental analysis of both cabinet and freezer parts containing PCM, shows that the use of latent heat storage which is located inside the refrigerator, helps the storage of energy and prolongs food preservation time and uses the excessive stored energy to improve the fridge-freezer cooling cycle by its release at appropriate time. The energy stored in the PCM is yielded to the refrigerator cell during the off-cycle and allows several hours of continuous operation without power supply, also reduction of temperature fluctuations and increasing stability inside the refrigerator are very important achievements through using PCMs on refrigeration appliances.| File | Dimensione | Formato | |
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Master Thesis Mahsa Salimi 874583.pdf
non accessibile
Descrizione: This thesis contains of five main parts, introduction, materials and methods, results, discussion and conclusion. Firstly, before the introduction part, a very short and quick summary of all this five main parts, have been written as an abstract in almost 10 pages. In introduction part a comprehensive review of related studies has been done, along with some of their numerical analysis. In the materials and methods part, a full description of set-up condition of the tests as well as different test procedures have been fully described. All the figures related to the tests have been summarized in results section, and in the discussion part, all the obtained results have been compared, fully analyzed and described in detail along with some comparisons with literature. Finally, there is the conclusion part which is a brief comparison between all gathered data and future perspectives. For better understanding of analysis and obtained results, tables and figures have been used for understanding the outcomes, better, numerically and graphically. In the last place, there is a full list of references which have been used or studied through this process.
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45.11 MB
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https://hdl.handle.net/10589/151868