| Autor: |
B. Citarella, L. Viscito, K. Mochizuki, A.W. Mauro |
| Přispěvatelé: |
Citarella, B., Viscito, L., Mochizuki, K., Mauro, A. W. |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Popis: |
This paper presents the definition of a new method to obtain the optimum defrosting start time for a medium temperature refrigeration system with hot-gas bypass defrosting technique. A series of experiments is performed for a monoblock prototype placed in a cold room with controlled temperature (from −4 °C to +2 °C) and relative humidity (from 70% to 90%), whereas the ambient temperature is set to 25 °C and monitored in a calorimetric chamber. Specific tests are carried out by leaving the machine in operating mode up to the complete blockage of the evaporator, measuring the corresponding defrosting phase period and frost accumulated mass. A new method for data reduction of experimental data is presented to calculate the average energy consumption of the whole cycle (on–off operation and defrosting). With these results from experiments, firstly, the average energy consumption is used as one of the decisional parameters together with the number of hourly on–off cycles of a multi-criteria optimization under constrained heating load versus cooling capacity ratio. Secondly, an assessment of the results achievable with commercial defrosting method is carried out. The new method for data reduction could be used to collect performance maps under lab conditions and then use it as multi-criteria decisional basis for a control system. The commercial methods monitoring air-evaporator temperature difference or pressure drop across the evaporator do not allow to keep the heating load versus cooling capacity below a desired threshold value under all operating conditions. Conversely, a control system based on a defined maximum allowable heating load versus cooling capacity ratio permits to control the temperature of the cabinet. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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