Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Experimental study and energy performance analysis of a vapor compression refrigerator powered by photovoltaic solar energy for regions without electrification
Submission Author:
Davi Severo Lopes , MG , Brazil
Co-Authors:
Davi Severo Lopes, Willian Moreira Duarte, Luiz Machado, Beatriz Alves , Raphael Nunes Nunes de Oliveira
Presenter: Willian Moreira Duarte
doi://10.26678/ABCM.COBEM2023.COB2023-0950
Abstract
In regions with less assistance and without electrification, the absence of refrigeration systems for storing vaccines, medicines and foodstuffs was evident during the Covid-19 pandemic. To supply these demands, an alternative, in line with sustainable prerogatives, would be the use of a conventional vapor compression refrigerator operating with electricity generated in a photovoltaic panel (PVC). The objective of this work was the experimental determination of the overall coefficient of performance (COP) of a commercial refrigerator with a volume of 79 L associated with a photovoltaic panel with a power of 320 W and an efficiency of 19%. In addition to these components, the experimental bench had an MPPT charge controller, an AC-DC converter with 90% efficiency and two electric batteries with unit loads of 45 Ah. To obtain the refrigerator COP, an electrical resistor was placed into internal compartment. The resistor was supplied with electric current by a variable voltage source, which provided a dissipated power of 30 W to 70 W. In addition to this rate of internal heat generation, the input of energy from the environment to the interior of the refrigerator was obtained with the help of heat transfer correlations for natural convection and thermal radiation. These correlations and the corresponding energy balances were subsidized with values of temperature obtained by calibrated K-type thermocouples installed on the internal walls and on the coil of the refrigerator evaporator. A data acquisition system was used to record the internal temperatures and the environment. Compressor energy consumption was recorded by an energy meter, which was also connected to the data acquisition system. The results of 35 experimental tests revealed that the cooling capacity of the machine ranged from 75 W to 137 W, for which the corresponding COP values associated with the refrigeration cycle ranged from 1.05 to 1.40, while the values of the global COP ranged from 0.17 to 0.24. The energy performance of the solar refrigerator was less than that relative to standard operation, whose reference COP provided by the manufacturer is 1.45. The reason for this significant drop in efficiency was due to the combined efficiencies of the PVC, inverter, and electrical components in the system. However, the PVC refrigerator proved to be viable for use in areas without electrification, mainly in regions with high availability of solar energy.
Keywords
refrigerator, COP, photovoltaic panel, Vaccines, covid-19
