Study and Sizing of the Electrical Energy Components of a Photovoltaic Solar Cold Room Dedicated to the Preservation of Agri-Food Products

The aim of this work is to carry out a study on the design and theoretical analysis of a cold room intended for the preservation of agricultural products, designed with a technical room for the installation of electrical equipment and the refrigeration unit, and using the refrigerant R404A. The refrigeration space studied, powered by photovoltaic solar panels installed above the roof, and features two ceiling-type evaporator units for air flow diffusion. The cold store, including the equipment room, has external dimensions of 5.00 × 3.00 × 2.60 m3 (L × W × H). Thermodynamic modelling was carried out, not only to determine the optimum thickness of the thermal insulation of the wall, but also to establish the heat balance, the purpose of which is to determine the cooling capacity of the chiller required to ensure the correct operation of the installation. Dynamic modeling of the refrigeration circuit is also carried out to determine the electrical energy required to operate the compressor. The energy requirements were sized to determine the appropriate configuration for the solar photovoltaic array. The results of this study showed that heat loss increases with wall thickness, so the choice of insulation thickness would depend on the specific requirements of the products to be preserved. On the basis of onion preservation, the optimum power for the motor-compressor unit was calculated at 1104.4 Watts, or 1.5 horsepower, to ensure reliable operation of the refrigeration machine in the installation area. Keywords: cold room, refrigeration unit, photovoltaic solar system, refrigerant, cooling capacity