Design of a refrigerated complex for short-term storage of tropical fruits with a solar energy plant

Abstract

The object of research is a refrigerated complex for short-term storage of tropical fruits in conditions of significant seasonal and daily fluctuations in ambient temperature, that typical for regions with a tropical climate. One of the problems is that the complexes are autonomous small firms for the year-round processing and storage of tropical fruits, located far from the central electric networks. In the presence of solar radiation, the complexes receive energy from small solar power plants. Such complexes are called «trigeneration system». In the course of the study, data on modes were used low temperature heat treatment and preservation of various tropical fruits, ripening times and climatic conditions of Tunisia. It has been established that citrus fruits are stored in chambers with high temperature, olives are frozen and stored for a short time before processing. The total amount of heat entering the citrus chambers is determined by changes in the ambient temperature. The thermal load of the olives chamber is determined by the heat treatment time. It was found that the cargo capacity of chambers with different temperatures differs six times. The thermal load of the olive storage chambers is only four times less. This is due to the peculiarities of the building structure of the complex, technological processes of cooling and freezing. Based on the thermal calculation, the cooling of the chambers is provided by a two-stage booster refrigeration machine with CO₂ refrigerant in a transcritical cycle. To ensure the operation of the complex, a solar photoelectric converter is designed. This ensures the environmental safety of the complex and the possibility of obtaining energy savings by regulating the thermal power of the compressors with frequency converters, depending on the ambient temperature. The designed complex can be offered to a private investor for practical implementation.