Energy consumption comparison of two cooling systems equipped with the heat exchangers in different agricultural postharvest storage conditions

Abstract

In a hot, humid, and fluctuating climate due to global climate change, agricultural postharvest relies prominently on refrigerating systems. To enhance thermal performance, such as in refrigerating systems, heat exchangers can be used. This work focused on expressing the air temperature, air relative humidity, and energy consumption (EC) profiles of two refrigerating storages using the HFC-32 fixed- and variable-speed compressor (FSC and VSC) systems in four experimental investigations. The profiles were recorded before and after the double-pipe heat exchanger (DPHEx) installations. Both storages had heaters, humidifiers, and hot water pots to generate heat and humidity at 18 °C and 22 °C, a storage temperature range for many postharvest products. From the results, both systems performances in reducing the EC of the FSC and VSC systems were enhanced by using the DPHExs. The EC of the FSC and VSC systems were reduced by 52.33 % and 17.19 % at 18 °C and 50.63 % and 20.00 % at 22 °C, respectively. All experiments with storage using the FSC system resulted in fluctuating profiles. This research information provides basic information for preliminary decisions about using DPHExs in postharvest refrigerating systems and selecting systems targeting the FSC and VSC systems in different situations. The power demand and operating cost relating to agricultural product storage can be calculated by using the EC correlation of each cooling system. Product freshness and abundance depend on fluctuating conditions, postharvest storage conditions, temperature, and relative humidity. The VSC system, coupled with the DPHEx, demonstrated enhancements on the EC and stable conditions.