Experimental analysis of the temperature distribution inside vaccine freezer compartment based on hybrid refrigeration system

Abstract

Recently, the demand for refrigeration globally has been increasing in the fields of vaccine storage, medical services, food preservation, and cooling for electronic components. This has resulted in the generation of more electrical power and thus releasing more CO2 around the world which has led to many climatic changes, such as global warming. The vapour compression refrigeration cycle (VCC) is the most common as it has a high coefficient of performance (COP), although it only operates down to temperatures of around −20 °C. The thermoelectric cooler (TEC) modules offer a featured method for cooling technology, which is not mainly considered by energy efficiency but offers distinctive merits in specific applications. Although the TEC system is not conventionally known for incomparable energy efficiency, it offers a range of exceptional attributes that make it a desirable option for certain scenarios. Therefore, this work aims to assess the performance of the innovative hybrid vaccine freezer system depending on how well the VCC system and the TEC work together. Also, the temperature distribution within the freezer compartment has been investigated under various operating conditions. The newly developed hybrid vaccine refrigerator system consists of four pieces of TEC-12706 modules that function well at low temperatures. The results indicate that the best coefficient of performance (COP) of 1.05 is achieved with a total power consumption of 172.8 W when the TEC is operating at 5.5 V and the fan is running at 12 V. The cooling capacities of the freezer and cooler compartments are 9.2 W and 165 W, respectively. Furthermore, the best distribution and lowest temperatures were obtained, with temperatures in the lateral area of −40 °C compared with −37 °C in the central area.