A numerical study on the usage of phase change material (PCM) to prolong compressor off period in a beverage cooler

Highlights: • A 3D transient model is developed in a commercial CFD solver for vertical beverage cooler with PCM. • PCM slab is directly contacted with the airflow. • Regarding the run-time ratio best performance is achieved with 6 mm PCM slab. • Due to thermal inertia within the PCM domain, the VBC preserves its temperature for a long time. - Abstract: This study numerically investigates the influence of integration of a phase change material (PCM) slab inside a vertical beverage cooler (VBC) on the energy consumption, the thermal stability and flow characteristics of air inside the cooler. The PCM, water, slab is placed on the rear side of the flat plate roll bond evaporator with five different thicknesses, such as 2, 4, 6, 8, and 10 mm. In the current work, transient numerical analyses are performed with ANSYS-FLUENT software for an empty cooler. To simulate the on/off controller of the cooling system a dedicated user-defined-function (UDF) is implemented in the software. Unlike the counterparts in the recent literature, instead of reducing the problem into a 1D or 2D lumped models a three-dimensional cooler domain is simulated in a commercial CFD solver. The predictions are compared with the experimental measurement for the cooler without PCM regarding the transient variations of the mean temperatures of evaporator surface and the indoor air. Consequently, the parametric set of analyses deduced that the PCM integration into the cooler enhances the cooling performance of the VBC by prolonging compressor off duration. Moreover, during the compressor off time, PCM preserves the air temperature inside the refrigerated space in the desired range by limiting the sudden temperature increments.