Analysis of a PCM-based condenser of a refrigeration system for personal cooling by numerical simulation

This thesis work describes the research activity regarding a personal cooling system with integrated PCM (phase change material). The experimental analyzes were carried out in the ENEA research center in Portici. The system under consideration has the purpose of creating personal cooling, or localized cooling (for example, for a workstation inside an office). Such a system, characterized by low power, is generally coupled to a centralized air conditioning system. As demonstrated by multiple studies, if such a system is present, it allows for better conditions of comfort within the occupied spaces and to raise the set point temperature of the centralized system, allowing for significant energy savings. The system is based on the use of a phase change material inside the condenser of a vapor compression system, which absorbs the heat released from the refrigerant fluid during the condensation, thus allowing for the creation of a portable system with a high storage capacity, without the need to exchange heat with the external environment during the operation of the system. The development of a numerical model to be able to simulate the system in question is of fundamental importance, since, in general, a numerical model allows to design, analyze, and optimize a system without the need to carry out multiple onerous experimental tests. It is also evident that there is a need to have a valid model, sohaving experimental data with which to compare and therefore validate the results ofthe simulations is essential. This thesis work is divided in two different sections: in the first section, an introduction on the topics of energy storage, phase change materials, personal cooling, numerical modeling techniques is presented. The second section presents the implemented model and the experimental setup that has been realized, as well as the results of the experimental tests and numerical simulations.