Energy and Exergy Analysis of a Domestic Hot Water Production System with a Heat Pump and Thermal Storage

The objective of this article is to study a thermodynamic water heater which uses the energy of the exhaust air from an apartment building to meet the needs for domestic hot water. The investigated energy system, based on an experimental bench of the IUSTI laboratory, is composed of two heat exchangers, a heat pump and a thermal storage to store and draw hot water. Energy and exergy analysis were performed for each component, in order to assess the thermal losses and the irreversibilities of the system, by means of a model developed on Matlab environment. The criteria used to evaluate the performance of the devices are the energy and exergy efficiencies, as well as the coefficient of performance. According the exergetic analysis, the heat pump is mainly responsible for the degradation of the energy quality involved in the system, followed by the recovery heat exchanger, the storage tank and the heat exchanger. The results show that the energy efficiency of the system is \(96 \%\) while the exergy efficiency is \(60 \%\) , which implies low heat losses but high irreversibilities.