Physical modelling of heat pump for simultaneous space heating and hot water demand

According to Danish Energy Agency, over 63 % of Danish houses are connected to District Heatng (DH) for their heatng demand where more than 70 % of DH is generated from combined heat and power (CHP). However, the supply of heat and power to residental as well as commercial buildings is not always accessible. Dense urban areas with high peak demands and complex network of pipes; and newly developed urban areas with uncertain consumpton demands pose numerous challenges on DH. Due to larger volumes of water at extremely high pressure, higher peak demands strain DH grid. Moreover, Danish energy system is exposed to strict regulatons to have all energy demands in electricity and heatng by renewable energy by 2030 and become fossil fuel independent by 2050. Implementaton of heat pumps for local heat producton mainly in urban areas can reduce the need for expensive DH grid extension and stll meet the heat demand. They can also improve fexibility in power supply by utlising the surplus electricity generated by intermitent renewable energy sources for heat producton. This paper aims to access the potental of the heat pump to provide a fexible thermal load at a smaller household level using a physical modelling approach. A dynamic model of an air-to-water, vapour-compression heat pump unit integrated with a hot water storage tank is developed. A ‘two-phase fuid’ library of MATLAB-Simscape in combinaton with ‘foundaton’ library is used to simulate the physical components such as such as evaporator, compressor, condenser, expansion valve, house, hot water storage tank and the controller. The modelling framework of the whole system is described and used to analyse simultaneous space heatng and hot water demand. An analysis of the system behaviour, based on the consumpton profle of a typical residental building in Denmark during the winter season, is presented. The physical modelling in the present work is focused on the requirements to integrate more local heat producton units, mainly in dense urban areas, to eliminate the need for new DH pipes. The results show that model satsfactorily depicts the dynamic behaviour of the Shobhana Singh is an Assistant Professor at the Department of Energy Technology, Aalborg University. She is working in the domain of thermal energy systems. She is actively engaged in various aspects of thermal energy systems such as thermal storage, heating systems, drying systems and their integration with renewable energy. She holds a MSc in Physics and a PhD in solar energy assisted drying systems heat pump with simultaneous heatng and hot water demand. In additon, the operaton of the heatng system is ensured within limits to maintain the indoor thermal comfort. The model is fexible to the changes in the physical input parameters, therefore, will be utlised to investgate performance characteristcs of heat pumpbased heatng systems for local producton.