Perspectives of deployment of Large Heat Pumps (LHPs) combined with waste heat recovery and powered by renewable green electricity in fourth-Generation District Heating (4GDH)

The decarbonization of the heating sector is a central component of the European Union's energy and climate strategy, as reinforced by the revised Energy Efficiency Directive (EU) 2023/1791) [1] and the Renewable Energy Directive (RED III) [2]. These frameworks mandate the progressive deployment of heating and cooling efficient systems, in all sectors, which must integrate increasing shares of renewable energies, high energy efficiency technologies and possibly allow waste heat recovery. Within this legislative landscape, beside the wide range of individual heating solutions for the different fields of residential, commercial and industrial applications, fourth-generation district heating (4GDH) systems are emerging as a very valuable solution for the future, in particular if they will be able to provide low primary energy space heating and cooling inside buildings and use innovative technologies to recover waste heat. In this paper we investigate the possible solutions of waste heat recovery trough the adoption of Large Heat Pumps (LHPs), more commonly known as HTHP (High Temperature Heat Pumps) and VHTHP (Very High Temperature Heat Pumps), alimented as much as possible by green electricity coming from renewable energy sources.