MODELLING AND ENERGY ANALYSIS OF A DUAL SOURCE HEAT PUMP SYSTEM IN AN OFFICE BUILDING

This paper presents the modelling and energy analysis of a dual source heat pump system for the production of heating, cooling and domestic hot water (DHW) in buildings. The research work was carried out in the framework of the Geot€ch project ‘GEOthermal Technology for economic Cooling and Heating’. The Geot€ch project, funded by the European commission within the H2020 program, is a four years’ duration project which demonstrates the next generation of ground source heat pump systems with a high energy efficiency but also with lower system costs with respect to those already existing in the market. To this end, one of the objectives of the project is the design of an efficient and comparative low cost ‘plug& play’ system for providing the heating, cooling and DHW needs in three demonstration sites located in Italy, the United Kingdom and the Netherlands respectively. In this context, an innovative dual source heat pump has been developed, which is capable of making optimal use of ground or air environmental heat sources according to operating and climate conditions. On the other hand, in order to reduce the costs of the installation, a new more efficient technology of coaxial borehole heat exchangers will be developed within the framework of the project. The project started on May 2015 and it is still ongoing. This paper first describes the characteristics of the dual source heat pump designed in the project. Then, in order to assist both in the optimal design and energy optimization of the operation of the system, a model of the ‘plug&play’ system in TRNSYS including all the integrated system components (dual source heat pump, ground source heat exchanger, air conditioning and DHW hydraulic loops) is presented for the demo site located in the Netherlands. Finally, the paper presents an analysis of the system operation as well as a first energy assessment in order to identify key control strategies needed to optimize the seasonal energy performance of the system.