Energy performance of Ground Source Heat Pump systems with flat-panel ground heat exchangers

The important role of heat pump technology in the decarbonization challenge of Heating Ventilation and Air Conditioning systems is nowadays widely recognized by the scientific community and stakeholders. In this field, Ground Source Heat Pump systems represent one of the most promising solutions because of the much more favourable temperature of the ground if compared to ambient air, which is affected by weather conditions. Furthermore, air source heat pumps are further penalized by the defrosting cycles of the finned coil heat exchanger during the heating period. The continuous reduction of the building peak thermal loads and energy needs, thanks to the improvement of standards and European targets in the building sector, has revived the interest of operators in horizontal geothermal systems. In the past, this type of ground heat exchangers was normally not considered due to the large space needed for their installation. In the literature there is a lack of works and research of ground source heat pump systems coupled with shallow flat-panel ground heat exchangers. The present work improves the knowledge of this latter technology. The study analyses and compares the thermal behaviour of flat-panel and vertical 2U ground heat exchangers loops by means of using TRNSYS simulation tool. The simulations have been used to obtain the energy performance of the ground loops coupled with the heat pump. The comparison highlights the differences between different case studies and how the flat-panel ground heat exchangers field is a possible alternative to the current systems.