Impact of future climate on the performances of ground-source cooling system

Abstract

Newly constructed and renovated dwellings in Belgium are designed for the current climate context. However, due to the effects of global warming, extreme weather conditions like warmer summers and frequent heatwaves are expected in future climate scenarios. Future climate scenarios are nowadays not taken into consideration during the building and HVAC design process. This paper studies a case study dwelling equipped with a ground-water heat pump coupled with a heat exchanger to provide passive floor cooling, derived from two vertical boreholes with a depth of 100 meters. The aim of this study is to evaluate the impact of future climate scenario on the thermal comfort and the performance of radiant floor cooling system in a Belgian dwelling. Monitoring of the case study building (April-October 2020) and Building Energy Simulations (BES) in Open studio and EnergyPlus were conducted. Future weather files (future mid-term-2050s and future long-term-2090s according to the RCP8.5-scenario) were developed in the framework of IEA EBC Annex 80 Resilient Cooling of Buildings. The performance of the floor cooling system was analysed for four different climate scenarios for Melle, Belgium: typical historical-2010s, 2020 including a heatwave (observational data obtained from RMI), typical future mid-term-2050s and long-term 2090s. The evaluation was based on two parameters, (1) thermal comfort and (2) cooling capacity of the ground heat exchanger. Results demonstrate that in the future (long-term)weather scenario, the current design of the building including the floor cooling system is inadequate to provide a good thermal comfort. Due to the rising indoor and ground temperatures, the maximum cooling capacity will decrease 22,5% in future long-term scenario compared to the typical historical weather scenario. Results also confirm that the occupancy has a big impact on the thermal comfort, especially in thebedrooms. This study also indicates the importance of implementing shading as a good solution to obtain a better thermal comfort in future climate scenarios.