Control strategy evaluation framework for ground source heat pumps using standing column wells

Abstract

Standing column wells (SCWs) are efficient ground heat exchangers (GHEs) that have a significant cost saving potential. Recent developments have shown that they can also adapt successfully to cold climates despite previous concerns about operating near the freezing point. Therefore, new research frontiers are now being explored as the integration of this type of GHE to a real case study building model has hardly been analyzed until now. An institutional building has been selected for a SCW demonstration project in Mirabel, Canada. This paper includes in one single model the building, the Heating Ventilation and Air Conditioning (HVAC) system and the SCWs. The objective is to develop a software framework to analyze the impact of building operation strategies on the entire system during winter. Peak loads revealed to be the most critical points to control as the groundwater can freeze if the heat extraction is too high. Night indoor air temperature setbacks can bring significantly high peak loads whenever the building is heated to be occupied during the day. This paper shows that, using a bleed ratio above 20 %, a night setback can be successfully operated ramping up the temperature in around 3 hours.