Geothermal energy piles and boreholes design with heat pump in a whole building simulation software

• Heat pump with energy piles was modelled in a whole building simulation environment.
• Energy piles with floor heat loss were contrasted against similar borehole field.
• Heat pump performance map product data was modelled with IDA-ICE heat pump model.
• Validation of three-dimensional IDA-ICE borehole model showed good agreement.
• Building with energy piles used 23% less energy than with borehole field.

With growing demand in improving building's energy efficiency, utilization of energy from renewable sources, such as ground energy, becomes more common. This paper focuses on the detailed modelling issues in a whole building simulation environment providing an approach for a design of a heat pump plant with boreholes or energy piles, that was developed for a case of one storey commercial hall building. Modelling was performed in whole building simulation software IDA-ICE, where most of the modelled components were defined as manufacturer specific products. Recently developed three dimensional borehole model was validated with the use of actual borehole measurement data. Heat pump model calibration parameters equations, which are needed to setup model according to manufacturer specific performance map product data, were derived and applied. According to results of conducted 20-years long-term simulations, consideration of seasonal thermal storage can become feasible. Validation of borehole model showed that the model can simulate very accurate dynamic performance and is highly suitable for coupling with dynamic plant models. Different ground surfaces boundary conditions of geothermal energy piles and field of boreholes resulted in 23% more efficient performance of energy piles in the case of the same field configuration.