Incorporating variable refrigerant flow (VRF) heat pump systems in whole building energy simulation - Detailed case study using measured data

This paper presents results of energy consumption analysis conducted on a medium sized high performance office/institutional building utilizing VRF Heat Pump Systems with heat recovery as the primary heating and cooling strategy in the cold climate of south western Ontario (Canada). The objective of this research was to contribute towards optimizing the design of VRF heat pump (with heat recovery) based buildings through case study data and simulation showing various design optimization scenarios. EnergyPlus was used to create a building energy model reaching ASHRAE hourly calibration limits for zone temperatures (NMBE value of −6.8% and CV(RMSE) value of 17.2%). The results show the importance of integrated system design in minimizing energy consumption through correct sizing of equipment and optimizing VRF heat recovery; this is demonstrated by an overall energy savings of 16% by realistic reconfiguration and increasing the part-load ratio parameter of outdoor units. Appropriate sizing of outdoor units showed an effective savings of 29% space conditioning energy. The results highlight the importance of thoughtful design when utilizing VRF heat pumps as the primary heating and cooling method.