Numerical performance investigation of a CO2 heat pump and refrigeration system for a Nordic hotel

Abstract

This article evaluates the first adaptation of a CO2 supermarket unit as an integrated solution for hotel applications. The system consists of a single unit for heating, ventilation, air-conditioning (HVAC) and domestic hot water (DHW). The heat pump and chiller unit is installed in Northern Europe and has a heating and cooling capacity of 280 and 75 kW, respectively. Included in the thermal system is a 6 m3 DHW storage for peak load shaving. A dynamic model of the system is developed in the Modelica programming language and the validity of the model is discussed. The model behavior is similar to actual system performance. The operational benefits of applying fixedspeed compressors are evaluated through simulations. The results show that the overall efficiency of the complete thermal system is improved by 3.8% when compared to using the current variable speed drive (VSD) control strategy.