Comparison study of a novel solid desiccant heat pump system with EnergyPlus

The variable refrigerant flow (VRF) air conditioning system usually needs to be operated with a ventilation system, since the VRF system cannot provide fresh air. The commonly used ventilation unit with the VRF system is the heat recovery ventilation (HRV) unit due to its merits of energy saving. In this study, a novel solid desiccant heat pump unit (DESICA) is introduced and mathematical model of DESICA is developed based on the dynamic building energy simulation software-EnergyPlus. The mathematical model is validated with experimental results. Based on the model, performance comparison study is conducted among the novel joint DESICA and VRF (DES&VRF) system, the conventional joint HRV and VRF (HRV&VRF) system, and the original VRF standalone with ventilation (VRFSA) system in an office building in Shanghai. Simulation results show that, HRV&VRF and VRFSA can handle the sensible load, though both of them cannot well deal with the latent load. On the contrary, DES&VRF system can keep both indoor temperature and humidity ratio at the target value, resulting in the best indoor thermal comfort than the other two systems. In addition, through the whole year, DES&VRF consumes 5% more energy than VRFSA and 20% less energy than HRV&VRF.