2022 Volume 30 Pages 476-485
We designed and experimentally studied an online management framework for building variable refrigerant flow (VRF) heating/cooling systems, which achieve peak shaving and thermal comfort improvement. We also developed a thermal equivalent circuit model (TECM) to describe a building's thermal behavior. The TECM was experimentally validated under different ambient temperatures, heat/cooling loads, and occupations. The temperature responses obtained from it have good agreement with observations, and the maximum deviation is below 1.9°C. We formulated a model predictive control (MPC) problem for VRF heating/cooling system control whose objective is to minimize electric costs, reduce power demand peaks, and maximize thermal comfort. An online management framework of the VRF heating/cooling system, which was developed based on TECM, includes a monitoring system based on built-in sensors, embedded technology, and a real-time VRF system control module based on the MPC problem. We investigated the performance of the proposed framework with different operating conditions in an actual room. The VRF heating/cooling systems using this framework achieved better room temperature control and improved energy efficiency.
