Load rebound suppression strategy and demand response potential of thermal storage HVAC systems: An experimental and simulation study

Abstract

The problem of power imbalance caused by the large power consumption of heating, ventilation and air-conditioning (HVAC) units in the summertime can be alleviated by building demand response (DR) strategies. However, after DR, load rebound will occur due to the sudden increase in demand. Meanwhile, there is a general lack of information on effective DR strategies. To study the DR potential and load rebound suppression strategies of HVAC systems, nine operation strategies were devised and applied experimentally. The physical experiments were conducted on a central air-conditioning system to investigate control strategies such as regional temperature reset, active energy storage, cold source unit activation and deactivation, as well as pre-cooling. Additionally, a simulation model was developed utilizing TRNSYS. DR evaluation indices, such as duration, power reduction capability, system operation cost, etc. were applied. The experimental results show that after a water storage tank is added as a buffer tank, the start and stop times of the air source heat pump were reduced from 46 to 6. Utilizing the thermal inertia of building and HVAC system, while ensuring personnel's thermal comfort, the DR participation time can be extended to 40–50 min. This will result in an 8.9 %–12.6 % reduction in power consumption. The simulation results show that with active energy storage added, HVAC system's DR participation time can be increased to about 120 min, the maximum power consumption can be reduced by 23.4 %, and the maximum operating cost can be reduced by 21.7 %. The study shows that a slow recovery strategy and the extension of DR control time can limit load rebound effectively. From the result of load rebound suppression effect, if the load rebound suppression strategy is not adopted, the power after DR will be 3.7 % higher than that pre-DR; the load rebound suppression strategy is adopted, which is 3.6 % lower than that pre-DR. By implementing the proposed DR strategies, the issue of frequent activation and deactivation of refrigeration units can be effectively mitigated. This will greatly alleviate the power supply and demand contradiction, while also effectively suppressing the load rebound effect to prevent a secondary peak in power consumption.