基于商业HVAC系统的虚拟电池在负荷转移中的能效分析

Commercial buildings with significant thermal inertia can be regarded as virtual batteries (VBs) when their heating, ventilation, and air conditioning (HVAC) systems participate in demand response. This is attributed to their battery-like feature of converting surplus (deficit) power into stored (released) cooling capacity, thereby reducing (increasing) future energy demand without compromising occupant comfort. An HVAC-based VB achieves the optimal efficiency when charging energy equals discharging energy, thereby avoiding additional energy consumption and ensuring mutual benefits of the grid and buildings. However, primary factors contributing to VB inefficiency remain unresolved, hindering VB development and applications. This work shows that the indoor temperature trajectory throughout a complete VB cycle is the key factor impacting HVAC-based VBs’ additional energy consumption. We develop a method to quantify this impact based on a new concept, i.e., virtual leakage power. Furthermore, we derive the optimal efficiency condition, and propose an approach for quantifying the range of load shifting that a VB constrained by optimal efficiency can provide. Additionally, we design a model predictive control method for HVAC-based VBs to provide a specific amount of load shifting while ensuring optimal efficiency. Robustness of our results to assumptions made in the analysis is illustrated through simulation case studies.