Demand Response Potential Evaluation for Commercial HVAC Loads Considering Cooling Storage in Chilled Water Loops

Commercial HVAC systems offer great potential for demand response (DR). Existing methods for HVAC DR evaluation often neglect the cooling storage effect within chilled water loops. However, this effect provides substantial flexibility and its omission leads to considerable underestimation of DR potential. Incorporating this effect poses major modeling and computational challenges due to the spatiotemporal variation of chilled water temperature and the complex coupled dynamics between chilled water loops and the indoor environment. To address these challenges, this study proposes a novel method for evaluating HVAC DR potential considering cooling storage. First, we develop a model for chilled water loops based on 1-D advection-diffusion partial differential equations (PDEs). Then, a stepwise solution approach that leverages the identified stepwise rising pattern in chilled water temperature during DR events is proposed to solve the physical process effectively without directly solving the full PDEs. A high-fidelity simulation platform is established to validate the proposed method. Results indicate that, in most scenarios, the DR potential evaluated with the cooling storage effect is more than twice as high as that evaluated without it.