A study of pre-cooling impacts on peak demand limiting in commercial buildings

Peak demand cost usually contributes a considerable amount to the monthly electricity bills of commercial buildings, even up to 50%. Peak demand limiting is an effective way to minimize the bill, which has received attention from both academia and industry. However, existent studies do not systematically analyze the impacts of pre-cooling on the peak demand limiting in commercial buildings. This article presents a study to discuss the impacts of pre-cooling temperature and duration in two different types of buildings (i.e., a passive building and a building with phase change material) with and without use of the developed peak demand limiting method (i.e., proportional-integral-derivative peak demand limiting algorithm). The study compares the energy increase and peak demand reduction with a reference case as the benchmark at different pre-cooling temperatures and durations. A demand reduction effective index is introduced to evaluate the effectiveness of peak demand limiting in cost of energy rise. The results from the studies are shown to be useful for selecting proper pre-cooling temperature and duration for high-demand reduction effective index in peak demand limiting controls and for supporting the application of phase change material in reducing peak demand in commercial buildings.