A new perspective of solar hot water system operation optimization: Supply and demand matching

Abstract

Solar hot water (SHW) systems have been widely used in residential buildings for energy conservation and emission reduction. The system operation control from the supply side and the occupant's hot water behavior on the demand side both affect the energy performance of the SHW system. However, there is a lack of synergistic optimization analysis of the supply-demand matching process. Therefore, in this study, quantitative methods for describing the supply- and demand-side equivalent profiles of SHW systems were proposed. Based on the two equivalent profiles, commonly used regulation measures on the supply and demand sides were analyzed from the perspective of time and intensity modification by proposing simplified estimation methods for the adjustment effect. Five supply side adjustment strategies are investigated. Through a questionnaire, three specific demand-side guidance strategies were obtained to guide the user's hot water behavior, and it was found that the performance of these strategies differed in different user groups. Integrated supply and demand matching regulation processes were established and verified. The results showed that the proposed supply-demand matching optimization process can increase the annual solar energy utilization rate by 9.6%, which meant that one household could save 136.19 kWh of reheating energy and reducing 121.51 kg CO2 in a year.