District-Level Summertime Air-Conditioning Electricity Consumption and the Sensitivity of Peak Cooling Loads to Urban Weather Conditions in Beijing

Abstract

Understanding how energy use responds to meteorological conditions is essential for anticipation of energy demands, which is of significance to maintain sufficient power supply and to prevent brownouts or blackouts during peak hours. Using the quarter-hourly and district-level electricity data for Beijing, this study calculates the district-varying cooling electric loads due to air-conditioning (AC) systems in five consecutive summers. Results show the occurrence of two major features that are common for summertime cooling loads in most districts, namely, double-peaked diurnal profiles and weekday–weekend fluctuations. With the increasing distance from the city core, the evening peak cooling load around 21:00 local time (LT) becomes more pronounced and comparable with its afternoon counterpart around 15:00 LT. Conversely, the weekday–weekend fluctuation is greatly weakened in suburban and rural districts due to the stable cooling demands on weekdays and weekends. The district-level sensitivity of peak cooling loads to surface meteorological factors is further investigated by linear regression analysis, and results show significant decreases from urban to rural districts. The correlation coefficients between peak cooling loads and heat index that combines air temperature and relative humidity reach up to 0.8–0.9 in most districts. If using air temperature or specific humidity solely, the coefficients of determination with peak cooling loads are roughly 0.1–0.3 smaller, possibly indicating the greater potential of heat index for effectively predicting peak cooling demands in Beijing.