Interaction Between Urban Microclimate And Air-conditioning Load In High Temperature Seasons

While the global climate is changing and the number of extreme weather is rising,urban micro-climate is deteriorating at a faster rate, which brings a tremendous impacton the lives of more than50%of the world’s population and the proportion willfurther increase. The most important phenomenon of urban micro-climatedeterioration is the Urban Heat Island Effect (UHIE). The increase of air-conditioningload caused by UHIE has been widely studied. However, the actual air-conditioningload is also affected by Temperature and Humidity Effects (THE) and CumulativeEffects (CE), and waste heat of high-density air-conditioning load in the city would inturn exacerbate UHIE. To grasp the interrelationship between the urban micro-climateand air-conditioning load will help reducing the electricity energy consumption,improving the urban micro-climate and thus achieving the goal of saving energy&reducing emission and improving the city’s livable degree. At the same time, it alsohelps improving the accuracy of short-term load forecasting and making the operationof power system securer and more stable.Under the premise of hot seasons, the paper first discusses the relationshipbetween temperature and air-conditioning load, which was fitted with logistic curve.The paper also represents impacts on air-conditioning load caused by UHIE, THE andCE separately and proposes a new method to amend CE. Then the paper combinesthese three effects to study the interrelationship between urban micro-climate andair-conditioning load, which includes the impact on air-conditioning load caused bymicro-climate, the reaction on micro-climate caused by air-conditioning load and thevicious cycle between micro-climate and air-conditioning load. Finally, it analyzes theapplication of interrelationship in the fields of city scale energy saving&emissionreduction, city planning, city management and refined load forecasting.According to the analysis of2005summer’s load data and meteorological data inBeijing, about40%of air-conditioning energy consumption is resulted from theintegrated impact caused by UHIE, THE and CE. The waste heat of air-conditioningload will increase the city’s air temperature significantly. The amount of CO2emittedin the process of generating air-conditioning used power energy cannot be ignored too. Meanwhile, improving urban micro-climate a little can save significant energy andreduce plenty of emission. It can also turn the vicious cycle between micro-climateand air-conditioning load into a virtuous circle. Ultimately, these measures can reducethe vulnerability of the power system and air pollution, and mitigate the globalwarming trend.