Interaction Of Building Cooling System Heat Release And Urban Meteorological Environment In Beijing

Since the urbanization is accelerating in China, the effect of heat-release of building cooling system on urban climate is bigger and bigger. Aimed at this situation, the article is to improve the BEM(building energy model) and to test some relative parameters off-line, and then to study the interaction of the anthropogenic heat release of cooling system and the urban meteorology environment.Taking the case of August6-7in2010,(typical sunny day case in the Beijing area in summer), it’s found that the electrical energy consumption of different uses of the buildings has different diurnal variations, and it’s also mostly related to meteorological factors. Based on these foundations, the simulation on energy consumption and heat-rejection of cooling system (air-condition) is performed with the modified BEM (Build Energy Model).Firstly, according to the features of the diurnal variations of electrical energy consumption, simulate the heat rejection of disparate uses of buildings. The analysis shows that among the thermal load, the percent of heat conducted by walls and windows is more than60%, the rate of heat produced by humans and equipment is about30%and received through the ventilation is5-6%. Secondly, a sensitivity analysis of a few parameters vastly affecting the result is carried out. The most important factor of building parameters is building height, when it varies from18.3m to12m and6m, the building heat-release will decrease24.3%and49.6%respectively. The second important parameters following building height are wall-conduction and ventilation coefficient.The heat-release can rapidly raise94.4%while the target temperature falling from25℃to24℃Thirdly, the result of distribution of sensible heat and latent heat is calculated with the rate of the diverse air-condition in China, the value is12.69W m-2and45.87W m-2(about22%of the peak value is sensible heat and the remaining part is latent heat in a single day).These results will laid the foundation for building thermal effect on urban climate research.Finally, the online coupled WRF/NOAH/SLUCM/BEM results showed that, without the anthropogenic heat, the simulation result of summer night heat island in Beijing urban areas have a deviation at night, and can hardly simulate summer heat island in the daytime. WRF model with the urban anthropogenic heat could improve the extent and the intensity of urban heat island can be simulated more correctly. Added the building anthropogenic heat to WRF would perfect the simulation of temperature and specific humidity at2m, upward heat flux, latent flux and the upward moisture flux at the surface, the urban boundary layer height. In case2that added the building anthropogenic heat, the temperature at2m raising about0.2to0.4℃, specific humidity increased0.5to0.9g·kg-1, sensible heat flux increased20to35W m-2, latent heat flux increased80to140W m-2,the urban boundary layer height increased about100to150m with the delaying about1hour of the urban boundary layer height’s dropping time.The change of meteorological condition caused by the additional building anthropogenic heat made effect on the building anthropogenic heat. Compared the casel, case2’s anthropogenic sensible and latent heat respectively increased0.2-0.5W m-2and1-2.5W m-2, about1.11%-3.33%and0.67%-1.67%, and the energy consumption increased0.0003-0.00009KW·h·m-2,about0.625%-1.56%.This study shows that the coupling with the heat release of building cooling system to WRF can improve the simulation on the effect of meteorological elements in the surface layer, especially the simulation ability of temperature level and temporal variation under special weather conditions such as the extreme high temperature. The result can provide the related theory and numerical model tools for the simulation of the heat island, the measure-making of mitigation the heat island and the evaluation and dispatch of energy consumption.