Study On Night Natural Ventilation Potential Of Office Buildings In Typical Cities Of Anhui Province During Air Conditioning Season

With the accelerated development of modernization,the total energy consumption is also increasing,in which the building operation energy consumption accounts for a large proportion of the total energy consumption in China.The main reason is the high energy demand of the summer air conditioning system of a large number of office buildings.In addition,under the influence of the epidemic,people have higher requirements for indoor air quality and ventilation of office buildings.How to improve the energy efficiency and reduce carbon emissions of office buildings in summer has become a difficult problem on the premise of ensuring the health and comfort of indoor air.Night natural ventilation is considered to be an effective passive means.For office buildings,night natural ventilation in air conditioning season can not only effectively reduce the cooling load demand of daytime air conditioning and reduce building operation energy consumption,but also improve indoor air quality and reduce the probability of epidemic transmission.In this paper,the outdoor meteorological data of three typical cities in Anhui（Suzhou,Hefei and Huangshan）were used as basic parameters.De ST-C and Airpak simulation software were used to analyze the energy-saving and carbon reduction potential of natural ventilation in typical office buildings at night and the impact of increasing window area on indoor thermal environment and thermal comfort.On this basis,the potential of night natural ventilation of office buildings of typical cities in Anhui was comprehensively studied.The main research contents and conclusions are as follows:（1）Based on the meteorological data of the three cities for the past 30 years,the typical meteorological year was established to statistically analyze the laws and differences of air temperature and humidity distribution in typical cities in Anhui.According to the enthalpyhumidity diagram zoning method,the time range of their air-conditioning seasons were determined,and the distribution status and accumulated hours of outdoor air heat and humidity status at night in the air-conditioning seasons of the three cities were analyzed.The research show that the suitability of natural ventilation at night is high in typical cities,and the suitability of natural ventilation at night in Suzhou is the largest,while the ventilation suitability potential in Huangshan and Hefei is comparable with little difference.（2）Through field investigation,the types and characteristics of office buildings in Anhui are summarized and analyzed.A research office building on campus as an example to draw a model diagram,and the night natural ventilation and cooling model of typical office buildings was established by using De ST-C simulation software.Based on the two views of night ventilation time,selecting the night ventilation periods with 23:00 p.m.-8:00 the next day and 3:00-7:00 the next day,respectively.By analyzing the wind environment at night during the air-conditioning season under two natural ventilation times and the results of load and room temperature changes calculated by De ST-C natural ventilation simulation,the optimal time for night natural ventilation during the air-conditioning season in three typical cities were determined and the energy saving and carbon reduction potential were compared and analyzed.The results show that the energy saving and carbon reduction potential of nighttime natural ventilation in Suzhou,Hefei and Huangshan decreases in order.The night natural ventilation time in the air-conditioning season of the three typical cities is most suitable from 23:00 to 8:00 the next day,which has a high utilization rate of natural cold air and a high wind speed in the dominant wind direction,and has a better energy-saving and carbon-reducing effect.（3）Using an office in a typical office building established as the research object,the effect of increasing the window opening area on the indoor thermal environment and thermal comfort of night natural ventilation in three typical urban air-conditioning seasons was simulated in Airpak software.The results show that doubling the window area can reduce the indoor temperature and improve the uniform distribution of temperature,which has a greater impact on Hefei with the highest outdoor average temperature at night.Doubling the window area can reduce the value and distribution uniformity of indoor PMV and PPD,which has the greatest impact on Huangshan City with the lowest wind speed of outdoor dominant wind direction at night.Suzhou City is least affected by the change of window opening area,and the indoor temperature,PPD and PMV are evenly distributed before and after doubling the window opening area,which basically meet the thermal comfort requirements.Based on the above analysis,a comprehensive comparative analysis concluded that among the three typical cities in Anhui,the potential for applying night natural ventilation during the air-conditioning season is the greatest in Suzhou,followed by Hefei,and the smallest in Huangshan.For typical non-energy-efficient office buildings,night natural ventilation during the air-conditioning season is a relatively effective and economical energy-saving and carbon-reducing measure in Northern Anhui without changing the envelope structure.Figure [30] table [27] reference [72]...