The Effect Of Night Ventilation Mechanism About Office Building On Indoor Thermal Environment And Air Conditioning Energy Consumption

The building is a major part in the global energy and resource consumption. In theannual energy consumption structure in our country, building energy consumption hasgradually become the focus of attention. The biggest point of the building energyconsumption is heating and air conditioning. With China’s accelerated urbanization processand the improvement of people’s living standard, the construction of indoor comfortrequirements are also getting higher and higher. More and more office building useair-conditioning system, as a result the energy consumption is also increasing. In addition toequipment performance and system form, factors affecting the energy consumption of airconditioning system should consider the reasonable operation mode. Night ventilation is akind of method cooling buildings and reducing energy consumption. The focus of this paper isresearching the operation scheme of air conditioning and night ventilation combination fromthe perspective of energy conservation.In this paper, the research object is a room in an office building in Xi’an, to study thefollowing questions. First, in view of the influence of Xi’an city climate on thermal comfort,according to the model of thermal comfort determine human comfort temperature under thecondition of natural ventilation. Finding out the highest comfort temperature people canwithstanding under the condition of natural ventilation in summer of June to August in Xi’anCity, as to the basis of shutting the window. According to the Fanger thermal comfort equationproposed by professor Fanger of Technical University of Denmark, calculate the PMV valueunder the different activity levels, different clothes and different climate. Calculate thepercentage of PPD index of thermal comfort environment is not satisfactory. Through thecalculation and analysis of PMV-PPD index, calculate the comfort temperature range in airconditioning room so that majority of people satisfied. Second, Using diffusers, calculate theairflow distribution in air condition and whether jet lapping meets the requirements when itmeet the requirements of cold load. Using CFD calculation method, dynamic simulations ofindoor thermal environment with different night ventilation system for a cycle in24hours arereported in this paper. and it researches the daytime air conditioning load reduction by ventilation in the air conditioning room at night when not in use.Through the above study, a conclusion can be drawn. Natural ventilation at night maycool the building envelope and reduce indoor air temperature. When the natural ventilation allday cannot meet the indoor thermal comfort of human body in the office building, we can usethe method of using air conditioning at day and natural ventilation at night, reasonableventilation project can delay air conditioning time. At the same time, building envelope hasattenuation and delay to the outdoor air temperature fluctuations: Indoor air temperaturechanges smaller is beneficial to thermal comfort of users; Due to office buildings don’t use atnight, we can make use of night ventilation cooling envelope in advance, to achieve thepurpose of energy saving.