Optimizing Research On Performance Of Residential Building Cooled By Night Ventilation In Chongqing

As one of the means to reduce building energy consumption, night ventilation hasbroad application prospects. However, there are many problems worth studying, such ashow the night ventilation technology effectively implements in the conventional airconditioning system and how to solve the contradictions of indoor air quality, thermalcomfort and energy consumption.Firstly, the main factors affecting the night veltilation efficiency were summed upwith the heat balance method. Secondly, based on building bioclimatic chart and onlinesurvey, the feasibility of night ventilation applied in Chongqing was demonstrated. Thenthe cooling performance of the night ventilation operating with air conditioning for theresidential building in Chongqing was studied by means of experiment and softwaresimulation, and the influence factors on the effect of the night ventilation weresummarized. Finally, the energy-saving control strategy in Chongqing was discussed inthe form of a partitioning map, and a mornitoring system of the night ventilationoperating with air conditioning was built by the kingview software. Main researchresults are as follows:①Through the thermal process analysis, it_was pointed out that the main factorsof the cooling effect of night ventilation included outdoor meteorological elements,building structure and design characteristics, ventilation mode and control strategy, etc.②Based on the building bioclimatic chart, the thermal comfort area of ventilationin Chongqing was drew by Weather Tool, and the results showed that the time quantumfell on the thermal comfort area period increased significantly after adopting nightventilation, thereinto the time ratio in May and Septemper respectively increased from21.2%to86.5%and from0to80.5%. Meanwhile, the online survey on residents’behavior characteristics of energy saving in summer, and the results showed that about67.52%of the respondents had the habit and demand of opening doors and windows atnight.③Focusing on cooling performance, the residential architecture with the unifiedoperation of night ventilation and HVAC was researched, and the results indicated thatincreasing ventilation rate and ventilation time were effective measures to improve thenight ventilation efficiency during the appropriate time period. While outdoortemperature is greater than indoor temperature, the running time of air conditioning should be decreased and the cooling release time of indoor enclosure should beincreased under the premise of meeting the human body thermal comfort.④Based on the action rule and optimization measures, the concept of zone chartabout the control of indoor environmrnt of the residential architectures in Chongqing insummer was proposed. In figure, night ventilation can be applied whilet_s＜t_w＜t_n＜30℃, air conditioner must be opened whilet_n＞30℃ort_s＜t_n＜t_f＜t_w＜30℃, andthe cooling storage quantity of indoor building envelop will be used to maintain indoorthermal equilibrium whilet_s＜t_f＜t_n＜t_w＜30℃. In addition, the indoorenvironment can be controlled by adjusting the opening of doors and Windows if thewind speed is greater than0.25m/s, or else mechanical ventilation will be used tosupport_natural ventilation in the process of controlling of night ventilation.