Building Ventilation System Standards Contrast Between China And The US And Natural Ventilation Application Performances Analysis

With the rapid development of the construction industry, the energy andenvironmental crisis cause by it has also become a reality that the public have to facewith. Thus the building energy efficiency and green building boom is rising. The socialmaterial and economical level has been a significant improvement in recent years, andthe level of people’s lives also greatly improved, hence leads the requirements ofbuilding environmental gradually increased. Natural ventilation is an important mean toreduce building energy consumption and improve indoor air quality in the building.How to rational design and use natural ventilation is an important research area torealize building energy efficiency and green building.There are no specific special standards or guidelines for natural ventilation inChina, and the American Society of Heating, Refrigeration and Air ConditioningEngineers (ASHRAE) has more completed standard system about ventilation systemsand natural ventilation. This paper first compares the related building ventilationstandards bewteen China and the US. And conducts detailed comparison of theventilation standard system and the specific requirements of ventilation system. Thecomparison obtained some main differences and the author raised some benchmarkingrecommendations.Based on the main differences between the design standards of China and the US,the author executes a detailed comparison of the influence of natural ventilation toimprove indoor environment comfort in both countries, and found out that the thermalcomfort evaluation models and the methods make a great difference. Therefore theauthor uses two different evaluation system, calculated the comfort temperature rangeunder air conditioned environment and free running environment in different thermalcomfort level of Chongqing office building, and carries out comparison and analysis ofthe calculated results.The investigation of occupants in buildings of Chongqing shows that the expectedindoor wind speed in natural ventilation building is higher that of air conditioning.Therefore, with offset the indoor wind speed according to the expected value obtainedby the investigation, the author calculated the comfort temperature range under airconditioned running mode and free running modes, and set6conditions with differentgrades of comfort, natural ventilation strategies of air conditioned running mode and mixed ventilation operation mode altered with natural ventilation or night ventilation.By using DesignBuilder, an EnergyPlus user operation interface energy simulationsoftware, to calculate the energy consumption under different conditions, then using theresults to analysis the energy-saving effect of office buildings in Chongqing by usingnatural ventilation.The results show that the indoor wind speed and related humidity have an impacton the range of the comfort temperature under natural ventilation environment, and innatural ventilation environment, the range of adaptability comfort is wider than in airconditioned environment. On the basis of ensuring the comfort grade, mixed operationmode and using night ventilation can achieve the effect of energy-saving, and theenergy-saving rate can reach to15%. Using the daytime natural ventilation or nightventilation alone, the energy-saving rate is basically the same. And under the same levelof energy consumption, while condition that using daytime natural ventilation and nightgets higher comfort grade, also shows that the natural ventilation has significantinfluence to improve the building indoor environment. Thus, natural ventilation in officebuilding of Chongqing can achieve a dual effect of comfort and energy efficiency bysetting reasonable strategy. This method could also be used for different types ofbuildings in different climatic zones. The results could provide a theoretical basis forcompleting the ventilation system standards in China.