| With the development of the economy,rapid urbanization and population growth,the consumption level of energy resources is also rising at a high speed.The industrial revolution has brought about new production methods with high efficiency and standardization,and at the same time brought new modern urban buildings and modern lifestyle.These standardized modern buildings often ignore local climate considerations.Faced with people’s requirements for indoor thermal comfort,they choose to use HVAC systems to meet the needs by consuming a lot of energy.With the outbreak of the energy crisis and the deterioration of environmental problems,ideas such as energy conservation,sustainable development,and low-carbon have emerged and received extensive attention from researchers.The development of ultra-low-energy and even near-zero-energy buildings has become the consensus of the construction industry to achieve "carbon peaking and carbon neutrality".The field of architecture has also begun to reflect on whether it is appropriate to use mechanical means to control the indoor environment,think about passive building design methods,and think about the response of the building itself to the climate.This paper takes the reduction of cooling energy consumption in summer as the entry point,and aims at the problem of determining the upper limit of the indoor design temperature in passive design of buildings,taking traditional residential buildings without artificial cooling sources and urban buildings using refrigeration systems in cold ⅡA and ⅡB areas as research objects.Explore the indoor critical temperature for cooling — That is,when the indoor temperature reaches how much people feel overheated and need to be cooled.On the basis of previous thermal environment tests and on-site thermal comfort research results,the method of combining on-site thermal environment tests,air conditioner opening behavior records,and thermal comfort questionnaires was used to obtain two levels of indoor critical temperature for cooling in cold regions,basic level and comfort level.This temperature threshold can be used as the control target of the building’s indoor thermal environment in summer,relying on the passive adjustment of the building body to control the indoor temperature below this value,or minimize the period of time when the indoor temperature is higher than this value,that is,shorten the cooling time of the air conditioner as much as possible;or cooperate with mechanical ventilation and other means to achieve the goal of controlling the indoor thermal environment below this value with lower energy consumption as much as possible,thereby reducing building cooling energy consumption.The main research work is as follows:(1)Carry out tests on the thermal environment conditions inside and outside the building.It is obtained that the way to control the indoor thermal environment of the traditional Guanzhong courtyard houses in Lianhu Village is to weaken the outdoor fluctuations layer by layer through the courtyard space,gray space,and indoor space,so as to cut peaks and fill valleys.At the same time,thick brick walls and adobe walls Good heat insulation and heat storage performance,together with the compact space layout,can maintain the basic stability of the indoor temperature.The volume of urban buildings has increased,and the area of a single room in a building that is directly exposed to the outdoor environment is reduced compared with traditional residential buildings,which is an advantageous condition for resisting the outdoor overheating environment.But at the same time,due to the shortage of land,urban buildings no longer have the conditions to build layers of space to weaken the outdoor thermal environment.A high-performance envelope structure is required to effectively weaken the outdoor thermal environment.On-site thermal environment tests were carried out on buildings of different ages and types of enclosure structures in Xi’an area.The results show that the insulation layer plus block walls and 370 clay brick walls can make the buildings achieve better indoor thermal environment effects in summer.However,the indoor thermal environment of buildings using 240 clay brick walls and large-area glass enclosure structures is not satisfactory in summer,and there is a long-term indoor overheating phenomenon,which requires a lot of cooling energy consumption to maintain indoor thermal comfort.(2)Carry out on-site thermal comfort questionnaire survey.The results show that the residents of Lianhu Village who live in natural ventilation for a long time and the residents of Xi’an who live in the condition of intermittent air conditioning for a long time have a certain difference in their adaptability to the hotter environment in summer.Based on the operative temperature,the results of the thermal comfort questionnaire survey in Lianhu Village show that,The measured neutral temperature of local personnel is 26.5℃,the 90% acceptable temperature range is 30.1℃,and the 80%acceptable temperature range is 31.2℃;the results of Xi’an thermal comfort questionnaire survey show that the measured neutral temperature of local personnel is25℃,the 90% acceptable temperature range is 27.2℃,and the 80% acceptable temperature range is 28.3℃.The summer neutral temperature and acceptable temperature range of people in Lianhu village are higher than those of people in Xi’an,indicating that people who live in naturally ventilated buildings for a long time have greater adaptability to the local hotter environment in summer.The requirements for the indoor thermal environment are also different.(3)Through the actual measurement of the indoor and outdoor thermal environment of traditional residential buildings in cold ⅡA and ⅡB areas and the collation of literature test data,taking the 24-hour data of each test residential room as a group,analyze parameters such as average indoor air temperature,average outdoor air temperature,average indoor and outdoor air temperature difference,indoor temperature fluctuation,outdoor temperature fluctuation,and attenuation multiples.The indoor critical temperature for cooling of the basic level is obtained: the indoor daily average air temperature is 2.4℃ lower than the outdoor daily average air temperature,and the outdoor daily air temperature fluctuation is 5.3 times that of the indoor daily air temperature fluctuation.This value can be widely used in the reconstruction,expansion and new construction of rural buildings without or little intervention of artificial cooling equipment.(4)Through the research on the opening behavior of air conditioners in urban buildings in Xi’an area,the indoor thermal environment conditions when people turn on the air conditioners are recorded.When the air conditioner in the test room is turned on,the average indoor operating temperature is 27.84℃.Combined with the "unacceptable rate-operating temperature" regression model measured in Xi’an area,the unacceptable rate corresponding to the actual measurement is 15% after group verification.Combined with the other field research results of thermal comfort in summer in coldⅡA and ⅡB areas,it is obtained that the indoor critical temperature for cooling of the comfort level is operative temperature 28℃.This value is a comprehensive result of various building types,and can be updated according to actual needs combined with thermal comfort research results.It can be widely used in the reconstruction,expansion and new construction of urban buildings that cover a large area of artificial refrigeration equipment for a long time. |
PDF Full Text Request