Study On The Unassured Hours Of Outdoor Design Temperature For Summer Air-conditioning Based On The Heat Storage Of Wall

At present,the economy in China is developing rapidly.And people's standard of living is also increasing,so the thermal comfort requirement for people is gradually improving.The building energy consumption all over the country is steadily on the rise,which increases the energy pressure of China.The comprehensive utilization of all kinds of energy-saving technologies and the reduction of building energy consumption level have very important significance.When outdoor design conditions for HVAC are created,the unsatisfied hours for indoor thermal comfort environment may not meet the expected requirements due to the limitations of the actual conditions.In other words,the statistical method of “non guaranteed rate” is based on outdoor meteorological data,but the change of indoor and outdoor temperature may have differences.On the other hand,the temperature in room,relative to the fluctuation of outdoor air temperature,exists attenuation because of the heat storage characteristics of the retaining structure.Therefore,the unsatisfied hours for average year of indoor temperature for summer air conditioning may not reach 50 hours.Such deviation would deviate from the initial assumption of the norm and would inevitably also affect the effect of energy saving.Hence,it is necessary to study the influence of heat storage characteristics for enclosure structure on the indoor temperature and the actual unsatisfied hours of 30 years in air-conditioning room in the summer.So the study can provide some advice for the methods of determining the outdoor design conditions to make it more reasonable.Ultimately,the expected unsatisfied hours for average year in the room will be required,and to some extent,this reduces the consumption of energy.At first,according to the determination method of outdoor design conditions for summer air-conditioning in our specification,this paper constructs a set of Chongqing's outdoor air design conditions for summer air conditioning using the original outdoor meteorological data for 30 years in Chongqing from 1987 to 2016 to ensure the consistency of meteorological data for air conditioning system design phase and software simulation phase.We define the air conditioning period of simulation as May to October.Taking a Chongqing's office building for instance,this paper calculates cooling load in summer,designs the air-conditioning system and ascertains related equipment parameters in succession.Finally,we gain unsatisfied hours for average year in room in summer air conditioning by using the Chongqing's hourly outdoor meteorological data of 30 years from 1987 to 2016 and the DeST software for simulation.According to the set temperature of 26? for indoor air conditioning system,the unsatisfied hours for average year got by simulated in the three representative rooms are less than the unassured 50 hours of outdoor design conditions set by “Design code for heating ventilation and air conditioning of civil buildings”(GB50736—2012).Then,this paper chooses a new kind of thermal inertia index for exterior wall of the building.Compared with the exterior wall before,the new exterior wall has the same thickness,total heat resistance and heat transfer coefficient.By simulating again,we gain new unsatisfied hours for average year indoor in summer air conditioning and analyze the heat storage characteristics of wall may have an impact on indoor air conditioning temperature.At this time,the unsatisfied hours for average year in the three representative rooms are also less than the unassured 50 hours of outdoor design conditions set by Chinese norms.And the exterior wall of building,which has slightly larger thermal inertia index,has smaller unsatisfied hours for average year indoor.So as for Chinese norms,the author proposed that when we choose the outdoor design conditions for summer air conditioning,we should consider the actual effect of the heat storage characteristics of wall on indoor temperature.If we want to achieve the result of unsatisfied 50 hours for average year indoor,we can properly increase the unassured hours in the selection of outdoor design conditions or improve the method of load calculation in some software.So the process about the effect of regenerator such as retaining structures on buildings' cooling load is more appropriate.Finally,this paper identifies the outdoor design conditions for summer air conditioning as unassured 55 hours for average year.Under these circumstances,Chongqing's outdoor design dry and wet bulb temperature for summer air conditioning are 36.6? and 27.5?,which slightly smaller than the unassured 50 hours of outdoor dry and wet bulb temperature.By simulating again,we also gain new unsatisfied hours for average year indoor in summer air conditioning.Compared with the unassured 50 hours',the new unsatisfied hours simulated for average year in the three representative rooms increase to a certain extent,and these are more close to 50 hours.And accordingly,when the outdoor unassured hours increase,the indoor unsatisfied hours increase correspondingly.Through the analysis of the data,it also verifies the relevant proposal proposed by author to a certain extent.