Study On The Performance Of Non-transparent Envelope Structure For Radiant Heating Of Residential Buildings In Chongqing Area

The prefabricated grooved floor radiant heating system is a relatively comfortable and efficient heating terminal.It is widely used in hot summer and cold winter areas such as Chongqing.In actual engineering,the thermal design of the building envelope does not take into account the intermittent operation characteristics of the radiant floor heating system’s time-sharing and compartments,resulting in problems such as slow response and large energy consumption in the application process.In this paper,through theoretical analysis calculation and numerical simulation,combined with the energy consumption model of residential buildings in Chongqing,calculation and analysis of indoor environmental parameters,temperature response time and system energy consumption of external walls and interior walls when different insulation methods and main materials are adopted Performance of non-transparent envelope structure suitable for radiant floor heating system.This paper first defines and classifies the operating mode of the intermittent heating system in the time and room based on the climate characteristics of Chongqing and the living habits of the residents.Firstly,a building model was built using EnergyPlus simulation software,and a grooved floor radiant heating system was constructed.Then,the hourly load of the building,the dynamic thermal load in different heating modes,and the heating power of the room were simulated.In addition,the indoor environmental parameters and the performance of the radiant heating system under the three thermal insulation methods of the external wall were studied to obtain the best thermal insulation method,and the optimal thermal insulation layer thickness was proposed for nine typical external wall structures in Chongqing.In addition,for indoor partition walls,the interior walls are classified according to the installation of the room heating system.Based on the specific heating mode,the indoor environment parameters and system energy consumption of different types of interior walls in the heating room are analyzed to determine the better insulation method and main material type of different types of interior walls when radiant heating.At last,the heating energy consumption of the whole house was simulated and calculated according to the standard mode of intermittent operation.According to the research on the characteristics of the external wall,it can be obtained that the external thermal insulation method has the greatest effect on maintaining the stability of indoor environmental parameters.At the beginning of heating,the temperature of the indoor air in the external thermal insulation,internal thermal insulation and no thermal insulation modes were 11.18℃,9.51℃,and 7.98℃.When the outer wall adopts the internal insulation method,the indoor air temperature has the fastest temperature rise rate before reaching the set value,and the final temperature that can be reached without limiting the room temperature is the highest.In the rapid heating stage of the initial heating period,the temperature rise of indoor air per unit time is ranked as follows:internal insulation（0.0592℃/min）>no insulation（0.0566℃/min）>external insulation（0.0508℃/min）.The room temperature response time of exterior walls under different thermal insulation methods is different.and with the increase of the room temperature setting value,the advantage of internal insulation gradually becomes prominent.When the room temperature setting value exceeds 18℃,the room temperature response time of the internal insulation is the shortest.When the heating system is relatively stable,if the room temperature is maintained at a certain value,the radiant floor required for internal insulation of the external wall provides the least amount of heat.By comprehensively comparing the effects of different insulation methods on the external wall on indoor environmental parameters and the floor radiant heating system,it can be determined that the internal insulation is a more suitable thermal insulation method for the external wall during intermittent heating of residential buildings in Chongqing.By studying the characteristics of the interior wall,it can be obtained that:for a single-sided heating interior wall of the same thickness,the indoor air temperature rise rate is faster when the internal insulation is installed and the hollow body material is used for heating,and the final temperature can be higher.During the first 100 minutes of the heating phase,the temperature rise per unit time of the indoor air of the interior wall-S-1/2/3/4/5/6 is:0.0607℃/min,0.0583℃/min,0.0679℃/min,0.0608℃/min,0.0590℃/min,0.0678℃/min;when the upper limit of the room temperature is not controlled,the room temperature of the interior wall-S-1/2/3/4/5/6 at the end of heating are:18.89℃,19.66℃,20.89℃,19.37℃,19.95℃,21.07℃.The energy saving rate of the thermal insulation interior wall of the hollow body is the largest compared to the host without the solid thermal insulation interior wall,which is 13.07%,and the energy saving rate of the hollow body without the thermal insulation inner wall is smaller than that of the solid thermal insulation wall,which is 3.10%.For the single-sided heating inner wall,the best matching degree is provided with internal insulation,using hollow body materials and floor radiant heating system.For double-sided heating interior walls,the use of double-sided insulation is the best way to improve its thermal performance.Under the premise of using double-sided insulation,the requirements for the heat transfer coefficient of the internal wall materials can be appropriately reduced.Through the calculation of the heating energy consumption of the whole house,it can be obtained that:when the room temperature is set to 16℃,the internal insulation of the external wall and the single-sided heating inner wall and the double-sided thermal insulation of the double-sided heating inner wall can effectively reduce the energy consumption of the host.Moreover,the reasonable setting of the thermal insulation method has a greater effect on reducing the energy consumption of the host than changing the type of main material of the envelope structure.Energy consumption per unit of building area during heating season:Plan 3(7.74 kWh·m^-2)<Plan 2(8.82 kWh·m^-2)<Plan1(9.23 kWh·m^-2),the energy saving rate of Plan 3 is 16.13%compared with Plan 1.