Research On Thermal Performance Of Residential Room With Intermittent Radiant Floor Heating And Application

In Hot Summer and Cold Winter(HSCW)zone of China,there is heating demand in winter,and convection air conditioning is often used.However,the indoor thermal environment in winter is not pleasant,and there is a demand to increase thermal comfort without increasing energy consumption significantly.The indoor thermal environment created by the radiant floor is more comfortable than the convection air conditioning,which has great application prospects.However,the intermittent heating mode generally exists in HSCW zone.When the radiant floor operates intermittently,the large heat capacity of the floor itself greatly extends the dynamic period of indoor thermal environment,where the heat transfer process of the room needs further study.The exterior wall is also an important factor affecting energy consumption.Different thermal insulation forms have different dynamic thermal performance,which further affects the dynamic thermal environment indoor and heating energy consumption.At the same time,the radiant floor transfers the long-wave radiant heat with the exterior wall directly,different from the convection air conditioning,which also affects the characteristics of heat transfer between the exterior wall and the room.Therefore,the influence of the insulation forms of exterior wall on the characteristics of heat transferred in the intermittent radiant floor heating room and the energy consumption of the room is different from those of convection heating terminal,which deserves further study.In this paper,the heat transfer between the exterior wall and indoor under the intermittent radiant floor heating was taken as the research object.Considering the characteristics of the large heat capacity of the radiant floor itself and the large proportion of radiant heat exchanged with the room,a simulation model for detailed calculation of the heat storage process and the radiant heat transfer process was established.Theoretical analysis,numerical simulation,measured calibration,comparative analysis methods,were used to explore the impact of different insulation forms of external walls on the heat transfer process of the room.Aiming to meet the needs of thermal comfort while minimizing energy consumption,guidance for the insulation renovation of existing residences with radiant floors was provided.The research results are as follows:(1)The heat transfer characteristics and practical performance of the exterior wall were selected and compared:heat flow on the inner surfac,heat storage on the exterior wall,response time of the indoor air temperature,and heat consumption in the room.Combining the indoor thermal comfort and the heat consumption of the room,the results show that the internal insulation has the shortest dynamic response time and the lowest heat consumption with intermittent radiant floor heating.(2)The difference of the influence on heat transfer characteristics among the three insulation types under convection air conditioning and radiant floor were further compared,to determine the best insulation form for different heating terminal forms.The results shows that under the heating terminal of the radiant floor,the internal insulation is 7%energy-saving than the external insulation,which is higher than the energy-saving rate of 4%under the convection terminal.Quantitatively,it is more urgent to choose the correct insulation form under the radiant floor to conserve energy than under the convection terminal.(3)Combined the application of cooling,the annual energy consumption is used as an indicator to provide guidance for the insulation renovation of existing residences.The results show that for existing residences before 2000,with poor thermal performance,adding 20mm of EPS(Expanded polystyrene board)internal insulation layer is the most energy-efficient for the radiant floor heating and cooling throughout the year.