Simulation And Analysis Of Heating Performance Of Low Temperature Hot Water Radiant Heating System

Low temperature hot water radiant heating system has been widely used in northern China for a long time.But its form of central heating has many disadvantages,such as high energy consumption,inaccurate measurement and so on.There are also obvious differences in building envelope between the north and the south.These factors have become obstacles to stop the heating system from promoting in hot summer and cold winter areas such as Chongqing.Therefore,in order to respond to the new policy of national green development,the study establishes a numerical simulation model of the heating end of the heating system according to the characteristics of buildings in Chongqing.Through the simulation and analysis of its heating performance,a heating strategy based on indoor temperature change rate is obtained.The indoor temperature fluctuation amplitude is reduced.In addition,the study proposes a reservation heating strategy,which can choose the appropriate water temperature according to the user's reservation time and outdoor temperature at the same time,so as to achieve the purpose of energy conservation.Firstly,the study establishes a numerical simulation model of a heating room in a residential building in Chongqing,and uses the multiphysics simulation software to analyze the performance of the heating end of the heating system.The heating system was simulated and calculated under different water supply temperature,water supply speed and outdoor temperature.The response speed,heating time and corresponding temperature change curve of the system under different conditions are obtained.It is found that the water supply temperature has the largest impact on the system temperature,followed by the outdoor temperature,and the water supply speed has the smallest impact.Secondly,a transient system simulation program is used to simulate the lowtemperature hot water radiant heating system under the on-off control.The penetration of doors and windows,the radiation of the sun and the influence of indoor lighting are comprehensively considered in this study.The change of heating load in a whole year is obtained.The change rule of indoor temperature with time in one month heating period is carried out.Furthermore,the theoretical calculation value of indoor heat load under the same conditions is compared with the simulation results.At the same time,the simulation results of indoor heat load under the same conditions are compared,and the causes of errors are analyzed.Finally,in order to reduce the fluctuation of indoor temperature in heating system,the change rate of indoor temperature is taken as the monitoring object in this study.The relationship between temperature rise rate and room temperature overflow,and the function between temperature drop rate and water supply speed are established.According to the function,the heating strategy under the condition of daily heating is put forward.In addition,through the combination of water supply temperature,heating time and outdoor temperature,a heating strategy that can meet the user's reservation needs is proposed to reduce waiting time and improve indoor thermal comfort.