Research On The Operation Mode Optimization Of Low-temperature Floor Radiant Heating In Residential Buildings In Chongqing

With the economic development and social progress,the poor indoor thermal environment in the Hot Summer-Cold Winter（HSCW）Climate Region conflicts with the increasing thermal comfort requirements of local residents.How to provide a winter indoor environment that meets the needs of residents at the cost of the lowest possible energy consumption has become the focus of scholars’research.Capillary floor radiant heating is highly recommended for its high comfort and energy-saving features.This article takes Chongqing,which is a typical HSCW Climate Region,as an example to study the optimization scheme of the operation mode of capillary floor radiant heating system in this region.Firstly,the heat transfer mechanism and process between the radiant heating system and the room are analyzed theoretically,the control parameters of the system that affect the indoor environment are analyzed,and a three-bedroom and one-dwelling residential building in Chongqing is selected as an experimental platform to study the heating operation mode.By comparing the energy consumption,thermal environment and thermal response time of continuous and intermittent operation,it is found that intermittent operation saves 44.5%,but the average effective heat dissipation in each room is 31%-40%lower,and the response time is as long as 4.3-5.3h.In order to improve the problems of high energy consumption in residential high-temperature continuous operation mode and long response time in intermittent operation mode,a low-temperature heating operation plan is proposed for typical office workers in the area.Then,Aiming at the operation plan of low-temperature on-duty heating,the indoor environment,response time,and system energy consumption changes under single-factor on-duty heating（room temperature or water temperature）are analyzed.It is found that when the single-factor duty is running,the higher the room temperature or water temperature on duty,the higher the average radiant temperature tr and the temperature controller temperature tk,the higher the effective heat dissipation,and the shorter the response time.When a single room temperature is on duty,the higher the room temperature on duty,the higher the energy consumption of the system is,but the COP changes little.When a single water temperature is on duty,the higher the water temperature on duty,the lower the COP is.The 30°C water temperature shift is 17%higher than 35℃and 49%higher than 40℃.The local dissatisfaction rate of one-factor duty LPD₃is between 6%and 15%,among which the single water temperature on duty is 3%-5%higher than that at a single room temperature.Based on the single-factor on-duty,a two-factor on-duty heating（room temperature and water temperature）is proposed,and the on-duty heating scheme at the required temperature of 22/20/18℃is analyzed.It is found that when the room set temperature is22 or 20℃,the effective heat dissipation in each room gradually decreases as the duty temperature decreases.When the room set temperature is 18℃,the effective heat dissipation changes little.Under different on-duty temperatures,the proportion of radiant heat dissipation is stable between 0.57-0.65.The higher the demand temperature,the greater the difference in power consumption of the same group of duty conditions,the more obvious the energy saving effect.The lower the on-duty temperature,the more the medium and low frequency ratios of the compressor during the on-duty operation phase under each operating condition,the smaller the power consumption,and the more the high frequency ratio during the response operation phase,the greater the power consumption.Looking at the whole day,the COP of the two-factor on-duty operation is5%-10%higher than that of the single-factor on-duty operation.At the same time,after performing a two-factor analysis of variance and calculation of Pearson correlation coefficient on room temperature and water temperature,it is found that the correlation between on-duty room temperature and local dissatisfaction rate,power consumption,and response time is greater than the on-duty water temperature.The interaction between on-duty water temperature and on-duty room temperature has a significant effect on power consumption,but not on response time and local dissatisfaction rate.Finally,based on the TOPSIS algorithm,the response system,local dissatisfaction rate,and power consumption are used as indicators to establish a comprehensive evaluation system.The optimal on-duty heating temperature data pairs at 22°C,20°C,and 18°C are obtained in order.（21,30）,（19,30）,（17,35）,and analyze the factors affecting the optimal on-duty heating temperature data pair,propose an on-duty heating intelligent decision-making system,and use PYTHON programming to realize the algorithm automation after data import.