Study On Operational Strategy Optimization Of Capillary Floor Heating System For Residential Buildings In Chongqing

As a typical city in the hot summer and cold winter area,Chongqing is always cold and humid in winter.And the insulation performance of existing building envelopes is poor which is resulting in poor indoor thermal and humid environment.With the development of economy and the improvement of living standards,the demand for heating by residential users is becoming more and more urgent.The capillary network floor radiation system is highly recommended by researchers as a new heating terminal because of comfort and energy saving which has great development potential in Chongqing.Most of the heating systems here are decentralized,so the operation mode of the heating system will directly affect the energy consumption in the future.The heat transfer mechanism,heat transfer process and heat transfer effect of the residential heating system are analyzed in detail through the theoretical analysis.We set up an experimental platform in a actual residential project.The operation mode of floor radiation heating system of residential capillary network in Chongqing area is studied in depth by means of field measurement.Firstly,three groups of pre-experiment are measured and analyzed.Different backwater temperatures(40?/45?/50?)and the control links between mainframe and thermostat are set up respectively and the comparative experiments of continuous and intermittent heating are carried out.By analyzing the differences of indoor environment and energy consumption,results shows that when the backwater is set at 45 C,the system can operate normally and has sufficient heating capacity.And the capillary network heating system is more suitable for linkage.The indoor heating natural decay rate is about0.451°C/h and the temperature response to system stability takes 4h50min.The total number of hours of heating,average effective heat dissipation,and power consumption of continuous heating are twice,1.86 times,and 2.01 times of intermittent conditions respectively.Based on the pre-experimental analysis,we propose a new operation mode which called duty heating.For the office workers in Chongqing,the different duty heating schemes with the required temperature of 22?/20?18?/16?were determined.Then we analyze the variation of water supply temperature,indoor thermal environment and energy consumption of different duty heating conditions at various demand temperatures through the actual measurement and comparison.The experimental results show that the water supply temperature fluctuates exponentially with time during the natural decay process,and the response process increases linearly.The average temperature of the ground and the temperature of the indoor air vary exponentially with time.And the rate of change is related to the initial temperature and the outdoor temperature.The lower the duty temperature,the longer the decay time and response time.When the demand temperature is 18?-22?,the average daily heat dissipation decreases with the decrease of the duty temperature,however the opposite is required when the demand temperature is 16?.The difference between the average effective heat dissipation of the adjacent working conditions is 3.724 W/m~2-17.632W/m~2,and the reduction or increase ratio is4.57%-18.26%.The proportion of the average radiation heat dissipation is stable from56.41%to 60.95%.When the demand temperature is 20?-22?,the energy consumption of the whole day decreases with the decrease of the duty temperature.When the demand temperature is 16?-18?,the above rules are not met.Finally,we choose response time and power consumption as indicators to establish an evaluation model for different duty heating schemes based on the gray comprehensive evaluation method.The preliminary evaluation indicated that the optimal duty temperatures at 22?,20?,18?,and 16?were 18?,17?,15?,and 15?,respectively.Then we analyze the influencing factors of the optimal duty temperature and optimize the evaluation model,and propose a block diagram of the optimal evaluation model of the capillary floor radiation optimal control for other projects.