Energy Saving Characteristics Of Household Air-source Heat Pump Floor Radiant Heating System Based On Behavioral Pattern

At present,saving resources and protecting environment have become the urgent concern for all countries.In order to cope with global warming,China has put forward the goal of carbon peaking and carbon neutrality.Because of its advantages of high efficiency,cleanliness and environmental protection,heat pump technology has once again become the focus of research and public attention.Among them,air-source heat pump can give full play to its flexibility for users to regulate the supply water temperature and change the operation strategy by themselves.Therefore it is important and urgent to study energy saving characteristics of household air-source heat pump floor radiant heating system to provide scientific guidance to the users for proper self-adjustment behavior.In this paper,a combination of questionnaire survey,experimental test and TRNSYS system simulation is adopted for research.The questionnaire survey was to obtain the artificial control strategies of the households and the energy consumption of the units during operation,and the results show that the preferred water supply temperature is30～40℃.The analysis revealed that the monthly electricity cost per square meter per month for this heating system is basically lower than that of the central heating of 5.8Yuan RMB.Taking the household air source heat pump floor heating system as the research object,the changes of indoor air temperature and energy consumption were studied in the process of temperature increasing,temperature stabilization and temperature dropping.The experiments were carried out by artificially changing the supply water temperature,setting different supply water temperature in different period inaccordance with the peakvally electricity price policy and changing heating area.The test experiment shows that the operation of water supply temperature of 30℃can meet the thermal comfort requirements of heating households.Compared with the indoor air temperature when the water supply temperature is 35℃,the indoor air temperature is closer under the two water supply temperatures,and the average temperature only decreases by 0.42℃,but the electricity consumption is reduced by 36.8%and the electricity cost is reduced by 35.5%.It was found that appropriately lowering the water supply temperature can reduce the electricity consumption to some extent.Further,the different-period differenttemperature mode of supply water enables both of energy saving effect and meet indoor thermal comfort requirements.Moreover,turning off the valves of floor heating for the unwanted heating area can somewhat increase the air temperature in the zone being heated.The air temperature difference at different heights in the same indoor location was also observed.The higher the location,the lower the air temperature.The indoor air relative humidity during heating season was in the range of 20%～25%,which could not meet the requirement of 40% to 60% of relative humidity for thermal comfort.The variation of heat load with outdoor air temperature throughout the heating season was obtained through TRNSYS building simulation,illustrating that the heat load and outdoor air temperature are negatively correlated.The building heat load of 8.37 k W was also obtained.By simulating the system,we obtained the change rule of supply and return water temperature with time,i.e.,the difference of supply and return water temperature is basically kept within 5℃ when the system is running,which indicates that each heating equipment is better matched,which is conducive to heat transfer and maintenance of equipment.By setting the water supply temperature at 35℃,the COP of the air source heat pump was stabilized at 4.0 during the operation of the unit,which was higher than the COP index value of 2.2 for the low-temperature multi-connector in the specification and close to the COP value of 4.1 for the heat pump under rated working condition,indicating the high efficiency and good energy-saving effect of the unit in normal operation.The research work and results is valuable to guide the occupants to choose the right strategy to operate the household air-source heat-pump radiant floor heating system in energy-saving way.