Study On Application Of Radiator Low Temperature Intermittent Heating In Hefei Area

The rapid economic development is inseparable from the consumption of energy,but a large amount of fossil energy consumption leads to the destruction of the ecological environment.Therefore,the form of energy development needs to be adjusted and transformed,and the development of environmental protection and energy-saving industries is emphasized.Building energy consumption accounts for one-third of China's energy consumption.Building energy efficiency has become the focus of national energy conservation efforts.The heating and air conditioning energy consumption accounts for 50%~70% of the total energy consumption of the building,especially heating energy consumption occupies a considerable proportion.Heating energy conservation is a major research content in the field of building energy conservation.The regional differences in heating methods are quite obvious.Hefei is located in cold winter and hot summer regions,with large temperature difference between day and night in winter,and outdoor humidity is high and cold.Generally,residential buildings do not adopt heating measures,so the indoor thermal environment in winter is not optimistic.With the improvement of living standards,people have a higher pursuit of quality of life.Under the conditions of energy saving,low carbon,and environmental protection,a healthy living environment with high comfort has become the focus of attention.This article starts from the comfort and energy-saving characteristics and conducts a study on the application of radiators for intermittent heating of low temperatures in Hefei.Based on the basic knowledge of heat transfer,the radiator heat transfer process is described,and the related calculation theories of indoor thermal environment and thermal comfort are introduced.Taking the air source heat pump as the main heat source,the electric heating as the auxiliary heat source,and the end as the radiator for the low-temperature intermittent heating,the experiment was conducted on the second floor of an experimental building in Hefei City.The indoor and outdoor temperature and humidity,also the internal surface temperature of building envelopes are measured.And the system power consumption is calculated.Taking into account the large temperature difference between day and night in Hefei area,more time does not need heating during the day,and for the current increase in the number of commuter workers,set the experimental operating conditions: 30 minutes before the experiment to take the water temperature 60 °C,air source The heat pump and electric heating equipment work together to quickly increase the indoor air temperature.After 30 minutes,the water supply temperature is set to 40°C.The air source heat pump operates independently.The intermittent operating time is 17:30 and the power is off at 07:00 the next day.Airpak simulation software was used to model the experimental room.The initial temperature rise rate curve,room temperature field,velocity field distribution and PMV-PPD index were calculated by simulation calculation.The above research shows that the radiator low-temperature intermittent heating method is feasible in the Hefei area,and the heating system has a good operating effect,which can not only meet the requirements of indoor thermal comfort,but also achieve more energy-saving effects.The experimental results show that when the initial water supply temperature is 60°C,the indoor temperature can be rapidly increased.The average temperature rise rate of the indoor air is 10.4°C/h.When the water temperature is 40°C,the indoor temperature field is stable and the internal surface temperature of the envelope structure is stable.The average temperature of the indoor air was 18.1°C.The vertical temperature difference between the head and foot of the human activity area was 2.9°C and the indoor relative humidity was maintained at 37%.The experimental operating conditions can save at least 18% of the cost compared to the air-source heat pump radiator low-temperature heating continuous operation,which can save 13.3 yuan /(m2 · season).Airpak simulation software was used to simulate the experimental room.The results showed that the radiator low-temperature intermittent heating method can meet the indoor thermal comfort requirements of Hefei area,and the indoor thermal comfort is better.The simulation data and actual measurement data have a high degree of coincidence,and the simulation and experimental initial temperature rising rate change trends are consistent.The simulation and actual measurement temperature gradients in the vertical direction are also consistent;the indoor average temperature can reach 18°C,but the indoor temperature distribution has a stratification phenomenon.The air temperature near the inner wall is higher than the temperature near the outer wall,the upper air temperature is higher than the temperature in other areas;the average air velocity in the room is less than 1m/s,and the human body has no sense of blowing air,and the indoor air flow rate changes more steadily with less change;The PMV value is around 0 ~-0.5,and the human body feels cold.However,within the comfort range,the indoor PPD value is less than 10%,and the dissatisfaction rate is low,which conforms to the ISO 7730 international standard.