Analysis Of Energy Consumption Of Solar Heating In Kunming In Winter

With the large temperature difference between day time and night time in winter in Kunming area,there is still a certain demand for space heating at night,and the abundant solar energy resources in Kunming area provide a favorable condition for using solar space heating.Therefore,it is very necessary to carry out the research on space heating with solar energy based on the climate characteristics of Kunming in winter.In addition,Through the organic combination of solar energy and space heating,the purpose of energy saving and emission reduction can be achieved while improving indoor thermal comfort,which is of great significance to achieve the carbon peaking and carbon neutrality goals.Based on this research background,a solar space heating system in Kunming area is designed and built,with air source heat pump as the auxiliary heat source,using theoretical analysis,experimental testing and Polysun software simulation research method to analyze the energy consumption of space heating with solar water heating system.In winter（November ～ February）,the space heating characteristics and influencing factors of the solar space heating system were tested and simulated.The main research results are as follows:Firstly,the key influencing factors of indoor thermal environment are explored based on experimental analysis,and the three main influencing factors,namely ambient temperature,indoor heating temperature and heating end,are compared and analyzed to explore their effects on system energy consumption.The results show that:（1）In sunny day,cloudy day and cold day with different ambient temperatures at night when indoor heating temperature is set at 18 ℃,using designed solar energy heating system,the indoor temperature can be maintained at 18 ℃ when the average ambient temperature is about 11 ℃ at night;on cloudy days,indoor temperature can be maintained at 16 ℃ when the average ambient temperature is about 4 ℃,which can basically meet the indoor heating temperature;in cold day,the ambient temperature is just about 2 ℃,the indoor temperature is maintained at about 12 ℃.Although it cannot meet the heating temperature,the indoor thermal environment improved to a certain extent.（2）When floor radiant heating is used and the indoor heating temperature is set at 18 ℃,it is obtained by analyzing the experimental data under typical weather:when the average outdoor temperature at night is 11 ℃ in sunny weather,the heat supply from the heat pump is about 31.1% of the total heating supply of the system;when the average outdoor temperature at night is about 4 ℃ in cold weather,the heat load of the heat pump increases,and the heat pump heating supply reaches 56.6 % of the total heating supply;in low temperature weather,when the average outdoor temperature is about 2 ℃ in all day,the heating supply is almost provided by heat pump.（3）When radiant floor is used,compared with radiator,the average indoor temperature using radiant floor heating is about 2.4 ℃ higher than using radiator,and the overall energy consumption is lower.When heating temperature is set at 18 ℃,and average temperature is 11 ℃ at night time in sunny day,the energy consumption using radiator should be higher than radiant floor heating 12.7 % above and higher than 27.4% when average ambient at 4 ℃ at night on cloudy days.（4）The indoor heat load is obtained through measured calculation,and the difference value between ambient temperature at night and indoor heating temperature setting value is introduced to describe the variation rule of measured heat load,and the empirical formula of measured heat load changing with temperature difference δ T is fitted as bellow:Q_C=3.6015ΔT~2-30.5443ΔT+1048.8751（3＜ΔT＜14）Secondly,combined with Kunming meteorological data,according to the actual parameters of the laboratory,the Polysun software is used to simulate.The simulation system model is built,and the measured data of sunny and cloudy days are used to verify the model,and the error is within a reasonable range.（1）The software is used to evaluate the operation of the space heating system when the indoor heating temperature is set at 18 ℃,the system runs well and the average solar fraction can reach 67.7 % in winter.（2）The marginal benefit point of indoor heating temperature is 19 ℃ when the insulation of the building is good under the heating system.If the heating temperature exceeds this value,the power consumption of the system will increase sharply,so the heating temperature setting below 19 ℃ is a more economical and environmentally friendly choice.（3）Using radiant floor as the heating end has a higher solar fraction,and it has more energy saving than using radiator,which is similar to the experimental results.In January,for example,the radiant floor saves 18.4% more energy than the radiator.（4）In January,the system heating demand would increase by 1000 k J when the average outdoor temperature decreased by 1.41 ℃ when the indoor heating temperature is set at 18 ℃,and the relationship between heating demand and the average ambient temperature T at night is obtained by fitting as bellow.Q_W=-707.8402T+20816.5986（4＜T＜13）...