| Because solar energy is green and pollution-free,it has been widely used in space heating in China in recent years.Although Kunming has a mild climate,there is a large temperature difference between morning and evening in winter,and there is a demand for space heating at night and cold days.Winter is just a good period of solar radiation resources in Kunming.Using solar heating can not only improve the comfort of life,but also have obvious effect of energy saving and emission reduction.In order to study the operation characteristics of solar space heating in Kunming area,this paper set up a solar heating system with air source heat pump as auxiliary source.Two different types of heating terminals,which are radiator and floor radiant,were taken as the research objects respectively,and solar space heating is studied in single building.Analysis and comparison of different heating terminals,different weather conditions and heating temperatures,the heating demand,indoor heating temperature and air flow distribution,thermal comfort and other characteristics.In order to provide some reference for the research and engineering application of solar space heating in Kunming area.The main research contents and conclusions are as follows:（1）In consecutive sunny days with similar outdoor ambient temperature,the room heating temperature was set at 18℃ for the night experiment.The results show that the average indoor temperature of floor radiant heating is higher than the average indoor temperature of radiator heating,and the horizontal and vertical temperature differences of the two kinds of heating terminal are not large,which meet the requirements of ISO 7730 standard that the maximum indoor vertical temperature difference does not exceed 3℃.The indoor temperature difference of floor radiant heating is lower than that of radiator heating,and the temperature uniformity is better.From 21:00 to 8:00 the next day,the PMV（Predicted Mean Vote）for radiator heating fluctuated between-0.93 and-0.64,the PPD（Predicted Percent Dissatisfied）ranged from 13% to 24%,the PMV for floor radiant heating fluctuated between 0.06 and0.23,and the PPD ranged from 5% to 6%.Floor radiant heating has high thermal comfort.The heat released by the radiator is in the range of 1012 k J to 2564 k J,and by the radiant floor heating is in the range of 1105 k J to 1728 k J,which can show that the use of floor radiation to more energy saving.（2）In the continuous cold weather with similar outdoor ambient temperature,the heating temperature was set at 14℃ for the night experiment.Night experiments were carried out in continuous cloudy and cold weather with similar outdoor ambient temperature,and the heating temperature was set to 14°C.The results show that: from the overall trend,the indoor average temperature of the two kinds of heating terminal is roughly the same,rising first and then stable,after stable condition,the indoor temperature is about 11℃ for floor heating,and temperature is about 10℃ for radiator heating.Based on the experiment,Fluent simulation software is used to simulate radiant heating of radiator and floor.For the accuracy of the simulation results,it is necessary to verify the grid independence of the three-dimensional model and ensure the simulation accuracy of the two heating models according to the experimental data.The main conclusions are as follows:（1）When the room heating temperature is set at 18℃ on a sunny day and night,the results show that: The temperature of radiator heating section gradually increases from bottom to top,the temperature of floor radiating heating section gradually decreases from bottom to top,and the vertical temperature difference does not exceed3℃;The indoor temperature and air flow velocity with floor radiant are higher than the radiator heating,and the temperature distribution is more uniform with floor radiant.The temperature stratification phenomenon is not obvious as the radiator heating.The indoor temperature change with simulations are basically the same with experiments.The indoor temperature is about 18.2℃and 19.3℃with radiator heating and floor radiant heating respectively.After that,the indoor temperature changes more evenly.The temperature of the inner wall with the floor radiant heating is more uniform than that of the radiator heating.（2）The simulation results show when the room temperature is set at 14℃ in cold weather: The average indoor temperature is10.7℃and 13.2℃with the radiator heating and the floor heating respectively.The indoor temperature of different sections with the radiator heating is lower than the floor heating,and the indoor temperature stratification with the radiator heating is obvious,and the temperature uniformity is higher than that of floor radiation heating. |
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