The Dynamic Relationship Between Ambient Temperature And Solar Radiation

It is well known that solar radiation is the basic meteorological parameter in solar energy application, and is also the important factor for building energy consumption. Due to the difficult measurement of solar radiation in early, many countries in the world are lack of adequate long-term solar radiation data. Considering the test records of solar radiation data for the current meteorological offices and stations are not hourly, only record one time for 4 hours or 6 hours. Therefore, it is extremely difficult to obtain the hourly solar radiation data from the meteorological offices and stations. The lack of the hourly solar radiation data makes a great challenge for the research and application of solar energy, especially in the field of HVAC, the meteorological parameters such as solar radiation are important factors that affect building energy consumption, if lack of hourly meteorological parameters, it will make the building energy consumption simulation hard to ensure the accuracy of analysis results.In spite of this, due to the importance in each field of different meteorological parameters, other commonly measured meteorological parameters such as sunshine duration, air temperature, relative humidity and pressure et al keep a large amount of data. Indirect estimation of solar radiation from commonly measured meteorological variables such as temperatures, therefore, can provide scientific method to makeup for the missing solar radiation data due to various reasons.Currently most of China’s urban weather stations only have the observation data of horizontal total solar radiation, and lack of corresponding direct and diffuse radiation observation data, except a few primary stations can provide the diffuse radiation, most stations can only provide horizontal total radiation. But in the field of building energy efficiency, accurate hourly direct and diffuse radiation data decides whether building energy consumption simulation resultis accurate or not. In building energy efficiency design, therefore, the fraction of direct and diffuse solar radiation on a horizontal surface becomes a important subject in front of many scholars.According to current situation of domestic and foreign related research, the paper selectes outdoor air temperature which is most related to solar radiation, trying to build a general model for estimation of hourly global solar radiation using air temperatures. By establishing the relevant relation between solar radiation and the ground surface temperature, and the relevant relation between the ground surface temperature and air temperature, and taking the ground surface temperature as intermediate variable, the dynamic relationship between air temperature and solar radiation is established. Based on the above research, establish the regression function between max air temperature and max solar radiation, so as that between average air temperature and average solar radiation. According to the different weather conditions, the daily variation mathematical expressions of outdoor air temperature and solar radiation in a typical day are established. Then the transition between outdoor air temperature and solar radiation is reached. To find out the fraction method of diffuse and direct solar radiation on a horizontal surface, the fraction method is put forward by establishing the relationship between hourly atmospheric diffuse transmittance andhourly clearness index. This method is very well used and can provide a scientific basis forthe fraction of diffuse and direct solar radiationon a horizontal surface.According to the study, the main conclusions: 1) For high altitude areas, solar radiation can be calculated as a linear function of outdoor air temperature and time, for the plains, the solar radiation can be calculated as a logarithmic function of temperature and time. 2) Either the outdoor air temperature or global solar radiation data is known, another date can be get according to the correlation between outdoor temperature and solar radiation, based on the mathematical expressions of daily change. 3) there is a significant correlation between the atmospheric scattering transmission ratio and the clearness index, by establishing the regression model of which can achieve the fraction of the horizontal total solar radiation.