| Tibet is located on the Qinghai-Tibet Plateau,which is high in the cold and high altitude of China.It is rich in solar energy,lack of conventional fossil energy,and fragile ecological environment.In order to improve the local energy shortage,it is necessary to efficiently develop and utilize solar energy resource.As the most common heat collection device in solar thermal utilization in Tibet,the analysis of its thermal performance provides a theoretical reference for design and manufacture of heat collection equipment,which is significant for the development of Tibet’s solar heating industry.It takes the flat plate collector in Lhasa,Tibet as the research object,and conducts experiments on the thermal performance of the flat plate collector.The effects of solar incident angle,time constant,fluid flow and other parameters on the performance of the collector are mainly studied main tasks as follows: firstly,the basic structure and its basic heat transfer theory are analyzed.Secondly,in order to carry out the research on the inclination of the flat collector and the thermal performance under variable conditions,an experimental platform is set up;the self-designed adjustable bracket platform can realize the plate heat collection on the basis of the steady state test method.Dynamic adjustment of the inclination angle of the mounting device,the angle range is 36°～45°.Thirdly,through the dynamic adjustment of the tilt angle,the variation law of solar radiation intensity on the flat-plate collector under different installation tilt angles is discussed.It shows that in summer,the daily solar radiation quantity increases with the decrease of the tilt angle,until the amount of solar radiation collected at the optimal angle reaches the maximum,the opposite in winter.Finally,carry out research of variable conditions.The measured time constant of collector is 252 s,a 50° incident angle correction factor is 0.83,and an instantaneous efficiency intercept is 0.64.The heat loss coefficient is 6.47 W·m-2·℃-1;through pressure drop experiments,it obtained that the pressure difference increases with the increase of the flow rate,the thermal efficiency of the collector increases with the increase of the flow rate of the medium,but When the flow rate is greater than 0.04 kg/s,the increasing trend tends to be gentle.Figure 36;Table 12;Reference 55... |
