The out let pipe is connected to the other end of the absorber tube and generated steam is delivered to the application. The circulating fluid flow measured by collecting in a vessel with respect to the time. The reflection surface can be deteriorated when exposed to the open atmosphere, and it can be cleaned by rubbing polish and can be washed. It can be maintained with good environment stability and weatherablity to be monitored during the test. Many methods have been developed to study the focal image characteristic of heat flux and heat flux on the absorber