Solar vacuum tubes are tubes covered with a vacuum jacket so that no heat can be dissipated by conduction and convection of air. By this process, we can get pretty high temperature even at very cold temperature. In this video, you can see how very temperature water can be produced by using such a tube even at -29°C temperature. As this tube directly converts solar radiation into heat, I want to know if the input is at higher temperature, then can we get greater temperature output? Efficiency of market available solar troughs falls with rising temperature as higher temperature also means loss of more energy by means of conduction and convection of air from the outer body of the collecting tube. I just want to know whether the vacuum tube get rid of that problem or not.