A  heat-pipe is a sealed copper pipe containing a small quantity of volatile  liquid with no air.Heat pipe vacuum tube consists of  the glass vacuum tube and a copper heat pipe which is fixed by aluminium flake  and silicon plug. When copper heat pipe to be heated then it will conduct heat to  its tip (condenser) which is plugged into the header pipe(inside of manifold). Water  run through the header pipe so that heat is transferred from the heat pipe  condenser to the water. Solar collector conversion efficiency at 72% in full  bright sunlight.