the present invention comprises a heat source , a heat pipe , and a thermal transformer in thermal contact with said heat pipe and proximately disposed to said heat source , whereby a uniform heat transfer from said heat source to a heating system is obtained . the thermal transformer includes a container , a working fluid and its vapor which are essentially in equillibrium , evaporating surfaces depending from the internal surfaces of the transformer that are wetted with the working fluid and that are proximate to the heat source , and condensing surfaces depending from the exterior of those areas of said heat pipe that are in thermal contact with said transformer .