Active heat-pipe filled with glycol-water solution

A new type of heat pipe containing an active porous material that by decomposition first gives up water and then undergoes a change in porosity is discussed. The length is 600 mm and the diameter 35 mm; the circulating liquid is a glycol-water solution. Various properties of the porous medium are evaluated, among them porosity, thermal conductivity, density, and permeability. The relationship between the efficiency of the heat pipe in steady state operation and its temperature difference between evaporator temperature and air temperature is studied experimentally, as is the relationship between the efficiency and the temperature difference versus the supplied electric power per unit of heat pipe exterior surface.