| 摘要 |
PURPOSE:To enlarge a working temperature range of the titled device, by using an alcoholic aqueous solution as the working medium of heat pipe, in a heat pipe type vacuum glass tube-shaped solar energy collector. CONSTITUTION:An aqueous solution B of 85wt% of propylene glycol or an aqueous solution C of 70wt% of ethanol is used as a working medium to be filled into a heat pipe. Because the aqueous solution B has a high boiling point, i.e., about 150 deg.C under an atmospheric pressure, the solution B is filled into the heat pipe after the reduction of its pressure to lower than 0.1kg/cm<2>. The aqueous solution C of ethanol is used only after the reduction of its pressure to lower than 0.1kg/cm<2>. The freezing point of propylene glycol aqueous solution B is about -40 deg.C at the concentration of 85wt%. Similary, the ethanol aqueous solution has the freezing point of about -50 deg.C at a 70wt% concentration. In this manner, the alcoholic aqueous solution can lower a freezing temperature range, prevent the decomposition and metamorphosis at elevated temperature, and thereby allowing an application in an extended temperature range from -40 deg.C to 200 deg.C. |
