Figure 1 crosssectional view of a typical wicked heat pipe 2 3. Plate heat exchanger, how it works working principle hvac industrial engineering phx heat transfer duration. Pdf the heat pipe is one of the remarkable achievements of thermal. Careful design can minimize the performance loss and allow an accurate predictio n performance. The design of a standard heat pipe are illustrated in figure 1. Heat pipe principle it is not within the scope of the article to go into details of heat pipe theory. Pdf basic principles of heat pipes and history researchgate. A heat pipe is a heattransfer device that combines the principles of both thermal conductivity. Heat pipes employ phase change to transfer thermal energy from one point to another by the vaporization and condensation of a working fluid or coolant. It is a vacuum tight device consisting of an envelope, a working fluid, and a wick structure. Mvk160 heat and mass transfer may 7, 2012, lund, sweden heat pipe, selection of working. Transports heat from a heat source to a heat sink works as an isothermalizer why twophase thermal system.
Heat pipes hardware m t l l i t b ith th i fmetal aluminum tube with grooves on the inner surface cold t ild extrusion grooves are filled with the working fluid water, ammonia, propylene, etc. Their operation is based on the principle of oscillation for the working fluid and a phase change phenomena in a capillary tube. Hvac ducting principles and fundamentals 2012 instructor. In this section we will briefly describe the basic working principle and the performance limits of heat pipes. Initially, the oph is evacuated and partially filled with the working fluid. Heat is applied to the evaporator section and is conducted through the wick and. The heat pipe principle is indeed applicable over a very wide range of sizes, shapes, temperatures and materials. Heat pipes rely on a temperature difference between the ends of the pipe, and cannot lower temperatures at either end below the ambient temperature hence they tend to equalize the temperature within the pipe. Flanges can be added on the outer surface for easy integration with instruments or radiators the flange is an integral part of the extrusion. Heat pipe is generally selfheat recovery devices that is used to transfer heat from one end heat injection to another destination with minimum temperature differences and also to pass the heat across internal surface. The principle of wick heat pipe operation is illustrated with the aid of fig.
Use 2 phase flow, latent heat of vaporization, and capillary action to circulate a working fluid between heated and cooled regions via a wick. The principle of operation of a heat pipe is best described by using the simple cylindrical geometry. Many specialists in fluid mechanics probably have not heard of heat pipes or fully. The design of a standard heat pipe are illustrated in. Efficient heat transferefficient heat transfer boiling and condensationboiling and condensation small temperature difference between the heat source and. The basic idea behind a heat pipe is the circular process shown. There are many different kinds of heat pipes but the working principle is similar. Introduction heat pipe is a capillary twophase heat transfer device.
Circular process of a heat pipe at the heat source the cold liquid is evaporated, the hot vapor flow is afterwards transported to the heat sink where the vapor condensates again and is transported back to the heat source. Heat pipe introduction,working principle,types,application maniks. Heat pipes a novel cooling principle for generator. Heat pipes can transfer heat with minimal temperature difference between one end and the other. The working fluid mass is chosen so that the heat pipe contains both vapor and liquid over the operating temperature range. The liquid is evaporated at the hot end then transfered to the cool end and condensed to liquid again. In order to work properly the length of the heat pipe should not exceed this z max.