Introduction
A heat pipe is an appliance that enables the amalgamation of conductivity to heat as well as it is a transitive phase in an efficient way that allows heat transfer to occur between two solids. In 1942, the idea of heat pipes had first been proposed by Gaugler, but it was in 1962, when Grover created it, and thereafter it has been studied and improvements have been done to it (Gaugler 4).
In summary, the mechanism of the heat pipe is such that upon the liquid within the pipe coming into direct contact with the solid outer covering, evaporates are a result of heat absorption. This then goes through it to a cold crossing point where it evaporates once again, and the cycle repeats itself. But each heat pipe can be adjusted to fit the thermal working conditions of the system in case. This report expounds in detail on how the heat pipes work, how they are made, their applications and their comparison with other heat conductors.
Construction and Operation
A heat pipe is sometimes comprised of a sealed pipe, and at other instances, it is a tube made of a material that has high heat conductivity on both the hot and the cold ends like aluminium or copper. After this, a process of air removal and the sealing of the pipe with a coolant is done to create conducive temperatures. Otherwise, the pipe is heated so as to make the fluids (like water, ethanol, acetone, sodium or mercury) within it boil, and then it is sealed while hot.
This in turn causes some of the fluids to be in a liquid state while the rest are in gaseous state, which is caused by the partial vacuum. The vacuum enables the elimination of the diffusion of the gas through another gas, thus causing the major vapour to transfer rapidly as molecules to the cold end. What confines the degree of heat transfer is just how fast condensation of the gas happens at the cold end (Faghri 33).
Capillary pressure is used inside the walls of the heat pipes, while the fluid is still in liquid state. This is made up of a material that has the capability of employing capillary pressure on the liquid that has undergone condensation so as to direct it back to the hot end of the pipe. The structural specification of a heat pipe requires that a source of speeding up the process occurs if gravity is insufficient, and therefore, the input of a structure is done to achieve this.
It is important to note that a heat pipe is not a thermo-siphon as it does not contain a siphon in its structure. On the other hand, they contain no motorized moving parts and thus do not really require maintenance. Unfortunately, over time, non-condensing gases may cause the pipe to become less effective in heat transfer.
Comparison of heat transfer and effective conductivity of heat pipe
Evaporation and condensation are the means used to ensure the transfer of the heat energy from one point to another. This is done through a process known as the cooling mechanism. Usually, the ends of the heat pipes are not allowed to be below certain temperatures because the heat pipes rely on difference of the two ends, hot and cold.
As a result, they tend to try to stabilize the process by equalizing those temperatures. Consequently, absorption of the latent heat of evaporation of the working fluid decreases the overall temperature at that hot end. Heat pipes must in turn, while being manufactured, be tuned to precise cooling conditions. The temperatures are easily affected, and thus it is important to wisely select the material of the pipe’s outer covering by considering the size and coolant carefully.
When a heat pipe is heated beyond temperatures that they can stand, it causes the fluid within to evaporate, which in turn results in the stoppage of the process. This also causes the heat conductivity to be reduced significantly, and the conducting capabilities of the metallic outer covering are severely affected.
Heat pipes are mostly made of copper which has high heat conductivity, and therefore, an overheated heat pipe will commonly continue generating heat at a ratio of 1:80 of the pipe’s original conductivity (Gauglier 4). The desired operational range of temperatures is a key criterion for the selection of a working fluid.
Application of heat pipes domestically & industrially
Generally, they are used to ensure the movement of heat from one place to another without using a mechanical power supply. This technology is employed mostly in HVAC or heat, venting and air-conditioning applications mostly used in our day to day lives, be it in our homes, schools or workspaces.
They are also used to avoid our machinery and devices from overheating, especially those we use a lot, by dissipating the heat into the thin air. This in turn creates an environment that is suitable for the employees to work subsequently, making the company flourish in all spheres as there is more concentration on the important aspects of the business.
Heat pipes are not only used for moisture and humidity in workplaces, but they are also used for the same in buildings, for example, in eateries, supermarkets, libraries, storage areas and other places, especially where the products are sensitive to high moisture like food and other ingredients (Reay and Kew 309). Controlled humidity also enables customers to feel at home for they feel comfortable in these areas due to the atmosphere created for them.
Heat pipe technology is used to recover heat that would have gone to waste. What this means is that the heat transferred by these pipes can be used as an energy source for whatever structures meaning the business does not spend on payment for energy but instead conserves and as a result saves costs. This is done in places like offices, factories and other industrial areas, locally and internationally.
Conclusion
Therefore, heat pipes are generally used for the purpose of moving heat from one place to another without mechanically powered assistance which is a method that proves to be both effective for it eradicates heat and at the same time sustainable due to its saving costs factor.
When choosing the material of the pipe to be used, its size and the coolant within it affects the ideal temperatures in which they work. Application of this method is beneficial to a wide range of areas, and if profoundly researched into over the years, it will prove to give benefits due to discovering more ways of implementing this technology.
Work Cited
Faghri, Amir. Heat Pipe Science and Technology. New York, NY: Taylor & Francis Group, 1995. Print.
Gaugler, Richard. Heat Transfer Devices. Dayton, Ohio: U.S. Patent Office, 1995. Print.
Reay, David, and Peter Kew. Heat pipes. 5th ed. Oxford: Butterworth-Heinemann, 2006. Print.