Heat pipe

About: Heat pipe is a research topic. Over the lifetime, 30354 publications have been published within this topic receiving 243669 citations. The topic is also known as: heatpipe & heat-pipe.

Passive integral solar heat collector system

Abstract: The present invention relates to an improved apparatus for collecting, absorbing, transferring, and storing solar heat energy, economically and passively, without pumps or electric power. The apparatus comprises a solar collector with a flat finned heat pipe absorber and an attached integral insulated storage tank with a double wall heat exchanger. The absorber, made of one or more slightly tilted gravity assisted heat pipes with flat absorber fins, absorbs and transfers solar heat by evaporation, vapor transport, and condensation to the slightly elevated heat storage tank. The one or more heat pipes turn on when the sun is shining and turn off automatically when the sun is not shining.

Development and validation of a TRNSYS type to simulate heat pipe heat exchangers in transient applications of waste heat recovery

Abstract: Heat pipe heat exchangers (HPHEs) are being more frequently used in energy intensive industries as a method of low-grade waste heat recovery. Prior to the installation of a HPHE, the effect of the heat exchanger within the system requires modelling to simulate the overall impact. From this, potential savings and emission reductions can be determined, and the utilisation of the waste heat can be optimised. One such simulation software is TRNSYS. Currently available heat exchanger simulation components in TRNSYS use averaged values such as a constant effectiveness, constant heat transfer coefficient or conductance for the inputs, which are fixed during the entire simulation. These predictions are useful in a steady-state controlled temperature environment such as a heat treatment facility, but not optimal for the majority of energy recovery applications which operate with fluctuating conditions. A transient TRNSYS HPHE component has been developed using the Effectiveness-Number of Transfer Units (ɛ-NTU) method and validated against experimental results. The model predicts outlet temperatures and energy recovery well within an accuracy of 15% and an average of 4.4% error when compared to existing experimental results, which is acceptable for engineering applications.

Investigation of dry machining with embedded heat pipe cooling by finite element analysis and experiments.

Abstract: This paper investigates the performance of a cutting tool embedded with a heat pipe on reducing cutting temperature and wear in machining. The temperature of a tool plays an important role in thermal distortion and the machined part’s dimensional accuracy, as well as the tool life in machining. A new embedded heat pipe technology has been developed to effectively remove the heat generated at the tool–chip interface in machining, thereby, reducing tool wear and prolonging tool life. In particular, the technique can effectively minimize pollution and contamination of the environment caused by cutting fluids, and the health problems of skin exposure and particulate inhalation in manufacturing. The ANSYS finite element analysis simulations show that the temperature near the cutting edge drops significantly with an embedded heat pipe during machining. Temperature measurements at several locations on the cutting tool insert agree with the simulation results both with and without the heat pipe. Experiments were carried out to characterize the temperature distributions when performing turning experiments using a cutting tool installed with an embedded heat pipe. The performance of the heat pipe on reducing the cutting tool temperature was further supported by the observations of cutting tool material color, chip color, and the chip radius of curvature.

Performance of a Heat Pipe Solar Collector

Abstract: This paper presents a comparative study between theoretical predictions and experimental results of a flat-plate solar collector with heat pipes. The theoretical model for the heat pipe solar collector is based upon the method by Duffie and Beckman (1980), modified to use heat pipes for energy transport. The methanol filled heat pipes are self-contained devices whose evaporators are inserted under pressure in the flat plate of the solar collector and the heat exchange is carried out at their condensers. The evaporators contain a wick of one mesh layer to ensure a better distribution of the working fluid. The condensers are wickless and inclined 15 deg more than the inclination of the evaporators to facilitate the return of the condensate to the evaporators. The time constant of the heat pipe solar collector was calculated and found to be about 23 minutes. Also presented in this paper are comparative experimental results of the proposed solar collector and a conventional commercial solar collector. The two collectors were tested simultaneously. The instantaneous efficiencies of the heat pipe solar collector are lower than the conventional collector in the morning and higher when the heat pipes reach their operating temperatures.