An experimental study on a plate gravity heat pipe (PGHP) with inner cavity size of length 100 mm (X), width 2.5 mm (Y), and height 210 mm (Z) with acetone as the working fluid was carried out. The effects of heating power inputs (80–180 W) and fluid filling ratios (25%, 48%, and 55%) on the start-up temperature, start-up time, temperature difference, and relative thermal resistance on the Z-ax...

Loop heat pipe evaporators operating under steady state conditions were numerically investigated to describe evaporator characteristics and evaluate evaporator performance. Numerical solutions were obtained for conjugate flow and heat transfer in primary evaporator components. Two geometrical configurations used for cylindrical LHP evaporators, a non-bayonet evaporator and a bayonet evaporator,...

In order to study the heat transfer characteristics, a micro heat pipe (MHP) of circular geometry having inner diameter 1.8 mm and length 150 mm is designed and fabricated. An experimental investigation is carried out also to investigate the performance of the MHP with different experimental parameters. These experimental parameters include inclination angle, coolant flow rate, working fluid an...

An investigation on enhancement of heat transfer is carried out for a double pipe exchanger in which the outer wall inner provided with circumferential labyrinth passages. Rectangular and triangular cavities fixed tooth thickness, height, pitch are considered effect added structures characteristics discussed. A two-dimensional steady numerical simulation using ANSYS-FLUENT software. The flow Re...

Waste heat recovery is very important, because not only it reduces the expenditure of heat generation, but also it is of high priority in environmental consideration, such as reduction in greenhouse gases. One of the devices is used in waste heat recovery is heat pipe heat exchanger.Anexperimental research has been carried out to investigate the hydrodynamic and thermal performance of a gas...

0196-8904/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.enconman.2011.11.011 ⇑ Corresponding authors. Tel./fax: +86 551 3607367 E-mail addresses: [email protected] (P. Gang), j Heat-pipe photovoltaic/thermal (HP-PV/T) systems can simultaneously provide electrical and thermal energy. Compared with traditional water-type photovoltaic/thermal systems, HP-PV/T systems can be used in cold ...

1. ABSTRACT It has been about fifty years ago since the first unplasticized poly(vinyl chloride) (uPVC) pipes were installed for use in gas distribution purposes. Currently, about 22,500 km of uPVC is still in use in the Dutch gas distribution network. The pipes were originally designed for a lifetime of 50 years, but due to positive experiences the question arises if (and how long) the lifetim...

This paper investigates the enhancement of heat transfer coefficient and Nusselt number of a nanofluid containing nanoparticles (γ-AL2O3) with a particle size of 20 nm and volume fraction of 0.1%-0.3% (V/V). Effects of temperature and concentration of nanoparticles on Nusselt number changes and heat transfer coefficient in a double pipe heat exchanger with counter turbulent flow are investigate...

A novel experimental approach is developed for characterizing the performance of heat pipe wick structures. This approach simulates the actual operation of wick structures in a heat pipe. Open, partially submerged, sintered copper wicks of varying pore size are studied under the partially saturated conditions found in normal heat pipe operation. A vertical wick orientation, where the capillary ...