Heat Transfer Enhancement Using Passive Technique: Review

Abstract

Preserving and saving energy have never been more important, thus the requirement for more effective and efficient heat exchangers has never been more important. However, in order to pave the way for the proposal of a truly efficient technique, there is a need to understand the shortcomings and strengths of various aspects of heat transfer techniques. This review aims to systematically identify these characteristics two of the most popular passive heat transfer techniques: nanofluids and helically coiled tubes. The review indicated that nanoparticles improve thermal conductivity of base fluid and that the nanoparticle size, as well as the concentrations of the nanoparticles plays a major role in the effectiveness of the nanofluids. Regarding the helically coiled tubes, it was discovered that the use of a coiled tube produces secondary flows, which ultimately improves the heat transfer enhancement. The third part of the review focused on microchannels and microtubes. This is mainly due to the growing need and requirement of smaller and more compact thermal cooling systems. Thus, ultimately the result of the review indicates that a combination of all these three techniques can lead to a compact and minimized heat exchanger that uses the benefits obtained from both nanofluids and helically coiled tubes in order to improve the heat transfer rate of the thermal systems.

An Heat Transfer Coefficient and Pressure Characteristics in a Copper Pipe Flow System: A Preliminary study Utilizing an EG/Water Mixture

“…It is affected by parameters such as fluid velocity [10][11][12], density [13], viscosity [14], thermal conductivity [15], and the presence of nanoparticles throughout the fluid [16,17]. An accurate understanding of the heat transfer coefficient is essential when designing and optimizing cooling systems [18], heat exchangers [17], and other heat transfer devices, as it has an immediate effect on the overall heat transfer rate [19] and efficiency [20].…”

The Heat Transfer Coefficient in a Copper Pipe Flow System Using a 40/60 Volume Ratio Ethylene Glycol/Water (EG/H2O) Blended Fluid

“…The heat transfer coefficient depends on several factors, including the physical properties of the fluid, the flow conditions, and the nature of the surface [7] [8]. It is influenced by parameters such as fluid velocity [9][10], temperature [11], viscosity [12], density [13], thermal conductivity [14], and the presence of any additives or nanoparticles in the fluid [15] [16]. Accurate knowledge of the heat transfer coefficient is essential for designing and optimizing heat exchangers [17], cooling systems [18] , and other heat transfer equipment, as it directly affects the overall heat transfer rate [19] and system performance [20].…”