Randeep Singh^a,*,†, Gero Lapp^a, Jason Velardo^b, Phan Thanh Long^a, Masataka Mochizuki^c, Aliakbar Akbarzadeh^d, Abhijit Date^d, Karsten Mausolf^e, Kristin Busse^e

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-8, 2021, DOI:10.5098/hmt.16.2

Abstract In this paper, different options, based on heat pipes, for thermal management of electric vehicle (EV) battery system, at cell, module and pack level, for 40 to 400 W output heat, has been explored, analysed and compared. Cooling architecture based on embedded heat pipe (EHP) with single phase pumped cold plate (CP), as most adaptable design for low to medium range EVs, while EHP with loop heat pipe (LHP) as high performance design for high-end carlines, has been classified as potential cooling systems. Experimentally, it was shown that EHPs will provide best performance for heat acquisition at cell/module level, while… More >

Yasushi Koito^a,*

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-7, 2021, DOI:10.5098/hmt.16.1

Abstract For ultra-thin heat pipes, a centered wick structure is often used. In this study, a numerical analysis is performed on an ultra-thin heat pipe in which the wick structure’s position has deviated from the center. A 3D heat pipe model, developed by the author in a previous study, is extended, and numerical calculations are conducted to determine any differences in performance because of an off-center wick. The major findings are as follows: (1) a completely centered wick structure is recommended for optimum performance; (2) accurate central positioning of the wick structure is important in the fabrication process of ultra-thin heat… More >

Felix Schily^a,∗, Wolfgang Polifke^a

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-15, 2021, DOI:10.5098/hmt.17.16

Abstract A simple open-loop pulsating heat pipe model is proposed, which allows to analytically determine the start-up behavior by a linear stability analysis. Two distinct types of instability can occur in such a pulsating heat pipe: oscillatory and non-oscillatory. This paper demonstrates that for bubbles consisting of non-condensible gas, large temperature gradients along the wall are required to achieve start-up, whereas start-up is fairly easy to achieve when there is only a single working medium that forms bubbles from its vapor. The study also finds that surface tension as such only influences start-up indirectly, while contact angle hysteresis dampens out any… More >

Jason Velardo^a, Randeep Singh^a,*, Mohammad Shahed Ahamed^a, Masataka Mochizuki^b, Abhijit Date^c, Aliakbar Akbarzadeh^c

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-11, 2021, DOI:10.5098/hmt.17.1

Abstract Thermal solutions play an integral role in managing heat loads for electronic devices. As these electronics become more compact and portable, improved thermal management solutions need to be introduced. Thin flattened heat pipes (0.8mm – 2.0mm thick) and piezoelectric fans (1mm thick) have been proposed here for this purpose. The maximum heat carrying capacity of the flattened heat pipe was experimentally determined and found to be a function of the flattened heat pipe thickness. Reductions from 48W at 2.0mm to 7W at 0.8mm were observed. This was expected to be due to capillary limitations. The piezoelectric fan could be operated… More >

Ningxiang Lu, Jinwang Li^*, Yongkang Sun

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-15, 2022, DOI:10.5098/hmt.18.24

Abstract Heat pipe is a kind of high-efficiency heat transfer element which depends on the phase change of its internal working liquid. It has the characteristics of high heat conductivity and excellent average temperature performance. As the core component of heat pipe, capillary wicks play the role of transmitting working fluid and have a crucial impact on the heat transfer performance of heat pipe. In this paper, the research progress of capillary wicks in recent years is introduced from the aspects of structure, fabrication method, performance research, numerical analysis and so on. The current research results of capillary wicks are summarized,… More >

Yu.E. Nikolaenko^a , D.V. Pekur^b,*, V.Yu. Кravets^a, V.M. Sorokin^b, D.V. Kozaka , R.S. Melnyk^a, L.V. Lipnitskyi^a, A.S. Solomakha^a

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-13, 2022, DOI:10.5098/hmt.18.23

Abstract This study compares thermal characteristics of two design versions of a new low-cost air-cooling system with a standard heat sink profile and built-in flat heat pipes of a simple design with a similar cooling system design without the heat pipes. The aim of the work is to determining the thermal characteristics and choosing the most effective option in a practical context. Using computer simulation in the Solidworks Flow Simulation standard software package allowed determining how the temperature of 8 transistors with a total power of 224 W was affected by changes in air velocity from 1 to 30 m/s, effective… More >

Ayad S. Abdallah^a,b,*, Nabil Jamil Yasin^a, Hani Aziz Ameen^a

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-7, 2022, DOI:10.5098/hmt.18.10

Abstract To reduce the energy consumption in air-conditioning systems without changing the required temperature level in the air-conditioned space, Heat Pipe Heat Exchanger (HPHE) has been experimentally used and tested. The heat pipe has been filled with working fluid by about 50% of the volume of the evaporator which represents the filling ratio. In this research, three mass concentration of nanoparticle from copper oxide (CuO), 1wt%, 3wt% and 5wt% have been used and studied. Additionally, its effect on the HPHE effectiveness and the heat recovery ratio at different inlet air temperatures, 30, 35, 40, 45, 50, and 55 °C, have been… More >

Nagham Yass Khudair^a,*, Ahmed Kadhim Hussein^b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-6, 2022, DOI:10.5098/hmt.19.29

Abstract There has been a shift in our concern for energy towards renewable energy sources as a result of the increasing demand for energy and the decreasing supply of fossil fuels. Solar energy is, without a shadow of a doubt, the most environmentally friendly and beneficial alternative among all of the other sources that are now available. In today's world, many people harvest energy from the sun using a variety of various kinds of solar collectors. It has been discovered that the efficiency of the solar collector is reliant on the properties of the working fluid, which is responsible for the… More >

Zhun Li^1,2,3,*, Zhengrong Ouyang^1,2, Tianbao Sun³, Qiang Li³, Xiaobo Zhao³, Rong Yu³

Energy Engineering, Vol.119, No.4, pp. 1393-1402, 2022, DOI:10.32604/ee.2022.020488

Abstract The building energy consumption is an important part among the total society energy consumption, in which the energy consumption for air conditioning occupies almost 70%. The energy consumption of the air conditioning system for fresh air handling can be saved effectively when the exhaust air energy could be recovered to preheat or precool the fresh air. Considering the install locations requirements on field, the pump-driven heat pipes (PHP) were developed as heat recovery ventilators (HRVs) and used in an existing experiment building in Beijing Urban. The thermal performance of the PHP HRVs was tested in real operation time periods under… More >

Xuehui Wang¹, Edward Wright¹, Zeyu Liu¹, Neng Gao^2,*, Ying Li³

Energy Engineering, Vol.119, No.2, pp. 801-814, 2022, DOI:10.32604/ee.2022.018241

Abstract The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips, as it is characterised by excellent heat transfer ability and flexibility for miniaturisation. To boost the application of PHP, reliable heat transfer performance evaluation models are especially important. In this paper, a heat transfer correlation was firstly proposed for closed PHP with various working fluids (water, ethanol, methanol, R123, acetone) based on collected experimental data. Dimensional analysis was used to group the parameters. It was shown that the average absolute deviation (AAD) and correlation coefficient (r) of the correlation were… More >