scholarly journals An experiment to assess the heat transfer performance of thermoelectric-driven conditioned mattress

2021 ◽  
pp. 146-146
Author(s):  
Xiaxia Li ◽  
Liming Shen ◽  
Ying Huang

This study sets out to describe the design, construction and testing of thermoelectric-driven conditioned mattress intended to reduce the human-mattress interface temperature, in order to satisfy the personal sleep thermal comfort requirements in hot conditions. A prototype of thermoelectric-driven conditioned mattress is constructed and tested. A series of experimental studies related to the temperature of different cushion layers and time from start-up to stable state have been carried out, specifically to analyze the difference in heat transfer performance of two types of temperature control layers (i.e., integral water cushion and circulating water pipes) in cooling operations. The steady-state results showed that, the type of temperature control layer and pre-set temperature exhibited a remarkable influence on the cooling performance of mattress. The mattress with integral water cushion had a superior cooling performance as compared to mattress with circulating water pipes under similar consitons. Specifically, the upper surface temperature of mattress with integral water cushion at the the pre-set temperature of 20?C, 18?C and 16?C were 1.97?C, 2.46?C and 3.08?C lower than indoor air temperature, respectively. Besides, the temperature contour maps of temperature control layer and upper cushion layer for two types of mattresses were constructed using the bilinear interpolation, respectively, thus expected to provide reference for the untested temperatures in this study. This study aims to effectively evaluate the heat transfer performance of the thermoelectric-driven conditioned mattress, and shows highly practical value in further applications of this system in improving human thermal comfort during sleep.

Author(s):  
Sandesh S. Chougule ◽  
S. K. Sahu

In the present study, the forced convective heat transfer performance of two different nanofluids, namely, Al2O3-water and CNT-water has been studied experimentally in an automobile radiator. Four different concentrations of nanofluid in the range of 0.15–1 vol. % were prepared by the additions nanoparticles into the water as base fluid. The coolant flow rate is varied in the range of 2 l/min–5 l/min. Nanocoolants exhibit enormous change in the heat transfer compared with the pure water. The heat transfer performance of CNT-water nanofluid was found to be better than Al2O3-water nanocoolant. Furthermore, the Nusselt number is found to increase with the increase in the nanoparticle concentration and nanofluid velocity.


2008 ◽  
Vol 2008.83 (0) ◽  
pp. _1-3_
Author(s):  
Yoshiaki NISHIO ◽  
Toshiyuki SAKAMOTO ◽  
Katsuya FUKUDA ◽  
Qiusheng LIU ◽  
Hiroaki KUTSUNA

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 3015-3024
Author(s):  
Qiang Xie ◽  
Zuobing Chen ◽  
Gong Chen ◽  
Yongjie Yu ◽  
Zheyu Zhao

Spray cooling has been widely employed in many applications due to its high flux removal ability. A previous study has been conducted to reveal the large-scale spray cooling performance of an industrial used single nozzle. Continuously, influence of multiple-nozzle distribution has also been numerically investigated in present work. The mean heat flux and its standard deviation and uniformity are used to qualify the cooling performance. A flat wall with 1.6 m in length and 1.0 m in width has been taken as the research object. Effects of nozzle number, distance and offset have been parametrically compared. It is found that increasing nozzle number could promote mean heat flux, improve the uniformity of cooling patterns and enhance heat transfer performance. A best nozzle number of 10 could be obtained by an equation fitting. Decreasing nozzle distance turns out to be detrimental to heat transfer. The reason comes from the collisions and interactions of two too adjacent nozzles. Based on choices in real practice, two types of arrays i. e. perpendicular and skew array have been discussed and compared. It is concluded that the skew array could obtain higher heat flux with more uniform distribution.


2016 ◽  
Vol 40 (5) ◽  
pp. 947-958 ◽  
Author(s):  
Li-Chieh Hsu ◽  
Guo-Wei Wong ◽  
Kung-Ting Chen

The influence factors on the heat transfer performance of a loop thermosyphon system, a passive cooling device, are studied systematically. The parameters investigated include types of enhanced boiling structure, the depth to width ratio of enhanced boiling structures, the gap of evaporator, the condenser height and the inclination of evaporator. The results show the depth to width ratio and the condenser height has positive influences on the heat transfer performance. An optimal channel gap of evaporator exists and possesses better heat transfer performance. The inclination effect of evaporator may not be favorable to heat transfer. Among those, the horizontal and 90° inclination of evaporator has better cooling performance.


Author(s):  
Junfei Zhou ◽  
Xinjun Wang ◽  
Jun Li ◽  
Daren Zheng

A double swirl cooling method has been raised recently to enhance the internal cooling performance at the blade leading edge. This paper mainly focuses on investigating the flow and heat transfer characteristics of the double swirl cooling method. Further more, four kinds of elliptical holes are applied to show effects of impinging hole shapes on the cooling performance. Results of all double swirl cooling cases are compared with that of an impingement cooling structure under four Reynolds numbers. Overall averaged Nusselt number, friction factor and thermal performance factor are compared in all cases, Vortexes induced by different impinging hole types and target chambers are studied and compared. The spanwise averaged Nusselt number, Nusselt number contours and Nusselt number distributions at several cross sections are studied and compared. Results show that the double swirl cooling method can significantly enhance the heat transfer performance compared with the traditional impingement cooling structure. Double swirl cooling with cylindrical impinging hole shows the best thermal performance and lowest flow losses. By applying the elliptical impinging hole with the sharp side faced the mainstream flow direction and a larger major to minor axis length ratio, the rotational vortex inside the double swirl chamber can be better developed and the heat transfer performance is also promoted.


Author(s):  
Muhammad Arif Harun ◽  
Nor Azwadi Che Sidik

Electronic devices are becoming more efficient while getting a smaller size and compact design thus increase heat generation significantly. High heat generation from high technology electronic devices are needed to be cool down or control its temperature to prevent overheating problems. Due to the high cooling performance of liquid cooling, the electronic cooling system is shifting from an air-cooling system to a liquid cooling system. In the past few decades, numerous methods proposed by researchers for the central process unit (CPU) cooling using the liquid system either active cooling or passive cooling system. Other than physical configuration such as heat sink design, different configurations of working fluids are widely been studied by most of the researchers. Different working fluids have different heat transfer performance. Furthermore, a recent study has come out more interesting finding using nanofluid which can enhance heat transfer performance of liquid cooling. Nanofluid is a working fluid that has nanoparticles disperse in the base fluid which can increase the thermal properties of the based fluid. In this paper, comprehensive literature on the type of working fluid used in the respective system and methods of liquid cooling system for CPU including its cooling performance. Furthermore, this review paper discussed the different configuration of the liquid block and also the working fluid that had been used in the CPU cooling system.


Author(s):  
Manuel Auliano ◽  
Maria Fernandino ◽  
Peng Zhang ◽  
Carlos Alberto Dorao

In this paper, the effect of Si sub-micron tapered pillars on the Leidenfrost point of water droplets at different impact velocities is presented. In the Leidenfrost regime, the low thermal conductivity of the vapor layer deteriorates the heat transfer performance. Micro and nanostructured surfaces can significantly shift the Leidenfrost point towards higher temperatures. To determine this point, the droplet lifetime method was employed. The cooling performance was discussed in terms of the droplet evaporation time and the Weber number. It was observed that Si sub-micron tapered pillars can shift the Leidenfrost point for all the Weber numbers investigated (1–60). The displacement of the Leidenfrost point is enhanced by increasing the droplet impact velocity.


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