Volume 49 Number 3 (2018.9)
Special Feature
Advanced Thermal Management Technology for Developing the High-efficiency Vehicle
Special Feature
Overview
Research Reports
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2. Reaction Kinetics of Ammonia Absorption/Desorption of Metal Salts
(1163kB)pages 1-8
Ryuichi Iwata, Takafumi Yamauchi, Yasuki Hirota, Masakazu Aoki and Takashi Shimazu
The reversible reactions between ammine magnesium complex and ammonia are studied by volumetric method and the heterogeneous reaction kinetic analysis at a grain level. The analysis reveals that the heterogeneous temperature or pressure distribution in the grain is the predominant factor on the overall absorption/desorption rate.
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pages 9-17
Yasuki Hirota, Ryuichi Iwata and Takafumi Yamauchi
Herein, we propose a compact adsorption heat pump (AHP) that uses exhaust heat from the engine coolant system. It is characterized by honeycombed composite plates of an adsorbent bonded to a plate-type heat exchanger. The volumetric power density of the adsorber was 1.81 times larger than a reported coating-type adsorber.
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4. Smart Design of Thermoelectric Materials for a Waste Heat Regenerati System
(1629kB)pages 19-28
Hirofumi Hazama, Masato Matsubara, Yumi Masuoka and Ryoji Asahi
Thermoelectric conversion efficiency is characterized by the dimensionless figure of merit (ZT) for thermoelectric materials. In order to improve ZT, we propose the strategies of co-doping, crystallographic defects, and energy filtering, based on first-principles calculations. Experimental results show a significant improvement in thermoelectric properties, thus confirming these design concepts.
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pages 29-41
Hajime Ikuno
A new thermal fatigue test system that circulates a uniform temperature-controlled air shower around test samples was developed. This system reduces the cycle period applied to electronic circuit boards from 60 to 12 min while generating an equivalent degree of crack damage and the same fracture mode at solder joints.
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6. A Study on Thermal Conductivity Increase in Nanofluids
(903kB)pages 43-49
Kazuhisa Yano and Koji Yoshida
Significant increases in thermal conductivity in ethylene glycol are obtained with Cu nanoparticles, although alumina NPs in water has a minimal effect. High-frequency sound velocities (HFSV) are also found to closely correlate with thermal conductivity values. These results demonstrate that the Cu nanoparticles increase the thermal conductivity by greatly restraining the solvent molecules in the nanofluid.
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7. Tailoring Thermal Radiation toward Novel Thermal Devices
(1897kB)pages 51-59
Kota Ito, Kazutaka Nishikawa, Atsushi Miura, Hiroshi Toshiyoshi and Hideo Iizuka
Thermal radiation is controlled by sub-wavelength structures or phase-change materials. We present six types of thermal radiative devices, including thermal diodes, multilevel thermal information storage, metal-insulator-metal metamaterials, tunable and directional thermal emitter controlled by graphene plasmons, a gap formation method by near-field radiative heat transfer, and near-field thermal switches.