• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.437-440
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• 2006

In process of the mass concrete structure, the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete, this paper results of hydration heat control of mass concrete using the Oscillating Capillary tube Heat Pipe(OCHP). There were the several molds which shows a difference as compared with each other. One was not equipped with OCHP. Other were laid with OCHP, and the other were laid in 100cm, and exposed out 50cm. All of them were cooled with natural air convection. The OCHP was composed of copper pipe(outer diameter : 4mm, inner diameter : 2.8mm) and heat type was non-looped type. The working fluid was R-22 and its charging ratio was 40% by volume. The core of the concrete temperature was approximately $53^{\circ}C$ without OCHP. But the concrete temperature with OCHP was reduced its difference in temperature with the outdoor temperature to $12{\sim}15^{\circ}C$. Finally we saw the index figure of the thermal crack of the structures were varied from 0.6 to 1.6.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.1
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• pp.31-38
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• 1985

By using the hollow shaft with $0.5^{\circ}$ internal taper, ball valve and rubber packing, charging the working fluid at engineering vacuum degree (vacuum pressure higher than 1 torr) and carrying out experiments, it was investigated the performance of rotating heat pipe with variant operating conditions. In this experiment, it was shown that it is impossible the internal liquid flow was laminar film flow which agree with the assumption of present theoretical analyses, but the internal vorticity makes the heat transfer increase and for the maximum heat transfer there is optimal mass loading for the given heat pipe geometry and operational conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.12
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• pp.1139-1144
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• 2005

This study has been performed to investigate the thermal performance of variable conductance heat pipe (VCHP) with meshed wick. The length of condenser portion in a VCHP is varied by the expansion of inert gas with the operation temperature, and the heat transport capacity is thus varied with the operating temperature. In this study, numerical evaluation of the VCHP is made for the thermal performance of VCHP, based on the diffusion model of inert gas. Water is used as a working fluid and nitrogen as a control inert gas in the copper tube. As a result, the thermal performance of VCHP has been compared with that of constant conductance heat pipe (CCHP) according to the variation of operation temperature. Maximum heat transport capacity of VCHP is mainly presented for operation temperature and the variation of operation temperature is also presented for heat transfer rate of VCHP.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.169-174
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• 2007

In process of reinforced concrete (RC) box structure, the heat of hydration may cause serious thermal cracking. This paper reports results of hydration heat control in mass concrete using the oscillating heat pipe. There were three RC box molds ($1.2m{\times}1.8m{\times}2.4m$) which were different from each other. One was not equipped with pulsating heat pipe. The others were equipped with pulsating heat pipe. All of them were cooled with natural air convection. The pulsating heat pipe was composed of 10 turns of serpentine type copper pipe whose outer and inner diameters were 4 and 2.8 mm respectively. The working fluid was R-22 and charging ratio was 40% by volume. The temperature of the concrete core was approximately $55^{\circ}C$ in the winter without pulsating heat pipe. For a concrete with pulsating heat pipe, however, the temperature difference with the outdoor one reduced up to $12^{\circ}C$. The index figure of crack was varied from 0.75 to 1.38.