2005 Fiscal Year Final Research Report Summary
Development of a Heat Recovery System Utilizing Heat Transport and Thermoelectric Devices
| Project/Area Number |
13852008
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NISHIO Shigefumi The University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (00111568)
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| Co-Investigator(Kenkyū-buntansha) |
AIZAWA Tatsuhiko The University of Tokyo, Center of Collaborative Research, Professor, 国際・産学共同研究センター, 教授 (10134660)
SHIRAKASI Ryo The University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (80292754)
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| Project Period (FY) |
2001 – 2005
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| Keywords | Energy Utilization / Low-Temperature Waste Heat / Heat Pipe / Thermoelectric Device / Soft Engine |
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| Research Abstract |
The amount of low-temperature waste heat in Japan was estimated using statistical energy data and it was found that the amount of low-temperature waste heat higher than 573K was at least 7% of the total amount of primary energy and the amount at 358-573K was at least 4%.
SEMOS heat pipes were chosen as the heat transport device for heat recovery of low-temperature waste heat because its outer heat transfer was expected to be improved remarkably by reducing its outer diameter. It was proved that the heat transport characteristics of micro and short SEMOS heat pipes with R141b as the operating fluid were independent of orientation. Its typical outer diameter was 0.5mm. A high temperature type of the micro and short SEMOS heat pipe working at temperatures up to 520K was developed and it was proved that it operated well under both top and bottom heating modes worked at high temperatures. A numerical simulation based on a unit consisting of a vapor plug and a liquid slug was developed to est
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imate the heat transport characteristics of SEMOS heat pipes.
The solid state processing was developed with success to synthesize and fabricate various types of thermoelectric semi-conductive compounds and alloys. At first, it was found that Zn-Sb compounds can attain high ZT in the middle range of temperature from 400K to 800K. New solid-state processing was proposed and it was proved that the process can solve the intrinsic problem to the thermoelectric materials : trade-off-balancing between thermoelectricity and strength. New module manufacturing process was proposed to produce crack-free module interface between thermoelectric materials and electrodes.
A soft engine was developed with a Bi-Te thermoelectric module and two sets of the micro and short SEMOS heat pipe. One of the two heat pipes was the heating heat pipe and the other the cooling heat pipe. The heating heat pipe was attached to the heating surface of the module and it transported recovered heat to the heating surface. The cooling heat pipe was attached the other surface, that is the cooling surface of the module, and it transported heat from the cooling surface to cold water. Effective thermal conductivities of the heat pipes were as high as 100 times of the thermal conductivity of copper but the efficiency of the soft engine was 0.86%. Less
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