成果報告書詳細
管理番号20120000000825
タイトル*平成23年度中間年報 風力等自然エネルギー技術研究開発 海洋エネルギー技術研究開発 次世代海洋エネルギー発電技術研究開発(海洋温度差発電)
公開日2012/8/9
報告書年度2011 - 2011
委託先名国立大学法人佐賀大学、株式会社神戸製鋼所
プロジェクト番号P07015
部署名新エネルギー部
和文要約和文要約等以下本編抜粋:
1. 研究開発の内容及び成果等
(1) はじめに
本研究開発では、海洋温度差発電の発電効率、経済性、および海水腐食に曝される条件下の長期的信頼性向上に対して寄与が大きい「熱交換器」を中心とした要素技術開発を実施している。
英文要約1) Introduction
In this study and development "Heat Exchanger" has been focused, which is considered to have large effects on power generation efficiency, economy and long time reliability under corrosive circumstances from seawater on Ocean Thernal Energy Conversion (OTEC).
KOBE STEEL., LTD has been developing processing technology to print heat transfer enhancement on higher strength material. The aim of this development is cost reduction of heat exchanger by reduction of amount of Titanium materials to be used. Saga University is to conduct experiments and evluations on thermal cycle efficiency and power generation performance of the OTEC plant using heat exchangers with the above heat transfer enhanced plates.
Target of this development is to clarify the processing conditions required for heat transfer enhanced plate having strength higher than the present plate by 30% to reduce the plate thickness by 15%, and is to improve thermal cycle efficiency by 10% using that plate.
2) Outcome of the study and development in FY2011
(1) Development on processing technology on heat transfer enhancement surface
We aimed designing surface minute and ruggedness shape/size to improve the evaporation heat transfer coefficient by 10% compared with a present smooth plate, and clarifying the basic characteristic to transcribe the designed minute and ruggedness shape in the high strength material and by rolling that is the processing method enabling mass-production.
(2) Development on evaluation technology on press formability
Two compact die sets (herring bone type / port modulus type) were developed to examine the effect of the sheet strength and the surface status on the formability with several materials and lubricant conditions. Higher strength materials and lower lubricant result in poor formability. Therefore, the evaluation of the formability of pure titanium sheet can be performed with these die sets.
Finite element analyses that considered the anisotropic hardening properties of pure titanium sheet were performed. The thinnest elements were calculated where the fracture were observed in the experiment. Forming limiting diagram obtained by flat-headed punch stretching test well contributed to the determination of the maximum punch stroke without fracture.
(3) Development on improvement on balance between strength and formability
In order to improve the press formability for high strength titanium sheets, the approach was surveyed and several ones were selected. In this FY, one of the approaches was examined, which control the orientation distributions to activate the twinning deformation focusing on improvement of uniform deformation.
(4) Experimental evaluation on thermal cycle and heat exchanger
Relationship between heat exchanger performance (overall heat transfer coefficient and minimum pinch temperature) and power generation cost has been clarified by developped simulation program. This simulation results are to be used in the succeeding experiment in the next FY.
(5) Experimental evaluation on thermal cycle and working fluid
A lot of fluorochemical substances has been developed in the recent years. In this FY, we screened these fluorochemical substances and other substances such as ammonia or propane in terms of pressure at dew/evaporating point, environmentl friendliness on ODP and CWP, availability and cost in market, etc. In most cases, ammonia is selected as an optimum working fluid except for small on-land type plant case which considers easy handling more important than other cases.
In the next FY, effects on this study and development are to be evaluated based on the actual data from the experiments and perfoemance tests on developped heat exchanger.
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