成果報告書詳細
管理番号20090000000278
タイトル*平成20年度中間年報 エネルギー使用合理化技術戦略的開発/エネルギー有効利用基盤技術先導研究開発(事前調査)/化学ポテンシャルを利用した排熱の長距離常温輸送技術
公開日2009/9/15
報告書年度2008 - 2008
委託先名国立大学法人東京農工大学
プロジェクト番号P03033
部署名省エネルギー技術開発部 研究開発グループ
和文要約以下本編抜粋:1.研究開発の内容および成果等 (1)溶液熱輸送システムのサイクルシミュレーションによる特性把握  提案する排熱の長距離常温輸送はアンモニアを冷媒,アンモニア水溶液を吸収溶液とする吸収冷凍サイクルを基盤としている.投入する排熱から冷熱発生までの効率(COP:成績係数)および溶液輸送量を把握するため,サイクルシミュレーションモデルを作成し,排熱温度に対する感度分析を行った.排熱温度が120℃-200℃の範囲において,140℃以上であればCOPは約0.6でほぼ一定であるのに対し,140℃を下回るとCOPの低下傾向が徐々に大きくなる.また,排熱温度が低下すると,溶液濃度差が小さくなることから溶液輸送量が急激に増大することが判明した.すなわち,輸送動力が急拡大することになるため,排熱温度はある程度高い(150℃以上)ことが本システムの条件となることがわかった.
英文要約Title:Thermal Energy Transporting Technology at Ambient Temperature based on Chemical Potentials(FY2008-FY2009)FY2008Annual Report Tokyo University of Agriculture and Technology Abstract The objective of this study is to construct a technology based on absorption heat pump mechanism so that thermal energy can be transferred from waste heat source to heat demand side over long distance. Ammonia absorption cycle with separated generator and evaporator takes waste heat at heat source side and produces chilled water at demand side. The feature is long pipelines transporting solutions and refrigerant connect the generator and the remote evaporator. Because thermal energy is converted into chemical potential of working fluid, the pipelines require no thermal insulation, which results in thermal energy transportation at ambient temperature. As conventional absorption chillers use LiBr-water as working fluid, LiBr-water can be used in the proposed system. However, it is a significant disadvantage of LiBr-water that LiBr can crystalize when the solution temperature becomes low. In contrast, because ammonia-water does not have crystalization, it can be a candidate of working fluid in the proposed system. There are various kinds of waste heat sources such as factories, power stations and so on. This study focuses on refuse incineration plants because they are necessarily located in municipal areas and are always operated. In this study, the following is conducted to find possible ways to enhance energy conversion efficiency of the system and to recognize heat transportation distance. First, cycle simulation to estimate the performance of the system was employed for analyzing COP (Coefficient of performance) and mass flow rate of strong and weak solutions. COP is approximately 0.6. However, COP decreases and mass flow rates increase remarkably when heat source temperature is below 140 degC. It suggests that the temperature should be high to some extent in order to reduce pumping power requirement. Second, 2 stage absorption cycle was examined to improve COP so that the system can produce ice and chilled water at two separate evaporators at the same time. Furthermore, hot water recovery at the absorber was investigated, which lifts up the COP twice as high as that of only cooling system. It is expected that the proposed system supplies larger amount of energy from given waste heat of refuse incineration plant. Optimal heat source temperature was observed around 180 degC taking heating, cooling and ice making into account. Third, the location of refuse incineration plants in Japan was surveyed to measure distance from city hall. The profile of the distance seemed logarithmic normal distribution function where the peak is around 3-4 km and 80% of the plants are located within 6 km. It suggests that pipeline length of 10 km will be enough for the proposed system. Fourth, discussion on the advantage of the proposed system compared with conventional steam transportation revealed that it would be possible for the proposed system to set pipelines under water in canals, revers and sea area, which can enlarge the opportunity to install the system.
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