成果報告書詳細
管理番号20110000001540
タイトル*平成22年度中間年報 省エネルギー革新技術開発事業 先導研究 蒸気ボイラ代替が可能な産業用高温ヒートポンプに関する要素技術の研究開発
公開日2011/10/12
報告書年度2010 - 2010
委託先名株式会社前川製作所
プロジェクト番号P09015
部署名エネルギー対策推進部
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) 最適冷媒・冷凍機油の探索及び基本物性評価
前年度の研究開発において、冷媒はノルマル~ペンタン(GWP=3)を選定し、最適冷凍機油としてPAG(ポリアルキレングリコール)を選定した。本年度は、圧縮機の最高使用温度180℃において冷媒との混合時の最低動粘度を5mm2/sを確保でき、高温安定性に優れた冷凍機油をPAGベースオイルに種々の添加剤を添加して確認試験を行い、本高温ヒートポンプに最適な冷凍機油を開発した。但し、大気中における酸化劣化特性において160℃以下にする必要があり、メカニカルシール部の温度を下げる工夫が必要であることが分かった。
英文要約Title: Development of basic technology for an industrial high temperature heat pump system which can be an alternative to a steam boiler (FY2009-FY2011) FY2010 Annual Report.
Considering ODP, GWP, heating capacity, and COPh, normal pentane was selected as the working refrigerant while considering heat stability and solubility PAG (poly-alkylene-glycol) was selected as the lubricating oil. A minimum kinematic viscosity of 10mm2/s can be realized with PAG at the compressors maximum working temperature of 180 deg.C. Additives were tested with PAG to ensure stability at high temperatures. In order to verify basic technologies for the screw compressor bearings, mechanical face seals and elastomers, basic tests were carried out and results showed that the components could be used at the design temperature of 160 deg.C. Various bearings were designed considering lubricity during contact with the shaft as well as heat resistance. Tests conducted at oil temperature of 180 deg.C and for revolution speeds from 2400 to 4200 showed that the eccentricity ratios and angles were within the allowable limits for all the load conditions. Three types of mechanical face seals were tested under the compressor operating conditions. The mechanical face seal with the smallest leak had a leak volume which was a tenth of the standard Mayekawa value. Tests also showed that a shower flashing sleeve improved the cooling effect on the moving parts and kept the temperatures below 160 deg.C. Immersion tests were conducted on four types of O rings under operating conditions and suitable O rings were selected. In order to minimize refrigerant charge, plate heat exchangers were chosen. A shell and tube heat exchanger was chosen for the storage heat exchanger. Erythritol and mannitol were chosen as the heat storage materials. The mixing ratios will be determined by the storage temperatures. In order to verify the heat transfer characteristics of the storage heat exchanger test using mannitol as the storage material were carried out. A 5kW apparatus was designed and fabricated. Tests on the apparatus showed that the overall heat transfer coefficients were in the range of 120 to 150W/m2K during storage at 180 deg.C and 70 to 90W/m2K during heat dissipation at 150 deg.C respectively. The thermal storage efficiency was 67%. This data will be used in design of the storage heat exchanger. The storage efficiency is expected to be improved by better insulation and packing of the storage material from the current 67% to the target efficiency of 80%. The mixing ratio of the heat storage material at storage temperatures of 150 deg.C was determined as Erythritol/mannitol:30/70mass%. Experiments with this mixture showed that, the storage speed increased while the heat dissipating speed decreased by more than 50% because of the drop in the melting point. Regardless of the decrease in the heat dissipating speed, this mixture has a stable latent heat at 150 deg.C and offers good storage and heat dissipation capacity. A one dimensional heat conduction analysis was carried out using this mixture with the secondary refrigerant flowing in the tube and the storage material around the outer side of the tube. Results of the analysis were in good agreement with both the shell and tube heat exchanger experiments with mannitol and the mixture mentioned above. The results verified that a shell and tube storage heat exchanger can be designed with data obtained from the experiments. A system simulation was carried out on the heat pump to clarify the necessary conditions needed to meet the targeted COP of 3. The simulation showed that a COP of 3.02 and heating capacity of 262kW will be realized with the compressor to be fabricated in the next fiscal year. The COP can be improved to 3.06 with an economizer cycle.
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