Experiment of Adsorption Heat Pump/Thermal Storage Systems (吸着式ヒートポンプ・蓄熱システムの実験) Study on Desiccant Air Conditioning (デシカント空調に関する研究) Measurement and Analysis of Adsorption Characteristics (吸着特性の測定および解析)
Experiment of Adsorption Heat Pump/Thermal Storage Systems
Experimental set up for activated-carbon adsorption heat pump/thermal storage system
活性炭とエタノールを利用した吸着式ヒートポンプ・蓄熱システム実験装置
We perform experiment of adsorption heat pump/thermal storage systems with activated carbon-ethanol pair. The commercialized adsorption chillers use water as a refrigerant and hydrophilic materials, such as silica gel and zeolite, as adsorbents. We focused on activated carbons as an adsorbent for heat pump applications because it has a large specific surface area, it adsorbs various type of refrigerant such as alcohols, hydrofluorocarbons etc., and it can be produced from a variety of orignal materials. Activated carbons can adsorb even water at a large capacity under humid conditions.
We study on performance improvement of an adsorption heat exchanger using activated carbons. Activated carbons have a large surface area and a large micro pore volume, which asures a large adsorption uptake. On the other hand, a large porocity results in low effective thmal conductivity. In addition, high performance activated carbons are in microscale particles, which also causes several technical issues on heat transfer as well as on production of heat exchangers. Therefore, we also study a composite adsorbent to enhance the heat transfer of activated carbons.
We attempted to produce a functional activated carbon for adsorption cooling systems in a collaborative project with Prof. Seong-Ho Yoon and Prof. Jin Miyawaki, Institute for Materials Chemistry and Engineering, Kyushu University. Our concept was to incrase effective adsorption based on operating temperature conditions of adsorption heat pumps. We modified the adsorptin isotherm of activated carbons by changing the micropore width. It was sucessful that the effective adsorption for a cooling condition was enhanced by adjusting the mircropore width.