In air-conditioning field, a dehumidification and humidification have become increasingly important for human health and comfort. Much attention has been paid recently to a desiccant air-conditioning system as an alternative to the conventional system with a vapor compression cycle. In this paper, we focus on a liquid desiccant air-conditioning system using lithium chloride – water solution and investigate the heat and mass transfer of packed bed regenerator experimentally. In the experiment, effects of the air superficial velocity and solution mass flux on the outlet air conditions and the average overall heat and mass transfer coefficients are examined. As a result, the average overall heat and mass transfer coefficients increase with increasing of the air superficial velocity, however, the average overall heat transfer coefficient is almost constant with increasing of the solution mass flux.
本研究では，微細流路を流れる気液二相流の流動様式及びスラグ流における気泡速度と液膜厚さを，レーザー共焦点変位計と高速度カメラを用いて実験的に観察を行った．液相の物性や流路の寸法による影響を包括的に評価するため，内径が0.5 mm, 1.0 mm, 2.0 mm のガラス円管と，液相には水, エタノール, FC72, 二種類のシリコンオイルKF-96L-0.65cs とKF-96L-2cs を用いた．微細流路における流動様式は，管径が大きくなり，液相の表面張力が小さくなるという影響により，微細流路を用いた既存研究で提案されている流動様式線図と異なる一方，粘性による影響は小さいことが確認された．また，気泡速度と液膜厚さに関しては，実験結果と既存研究における相関式がおおむね一致したが，特に液相の表面張力や粘性が低い条件では，既存の相関式よりも実験値が低い値を示した．また管径が大きくなるに従って，その誤差も大きくなることが確認された．
This paper proposes a three-bed three-stage adsorption cycle with a new operational strategy. The cycle consists of three adsorber/desorber heat exchangers, one evaporator, and one condenser. The two beds on the low-pressure side operate in a re-heat cycle, and another bed on the high-pressure side operates in a conventional cycle. The objectives of the current study were to evaluate the cycle at a low heat source temperature such that it can be driven by solar or waste heat and to reduce the number of heat exchangers from six beds to three beds. A simulation model was developed, and the system behavior and its performance were predicted. The performance of the proposed cycle was compared with that of a conventional six-bed three-stage adsorption cycle. The simulation results showed that the proposed cycle with the new operational strategy could operate at low heat source temperature i.e., 45 °C, and offers approximately five times higher performance in terms of SCP than the conventional cycle. Consequently, the proposed cycle is effective for use of a low-grade heat source, even with three beds.