A Theoretical Study on the Overall Performance of a Falling Film Vertical Tube Absorber

Abstract

This work is an attempt to study theoretically the performance of a falling film multi vertical tube absorber. The governing heat and mass transfer equations were solved numerically using finite difference. The mass, cooling effectiveness, contact-space area ratio and the overall absorber performance were defined. Results were presented in terms of Lewis number, heat of absorption and thermal capacity ratio. The mass effectiveness was found to increase with increasing the Lewis number and reduce with increasing heat of absorption. The tube radius was found to have an insignificantly small effect on the mass effectiveness. The contact-space area ratio and the overall performance have greatly increased with decreasing the tube radius. An increase in overall performance means for the same absorber size, the mass flow rate of vapor increases and so does the cooling capacity in the evaporator. However, the overall performance has almost no effect on the system heat ratio