Experimental heat and mass transfer studies on horizontal falling film absorber using water-lithium bromide

Abstract

Vapour absorption systems are more viable technology option in energy and environmental perspective in cooling and heating applications. Among the four major components of vapour absorption system, the absorber plays a vital role in deciding the performance, size and cost. Horizontal falling film absorbers comparatively contain good heat and mass transfer characteristics than other type of absorbers for working fluids such as water-lithium bromide. Literature shows that experimental approach of performance evaluation of absorber is more realistic and accurate than the theoretical approach. Hence in the present work, a detail experimental study has been done on horizontal tube falling film absorber using water-lithium bromide as a working fluid. The setup consists of two major components viz. absorber and generator. Absorber contains three columns of tubes, with eight rows in each column. Detailed parametric study has been done by considering influence of spray density, cooling water-flow rate, cooling water temperature and concentration on solution temperatures, cooling water temperatures, inlet and outlet concentrations, heat flux, mass flux, heat transfer coefficient, and mass transfer coefficient with the help of plots. Results have been validated and literature gaps have been discussed.

Numerical analysis of the heat and mass transfer process in absorbers using water and lithium bromide

“…Toppi et al (2015) performed modeling and experimental validation of heat and mass transfer in a tube-in-tube absorber, considering the pressure drop along the equipment. Arshi and Sudharsan (2020) carried out a detailed experimental study on a horizontal tube falling film absorber used in a LiBr/H2O system, considering the influence of the cooling water flow rate, its inlet temperature and spray density on the temperatures and solution concentrations, heat and mass fluxes, and heat transfer coefficients. They found, among other things, the better performance in absorption, the higher the flow of cooling water, while the increase in the temperature of this water caused the opposite.…”

Numerical study on heat and mass transfer behavior of pool boiling in LiBr/H2O absorption chiller generator considering different tube surfaces

“…Several studies have been carried out to examine the pool boiling effects in different engineering areas. These studies have focused on the horizontal falling film absorber [9,10], the boiling heat transfer coefficient in mechanical refrigeration systems [11], the desorption and nucleate boiling in a droplet of LiBr/H 2 O solution to check how an increase in the salt concentration of a liquid-layer may lead to a significant decrease in the rate of desorption [12,13], and the process of stationary evaporation of aqueous solutions [14,15]. Concerning previous literature, the pool boiling process in the absorption chiller generator might be enhanced by improving the useful parameters, causing an increase in the COP of the chiller.…”