AIR CONDITIONING BY EVAPORATIVE COOLING USING LITHIUM – BROMIDE ABSORPTION UNIT AS A DEHUMIDIFIER

Abstract

This work involves a design and study of using lithium bromide solution for dehumidification of moist which is necessary for good evaporative cooling which is popular and have extended use at the southern part of Iraq. At dehumidification unit (drying unit), Lithium Bromide solution atomized from drilled holes as droplets in the air stream to absorb moisture. The weak solution then collected and heated electrically to get strong solution which is pumped by 1.5 Kg/Cm² through (water-solution) heat exchanger of tube within tube type to eliminate its sensible load. Test was done during the period of July month and for 6 hr daily. The dried air then passed through heat exchanger ( air-water) to eliminate heat of absorption. Then the air was passed through an evaporative cooling unit and then forced to the space to be conditioned. Temperature and humidity of the air stream was measured at inlet, after humidification, after heat exchanger and at outlet of the system .The basis used in this work about the air leaving the unit is the comfort zone on psychometric chart. The work was done with and without drying unit to make comparison. It was found that all uncomfortable conditions of air through the test entered the comfort zone by using a dehumidification unit, and the dehumidification unit can be stopped when the relative humidity of the outdoor air decreased below 25% at July. It was found also that the unit become more efficient at midday time.