An Overview of Recent Studies on the Development of Desiccant Air-conditioning Systems

Abstract

In the past decades, desiccant cooling systems have received much attention. These systems are considered as an alternative way to decrease energy consumption and greenhouse gas emission in humid and hot locations. To address the importance of desiccant air-conditioning systems, the present research aims to provide an overview of recent studies on the development of desiccant air conditioning system. Another objective is to consider the numerical and theoretical analysis of desiccant systems. Moreover, for the first time, a summary of recent researches regarding the use of Computational Fluid Dynamics (CFD) technique for numerical modeling of desiccant cooling systems has been especially reviewed in detail. Finally, in the present review, the principle of regeneration of liquid desiccant using solar energy have also been considered briefly.

Experimental Study of the Effects of Silica-gel Bed Thickness on The Regeneration Process in a Desiccant Column

“…Table (2) shows the change in the properties of the regeneration air coming out of the desiccant column with time during regeneration process when the thickness of silica gel is 10 cm. The properties of the incoming regeneration air are the same as those mentioned in the previous case.…”

“…The dimensions of the desiccant column are 30 cm long × 30 cm wide × 30 cm height. The hot air is used to regeneration the saturated silica gel enters the drying unit from the lower side and exit from the upper side, as shown in figure (2). The value of regeneration air flow rate was (3.72) kg/min.…”

“…The phenomenon of physical adsorption has been known for over two centuries and extensively studied over the past couple of decades [1] . A significant fraction of the energy in air-conditioned buildings is required for the removal of moisture [2] . Desiccant cooling and air dehumidification is a good alternative to the conventional vapor compression system for air conditioning [3] .The conventional method for the production of dry air involves cooling air below its dew point temperature, but this method consumes high-grade energy.…”

Desiccant-based air dehumidifier and cooling system

“…Ω 2,𝑖𝑑𝑒𝑎𝑙 , 6.666 g/kg which was taken from psychometric chart using the boundary condition set, T (300 K) and its ideal relative humidity, 45% as suggested by Daikin Malaysia. Therefore, these values are used to evaluate the dehumidification efficiency, Dh, of the system using equation (2). where 𝜔 1 =Inlet specific humidity, 𝜔 2,𝑖𝑑𝑒𝑎𝑙 = Ideal humidity for proper cooling, (RH=45%).…”

“…One of the problems is that the air conditioners could not rely on fossil fuels anymore to obtain power source in the next few decades due to the declining trend of fossil fuel availability [2]. This can be a potential reason for the drop of air conditioners production in the upcoming years.…”