HEAT AND MASS TRANSFER IN AIR CONDITIONING COOLING COILS

1982 ◽  
Author(s):  
H. Sofrata
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Air Conditioning ◽  
Cooling Coils

Performance Analysis on the Internally Cooled Dehumidifier Using Two Liquid Desiccant Solutions

2012 ◽  
Author(s):  
I. P. Koronaki ◽  
R. I. Christodoulaki ◽  
V. D. Papaefthimiou ◽  
E. D. Rogdakis
Keyword(s):  
Mass Transfer ◽  
Theoretical Model ◽  
Heat And Mass Transfer ◽  
Flow Rate ◽  
Air Conditioning ◽  
Cooling Water ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Liquid Desiccant ◽  
Internally Cooled

Liquid desiccant air conditioning systems have recently been attracting attention due to their capability of handling the latent load without super-cooling and then reheating the air, as happens in a conventional compression-type air conditioning system. This paper presents the results from a study of the performance of an internally cooled liquid desiccant dehumidifier. A plate heat exchanger is proposed as the internally cooled element of the dehumidifier and water as the cooling fluid. The desiccant solution is sprayed into the internally cooled dehumidifier from the top and flows down by gravity. At the same time, fresh humid air is blown from the bottom or top, counter-flowing or co-flowing with the desiccant solution. The desiccant is in direct contact with the air, allowing for heat and mass transfer. The cooling water, flowing inside the plates of the dehumidifier, carries out the heat of the crossed air and solution. A heat and mass transfer theoretical model has been developed, based on the Runge-Kutta fixed step method, to predict the performance of the device under various operating conditions. Experimental data from previous literature have been used to validate the model. Excellent agreement has been found between experimental tests and the theoretical model, with the deviation not exceeding ±4.1% for outlet air temperature and ±4.0% for outlet humidity ratio. Following the validation of the mathematical model, the dominating effects on the absorption process have been discussed in detail. Namely, effects of flow configuration, air inlet temperature, humidity and flow rate, as well as desiccant inlet temperature, concentration and flow rate have been investigated against the dehumidification rate and the cooling efficiency. The two most commonly used liquid desiccant solutions, namely LiCl and LiBr have been also evaluated against each other. The results suggested that high dehumidification mass rate can be achieved under counter flow between air and solution, low air mass flow rates, low cooling water temperature, low desiccant temperature and LiCl as the desiccant solution.

Prediction of Heat and Mass Regenerator Performance Using Nonlinear Analogy Method: Part 1—Basis

1985 ◽  
Vol 107 (1) ◽  
pp. 222-229 ◽  
Author(s):  
P. J. Banks
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Air Conditioning ◽  
Energy Recovery ◽  
Sorption Properties ◽  
Convective Transfer ◽  
Analogy Method

Coupled heat and mass transfer between fluid streams by a regenerator with a sorbent matrix may be predicted by the superposition of two independent regenerators, in each of which transfer is driven by a combined potential, analogous to temperature in a similar regenerator transferring heat alone. An air-conditioning regenerator for energy recovery or dehumidification with convective transfer controlling is considered. The combined potentials and associated specific capacities are examined, and the nature of the analogy explored, in view of the dependence of matrix sorption properties on state. Approximate nonlinear expressions for the combined potentials, applicable to air-conditioning regenerators, are derived and utilized.

scholarly journals Experimental and theoretical studies on heat and mass transfer in anti-condensation coatings

2011 ◽  
Vol 32 (3) ◽  
pp. 45-56 ◽  
Author(s):  
Andrzej Grzebielec ◽  
Artur Rusowicz
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Forced Convection ◽  
Experimental Research ◽  
Air Conditioning ◽  
Theoretical Studies ◽  
Favorable Conditions ◽  
Inclined Plates ◽  
Experimental And Theoretical Studies

Experimental and theoretical studies on heat and mass transfer in anti-condensation coatings Anti-condensation coatings are widely used in refrigeration, air conditioning and ships technology. They can store a certain amount of water in its own volume, and then return it back in favorable conditions. Anti-condensation coatings are used also to protect structures from the moisture. This paper presents the results of experimental research on heat and mass transfer in an anti-condensation coating under natural and forced convection. Experimental results are obtained for horizontal and inclined plates. Experimental data are compared with different models of computation.

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