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.

Prediction of Heat and Mass Regenerator Performance Using Nonlinear Analogy Method: Part 2—Comparison of Methods

1985 ◽  
Vol 107 (1) ◽  
pp. 230-238 ◽  
Author(s):  
P. J. Banks
Keyword(s):  
Silica Gel ◽  
Air Conditioning ◽  
Energy Recovery ◽  
Sorption Properties ◽  
Comparison Of Methods ◽  
Nonlinear Method ◽  
Convective Transfer ◽  
Analogy Method ◽  
Sources Of Error

The prediction of heat and mass regenerator performance by analogy from that of a similar regenerator transferring heat alone is studied in view of the dependence of matrix sorption properties on state. Air-conditioning regenerators with convective transfer controlling are considered. For an energy recovery regenerator, the previous linear analogy method is shown to be satisfactory, while a nonlinear method is required for a regenerative dehumidifier. A nonlinear method using approximate nonlinear expressions for the combined potentials is described and is compared with the previous nonlinear method that is shown to be partly linear. The sources of error in the methods are explored for a silica gel dehumidifier, and ways of improvement are indicated.

scholarly journals ANALYSIS OF HEAT AND MASS TRANSFER ON COOLING TOWER FILL

2020 ◽  
Vol 14 (1) ◽  
pp. 25
Author(s):  
Abdul Aziz Rohman Hakim ◽  
Engkos Achmad Kosasih
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Relative Humidity ◽  
Heat And Mass Transfer ◽  
Cooling Tower ◽  
Stream Velocity ◽  
Design Data ◽  
Analogy Method ◽  
Ambient Relative Humidity ◽  
Air Stream

This paper discusses heat and mass transfer in cooling tower fill. In this research, dry bulb temperature at the bottom fill, ambient relative humidity, air stream velocity entering fill, dry bulb temperature leaving the fill, relative humidity of air leaving the fill, inlet and outlet water temperature of cooling tower were measured. Those data used in heat and mass transfer calculation in cooling tower fill. Then, do the heat and mass transfer calculation based on proposed approch. The results are compared with design data. The design and analogy method showed different  result. The parameter which influence the heat transfer at cooling tower are represented by coefficient of heat transfer hl and coefficient of mass transfer k­l. The differencies result between design and analogy method shows that there is important parameter which different. Deeply study needed for it.

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.

Combined Heat and Mass Transfer in Porous Media Heat Exchanger

2002 ◽  
Author(s):  
Adriana M. Druma ◽  
Khairul M. Alam
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Energy Recovery ◽  
Low Cost ◽  
Porous Matrix ◽  
Air Stream ◽  
The Matrix ◽  
Heat And Moisture

A numerical and experimental study of heat and mass transfer has been carried out for an energy recovery ventilator with a porous media heat exchanger. The energy recovery ventilator selected for this study has a rotary periodic heat exchanger that can transfer heat and moisture from one air stream to another. Such heat exchangers can be operated with high effectiveness by using a low-cost porous matrix as the heat exchanger medium. The influence of porosity in the matrix has been studied numerically and the performance of the energy recovery ventilator in recovering both heat and moisture has been modeled.

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