Experimental Analysis on Chemical Dehumidification of Air by Liquid Desiccant and Desiccant Regeneration in a Packed Tower

2004 ◽  
Vol 126 (1) ◽  
pp. 587-591 ◽  
Author(s):  
Giovanni A. Longo ◽  
Andrea Gasparella
Keyword(s):  
Air Conditioning ◽  
Experimental Tests ◽  
Experimental Results ◽  
Liquid Desiccant ◽  
Humidity Ratio ◽  
Simulation Code ◽  
Packed Tower ◽  
One Dimensional ◽  
Dimensional Simulation ◽  
Set Up

This paper presents the experimental tests on the chemical dehumidification of air by a liquid desiccant and desiccant regeneration carried out in an absorption/desorption tower with random packing. The experimental set-up is fully described together with measurements, procedures, data reduction, and accuracy. The experimental tests include 46 dehumidification runs and 38 desiccant regeneration runs carried out with the traditional hygroscopic solution H2O/LiBr and the new solution H2O/KCOOH in the typical operative ranges of air conditioning applications. The experimental results are reported in terms of humidity reduction, desiccant concentration change, and tower efficiency. The experimental tests show that chemical dehumidification of air by liquid desiccants ensures consistent reduction in humidity ratio, which is suitable for the application to air conditioning or drying processes. The experimental results are also compared to a one-dimensional simulation code of a packed tower: a fair agreement was found between experimental and calculated performance.

One Dimensional Modeling of Catalyst for Internal Combustion Engine Simulation

2006 ◽  
Author(s):  
David Chalet ◽  
Jose´ Galindo ◽  
He´ctor Climent
Keyword(s):  
Shock Wave ◽  
Steady Flow ◽  
Experimental Test ◽  
Test Bench ◽  
Experimental Tests ◽  
Experimental Results ◽  
One Dimensional ◽  
Set Up ◽  
Experimental Test Bench ◽  
Good Agreement

The aim of this paper consists of establishing a methodology for oxidation catalyst modeling based on experimental tests and the development of a theoretical model with zero and one dimensional elements. Related to the theoretical work, the main aspects of such modeling are presented. It consists of describing the inner catalyst geometry by a combination of volumes and simple pipes network. The gas properties in volumes are calculated with a filling and emptying approach whereas the unsteady flow in pipes elements is considered to be one-dimensional and solved by using a finite difference scheme. Concerning the experimental tests, a study is carried out on a shock tube bench. The advantage of this experimental test bench is to study the propagation of a shock wave in the catalyst under controlled and convenient conditions, i.e. cold and non steady flow. Later, the model is set up by comparing the upstream and downstream pressure signals with the simulation results. Since the model lacks of relevant information of pressure losses at the inlet and outlet of the channels, which are rather difficult to compute due to the complex phenomena and flow maldistributions if the use of a 3D CFD code is avoided, the calibration of the model to match the experimental data is the decided approach. In this context, the shock wave test bench is used in order to excite the catalyst with non-steady flow conditions rather than to reproduce the conditions that will appear in real engine operation. The comparison shows good agreement between one-dimensional and experimental results. In order to validate this new modeling on a real engine configuration, an experimental validation is carried out in a four-stroke turbocharged Diesel engine. This experimental test bench allows to measure the main engine characteristics and performance as well as the instantaneous pressure upstream and downstream the catalyst. A simulation code has been also set up to model the engine and the comparison in terms of exhaust pressure pulses propagation inside the catalyst shows good agreement between the one-dimensional model and the experimental results.

scholarly journals Multilayered artificial neural network for performance prediction of an adiabatic solar liquid desiccant dehumidifier

2019 ◽  
Vol 14 (3) ◽  
pp. 351-363
Author(s):  
Andrew Y A Oyieke ◽  
Freddie L Inambao
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Vapour Pressure ◽  
Air Conditioning ◽  
Ann Model ◽  
Liquid Desiccant ◽  
Humidity Ratio ◽  
Packed Tower ◽  
The Mean ◽  
Artificial Neural

Abstract In this study, a multi-layered artificial neural network (ANN) algorithm was developed and trained to predict the performance of a solar powered liquid desiccant air conditioning (LDAC) system particularly the adiabatic packed tower dehumidifier using Lithium Bromide (LiBr) desiccant. A reinforced technique of supervised learning based on error correction principle rule coupled with perceptron convergence theorem was applied to create the algorithm. The parameters such as temperature, flow rates and humidity ratio of both air and desiccant fluid were fed as inputs to the ANN algorithm and their respective outputs used to determine dehumidifier effectiveness and moisture removal rate (MRR). The ANN model when subjected to validity tests using vapour pressure of LiBr desiccant solution at specific random temperatures and concentrations, gave astounding outcomes with precise estimation to R2 values of 0.9999 for all desiccant concentration levels. Due to the variation in solar radiation, the MRR and effectiveness fluctuated with the change in desiccant and air temperatures, giving maximum differences of 0.2 g/s and 1.8% respectively between the predicted and measured values depicting a perfect match. With respect to humidity ratio, MRR was accurately predicted by ANN algorithm with maximum difference of 3.4969% while the mean variation was −0.5957%. With respect to air temperature, the dehumidifier effectiveness was perfectly predicted by the ANN algorithm to an average accuracy of 0.53% and extreme positive deviation of 4.14%. The MRR was replicated to a mean variation of 0.013% and highest point difference of 0.08%. In all the above cases, the mean and maximum differences between the ANN model and experimental values were far below the allowable limit of ± 5%, hence the algorithm was deemed to be successful and could find use in air conditioning scenarios. The ANN algorithm’s capability and flexibility test of processing unforeseen inputs was accurate with negligible deviations and prospects of predicting the desiccant’s vapour pressure, dehumidifier effectiveness and MRR within all ranges of temperature and concentration which then eliminates the need for use of charts.

scholarly journals Numerical and Experimental Study on the Locally Blast Loaded Polyurea Coated Steel Plates

2019 ◽  
Vol 56 (3) ◽  
pp. 492-499
Author(s):  
Florina Bucur ◽  
Eugen Trana ◽  
Adrian Rotariu
Keyword(s):  
Experimental Tests ◽  
Cost Effective ◽  
Experimental Results ◽  
Steel Plates ◽  
Coated Steel ◽  
Quick Response ◽  
Blast Mitigation ◽  
Private Research ◽  
Set Up ◽  
Research Facilities

The damages and casualties inflicted by mine and IED attacks in security challenging areas generated a strong and quick response from nations all over the world. As a part of this response several national and private research facilities increased their efforts in identifying and implementing new ways or technologies to enable blast wave mitigation. The current paper aim to investigate the opportunity of using polyurea coated steel plates as a possible new blast mitigation approach, as suggested by several investigators. In order to objectively conclude about the ability of polyurea coated plates to sustain locally blast loads several experimental tests were performed according to STANAG 4569 demands for a 1/6 scaled plate structure. In order to numerically validate the experimental results several Autodyn simulations were set-up. The numerical and experimental results exibits a fair correlation, both pointing towards a dismiss of the idea of using polyurea coated steel plates as structural and cost effective blast mitigation approach.

Experimental Study on a Hybrid Desiccant Dehumidification and Air Conditioning System

2005 ◽  
Vol 128 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Li Yong ◽  
K. Sumathy ◽  
Y. J. Dai ◽  
J. H. Zhong ◽  
R. Z. Wang
Keyword(s):  
Air Conditioning ◽  
Experimental Tests ◽  
Electrical Energy ◽  
Primary Energy ◽  
Coefficient Of Performance ◽  
Air Flow Rate ◽  
Energy Usage ◽  
Humidity Ratio ◽  
Air Conditioning System ◽  
Air Conditioning Systems

This paper presents the experimental tests on hybrid desiccant dehumidification and air conditioning systems. Experimental tests are carried out with LiCl desiccant at typical operative ranges for air conditioning applications, particularly for high humid regions like Hong Kong. Results are reported in terms of coefficient of performance (COP) based on primary energy usage and electrical energy usage, respectively. Experiments have demonstrated consistent reduction in humidity ratio satisfying the sensible as well as latent load through a respective subsystem and thereby resulting in a higher COP based on primary energy usage. Also, results show that the regeneration temperature as well as process air flow rate have a significant role on the system performance. It is found that the hybrid system can achieve a higher part load performance, and hence can assure of its effective operation all year around in hot humid regions.

Experimental analysis and performance optimization of a counter-flow enthalpy recovery device using liquid desiccant

2018 ◽  
Vol 39 (6) ◽  
pp. 679-697 ◽  
Author(s):  
Xiaochen Liu ◽  
Xiaohua Liu ◽  
Tao Zhang ◽  
Ying Xie
Keyword(s):  
Performance Optimization ◽  
Air Conditioning ◽  
Cross Flow ◽  
Transfer Model ◽  
Liquid Desiccant ◽  
Air Velocity ◽  
Counter Flow ◽  
Packed Tower ◽  
Enthalpy Recovery ◽  
Air Conditioning Systems

The liquid desiccant enthalpy recovery is an efficient way to save energy in air-conditioning systems. In this study, a counter-flow liquid desiccant enthalpy recovery device was proposed and experimentally analyzed. Enthalpy transfer capacity, enthalpy efficiency and pressure drop per height of packing were used as indices to describe its performances. Based on the experiment results, the heat and mass transfer model of a packed tower was used to simulate and optimize the performance of this device. The maximum enthalpy efficiency and enthalpy transfer capacity were achieved when the optimal air velocity (1.9–2.1 m/s in this study) maintained to be slightly below the air velocity at the loading point and the thermal capacity ratio of air to desiccant ( m*) equaled to 1. These conclusions are valuable to both design and operation of such an enthalpy recovery device. Practical application: A counter-flow enthalpy recovery device with liquid desiccant was proposed and experimentally investigated. Based on the experiment results, a numerical model for this device was built and validated. The optimal air and desiccant mass fluxes were analyzed to maximize the enthalpy efficiency of this device, which could be higher than the conventional device with cross-flow pattern. These results could provide guidelines for both design and operation management of counter-flow enthalpy recovery devices in liquid desiccant-based air-conditioning systems.

scholarly journals Simulation of direct contact membrane distillation regeneration of liquid desiccant solutions used in air-conditioning

2020 ◽  
Vol 58 (6) ◽  
pp. 747
Author(s):  
Hung Cong Duong ◽  
Lan Thi Thu Tran
Keyword(s):  
Direct Contact ◽  
Air Conditioning ◽  
Water Flux ◽  
Experimental Tests ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Membrane Properties ◽  
Experimental Investigations ◽  
Liquid Desiccant ◽  
Direct Contact Membrane Distillation

Membrane distillation (MD) has great potential for the treatment of hyper saline waters, including liquid desiccant solutions used in air-conditioning systems. Previous experimental investigations have demonstrated the technical feasibility of MD for regeneration of liquid desiccant solutions. In this study, a direct contact membrane distillation (DCMD) process of the LiCl liquid desiccant solution was simulated using MATLAB software. The simulation was first validated using data obtained from experimental tests. Then, it was used to elucidate the water temperatures, LiCl concentration, and water flux profiles along the membrane leaf inside the DCMD membrane module. Finally, with the help of the simulation, the effects of membrane properties and process operating conditions on the DCMD process performance were systematically examined. The results obtained from this simulation enrich the knowledge and hence facilitate the realization of MD for the liquid desiccant solution regeneration application.

scholarly journals EMITTANCE LIMITATION OF A CONDITIONED BEAM IN A STRONG FOCUSING FEL UNDULATOR

2007 ◽  
Vol 22 (22) ◽  
pp. 3826-3837 ◽  
Author(s):  
Z. HUANG ◽  
G. STUPAKOV ◽  
S. REICHE
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Free Electron Laser ◽  
Three Dimensional ◽  
Complete Elimination ◽  
Dimensional Model ◽  
Simulation Code ◽  
One Dimensional ◽  
Strong Focusing ◽  
Dimensional Simulation

Various methods have been proposed to condition an electron beam in order to reduce its emittance effect and to improve the short-wavelength free electron laser (FEL) performance. In this paper, we show that beam conditioning does not result in a complete elimination of the emittance effect in an alternating-gradient focusing FEL undulator. Using a one-dimensional model and a three-dimensional simulation code, we derive a criteria for the emittance limitation of a perfectly conditioned beam that depends on the focusing structure.

Experimental Study of Dehumidification Process by CaCl2 Liquid Desiccant Containing CuO Nanoparticles

2020 ◽  
Vol 28 (01) ◽  
pp. 2050009
Author(s):  
Nader Shoaib ◽  
Zahra Arab Aboosadi ◽  
Nadia Esfandiari ◽  
Bizhan Honarvar
Keyword(s):  
Experimental Study ◽  
Air Conditioning ◽  
Copper Oxide Nanoparticles ◽  
Cuo Nanoparticles ◽  
Operating Parameters ◽  
Air Humidity ◽  
Liquid Desiccant ◽  
Humidity Ratio ◽  
Cuo Nps ◽  
Simple Technology

A conditioning dehumidifier system is a simple technology to improve air quality and also reduces air conditioning costs. This experimental study evaluated the performance of a liquid desiccant system by adding copper oxide nanoparticles (NPs). The effect of operating parameters, such as inlet air humidity ratio and desiccant flow rate on air dehumidification rate, was also investigated. The desiccant solution contained 48[Formula: see text]wt.% CaCl2 and 0.35[Formula: see text]vol.% of CuO NPs. Comparison of liquid desiccants demonstrated a mean difference of 4.5[Formula: see text]g/s[Formula: see text][Formula: see text][Formula: see text]m2 in the air dehumidification rate by solutions with and without CuO NPs.

Mathematical Modeling for the Regenerator of Liquid Desiccant Air-Conditioning System

2013 ◽  
Vol 465-466 ◽  
pp. 226-231
Author(s):  
Majid Ali Wassan ◽  
Khairul Habib ◽  
Suhaimi B. Hassan
Keyword(s):  
Mathematical Model ◽  
Air Conditioning ◽  
Flow Direction ◽  
Model Performance ◽  
Dilute Solution ◽  
Liquid Desiccant ◽  
Humidity Ratio ◽  
Counter Flow ◽  
Air Conditioning System ◽  
Flow Configuration

T his paper presents mathematical model for regenerator of liquid desiccant air conditioning system. Regression analysis was used to get the relation between enthalpy and humidity ratio. Performance of regenerator is highly affected by varying the flow direction between air & desiccant thus to get proper regeneration results counter-flow configuration is considered. Previous studies show better regeneration results for counter-flow direction of air to desiccant. Validation is done by comparing results of present study the experimental results of previous studies and comparison was found to be quite satisfactory. Based on above mathematical model performance of regenerator was analyzed. The purpose of this research was regeneration of liquid desiccant from its dilute-solution form to strong-solution.

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