Performance Evaluations of LiCl and LiBr for Absorber Design Applications in the Open-Cycle Absorption Refrigeration System

1997 ◽  
Vol 119 (2) ◽  
pp. 165-173 ◽  
Author(s):  
K. J. Kim ◽  
T. A. Ameel ◽  
B. D. Wood
Keyword(s):  
Chemical Potential ◽  
Mass Transfer Rate ◽  
Cooling Water ◽  
Solution Concentration ◽  
Operating Conditions ◽  
Solution Temperature ◽  
Solution Flow Rate ◽  
Absorption Refrigeration ◽  
Solution Flow ◽  
Open Cycle

Both LiCl and LiBr solutions were considered for potential use in a solar-driven Open-Cycle Absorption Refrigeration (OCAR) system. A vertical falling film absorber was proposed and built to evaluate the performance of LiCl and LiBr as an absorbent. Absorption experiments were performed and the results are reported for typical operating conditions of nonabsorbable concentrations, solution concentration, solution temperature, cooling water temperature, absorber pressure, and solution flow rate, in terms of mass transfer rate. In general, LiBr outperformed LiCl in terms of effective absorption rate. Based upon experimental results, the required absorber area was estimated for both LiCl and LiBr. The small chemical potential of LiCl relative to LiBr leads to a larger absorber area. The cost for the required solution storage for three-ton cooling capacity of the present OCAR system was found to be high for both LiCl and LiBr. The pumping cost was estimated to be less than 0.1 kW for both.

Effect of Tin Oxide Coatings by Spray Pyrolysis Process on Mechanical Properties of Aluminium, Brass and Mild Steel

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
M. Shunmugasundaram ◽  
A. Praveenkumar ◽  
L. Ponraj Sankar ◽  
S. Sivasankar
Keyword(s):  
Mechanical Properties ◽  
Mild Steel ◽  
Substrate Temperature ◽  
Spray Pyrolysis ◽  
Tin Oxide ◽  
Microstructural Analysis ◽  
Solution Concentration ◽  
Solution Flow Rate ◽  
Spray Pyrolysis Method ◽  
Solution Flow

Mechanical properties of materials are enhanced by different methods to increase the usage of the materials. In this research spray pyrolysis method is employed to increase the mechanical characteristics of three different materials. The tin oxide is chosen as coated material and aluminium, brass, mild steel are selected as substrate materials. The 500nm thin film is developed over the substrate materials by spray pyrolysis. The substrate temperature are chosen as 300? C for aluminium, 400? C for brass and mildsteel. Nozzle to substrate distance is 0.4 m, substrate temperature is 300? C for aluminium and 400? C for solution concentration as 0.2 mole and solution flow rate is 1ml/min are selected for constant deposition parameters. The hardness and tensile strength result clearly shows that strength is increased by adding the coating over the surface. The material is heated above crystallization temperature and SnO2 increases the tensile and hardness strength of the materials. The triangular metrological microscope is used to examine the microstructure of non coated and coated substrate materials. The microstructural analysis is showed that the uncoated surface of the substrate material is full of rough and pores. And displays that the tin oxide coated surface of the substrates after the initial deposition disclosed a surface with a agglomeration of tin oxide in homogeneous and uniform than the uncoated substrates.

scholarly journals Neutralization Dialysis for Phenylalanine and Mineral Salt Separation. Simple Theory and Experiment

Membranes ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 171 ◽  
Author(s):  
Anton Kozmai ◽  
Elena Goleva ◽  
Vera Vasil’eva ◽  
Victor Nikonenko ◽  
Natalia Pismenskaya
Keyword(s):  
Amino Acid ◽  
Flow Rate ◽  
Solution Concentration ◽  
Exchange Capacity ◽  
Ion Concentration ◽  
Solution Flow Rate ◽  
Strong Electrolyte ◽  
Mineral Salts ◽  
Solution Flow ◽  
Hydrodynamic Mode

A simple non-steady state mathematical model is proposed for the process of purification of an amino acid solution from mineral salts by the method of neutralization dialysis (ND), carried out in a circulating hydrodynamic mode. The model takes into account the characteristics of membranes (thickness, exchange capacity and electric conductivity) and solution (concentration and components nature) as well as the solution flow rate in dialyzer compartments. In contrast to the known models, the new model considers a local change in the ion concentration in membranes and the adjacent diffusion layers. In addition, the model takes into consideration the ability of the amino acid to enter the protonation/deprotonation reactions. A comparison of the results of simulations with experimental data allows us to conclude that the model adequately describes the ND of a strong electrolyte (NaCl) and amino acid (phenylalanine) mixture solutions in the case where the diffusion ability of amino acids in membranes is much less, than mineral salts. An example shows the application of the model to predict the fluxes of salt ions through ion exchange membranes as well as pH of the desalination solution at a higher than in experiments flow rate of solutions in ND dialyzer compartments.

scholarly journals Investigation on the Regeneration Performance of a New Mixed Liquid Desiccant Solution in Falling Film Regenerator

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1374
Author(s):  
Tao Wen ◽  
Dan Zhong ◽  
Yuanhao Wang ◽  
Yimo Luo
Keyword(s):  
Flow Rate ◽  
Solution Temperature ◽  
Solution Flow Rate ◽  
Mixed Solution ◽  
Falling Film ◽  
Liquid Desiccant ◽  
Solution Flow ◽  
Regeneration Rate ◽  
Air Inlet ◽  
Selection Of

The present study firstly developed a new kind of mixed liquid desiccant for the purpose of causticity reduction on metal based regenerator. The formula of the mixed liquid desiccant is 25% LiCl + 39% hydroxyethyl urea + 36% water. Experimental results show that the causticity of the mixed solution is much less severe than that of conventional LiCl solution. The regeneration rate increases with the increase of air flow rate and solution temperature and decreases with the increase of air inlet humidity. The air temperature and solution flow rate has negligible influence on the regeneration performance. The present study provides a practical alternative for the selection of liquid desiccant and also give useful guidance for the design of regenerator.

The Development of Electrospinning Apparatus to Fabricate Nanofiber for Future Material Applications

2017 ◽  
Vol 866 ◽  
pp. 244-247
Author(s):  
Pattarinee Klumdoung ◽  
Piyapong Pankaew
Keyword(s):  
Flow Rate ◽  
Low Cost ◽  
Average Diameter ◽  
Operating Conditions ◽  
Solution Flow Rate ◽  
Syringe Pump ◽  
Sem Images ◽  
Solution Flow

This research examines the development of a low cost mobile electrospinning system for fabricating nanofiber. The electrospinning system developed in this study consists of a horizontal needle arrangement and a motor which supports the working system that controls the solution flow rate without an external syringe pump. In order to discover the equipment operating conditions for nanofiber fabrication, the distance from the needle to the target was studied. A PVA solution of 8wt% was used and voltage was applied at 13 kV. The needle to target distances were varied from 8-18 cm. At a distance of 10 cm, the SEM images showed that the smallest diameter of the fiber was 119 nm. The average diameter was in the range of 119-240 nm. Concentrations of the 3 different solutions of PVA, PEO and PCL with the variation of voltage at each concentration were studied. The results show the diameter of PVA at 8 wt% and 12%wt are in the range of 127-197 nm and 222-402 nm, respectively. The diameter of PCL solution at a 20 wt% concentration is in the range of 32-60 nm. PEO at 2 wt% and 4wt% was not able to form as a fiber.

scholarly journals Preparation, Characterization, and Dissolution RateIn VitroEvaluation of TotalPanaxNotoginsenoside Nanoparticles, Typical Multicomponent Extracts from Traditional Chinese Medicine, Using Supercritical Antisolvent Process

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Ying Zhang ◽  
Xiuhua Zhao ◽  
Wengang Li ◽  
Yuangang Zu ◽  
Yong Li ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
High Performance ◽  
Solution Concentration ◽  
Solution Flow Rate ◽  
Optimum Conditions ◽  
Solution Flow ◽  
Supercritical Antisolvent ◽  
Differential Scanning Calorimeters

TotalPanaxnotoginsenosides nanoparticles, typical multicomponent extracts from traditional Chinese medicine, were prepared with a supercritical antisolvent (SAS) process using ethanol as solvent and carbon dioxide as antisolvent. The optimum conditions were determined to be as follows: TPNS solution concentration of 2.5 mg/mL, TPNS solution flow rate of 6.6 mL/min, precipitation temperature of 40°C, and precipitation pressure of 20 MPa. Under the optimum conditions, TPNS nanoparticles with a MPS of 141.5 ± 18.2 nm and total saponins amounts (TSA) of 78.9% were obtained. The TPNS nanoparticles obtained were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimeters (DSC), and high performance liquid chromatography (HPLC). The results showed that the chemical and crystal structure of the obtained TPNS nanoparticles has not changed. Dissolutionin vitrostudies showed that the solubility and dissolution rate of notoginsenosides R1 and ginsenoside Rb1 in TPNS nanoparticles are higher than these in raw TPNS, with no obvious difference in Rg1. These results suggest that TPNS nanoparticles can be helpful to the improvement of its bioavailability for the treatment of cardiovascular diseases.

Performance Curves for Single-Stage Vapor Compression Cycles With Solution Circuit

1991 ◽  
Vol 113 (2) ◽  
pp. 221-227 ◽  
Author(s):  
K. Amrane ◽  
M. V. Rane ◽  
R. Radermacher
Keyword(s):  
Weak Solution ◽  
High Temperature ◽  
Heat Pump ◽  
Solution Concentration ◽  
Operating Conditions ◽  
Single Stage ◽  
Solution Temperature ◽  
Ammonia Vapor ◽  
Vapor Compression ◽  
Performance Curves

The performance curves for a single-stage vapor compression heat pump with solution circuit (VCHSC) and for its modified version, the cycle using a subcooler and a preheater, are obtained and are compared for the same total UA value including all heat exchangers. The two cycles are simulated at low and high temperature lifts. The weak solution concentration and flow rate are varied. The parameters studied are the cooling COP, the solution heat exchanger (SHX) effectiveness, the pressure ratio, the solution temperature glides in the absorber and the desorber, the desorber load, and the distribution of the UA value. Changing the weak solution concentration from 20 to 90 wt% ammonia increased the desorber load ten times. The cooling COP improved by as much as 20 percent by incorporating the preheater and the subcooler, for both the low and the high temperature lifts. Compared to the conventional ammonia vapor compression cycle, the modified VCHSC showed a maximum improvement in cooling COP of 88 and 35 percent for the low and high temperature lifts, respectively. The results indicate that VCHSC is a very versatile heat pump and/or refrigeration system suitable for a wide range of applications and changing operating conditions.

scholarly journals Comparative Study for Organic and Inorganic Draw Solutions in Forward Osmosis

2017 ◽  
Vol 13 (1) ◽  
pp. 94-102
Author(s):  
Ahmed Faiq Al-Alalawy ◽  
Talib Rashid Abbas ◽  
Hadeer Kadhim Mohammed
Keyword(s):  
Flow Rate ◽  
Water Flux ◽  
Forward Osmosis ◽  
Solution Concentration ◽  
Salt Flux ◽  
Effect Of Temperature ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Draw Solution ◽  
Reverse Salt Flux

The present work aims to study forward osmosis process using different kinds of draw solutions and membranes. Three types of draw solutions (sodium chloride, sodium formate, and sodium acetate) were used in forward osmosis process to evaluate their effectiveness with respect to water flux and reverse salt flux. Experiments conducted in a laboratory-scale forward osmosis (FO) unit in cross flow flat sheet membrane cell.  Three types of membranes (Thin film composite (TFC), Cellulose acetate (CA), and Cellulose triacetate (CTA)) were used to determine the water flux under osmotic pressure as a driving force. The effect of temperature, draw solution concentration, feed and draw solution flow rate, and membrane types, were studied with respect to water flux. The results showed an increase in water flux with increasing feed temperature and draw solution concentrations In addition, the flux increased with increasing feed flow rate while the flux was inversely proportional with the draw solution flow rate. The results showed that reverse osmosis membranes (TFC and CA) are not suitable for using in FO process due to the relatively obtained low water flux when compared with the flux obtained by forward osmosis membrane (CTA). NaCl draw solution gave higher water flux than other draw solutions and at the same time, revealed higher reverse salt flux.

scholarly journals Removal of Congo Red from Aqueous Solution by Circulating Fluidized Bed(CFB)

2021 ◽  
Vol 28 (2) ◽  
pp. 01-07
Author(s):  
Hamza Q. Ali ◽  
Ahmed A. Mohammed
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Congo Red ◽  
Circulating Fluidized Bed ◽  
Mass Transfer Rate ◽  
Breakthrough Curves ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Bed Height

In this study circulating fluidized bed was adopted to remove of Congo Red from wastewater using Eichhornia crassipes as a adsorbent. Solution flow rate(6,12 and 18)l/hr, bed height(2,4 and 6) cm and Congo Red initaial concentration (10,25 and 50)mg/l were examined in experiments to show their effects on breakthrough curves and time required to reach the adsorbent to fully saturated curve. The mass transfer coefficient "KL"decreased with decreasing the liquid flow rate. The minimum fluidization velocities of bed found equal to 1.6, 2, 2.5 mm/s for heights of 2, 4,6 cm respectively. The increasing of the bed height will increase the contact time of the solute in the bed, and these improve the solute removal efficiency. the increasing in flow rate and initial concentration will increase the mass transfer rate.

Mass Transfer Rate Enhancement in Sparged Vessel for Ammonia-Water Nano-Fluid in VARS by Adding Nanoparticles

2020 ◽  
Author(s):  
Rahul Bhujbal ◽  
Sanjay Nakate ◽  
Sunil V. Dingare
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Numerical Study ◽  
Mass Transfer Rate ◽  
Solution Flow Rate ◽  
Low Grade ◽  
Efficient Design ◽  
Operation Condition ◽  
Solution Flow ◽  
Ammonia Water

Abstract The refrigeration systems are used in domestic and commercial freezing applications. These systems are needed to be used energy efficiently to get the economic operation condition. The vapor compression refrigeration cycle (VCR) is getting replaced by vapor absorption refrigeration system (VARS) as they can use low grade energy. This VARS can be used by making use of waste energy in the form of heat which is readily available for many applications. Performance of the VARS is dependent on the generator and absorber performance. In absorber it is based on the amount of refrigerant absorbed and the solution flow rate. Experimental and Numerical study of bubble absorber and effect of nanoparticle on ammonia water mass transfer is carried out. In this study, different designs for the absorber chamber are viewed and compared together, based on the research did earlier. Looking at the aspects of bubble type absorber designs, these designs give better mass transfer performance as compared to other designs. These designs may be improved to get the energy efficient design of the absorber. Present study includes the enhancement of mass transfer rate by the addition of nanoparticles using aluminum oxide (Al2O3). Here, sparged vessels with NH3-H2O binary fluid are arranged with varying percentage of nanoparticle (Al2O3). This study includes the study of mass transfer enhancements by using nanoparticles. Based on the experimental results carried out for the varying mass flow rates it is found that the mass transfer rate is enhanced significantly, it is because the interfacial area is enhanced by the addition of nanoparticles to the base fluids.

Absorption Characteristics of Multilayered Thin Lithium Bromide (LiBr) Solution Film

2015 ◽  
Author(s):  
Mehdi Mortazavi ◽  
Rasool Nasr Isfahani ◽  
Sajjad Bigham ◽  
Saeed Moghaddam
Keyword(s):  
Absorption Rate ◽  
Numerical Models ◽  
Water Vapor Pressure ◽  
Lithium Bromide ◽  
Cooling Water ◽  
Solution Flow Rate ◽  
Inlet Temperature ◽  
Pressure Potential ◽  
Solution Flow ◽  
Uniform Solution

In this study, an alternative absorber design suitable for the plate-and-frame absorber configuration is introduced. The design utilizes a fin structure installed on a vertical flat plate to produce a uniform solution film and minimize its thickness and to continuously interrupt the boundary layer. Using numerical models supported by experiments employing dye visualization, the suitable fin spacing and size and wettability are determined. The solution flow thickness is measured using the laser confocal displacement measurement technique. The new surface structure is tested in an experimental absorption system. An absorption rate as high as 6×10−3 kg/m2s at a driving pressure potential of 700 Pa is achieved, which is considerably high in comparison with conventional absorption systems. The effect of water vapor pressure, solution flow rate, solution inlet concentration, cooling water inlet temperature and solution inlet temperature on the absorption rate is also investigated. The proposed design provides a potential framework for development of highly compact absorption refrigeration systems.

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