PERFORMANCE ASSESSMENT OF A SOLID DESICCANT AIR DEHUMIDIFIER

2016 ◽  
Vol 78 (8-4) ◽  
Author(s):  
Nazri Kamsah ◽  
Haslinda Mohamed Kamar ◽  
Muhammad Imran Wan Khairuzzaman ◽  
M. Idrus Alhamid ◽  
Fazila Mohd Zawawi
Keyword(s):  
Removal Rate ◽  
Operating Parameters ◽  
Inlet Temperature ◽  
Moisture Removal ◽  
Desiccant Wheel ◽  
Air Inlet ◽  
Low Humidity ◽  
Experimental Rig ◽  
Humidity Environment

The presence of moisture in the air along with temperature has a long term and devastating effect on man and material. One way to create a low humidity environment is by using a solid desiccant wheel system. In the present work, an experimental analysis has been carried out under steady-state conditions to investigate the effects of different operating parameters on a solid desiccant wheel system performances. An experimental rig consists of an FFB300 air dehumidifier system was constructed. A parametric investigation was carried out to examine the effects of the reactivation air inlet temperature and process air outlet velocity on the thermal effectiveness, dehumidification efficiency, and moisture removal rate of the desiccant wheel system. The analysis shows that both thermal effectiveness and dehumidification efficiency decrease with the increase of the reactivation air inlet temperature, by 2.5 % and 43 %, respectively. Likewise, when the process air outlet velocity increases both performances criteria reduce by 10 % and 28 %, respectively. The moisture removal rate increases significantly by 30 % as the reactivation air inlet temperature increases. However, the process air outlet velocity has no significant effect on the moisture removal rate. 

Theoretical Performance of Silica Gel Desiccant Wheel

2019 ◽  
Vol 7 (3) ◽  
pp. 66-74
Author(s):  
Zainab Mahdi Salih ◽  
Abdulsalam D. M.Hassan ◽  
Amer Majeed Al-Dabagh
Keyword(s):  
Silica Gel ◽  
Air Temperature ◽  
Inlet Temperature ◽  
Moisture Removal ◽  
Humidity Ratio ◽  
Desiccant Wheel ◽  
Operational Conditions ◽  
Removal Capacity ◽  
Air Inlet ◽  
Theoretical Performance

Abstract— Silica gel is a substance commonly used in desiccant wheel, which in turn is used in many applications to reduce moisture from the supplied air to a specific space. In this research,  the effect of different operational conditions on the performance of silica gel wheel were studied. The desiccant wheel, which has been used, has a diameter of 55 cm and thickness of 20 cm. It contains 34 kg of silica gel and rotate at a speed of 30 rph. The theoretical performance coefficients of the desiccant wheel which have been studied include ,moisture removal capacity(MRC),dehumidification performance(DCOP),latent coefficient of performance (COPlat), and desiccant wheel effectiveness(ϵ_d). The theoretical investigation of these coefficients was done by using Novel Aire Technology software program (Simulation program of desiccant wheel) (2012). While the operational conditions like process air (humid air)inlet temperature between(30 to 43.4)0C, process air inlet humidity ratio between (0.011 to 0.019)kg/kgdry air ,regeneration air inlet temperature between (56.5 to 70)0C,and process air mass flow rate between(0.0814 to 0.199)kg/s. The results shows that the effectiveness and the moisture removal capacity have the same behavior increase with the increasing in mass flow rate from(0.0814 to 0.199) kg/s, humidity ratio from(11 to19)g/kgdry air, and regeneration air temperature from(56 t0 70)oC. But they reduces with increasing of inlet process air temperature from(30 to43.4)oC..

scholarly journals Microencapsulation ofβ-Carotene by Spray Drying: Effect of Wall Material Concentration and Drying Inlet Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Luiz C. Corrêa-Filho ◽  
Maria M. Lourenço ◽  
Margarida Moldão-Martins ◽  
Vítor D. Alves
Keyword(s):  
Antioxidant Activity ◽  
Spray Drying ◽  
Encapsulation Efficiency ◽  
Fruits And Vegetables ◽  
Wall Material ◽  
Inlet Temperature ◽  
Carotene Content ◽  
Arabic Gum ◽  
Air Inlet ◽  
Adverse Environmental Conditions

Carotenoids are a class of natural pigments found mainly in fruits and vegetables. Among them,β-carotene is regarded the most potent precursor of vitamin A. However, it is susceptible to oxidation upon exposure to oxygen, light, and heat, which can result in loss of colour, antioxidant activity, and vitamin activity. Thus, the objective of this work was to study the microencapsulation process ofβ-carotene by spray drying, using arabic gum as wall material, to protect it against adverse environmental conditions. This was carried out using the response surface methodology coupled to a central composite rotatable design, evaluating simultaneously the effect of drying air inlet temperature (110-200°C) and the wall material concentration (5-35%) on the drying yield, encapsulation efficiency, loading capacity, and antioxidant activity. In addition, morphology and particles size distribution were evaluated. Scanning electron microscopy images have shown that the particles were microcapsules with a smooth surface when produced at the higher drying temperatures tested, most of them having a diameter lower than 10μm. The conditions that enabled obtaining simultaneously arabic gum microparticles with higherβ-carotene content, higher encapsulation efficiency, and higher drying yield were a wall material concentration of 11.9% and a drying inlet temperature of 173°C. The systematic approach used for the study ofβ-carotene microencapsulation process by spray drying using arabic gum may be easily applied for other core and wall materials.

UiO-66-NH2/graphene oxide nanocomposites as reactive adsorbents for soman upon long-term exposure to high-humidity environment

2021 ◽  
Vol 285 ◽  
pp. 129105
Author(s):  
Dongwon Ka ◽  
Seongon Jang ◽  
Min-Kun Kim ◽  
Hyunsook Jung ◽  
Jaeheon Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Humidity ◽  
High Humidity Environment ◽  
Humidity Environment

Rough Air-Soft Elastohydrodynamic Lubrication

2013 ◽  
Vol 420 ◽  
pp. 30-35
Author(s):  
Khanittha Wongseedakaew ◽  
Jesda Panichakorn
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Modulus Of Elasticity ◽  
Contact Region ◽  
Elastohydrodynamic Lubrication ◽  
Multilevel Methods ◽  
Inlet Temperature ◽  
Film Pressure ◽  
Air Inlet ◽  
Air Film

This paper presents the effects of rough surface air-soft elastohydrodynamic lubrication (EHL) of rollers for soft material under the effect of air molecular slip. The time independent modified Reynolds equation and elasticity equation were solved numerically using finite different method, Newton-Raphson method and multigrid multilevel methods were used to obtain the film pressure profiles and film thickness in the contact region. The effects of amplitude of surface roughness, modulus of elasticity and air inlet temperature are examined. The simulation results showed surface roughness has effect on film thickness but it little effect to air film pressure. When the amplitude of surface roughness and modulus of elasticity increased, the air film thickness decreased but air film pressure increased. However, the air inlet temperature increased when the air film thickness increased.

Experiment Study of Small Composite Desiccant Wheel Based on Ceramic

2012 ◽  
Vol 614-615 ◽  
pp. 665-669
Author(s):  
Chun Xia Jia
Keyword(s):  
Silica Gel ◽  
Residential Building ◽  
Experimental Results ◽  
Moisture Removal ◽  
Experiment Study ◽  
Desiccant Wheel ◽  
Rotating Speed ◽  
Removal Capacity

Small composite desiccant wheels based on ceramic are designed and developed. The experiments test the influence of the rotating speed and wheel thickness on the dehumidification performance. Furthermore the dehumidification performance of the composite desiccant wheel is compared with the silica gel wheel. The experimental results show increasing the rotating speed of the desiccant wheel can improve the moisture removal capacity. Compared with the silica gel wheel, the moisture removal amounts of the thin composite desiccant wheel are about similar with that of the thick silica gel wheel. It is further indentified that the new composite desiccant wheel can reduce the size of the dehumidifier and has more potential for residential building field.

scholarly journals Characteristics of a Non-Premixed Rotating Detonation Combustor Using Natural Gas-Hydrogen Blend at Elevated Air-Preheat Temperature and Backpressure

2018 ◽  
Author(s):  
Arnab Roy ◽  
Donald Ferguson ◽  
Todd Sidwell ◽  
Peter Strakey
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Detonation Wave ◽  
Inlet Temperature ◽  
Operational Mode ◽  
Atmospheric Conditions ◽  
Theoretical Understanding ◽  
Air Inlet ◽  
Continuous Detonation ◽  
Rotating Detonation

Operational characteristics of an air breathing Rotating Detonation Combustor (RDC) fueled by natural gas-hydrogen blends are discussed in this paper. Experiments were performed on a 152 mm diameter uncooled RDC with a combustor to inlet area ratio of 0.2 at elevated inlet temperature and combustor pressure while varying the fuel split between natural gas and hydrogen over a range of equivalence ratios. Experimental data from short-duration (∼6sec) tests are presented with an emphasis on identifying detonability limits and exploring detonation stability with the addition of natural gas. Although the nominal combustor used in this experiment was not specifically designed for natural gas-air mixtures, significant advances in understanding conditions necessary for sustaining a stable, continuous detonation wave in a natural gas-hydrogen blended fuel were achieved. Data from the experimental study suggests that at elevated combustor pressures (2–3bar), only a small amount of natural gas added to the hydrogen is needed to alter the detonation wave operational mode. Additional observations indicate that an increase in air inlet temperature (up to 204°C) at atmospheric conditions significantly affects RDC performance by increasing deflagration losses through an increase in the number of combustion (detonation/Deflagration) regions present in the combustor. At higher backpressure levels the RDC exhibited the ability to achieve stable detonation with increasing concentrations of natural gas (with natural gas / hydrogen-air blend). However, losses tend to increase at intermediate air preheat levels (∼120°C). It was observed that combustor pressure had a first order influence on RDC stability in the presence of natural gas. Combining the results from this limited experimental study with our theoretical understanding of detonation wave fundamentals provides a pathway for developing an advanced combustor capable of replacing conventional constant pressure combustors typical of most power generation processes with one that produces a pressure gain.

Optimization for Powder Yield of Spray-Dried Garlic Extract Powder Using Box-Behnken Experimental Design

2020 ◽  
Vol 859 ◽  
pp. 301-306
Author(s):  
Nattakanwadee Khumpirapang ◽  
Supreeya Srituptim ◽  
Worawut Kriangkrai
Keyword(s):  
Experimental Design ◽  
Spray Drying ◽  
Flow Rate ◽  
Interactive Effect ◽  
Garlic Extract ◽  
Process Conditions ◽  
Inlet Temperature ◽  
Feed Flow Rate ◽  
Air Inlet ◽  
Liquid Feed

Garlic exerts its pharmacological activities; antihyperglycemic, antihyperlipidemia, antihypercholesterolemic, and antihypertensive activity. Therefore, the aim of this study was to determine and optimize the influence of the individual and interactive effect of process conditions variables on the yield of garlic extract powders by three factors and three level-Box-Behnken design under response surface methodology. Spray drying processes the transformation of a garlic juice extract into a dried powder, where usually maltodextrin (MD) as a drying agent is used. According to experimental design, the mixing of garlic juice extract (85 – 95 %w/w) and MD (5 – 15 %w/w) were dried at an air inlet temperature 110°C - 150°C and liquid feed flow rate 5 – 35 rpm. The optimum spray-drying process conditions which maximized the yield of garlic extract powder (31%w/w) were found as follows: air inlet temperature of 150°C, the liquid feed flow rate of 16 rpm, and 5 %w/w MD. The experimental values slightly closed to the corresponding predicted values. Hence, the developed model was adequate and possible to use.

scholarly journals The effect of curing conditions on the expansion efficiency of MgO expansion agent

2021 ◽  
Vol 233 ◽  
pp. 03047
Author(s):  
Yu Fang ◽  
Li Yongchao
Keyword(s):  
Curing Temperature ◽  
Obvious Effect ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Temperature Conditions ◽  
Low Humidity ◽  
Humidity Environment

In order to further promote the research and application of MgO expansion agent in concrete field, this paper carried out the effect of different humidity and temperature conditions on the expansion properties of mortar and mortar specimens mixed with MgO expansion agent. In addition, the mechanism of the factors affecting the sensitivity of the MgO expansion agent is revealed by combining microscopic technology. The results show that the higher the curing temperature and the greater the curing humidity, the greater the expansion efficiency of the MgO expansion agent. The temperature of 20~40°C has no obvious effect on the efficiency of the MgO expansion agent, but the expansion value of the specimen doubles as the temperature rises to 40~80°C. Besides, the higher the curing humidity, the better the expansion efficiency of the MgO expansion agent, but the MgO expansion agent is more sensitive to the low humidity environment, and the specimen shrinks in the lower humidity environment (RH=60%).

Matching and Optimisation of Turbochargers for Upgradation of High Horse Power Diesel Electric Locomotives for Indian Railways

2005 ◽  
Author(s):  
Anirudh Gautam ◽  
Avinash Kumar Agarwal
Keyword(s):  
Engine Speed ◽  
Thermal Loading ◽  
Fuel Efficiency ◽  
Operating Point ◽  
Inlet Temperature ◽  
Test Bed ◽  
Optimum Configuration ◽  
Air Inlet ◽  
First Case ◽  
Brake Mean Effective Pressure

As a part of the upgradation program of its fleet of 1940 kW diesel electric locomotives, Indian Railways undertook evaluation, matching and optimization of different turbochargers. The objective was to increase engine output, improve fuel efficiency and limit thermal loading. Trials with different makes of turbochargers using different combinations of diffuser, nozzle rings and compressors were carried out for identifying the optimum configuration for an uprated engine rating of 2310 kW. Test bed evaluations have been carried out on Research Design & Standards Organization (RDSO) test beds for four different designs of turbochargers with different configurations. Two types of surge tests were carried out at each operating point i.e. constant brake mean effective pressure (BMEP) and constant power. In the first case, BMEP was kept constant and engine speed varied and in the second case, power was kept constant and engine speed was varied. The tests consisted of recording the parameters at various combinations of engine speed and power. With different combinations, the highest operating point for a test was governed by peak firing pressures. Some of the parameters, which were monitored, were the compressor air inlet temperature, representative peak firing pressures, turbine inlet temperature, average cylinder head temperature, brake specific fuel consumption (BSFC) and air manifold temperature. This paper discusses the methods adopted in carrying out these evaluations and optimizations and the results obtained thereof along with the decision criteria for making final selections.

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