Analysis of air dehumidification using liquid desiccant system (original) (raw)
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A novel method to evaluate the performance of liquid desiccant air dehumidifier system
Lancet
The system efficiency of desiccant air dehumidification is usually evaluated by a coefficient of performance (COP) that is defined as the ratio of the cooling capacity and the sum of net electrical power input. The common efficiency evaluation method has many weaknesses especially if applied on liquid type of desiccant, low humidity different between inlet and outlet, and also on the system that has automatic operating control. This paper offers a solution for weaknesses of common method with a proposed novel method to evaluate the performance of liquid desiccant air dehumidification system.
Performance analysis of liquid desiccant dehumidification systems
International Journal of Refrigeration, 2007
Desiccant systems find applications in a very large variety of industrial and daily usage products including the new HVAC installations. An overview of liquid desiccant technology has been presented in this paper along with a compilation of experimental performance data of liquid desiccant dehumidifiers, empirical dehumidification effectiveness and mass transfer correlations in a useful and easy to read tabular format. The latest trends in this area suggest that hybrid systems are of current interest to HVAC industry, not only for high latent load applications but also for improving indoor air quality. The paper presents a comprehensive comparative parametric analysis of packed bed dehumidifiers for three commonly used desiccant materials viz. triethylene glycol, lithium chloride and calcium chloride, using empirical correlations for dehumidification effectiveness from the literature. The analysis reveals significant variations and anomalies in trends between the predictions by various correlations for the same operating conditions, and highlights the need for benchmarking the performance of desiccant dehumidifiers.
Performance analysis of a solid desiccant air dehumidifier
2015
A desiccant air dehumidification system is widely used in many applications such as refrigeration, crops drying, food industries, pharmaceutical and air-conditioning. The thermal effectiveness is often used to represent the performance of the system. Its value depends on the psychrometric properties of the incoming air and several other parameters. This article presents an experimental study to determine the thermal performance of a compact solid desiccant air dehumidifier. The effects of percent opening combination of the control valve for the process and regeneration air ducting on the thermal performances of the dehumidifier was investigated. An experimental rig was fabricated for these purposes. It consists of a solid desiccant air dehumidifier, process and regeneration air ducts, instrumentation and data acquisition system. Experimental data were acquired under a steady-state operating condition, for three cases of control valve opening combinations. It was found that the therm...
Performance Assessment of a Solid Desiccant Air Dehumidifier
Jurnal Teknologi, 2016
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 b...
Dehumidifier is the most important part in liquid desiccant air conditioning systems. Internally cooled air dehumidifier was found to have better heat and mass transfer performance than the adiabatic one. This paper experimentally studies the performance of an internally cooled dehumidifier using Triethylene Glycol as a desiccant. During the experimental investigation, the dehumidifier inlet parameters, including air flow rate, humidity ratio, temperature, desiccant flow rate, and temperature are varied. The effect of these variables on the moisture condensation rate and dehumidifier effectiveness was studied. It is found that the moisture condensation rate increases with increasing the inlet air flow rate, inlet air humidity ratio, desiccant flow rate, and desiccant solution concentration. While the dehumidifier effectiveness increases with increasing desiccant flow rate and concentration. The dehumidifier effectiveness decreases with increasing inlet air flow rate and humidity ratios.
International Journal of Engineering Research and Technology (IJERT), 2014
https://www.ijert.org/experimental-analysis-of-inlet-variables-effecting-the-performance-of-cross-flow-liquid-desiccant-air-dehumidifier https://www.ijert.org/research/experimental-analysis-of-inlet-variables-effecting-the-performance-of-cross-flow-liquid-desiccant-air-dehumidifier-IJERTV3IS031800.pdf A Dehumidifier is a one of essential components in liquid desiccant air conditioning system. In summer the air contain more amount of moisture as compared to winter in Indian subcontinent environment. This moisture is the latent heat load of air which is to be removed by air conditioning system. In the vapour compression air conditioning system the air is cooled below its dew point temperature for removing this latent heat load then reheated for removing the sensible heat load. This paper is an experimental study of a cross flow air dehumidifier using triehtylene glycol (TEG) as liquid desiccant. The affect of inlet parameters were studied on some outlet parameters. It is concluded that dry bulb temperature, wet bulb temperature and enthalpy of air increases with increasing the air inlet temperature and humidity ratio, wet bulb temperature, specific enthalpy, moisture removal rate decreases on increasing the air mass flow rate. It is found that the higher mass flow rate of air does not effect on moisture removal rate significantly. KEYWORD-Desiccant, dehumidification system, humidity ratio, triethylene glycol (TEG).
Liquid Desiccant Dehumidification and Cooling System: A Review
Journal of Thermal and Fluid Science, 2021
Liquid dehumidification was shown to be an efficient way of extracting air moisture with comparatively minimal energy. Draining cooling systems have been given significant attention in recent years because they are capable of using little thermal energy. The potential for hybrid cooling (HCS) as well as simulation results shows the benefits of this system in comparison with traditional vapor compression systems (VCS). When one tone of the compressor is employed in an HCS instead of VCS the cooling impact and COP increase in the HCS by 60 percent and 45 percent correspondingly.
Simulation Study of Desiccant Dehumidifier: A Review
International Journal of Advanced Research in Science, Communication and Technology
Traditional cooling systems based on vapor compression are ineffective in humid climates due to their inability to remove moisture below the dew point of the conditioned air, which involves additional effort in the form of an electrical power supply to run vapor compressors. A solid desiccant cooling system reduces powerusage while simultaneously providing fresh and clean air. It is important toexamine and analyze the performance of desiccant dehumidifiers using the Different pattern in the desiccant wheel that will help to develop a more efficient cooling system. Like ahoneycomb, triangular, sinusoidal.To study different type of material used in desiccant wheeel to adsorp the air moisture. Study different simulation technique used in desiccant.
Experimental Study of the Heat and Mass Transfer in a Packed Bed Liquid Desiccant Air Dehumidifier
Desiccant cooling systems have the ability to provide efficient humidity and temperature control while reducing the electrical energy requirement for air conditioning as compared to a conventional system. Naturally, the desiccant air dehumidification process greatly influences the overall performance of the desiccant system. Therefore, the effects of variables such as air and desiccant flow rates, air temperature and humidity, desiccant temperature and concentration, and the area available for heat and mass transfer are of great interest. Due to the complexity of the dehumidification process, theoretical modeling relies heavily upon experimental studies. However, a limited number of experimental studies are reported in the literature. This paper presents results from a detailed experimental investigation of the heat and mass transfer between a liquid desiccant (triethylene glycol) and air in a packed bed absorption tower using high liquid flow rates. A high performance packing that combines good heat and mass transfer characteristics with low pressure drop is used. The rate of dehumidification, as well as the effectiveness of the dehumidification process are assessed based on the variables listed above. Good agreement is shown to exist between the experimental findings and predictions from finite difference modeling. In addition, a comparison between the findings in the present study and findings previously reported in the literature is made. The results obtained from this study make it possible to characterize the important variables which impact the system design.
A Statistical Analysis of Desiccant Dehumidifier for Air Conditioning Application
Due to the direct utilization of thermal energy and possibility of using renewable energy resources, the interest of using desiccant wheels for airconditioning application is increasing rapidly. The thermally driven desiccant cooling systems are environmental friendly and has a great potential to reduce the peak electricity demand. During the experiments the inlet and outlet parameters in the dehumidifier can be easily measured. However, in theoretical analysis it is difficult to predict the relationship between these parameters because of the complexity of combined heat and mass transfer process. In this paper a statistical analysis using Minitab software is used to predict the functional relationships between the input and output parameters in the dehumidifier. The factorial analysis is first carried out to eliminate the factors which does not affect the response, significantly. Then, the regression analysis is carried out to analyze the effect of significant operating variables (independent) on the moisture absorption rate in the dehumidifier and to develop a relationship between dependent and independent variables. Regression analysis shows that the inlet air humidity ratio, ratio of mass flow rates, and regeneration temperature cause significant variation (P<0.01) in the absorption rate.