دانلود مقاله ISI انگلیسی شماره 28338
عنوان فارسی مقاله

تجزیه و تحلیل عملکرد از یک سیستم جدید بازسازی الکترودیالیز خشک کننده بقبل از درمان رای خشک کننده مایع

کد مقاله سال انتشار مقاله انگلیسی ترجمه فارسی تعداد کلمات
28338 2013 15 صفحه PDF سفارش دهید محاسبه نشده
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عنوان انگلیسی
Performance analysis of a new desiccant pre-treatment electrodialysis regeneration system for liquid desiccant
منبع

Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)

Journal : Energy and Buildings, Volume 66, November 2013, Pages 1–15

کلمات کلیدی
خشک کننده مایع - بازسازی خشک کن - خشک کننده قبل از درمان -
پیش نمایش مقاله
پیش نمایش مقاله تجزیه و تحلیل عملکرد از یک سیستم جدید بازسازی الکترودیالیز خشک کننده بقبل از درمان رای خشک کننده مایع

چکیده انگلیسی

Liquid desiccant air-conditioning system (LDAS) is a novel air-conditioner with good energy saving potential. As a renewable energy, solar thermal energy (TH) can be used to regenerate desiccant for LDAS. One problem of the solar regeneration system is that solar energy will depend on weather conditions, which means that the solar regeneration system cannot meet the dehumidification requirements all the time. In this paper, a new desiccant pre-treatment electrodialysis (ED) regeneration system is proposed in order to improve the reliability and the performance of solar desiccant regeneration system for LDAS. The new system makes comprehensively use of solar energy and can work reliably under the variable conditions. Moreover, the new system can be used in the deep dehumidification field, which is required in industrial air-conditioning. Analysis of the new system, the solar TH regeneration system and the PV-ED regeneration system is made and the results reveal that the new system will be more energy efficient than others under the ideal operational condition. Among all factors, the most influential one is the concentration of desiccant at the entrance of concentrate cells in the ED regenerator, and the new system should be running under the ideal operational condition as possible.

مقدمه انگلیسی

In today's world, finding ways to produce comfortable living conditions in buildings is a popular and needed trend, which leads to the widespread use of air-conditioner. At present, the most widely used air-conditioner is the vapor compression cooling system, which is driven by electric power. However, the overuse of the vapor compression cooling system is harmful to the energy power supplying and the environment. As a result, many new types of air-conditioners are developed to solve the problems accompanying with the overuse of the vapor compression cooling system. Among all new air-conditioners, the liquid desiccant air-conditioning system (LDAS) is a novel air-conditioner with significant energy-saving potential [1], [2], [3] and [4]. It is also a promising technology that can meet the needs of space cooling and moisture management in artificial building spaces. The energy consumption of liquid desiccant air-conditioning system mainly relies on the regeneration process of the desiccant solution. At present, thermal energy (TH) is widely used for desiccant regeneration in liquid desiccant air-conditioning systems. This energy is usually obtained from low-temperature heat sources [5] and [6]. As a renewable energy source, solar thermal energy has many advantages and can be used to power this type of air-conditioning systems. There are many literatures shared with the investigation of the performance of the solar liquid desiccant air-conditioning system. Audah et al. [4] studied the feasibility of using a solar-powered liquid desiccant system to meet both building cooling and fresh water needed in Beirut humid climate using parabolic solar concentrators as a heat source for regenerating the liquid desiccant. Kabeel [7] investigated the regeneration of liquid solution using cross flow of air stream with flowing film of desiccant on the surface of a solar collector/regenerator. The results showed enhancement of regeneration efficiency for the forced cross flow compared with the free regeneration. Katejanekarn et al. [8] carried out an experiment of a solar-regenerated liquid desiccant ventilation pre-conditioning system. The results showed that the evaporation rate at the regeneration process was always greater than the moisture removal rate at the dehumidification process, which indicated that the concentration of the desiccant in the system would not decrease and so the performance would not drop during continuous operation. However, one problem of solar TH regeneration systems is that solar energy is cyclical and heavily dependent on weather conditions. This means that the system cannot always meet the dehumidification requirements. Therefore, it is imperative to find a backup way for solar desiccant regeneration when the solar energy cannot produce enough desiccant regeneration. Electrodialysis (ED) method is a technology based on the transport of ions through the selective membranes under the influence of an electrical field [9], [10] and [11]. In the electrodialyzer, the cation-exchange membrane and the anion-exchange membranes are placed alternately between the cathode and the anode. The anions and the cations in the cells of the electrodialyzer will move to the anode and the cathode under an electrical field. In the migration process, the anions and cations can go through the anion-exchange membrane and the cation-exchange membrane, respectively. However, the anions and cations cannot go through the cation-exchange membrane and the anion-exchange membrane, respectively. Finally, the concentration of liquid desiccant in some cells of the electrodialyzer will increase, and the others will decrease. Based on the ED technology, Li et al. [12] and [13] developed a new regeneration system for LDAS. The regeneration system was named as photovoltaic-electrodialysis (PV-ED) regeneration system. Based on the PV-ED regeneration system, Cheng et al. [14] developed a new double-stage photovoltaic/thermal ED regeneration system (PVT-ED). Analysis of the single-stage and double-stage regeneration system was made and the results showed that the double-stage PVT-ED regeneration system will be more applicable than the single-stage PV-ED regeneration system for LDAS. For the solar TH regeneration system, the TH regeneration style relies on the environmental situation seriously and can be unreliable when air is hot and wet. Compared with the solar TH regeneration system, the PV-ED regeneration system is a new regeneration system which has higher performance and reliability by using solar photovoltaic components to drive an ED regeneration process [14]. However, the PV-ED regeneration system will waste a large amount of solar thermal energy as the conversion efficiency of the PV cells is low. In this paper, a new desiccant pre-treatment ED regeneration system is proposed in order to improve the reliability and the performance of desiccant regeneration system for LDAS. The new system makes comprehensively use of the solar energy and can work reliably under the variable conditions. What's more, the new system can be used in the deep dehumidification field, which is required in industrial air-conditioning. Analysis of the new system, the solar TH regeneration system and the PV-ED regeneration system is made and the results reveal that the new system will be more energy efficient than the solar TH regeneration system and the PV-ED regeneration system under the ideal operational condition.

نتیجه گیری انگلیسی

In this paper, a new desiccant pre-treatment ED regeneration system is proposed in order to improve the reliability and the performance of desiccant regeneration system for LDAS. The new system makes comprehensively use of solar energy and can work reliably under the variable conditions. Moreover, the new system can be used in the deep dehumidification field, which is required in industrial air-conditioning. Compared with the solar TH regeneration system and the PV-ED regeneration system, the new desiccant pre-treatment ED regeneration system has many advantages. Firstly, the regeneration efficiency of the desiccant solution in the desiccant pre-treatment unit will increase with the temperature of the mixed desiccant solution. Meanwhile, the limiting current of the ED Regenerator will increase with the temperature of desiccant solution, which will cause the improvement of the regeneration efficiency of desiccant solution in the ED regenerator. Secondly, the mixed desiccant solution cools the PV cells in the PV/T components, which will cause the increase of the electric power generation efficiency of the PV cells. Finally, the regeneration efficiency of the desiccant solution in the ED regenerator will increase with the decrease of the difference between the concentrations of the desiccant solution in the concentrate cells and the dilute cells of the ED regenerator. Under the ideal operational condition, the desiccant pre-treatment ED regeneration system will be more energy efficient than the solar TH regeneration system and the PV-ED regeneration system. Among all factors, the most influential one is Con s,c,i, and the desiccant pre-treatment ED regeneration system should be running under the ideal operational condition as possible View the MathML source(Cons,c,i=Cons,c,ii). Moreover, the maximum value of ηdp (ηdp < 1) should be wanted in the designing of the desiccant pre-treatment ED regeneration system. What's more, the desiccant pre-treatment ED regeneration system will be more and more energy efficient with the decrease of k. However, the value of k will mainly rely on the dehumidification requirements of LDAS. The experimental research of the ED regenerator will be conducted in the near future, which is needed to better the analysis of the performance and the design of the desiccant pre-treatment ED regeneration system.

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