一种新型太阳能溶液预处理电渗析再生系统

太阳能溶液除湿空调系统是一种具有较大节能潜力的新型空调系统。然而,太阳能热再生系统严重依赖于环境工况,在高温或高湿的气候条件下其再生后得到的除湿溶液将不能满足除湿的需求。提出一种用于溶液除湿空调系统的新型太阳能溶液预处理电渗析再生系统,分析了该系统的工作原理,建立了该系统的耗能模型,并与传统太阳能热再生系统进行了对比研究。研究结果表明,太阳能溶液预处理电渗析再生系统具有较高的节能潜力。     

一种新型太阳能溶液预处理电渗析再生系统

太阳能溶液除湿空调系统是一种具有较大节能潜力的新型空调系统。然而,太阳能热再生系统严重依赖于环境工况,在高温或高湿的气候条件下其再生后得到的除湿溶液将不能满足除湿的需求。提出一种用于溶液除湿空调系统的新型太阳能溶液预处理电渗析再生系统,分析了该系统的工作原理,建立了该系统的耗能模型,并与传统太阳能热再生系统进行了对比研究。研究结果表明,太阳能溶液预处理电渗析再生系统具有较高的节能潜力。     

内热型与绝热型溶液再生器再生过程性能

设计了一种内热源盘管作为填料支架、溶液和空气采用逆流换热的内热型再生器,并将其用于一种冷凝热分段利用的热湿独立处理空调系统中,可大幅度提高再生性能。搭建了逆流内热型再生器实验台,以氯化锂溶液为除湿剂,研究了溶液温度、流量,空气温度、流量对再生热效率和再生量的影响,结果表明内热型再生过程中应尽量避免通过提高空气进口温度来提高再生性能。并将内热型与绝热型再生过程进行了对比研究,结果表明内热型再生器再生量高于绝热型再生器。     

内热型与绝热型溶液再生器再生过程性能

设计了一种内热源盘管作为填料支架、溶液和空气采用逆流换热的内热型再生器,并将其用于一种冷凝热分段利用的热湿独立处理空调系统中,可大幅度提高再生性能。搭建了逆流内热型再生器实验台,以氯化锂溶液为除湿剂,研究了溶液温度、流量,空气温度、流量对再生热效率和再生量的影响,结果表明内热型再生过程中应尽量避免通过提高空气进口温度来提高再生性能。并将内热型与绝热型再生过程进行了对比研究,结果表明内热型再生器再生量高于绝热型再生器。     

基于热质传递解耦特性的溶液除湿过程传热传质系数(Ⅰ)模型与Le-hD分离测量法

溶液除湿过程是溶液除湿空调系统中的一个非常重要的耦合传热传质过程。本文对填料塔结构的溶液除湿器建立了一种NTU-Le模型,并基于此模型得到了溶液除湿过程传热传质特性——Lewis数对空气出口含湿量基本无影响,提出一种溶液除湿耦合热质传递过程的热质传递解耦方法——Le -h_D分离测量法,来测定溶液除湿过程的耦合传热传质系数。     

天然气冷热电三联供CCHP系统的负荷匹配——负荷不均匀性的改善措施

文章介绍了内燃机应用技术的现状与存在的问题,首先简要分析了常规以冷除湿和转轮以热除湿的空气调节过程,介绍内燃机的原理分类以及电动冷水机组的原理分类。针对某项目中内燃机结合电动冷水机组所存在的冷热负荷匹配方面的问题,设计了回收内燃机余热用于转轮再生的新风处理方案,对于上海的夏季和冬季气候条件计算了空调季与采暖季中,使用转轮除湿与冷冻减湿两种方案的动态能耗情况。计算结果表明使用余热再生的除湿技术可有效降低能耗,改善冷热负荷的匹配。     

一种低位热驱动除湿冷却空调系统的热性能分析

溶液除湿蒸发冷却空调系统（LDECS）结合了溶液除湿与蒸发冷却技术的优势,是一种具有广阔发展前景的非压缩式空调系统。提出了一种低品位热能驱动的LDECS,该系统由处理全部湿负荷的溶液除湿系统和承担显热负荷的再生式间接蒸发冷却器构成。建立了系统各主要部件的数学模型,研究了再生器进口溶液温度T_s,reg,in、液-液热交换器效率ε_SSHX、室外空气温度和相对湿度对该系统用作全新风机组时稳态热力性能的影响。结果表明,在南京夏季典型工况下,该系统送风参数为17.9℃、9.2 g·kg,热力系数TCOP可达0.56。T_s,reg,in在70℃左右时可以满足送风参数的要求同时保持较高的TCOP。自循环比越小,ε_SSHX对TCOP以及溶液加热器和冷却器负荷的影响越大。此外,该系统适合应用在夏季高温高湿地区。     

基于热不平衡考虑的溶液除湿/再生传热传质系数(Ⅱ)实验与模型计算分析

溶液除湿和再生装置是溶液除湿空调系统中的重要组成部件,常用的溶液除湿和再生装置内部空气和溶液流道一般是非常复杂,其内部传热传质规律也不易精确得到.建立一套最简单的降膜除湿/再生装置,进行逆流除湿和再生实验.采用本文(I)报中的基于热不平衡考虑的Le-hD测量法计算得到溶液平板降膜的耦合传热和传质系数随各种实验工况的变化...     

逆流填料式溶液除湿器的数值模拟和实验研究

对溶液除湿的除湿器中传热传质进行了热力学分析,根据除湿塔的结构及溶液与空气的流动方式,建立除湿器的热质交换物理和数学模型,模拟计算除湿器入口空气和溶液参数对除湿器出口空气参数的影响,模拟计算中设置入口空气流量0～5kg/s,入口空气温度20～40℃,入口空气含湿量为10～30g/kg,入口溶液温度25～40℃,入口溶液浓度25%～40%,入口溶液流量1～4kg/s,得到各入口参数对出口空气含湿量和温度的影响曲线。结果表明:入口空气含湿量、入口溶液浓度和温度对出口空气含湿量影响显著;入口空气含湿量和流量对出口空气温度影响显著。对模拟结果与实验结果进行了比较,发现两者的变化趋势是相同的,最大误差为13.08%。     

膜式液体除湿器研究进展

膜式液体除湿技术可很好地解决传统气液直接接触填料塔式液体除湿技术中存在的除湿溶液液滴夹带问题。在膜式液体除湿技术中,湿空气和除湿溶液被半透膜隔离。该膜只允许水蒸气的透过,而严格阻止其它气体和液体的渗透。本文概述了膜式液体除湿器中常用膜材料和膜组件的研究进展,重点阐述了膜式液体除湿器中的热质共轭传递数学模型,展望了膜式液体除湿器的发展方向。容易发现,在膜材料方面,在防止溶液泄露的前提下,应降低膜内部湿传递阻力;在膜组件（膜除湿器）方面,文献中获得的流动与传热传质基本准则数为膜组件的设计和优化提供了理论依据,另外,可通过增加翅片、冷却盘管或使用椭圆形中空纤维管来强化组件除湿性能。     

Experimental investigation on compressed air drying performance using pressurized liquid desiccant

As a new compressed air-drying method, the compressed air dehumidification using a pressurized liquid desiccant was proposed in our previous study. The pressurized dehumidifier is a complex and core component of the drying system. The mass transfer performance between the compressed air and LiCl aqueous solution is experimentally studied in a counter-flow pressurized dehumidifier filled with structured packing. The humidity ratio of outlet compressed air, vapor removal of processed compressed air, moisture removal rate, and dehumidification efficiency were selected as the performance indices. The results show that the minimum humidity ratio of processed compressed air could reach 0.23 g/kg under 0.71 MPa. Compressed air-drying performance could be remarkably enhanced through increasing the air pressure and liquid desiccant inlet concentration while the influence of liquid desiccant temperature is negative. Furthermore, in order to ensure high compressed air-drying performance, reduce the power consumption of the air compressor and liquid desiccant pump, and the possibility of carryover, the optimum ratio of liquid to compressed air flow rate is recommended to be around 1.5 under pressure around 0.50 MPa. Meanwhile, the energy consumption for per-gram moisture removal of a liquid-desiccant-based compressed air-drying system can reach 1.42 kJ/g lower than cooling dehumidification under 0.3 MPa, which is 16.0% lower than a compressed air-cooling dehumidification system.     

Efficiency of a Liquid Desiccant Dehumidification System Regenerated by Using Solar Collectors/ Regenerators with Photovoltaic Fans

Abstract

A hybrid solar dehumidification air-conditioning system was used to study the absorption of water vapor from moist air by contacting the air with aqueous solutions that contained from 90 to 94% triethylene glycol (TEG). For the packings of 2-inch polypropylene Jaeger Tri-Packs, which have a surface-to-volume ratio of 157 m²/m³ (48 ft²/ft³), the efficiency of dehumidification can reach 93.3%. The environmental air was introduced into the dehumidifier cocurrently flowing with the liquid desiccant, and the liquid desiccant was sprayed on the top of the packing material. The air-to-liquid mass flow ratio was controlled in a range of 0.46 to 1.36. As the moisture was absorbed from air by the TEG solution, the solution was diluted. The regeneration of the solution was carried out in 20-piece (38.8 m²) basin-type solar collectors/regenerators whose regeneration coefficients of performance are above 0.2. Air generated by photovoltaic fans was blown into the solar collectors/regenerators and carried away the water vapor from the evaporation of the aqueous desiccant solution. On the basis of the experimental results, the system performance is acceptable for most applications.     

平板降膜溶液除湿再生过程实验研究及模型验证

在平板降膜溶液除湿/再生实验平台上,以LiCl水溶液作为除湿溶液,实验研究了空气、溶液的入口参数对空气出口参数的影响,并根据实验数据得到了耦合传热传质系数的关联式,为NTU-Le模型提供了重要的数据支持,同时将实验数据与NTU-Le传热传质模型计算所得的数据进行比较,来验证NTU-Le传热传质模型在平板降膜溶液除湿/再生过程中的适用性和准确度。结果显示：实验数据和模型计算值之间的偏差均在10%以内,表示NTU-Le模型适用于平板降膜溶液除湿/再生过程。     

新型太阳能槽式与平板式联合集热溶液双效再生系统

提出了一种新型太阳能槽式与平板式联合集热溶液双效再生模式,采用槽式集热管与气液分离器实现沸腾式溶液再生,并回收利用其蒸汽冷凝热作为平板式集热再生装置的一部分热源供给,实现非沸腾式溶液再生。然后建立了其稳态传热传质过程的简化数学模型,对采用氯化钙溶液的再生过程进行了实例计算。结果表明：太阳能利用系数为68.8%,与普通平板式集热再生器相比,再生效果明显改善。     

Experimental investigation of a desiccant dehumidifier based on evacuated tube solar collector with a PCM storage unit

A rotary desiccant dehumidifier based on an evacuated tube solar air collector with a phase change material (PCM) storage unit has been experimentally investigated. The PCM (acetamide) simultaneously stores and transfers the heat to the air during day hours. The stored heat of the PCM is utilized to produce hot air during night hours. The performance of the system is analyzed for different air flow rates at different rotational speeds (rph) of desiccant wheel. The dehumidification effectiveness (?_A), regeneration effectiveness (?_R), and dehumidification coefficient of performance are 8.17, 10.35, and 0.0327%, respectively, at 16 rph of the desiccant wheel with 127.23?kg/h air flow rate. The system is also used to generate dry air for 14?h a day with PCM, which shows that acetamide used as the PCM has an ability to store an adequate amount of heat to regenerate the desiccant wheel during off-sunshine hours.     

Heat and Mass Transfer between Air and Liquid Desiccant in Cross‐flow Contact Systems

In this paper, an analytical solution of the coupled heat and mass transfer process in a cross‐flow liquid‐desiccant dehumidifier/regenerator is developed. By the use of reliable assumptions, the government equations for the system are solved by an analytical method. The results of the present analytical solution are compared with experimental data from the literature, and they show good agreement. The maximum error produced by the presented analytical solution is less than 12 %. The effect of the operating parameters is considered using the presented analytical solution. The results show that air inlet humidity, air flow rate, desiccant inlet temperature, and desiccant inlet concentration have more influence on the moisture removal rate in the cross‐flow dehumidifier. Also, air inlet humidity, desiccant inlet temperature, desiccant inlet concentration and desiccant flow rate have more effect on the moisture removal rate in the cross‐flow regenerator. The effect of the Lewis number on the performance of the dehumidifier/regenerator is investigated. As the results show, by the use of Le = 1.08 in the dehumidification process and Le = 0.96 in the regeneration process, instead of the value of unity, better results are obtained. The benefit of the present study is a simplified application for the evaluation of the outlet parameters of the cross‐flow air dehumidifier/regenerator.     

两种盐溶液除湿器的建模与对比

描述了绝热型与内冷型两类平板溶液除湿器的结构特点,在盐溶液竖直降膜与湿空气顺流、充分发展的工况下,基于Navier-Stokes动量方程建立盐溶液与湿空气热、质传递过程耦合数学模型,以LiCl水溶液作为除湿剂,考虑气液界面处的剪切力边界条件,在恒壁温与绝热边界条件下,对两种具有相同尺寸规格的除湿器的除湿过程进行了数值模拟,得到沿高度方向上盐溶液温度、浓度和湿空气温度、含湿量的变化情况,并对两者在相同工况下进行对比,定量描述了两类除湿器在除湿性能上的差异.结果发现内冷型除湿器的出口溶液的温度更低,接近于冷却介质温度,而且处理后的湿空气的含湿量比绝热型除湿器低5.1 g·kg^-1,空气的出口温度也要低近10.5℃,但除湿溶液的浓度变化很小,进、出口浓度差不到1％.     

溶液除湿能力强化

利用溶液除湿的制冷空调系统有着非常积极的节能意义,但与固体吸附除湿相比,溶液吸收除湿暴露了它除湿能力较差的缺点,这使它的应用普及受到了一定程度上的抑制。为了提高溶液除湿能力,本文介绍了从除湿器和除湿溶液两个方面进行改进的研究结果：利用固体吸附剂对溶液除湿器表面进行了处理;利用混合溶液作为溶液除湿剂。本文利用电解质溶液理论对LiCl和CaCl₂为代表的混合溶液进行了相关热物性的研究,并提出了选择理想溶液除湿剂及其合适配比的解决方案;进行了相应的除湿实验：实验结果揭示了改进的除湿器不仅从增大除湿面积方面对溶液除湿能力强化有所贡献,还可能存在着吸附势叠加的功效;混合溶液的使用使得溶液除湿能力相对于使用单种溶液大大提高。