太阳能液体除湿空调系统研究现状

本文论述了近年来国内外对太阳能液体除湿系统的研究状况。从太阳能液体除湿空调系统的实验研究，除湿／再生塔的传热传质模型的研究、液体除湿剂的研究等三个方面进行了阐述。     

太阳能液体除湿空调性能的实验研究

在对液体除湿机理研究的基础上，建立了太阳能液体除湿空调系统实验台，采用氯化钙溶液作为除湿剂，对系统的除湿性能进行了实验研究，对影响除湿的各主要因素进行了分析。     

太阳能液体除湿空调系统模型的建立与分析

对太阳能液体除湿空调系统进行了热力学分析，得到系统各主要部件的传热传质模型，并编制了计算机模拟程序，对影响系统性能的各参数进行了分析，探讨了该系统在高温高湿地区及大通风量下与压缩式空调系统相比的优势。     

太阳能液体除湿空调系统中除湿器型式的选择

太阳能液体除湿空调系统是一种利用太阳能等低温热源的节能空调系统。除湿器直接影响太阳能液体除湿空调系统的性能。本文从焓湿图、蓄能、MR的选取和除湿效果等几个方面对目前被广泛应用的两种典型的除湿器进行了比较分析。     

三种太阳能液体除湿空调系统除湿器的比较

太阳能液体除湿空调的除温器是系统的重要组成部分。文章通过对三种典型结构的除湿器的传热传质性能、被处理空气与除湿溶液的质量流量比率（MR）和蓄能能力（SC）等方面的比较，得出绝热型除湿器具有比表面积大，被处理的空气流量大等优点，但加湿器内沿程压降较大；水冷型除湿器蓄能能力强，但结构复杂；而交叉流型板式除湿器由于能充分利用回风，是一种可供选择的节能型除湿器。     

太阳能液体除湿空调系统再生和蓄能特性的研究

太阳能液体除湿空调系统中,能量在液体除湿剂中以化学能的形式存在,蓄能潜力大,再生温度低,可以利用太阳能或其它低位余热和废热。着重分析了液体除湿空调系统中溶液的再生原理和再生过程的传热传质特性,对再生过程进行了实验研究,获得了再生过程对流传质和对流换热的实验准则方程,讨论了各主要因素对再生量的影响。对再生器的蓄能特性进行了分析,讨论了太阳能液体除湿空调系统蓄能工况的运行方式。     

太阳能除湿空调系统

除湿型空调系统作为一种运行模式全新的概念型空调系统,与蒸汽压缩式空调系统和吸收式空调系统相比,人们了解还较少。除湿型空调系统按照工作介质划分,可分为固体除湿和液体除湿系统;按照制冷循环方式划分,可分为开式系统和闭式系统;按照结构划分,可分为简单系统和复合系统。     

液体除湿空调实验台的性能分析及实验研究

针对上海气候环境条件设计制造了利用80℃以下低品位热源驱动的全新风送风LiCl液体除湿空调实验台,用于为100m2空调区域提供19℃以下的送风,独立承担室内热湿负荷.分析测试了系统送风温度的影响因素,表明再生热源温度是主要影响因素.该系统结构适合采用除湿再生同时运行模式,该模式下系统运行性能为:夏季工况新风制冷量为35～49kW,热力COP为0.72～0.98;秋季工况为17～29kW,热力COP为0.30～0.51.最后验证了除湿再生独立运行模式的可行性与实际效果:新风制冷量45kW,热力COP为1.1,为今后实验台的改进指明了方向.     

液体除湿特性的实验研究

从保护环境、节约能源出发,对太阳能液体除湿空调系统的优点进行了讨论,建立了液体除湿实验台,提出一种新的氯化钙和氯化锌组成的混合工质（摩尔比为1：1）作为除湿系统的除湿剂、并对影响液体除湿特性的各因素分析,最后指出液体除湿空调系统是一种很有潜力的空调方式。     

Investigation on regeneration and energy storage characteristics of a solar liquid desiccant air-conditioning system

Solar liquid desiccant air-conditioner is a new air-conditioning system in which liquid desiccant can be regenerated by solar energy and energy can be stored in the form of chemical energy in the liquid desiccant. In this paper regeneration and energy storage characteristics were studied theoretically and experimentally. Two criterion equations for heat and mass transfer in the regeneration process were obtained. The main factors that influence the regeneration process were analyzed. A principal solar liquid desiccant air-conditioning system under energy storage operating mode is proposed. Translated from Acta Energlae Solaris Sinica, 2006, 27(1): 49–54 [译自: 太阳能学报]     

Research progress in liquid desiccant air-conditioning devices and systems

The developments on liquid desiccant air-conditioning systems were illustrated and summarized in this paper. In order to obtain a better dehumidification (or humidification) performance, liquid desiccant should be cooled (or heated) rather than air. Two fundamental modules were proposed, including basic spray module with extra heat exchanger and total heat recovery device, which could be combined to set up various kinds of liquid desiccant air processors. The operating principle of heat pump-driven outdoor air processor as well as heat-driven outdoor air processor was analyzed. The COP_air of the heat pump (or power)-driven outdoor air processor could be as high as 5.0 both in summer and in winter operating conditions. The COP_air of the hot water-driven processor (65°C–80°C) was 1.19 and 0.93, respectively, using evaporative indoor exhaust air or cooling water to cool the dehumidification process. The liquid desiccant air processor-based temperature and humidity-independent control air-conditioning system could save 20%–30% operating energy compared with the conventional air-conditioning system.     

Use of desiccant dehumidification to improve energy utilization in air-conditioning systems in Beirut

Humidity and indoor moist surrounding affect air cleanliness and protects harmful microorganisms when relative humidity is above 70%. In humid climates, the humidity issues are a major contributor to energy inefficiency in HVAC devices. The use of liquid desiccant dehumidification systems of supply air is a viable alternative to reduce the latent heat load on the HVAC system and improve efficiency. Thermal energy, at a temperature as low as 40–50°C, required for the operation of a liquid desiccant hybrid air conditioner can be efficiently obtained using a flat-plate solar collector. In this work a model of a solar-operated liquid desiccant system (using calcium Chloride) for air dehumidification is developed. The system utilizes packed beds of counter flow between an air stream and a solution of liquid desiccant for air dehumidification and solution regeneration. The desiccant system model is integrated with a solar heat source for performance evaluation at a wide range of recorded ambient conditions for Beirut city. Standard mass and energy balances are performed on the various components of the system and a computer simulation program is developed for the integrated system analysis. The desiccant system of the current study replaces a 3 TR (10.56 kW) vapour compression unit for a typical house as low latent load application, and is part of a hybrid desiccant–vapour compression system for a high latent load application, namely a small restaurant with an estimated cooling load of 11.39 TR (40 kW), including reheat. The relevant parameters of the desiccant system are optimized at peak load, and it is found out that there is an important energy saving if the ratio of the air flow rate in the regenerator to that in the dehumidifier is about 0.3 to 0.4. The COP of the desiccant unit is 0.41 for the house, and 0.45 for the restaurant. The size of the vapor compression unit of the restaurant is reduced to 8 TR when supplemented by a desiccant system. The performance is studied of the desiccant system integrated with a solar collector system and an auxiliary natural gas heater to heat the regenerator. The transient simulation of the solar desiccant system is performed for the entire cooling season. The solar fraction for the house is equal to 0.25, 0.47, and 0.68 for a collector area of 28.72, 57.44, and 86.16 m², respectively. The solar fraction for the restaurant is 0.19, 0.38, and 0.54, for the same collector areas. The life cycle savings for the house run solely on desiccant system were positive only if natural gas is available at a cheap price. For the restaurant, the economic benefit of the desiccant system is positive, because the need for reheat in the vapor compression system is eliminated. For a gas price of 0.5638 $/kg, the payback period for the restaurant turned out to be immediate if the energy is supplied solely by natural gas, and 11 years if an 86.16 m² solar collector is implemented to reduce the fuel consumption. Copyright © 2003 John Wiley & Sons, Ltd.     

空调系统溶液除湿基本问题的研究进展

分析溶液除湿的研究现状,总结溶液除湿的相关基本问题,其中包括除湿/再生原理、蓄能机理、对空气品质的影响和除湿剂及除湿器的选择。提出了溶液除湿的存在问题和发展前景。     

溶液除湿的地源热泵毛细管顶板空调系统

提出了一种基于溶液除湿的地源热泵毛细管顶板复合空调系统。该系统采用了溶液除湿承担潜热负荷,地源热泵制取的高温冷水承担显热负荷的方式,达到了节省高品位电能、减轻大气污染、减少运行费用的效果,与传统的空调系统相比具有节能、环保、高舒适性的特点。     

Proposal of a control strategy for desiccant air-conditioning systems

A control strategy for the operation of desiccant air-conditioning systems is proposed in this work. The proposed strategy consists of a basic scenario, while some alternative strategy schemes are also proposed on the basis of the approach adopted for the controlling of the humidifiers or the desiccant system operation modes included. The control strategy aims at sustaining the building conditions within values suitable for human thermal comfort, thus taking care of both temperature and humidity. The assessment of the proposed control strategy scenarios is performed in terms of effectiveness and efficiency, through the use of a desiccant system model, which takes into account the effect of transient phenomena as well. Specific information for the required hardware equipment and its implementation for the controlling of the respective system components is provided, pointing out the simplicity of the proposed solutions.     

Experimental investigation on desiccant air-conditioning system in India

An experimental investigation in India was presented to evaluate the performance and energy saving capacity of a desiccant air-conditioning system composed of a silica gel bed, a split type air-conditioner (1.0 ton refrigeration) installed in a room with a volume of 86.4 m³, air ducts and a blower. The experiment was made in such a way that the percentages of return air, outdoor air and indoor air mixed with the air leaving the desiccant and desiccant bed thickness could be adjusted. Tests were conducted on several days with relatively similar ambient conditions. Under the test conditions in this experiment, a 7cm bed thickness is recommended with a maximum adsorption rate of 403g/h. The optimum percentages of air ratios were as follows: 10% of outdoor air, 10% of return air (mixed together at the desiccant bed inlet) and 80% of indoor air mixed with the dry air leaving the desiccant. The corresponding electricity saving was about 19%. As expected, simple economic analysis indicates that the desiccant air-conditioning is not viable for smaller cooling capacities.     

Solid desiccant air-conditioning systems – Design parameters

Solid desiccant air-conditioning systems can take care of both the sensible and latent load of a conditioned space, as well as of the fresh air requirements, through the use of thermal energy. The development of desiccant systems, competitive to conventional cooling ones, would require the optimization of the parameters which are involved in the design of the systems for a range of ambient conditions the systems will face throughout their lifetime. The present work aims at identifying the main design parameters, and investigates their effect on the performance of the systems. Specific guidelines for the dimensioning of the systems are proposed, on the basis of an easy to implement steady state model.     

Performance evaluation of a solar-powered flat-plate multichannel liquid desiccant air conditioning system

There has been a limited application of liquid desiccant (LD) dehumidification systems in space air conditioning until now. The key elements responsible for this restricted implementation are leakage of desiccant solution, corrosion of components, and solution carryover along with the processed air to the space to be conditioned. To remove these problems, an evacuated tube solar heat collector-driven multichannel liquid desiccant air conditioning system has been proposed and experimentally investigated. In this study, dehumidification and regeneration rate, their effectiveness, cooling effect of the dehumidifier, and indirect evaporative cooling unit have been analyzed. The results obtained indicate that the process air has been dehumidified and cooled by 6.32 g kg⁻¹ and 5.26°C, respectively. The regeneration rate and effectiveness have been obtained to be 0.26 g s⁻¹ and 0.31, respectively. In terms of the cooling effect, the system output of 0.703 and 0.130 kW has been obtained from the dehumidifier and indirect evaporative cooling unit of the system, respectively. The proposed system validates the possibility of the novel solar-powered liquid desiccant air conditioning system concept and provides growth and development of the LD air conditioning technology for space air conditioning.     

固体吸附除湿技术用于民用建筑中央空调系统的经济性分析

针对传统空调冷却除湿方式的高能耗,提出将固体吸附除湿技术应用于民用建筑中央空调系统,并对采用这种除湿方式的干式风机盘管加固体吸附独立除湿新风系统与传统的风机盘管加新风系统在运行能耗方面进行经济性实例分析,结果表明干式风机盘管加固体吸附独立除湿新风系统较传统风机盘管加新风系统其夏季空调工况每天减少约14W/m2,有效降低建筑能耗。