热泵型溶液调湿新风机组冬季性能试验研究

搭建热泵型溶液调湿新风机组试验台,在冬季工况下,新风温度为9.5~10.1℃,含湿量为2.5~3.1 g/kg干空气时,试验比较填料类型、溶液温度、溶液浓度、溶液再生方式对机组制热加湿性能的影响。结果表明,在比较的3种填料中,7090湿帘填料综合性能最优;加湿单元入口溶液温度为32~34℃,且溶液槽中溶液浓度为45%~48%时,机组性能较好;机组采用回风再生较新风再生时的溶液再生能力提高,溶液槽中冷热抵消现象缓解,机组补水量减少47%,制热性能提高12%。试验结果可为热泵型溶液调湿新风机组的设计与冬季运行控制提供参考。     

溶液除湿新风机组控制策略仿真

利用Simulink构建由物性、传质单元数、空气和溶液出口参数等计算模块组成的溶液除湿新风机组仿真模型,分别将新风流量、溶液流量、溶液温度和溶液质量分数作为调节手段,分析其对机组送风含湿量的影响,并以除湿率为评价指标评价4种调节手段的优劣,提出适合夏季高温高湿和过渡季低温高湿工况溶液除湿新风机组的调节控制方案。仿真结果表明:夏季高温高湿工况溶液除湿新风机组应优先考虑调节新风流量和溶液质量分数;过渡季低温高湿工况溶液除湿新风机组应优先考虑调节溶液温度和溶液质量分数。     

热泵式溶液除湿新风机组性能研究

溶液除湿是一种具有较大节能潜力的湿度处理方式。本文针对热泵式溶液除湿新风机组进行试验研究,对新送风参数、室内外空气参数、系统功耗等进行测试,分析其除湿能力、制冷能力和能效比。结果表明其除湿效果良好,在与地面辐射系统的共同作用下,室内温湿度达到Ⅱ级热舒适度要求,且除湿性能会随着新风温度或新风含湿量的升高而增强。此外,将新风处理到同样的状态,溶液除湿较冷凝除湿直接节能54.8%,冷冻水温度提高近10℃也间接提高了系统的能效比,溶液除湿节能方面优势明显。     

调湿型新风机组在户式中央空调工程中的应用

一般家用空调系统只进行温度控制,湿度为被动调节,导致室内人员的舒适感较差。本文介绍了一种在户式中央空调系统内设置调湿型新风空调器的方案,通过在新风空调器内设置两级压缩制冷系统,对新风进行深度除湿,新风承担部分室内湿负荷,从而实现室内湿度的主动调节。同时通过回收利用除湿制冷排放的冷凝热提高新风送风温度来实现潮湿季节房间内供热除湿的需求。     

温湿度独立控制空调系统在民用建筑中的应用

分析常规空调难以实现真正的热湿平衡的情况,并提出温湿度独立控制空调系统是解决此问题的有效方法。重点研究温湿度独立控制空调系统中新风送风参数的确定方法。指出温湿度独立控制空调系统的新风需要承担室内全部的湿负荷,新风机组的送风含湿量与新风量之间存在一定的关系,从而在一定的设计参数下可以确定新风送风参数,实现真正的热湿平衡。     

旅馆客房采用独立新风空调系统时应注意的两个问题

通过对旅馆标准客房分析模型的计算,得到了此类建筑在采用干盘管加独立新风空调系统时,室内湿负荷的组成特点和新风机组的适用性。计算结果表明,新风渗透产湿量是客房室内湿负荷的重要组成,计算时必须考虑;新风机组的送风含湿量在不同地区差异较大,可以灵活选择合适的新风机组类型。     

空气处理机组的运行模拟

建立了空气处理机组各部分的模型，给定动态边界条件，求解出经过机组处理后的送风状态点参数，并给出在不同边界条件下求出的送风温湿度状态变化趋势。此模拟采用VB实现。     

双冷源热回收调温型冷却除湿系统设计及实验研究

针对温湿度独立控制空调系统中,新风采用冷却除湿方式存在能耗较高、送风温度低、相对湿度大容易产生湿冷感的问题,本文提出一种双冷源热回收调温型冷却除湿系统方案。通过对其进行理论分析及实验验证,确定不同因素,如压缩机频率、预冷器水流量、新风量,对送风状态点的影响情况,研究其变化规律,形成送风状态点控制策略,确认了系统调节能力可满足送风舒适的要求,在标准工况下,送风温度最高可调至25.0 ℃。与普通除湿系统相比,双冷源热回收调温型冷却除湿系统能效提升幅度最高可达93.6%。     

国家肝癌科学中心暖通空调设计

通过对国家肝癌科学中心空调通风系统的实际工程介绍,阐述了项目中冷热源、空调通风系统的选择以及SPF动物饲养房设计过程中的工艺要求和设计原则,通过对地源热泵系统和溶液调湿新风系统的结合运用,达到空调系统节能运行的目的,为类似医学科研中心工程设计提供参考。     

基于预冷型热泵式溶液调湿新风机组干盘管空调系统的技术经济性初判

随着干盘管空调系统理论研究与相关产品的不断发展完善,掌握该系统正确的设计方法、判断该系统在不同场合下应用的技术经济性对设计人员尤为重要。本文从设计人员的角度出发,构建基于预冷型热泵式溶液调湿新风机组干盘管空调系统的技术经济性初判工具,定量比较该系统在我国不同气候城市、不同类型场合应用下的系统用电功率和初投资。     

Performance investigation of desiccant liquid air membrane energy exchanger: Air and lithium chloride effects

The desiccant liquid air membrane energy exchanger is a promising technology used to recover both latent and sensible heat. In this paper, a numerical investigation is carried out to provide the optimal operating fluids properties as well as to enhance the exchanger performance. The physical problem involves a two dimensional model including the momentum, heat and mass transport equations in both air and desiccant liquid channels. The impact of air and desiccant liquid properties on the heat and mass transfer distributions is determined. Optimal values of inlet air and desiccant liquid properties are established. The thermal and mass fields inside desiccant liquid air membrane energy exchanger are numerically presented. This performance investigation provides a solution to improve the heat and mass transfer rates in the addressed membrane based technology.     

浅谈术语“气体吸湿剂＂

“固体吸湿剂”、“液体吸湿剂”常作为吸湿剂中的两大类型被提及。固体吸湿剂利用吸附原理,对湿空气进行除湿;液体吸湿剂利用吸收原理,使空气达到除湿的效果。而压缩空气作为一种极为干燥的空气,我们称之为“气体吸湿剂”,此空气通过和湿空气混合,实现对湿空气稀释除湿的目的。同时经过压缩空气气体吸湿剂除湿后的空气可以与蒸发冷却技术相结合应用于空调中,大大提高蒸发冷却降温的效率。另外,在我国西北等干燥地区大气中存在着一种经过大自然除湿后的天然干燥空气一千空气,我们可充分利用这种气体吸湿剂,直接送入建筑物内消除室内的湿负荷,大大降低人工制冷除湿的能耗,同时充分利用“干空气能”,达到尽量采用蒸发冷却天然冷源降温的效果,从而实现建筑低能耗的目的。“气体吸湿剂”是一种新的吸湿剂概念,为此,本文对术语“气体吸湿剂”进行了初步的探讨。     

Experimental performance analysis and modelling of liquid desiccant cooling systems for air conditioning in residential buildings

The paper presents a new desiccant cooling cycle to be integrated in residential mechanical ventilation systems. The process shifts the air treatment completely to the return air side, so that the supply air can be cooled by a heat exchanger. Purely sensible cooling is an essential requirement for residential buildings with no maintenance guarantee for supply air humidifiers. As the cooling power is generated on the exhaust air side, the dehumidification process needs to be highly efficient to provide low supply air temperatures. Solid rotating desiccant wheels have been experimentally compared with liquid sorption systems using contact matrix absorbers and cross flow heat exchangers. The best dehumidification performance at no temperature increase was obtained in an evaporatively cooled heat exchanger with sprayed lithium chloride solution. Up to 7 g kg⁻¹ dehumidification could be reached in an isothermal process, although the surface wetting of the first prototype was low. The process then provides inlet air conditions below 20 °C for the summer design conditions of 32 °C, 40% relative humidity. With air volume flow rates of 200 m³ h⁻¹ the system can provide 886 W of cooling power.A theoretical model for both the contact absorber and the cross flow system has been developed and validated against experimental data for a wide range of operating conditions. A simulation study identified the optimisation potential of the system, if for example the surface wetting of the liquid desiccant can be improved.     

除湿蒸发冷却空调系统的优化设计

设计一种可利用低品位热能的溶液除湿蒸发冷却空调系统。对此空调系统进行理论分析,得出如下结论：在溶液除湿蒸发冷却空调系统的多种实现形式中,新风经除湿后与回风混合比新回风混合后再除湿节能;将室内排风返回溶液再生器,进行热湿交换,既可加疆对处理空气的预冷,回收排风冷量,又可提高再生器的效率,降低系统能耗;把回热器吸收除湿浓溶液中的部分热量用于溶液再生器的稀溶液预热,可以提高溶液的再生性能。为除湿蒸发冷却空调系统的优化设计提供理论依据。     

Evaluation of heat and mass transfer coefficients in a gauze-type structured packing air dehumidifier operating with liquid desiccant

In this paper, high performance packing, namely, structured packing that has good heat and mass transfer characteristics, is proposed for dehumidification of air using liquid desiccants and for regeneration of liquid desiccants. In order to design a structured packing tower for liquid desiccant — air contacting operations, heat and mass transfer coefficients for each phase are required. This paper is concerned with the interface transfer of heat and mass when air is brought into contact with the liquid desiccant solution. A theoretical study of evaluating heat and mass coefficients in an air-desiccant contact system employing three liquid desiccants, namely calcium chloride, lithium chloride, and a mixture of 50% calcium chloride and 50% lithium chloride (called cost effective liquid desiccant, CELD) is investigated. Moreover, air phase transfer coefficients are correlated with flow rates of air and liquid and the temperature of air, whereas liquid phase coefficients are correlated with rates of air and liquid flow, and the temperature and concentration of the liquid. The findings for the three liquid desiccants are compared and discussed.     

A heat pump driven and hollow fiber membrane-based liquid desiccant air dehumidification system: A transient performance study

Heat pump driven and hollow fiber membrane based liquid desiccant systems have been adopted for air dehumidification because of their capabilities to prevent liquid desiccant droplets from crossing over into the process air and to achieve high energy efficiencies. Due to the transient operating conditions like load and weather conditions, a transient model for the novel system is proposed in this study. Based on experiments and model simulations, the transient behaviors of the system are analyzed both at the start-up and in the normal operation periods. It is found that the initial concentration of the liquid desiccant and the volume of solution stored in the container play key roles at the start-up period, while the initial temperature has less influences. Adjusting the compressor speed is a feasible way to track the load and weather fluctuations. The model developed in this work is necessary for the control and optimization of the air dehumidification technology.     

翅片式内冷型液体除湿器性能

以氯化锂溶液为除湿剂,建立测试翅片式内冷型液体除湿器性能的试验台,分析溶液和空气进口参数对除湿器性能（除湿量和除湿效率）的影响.     

Indoor temperature variations resulting from solar desiccant cooling in a building without thermal backup

The performance of a once-through solar desiccant cooling system, for air-conditioning a commercial office space, was modelled using the TRNSYS computer simulation software package. The study particularly focused on the potential for designing and operating a desiccant cooling system, without any thermal backup provided to mitigate for intermittent solar availability in three Australian cities.Increasing (i) indirect evaporative cooler effectiveness, (ii) air flow to the office space, and (iii) solar collector area were all shown to reduce the frequency of high temperature events inside the building occupied space. In the warm temperate climate of Melbourne (and to a lesser extent Sydney), high ventilation rates enabled comfort conditions to be maintained at or near acceptable levels in the occupied space, without the use of a backup thermal source.The synergy between evaporative cooling and solar desiccant cooling, observed in the warm temperate climates, was not evident in the tropical Darwin climate, suggesting that the selected ventilation desiccant cooling cycle is not appropriate for tropical climates.     

Performance analysis of liquid desiccant dehumidification systems

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.     

液体除湿空调除湿器性能研究

在液体除湿空调中,除湿器是系统的核心部件。本文搭建可用于实验研究的液体除湿空调系统中除湿器的实验台,对塔径300 mm、填料高度800 mm,以Li Cl溶液为除湿剂的除湿器布置测点进行实测。基于Mercel理论,根据热质平衡并结合D.I.Stevens的有效模型,建立适用于该液体除湿空调系统中的除湿器传热传质模型。从实验和理论模型两个方面分析除湿器进口各项参数对除湿量的影响,结果表明:理论值和实验值有很好的一致性,且数据差异较小,说明计算模型适应性良好,能准确的用于该除湿器的性能模拟测试,将实验与理论计算结果进行对比可知:在一定的工况范围内,除湿器的除湿量受进口溶液温度、浓度、质流密度等参数影响较大,其中溶液进口温度越低,除湿效果越显著,溶液进口浓度越低,除湿效果越好;溶液进口质流密度需控制在一定范围进行调节,才能显著提高除湿器性能;空气入口风速、干球温度以及含湿量对除湿出口的空气状态参数影响较弱。