湿空气进口温度、含湿量对固定床固体吸附除湿性能的影响

本文以硅胶作为吸附剂,对特定结构的固定床固体吸附除湿性能进行了实验研究.通过对吸附床体进出口温湿度的测量,分析了进口湿空气温度和含湿量在吸附除湿阶段对除湿结果的影响.结果表明,硅胶在湿空气进口温度为28℃时的固定床除湿量比30℃时平均多31.6％,湿空气进口含湿量为22.49 g/kg干空气时的除湿率比17.64 g/kg干空气时平均高出4.3％.     

固定床除湿材料性能分析

通过实验对4A分子筛与活性氧化铝的除湿性能进行了分析.结果表明:在风量3 638 m<'3>/h,空气温度55℃,含湿量5 g/kg再生条件下,4A分子筛的再生效果优于活性氧化铝;在吸附过程中,对于温度25.8℃,含湿量20.05 g/kg的湿空气,风量3 638 m<'3>/h时,在初始阶段,两类材料除湿性能相差不大,而在吸附稳定阶段,活性氧化铝单位时间吸附除湿量约为4A分子筛的3.5倍.因此,在该实验条件下,活性氧化铝更适用于固定床吸附除湿系统.     

转轮除湿系统除湿效率及空气净化效率实验研究

搭建了转轮除湿系统实验台,对其除湿性能及去除污染物的性能进行了测试。研究了再生温度、处理空气和再生空气风量、处理空气含湿量对转轮系统的除湿量和除湿效率的影响,同时也研究了再生温度、处理空气和再生空气风量、处理空气含湿量、污染物浓度对污染物净化效率的影响。实验结果显示:转轮除湿系统在除湿和去除污染物方面均具有良好的性能;除湿量、除湿效率及对污染物的净化效率均会随着再生温度的升高而增大;处理空气含湿量越高,除湿效率越低;处理空气风量越大,除湿量、除湿效率及对污染物的净化效率越低;再生空气风量越大,除湿量、除湿效率及对污染物的净化效率越高;当处理空气的相对湿度低于70%时,处理空气相对湿度对污染物的净化效率影响较小,当相对湿度高于80%时,随着相对湿度的增加,污染物的净化效率急剧下降。     

湿空气进口温度对固体吸附床吸附除湿性能的影响

本文实验以所设计的固体吸附床为研究对象,在吸附床进口空气含湿量恒定的条件下,研究了4A分子筛固体吸附床除湿能力随空气进口温度的变化.结果表明:湿空气进口温度为14.4℃时的固体吸附床的吸附性能优于进口温度为39℃时的吸附性能,且前者的吸附除湿量较后者平均约高出30%.     

植物气生根除湿能力的试验研究

提出利用植物气生根的生理功能对空气进行除湿,研究植物气生根在晴天和阴天两种不同天气下的吸水量和降温效果;研究了被处理空气的温度、含湿量和环境的温度、含湿量在一天中不同时刻对植物气生根吸水量的影响。结果表明,晴天时榕树气生根总除湿量平均值为7.94g/kg·干,最高可达11.45g/kg·干;平均每个气生根的除湿量为0.159g/kg·干。在晴天,榕树气生根吸水量受环境温度、相对湿度影响非常显著。     

基于PV/T和GHP再生的除湿转轮空调系统的仿真研究

本文建立了基于PV/T和GHP再生的转轮除湿空调系统,构建了除湿转轮子系统仿真模块、燃气热泵子系统仿真模块和PV/T子系统仿真模块,并在此基础之上构建整机系统仿真模块。对不同处理空气流量、处理空气温度、处理空气湿度、转轮转速、太阳光照、发动机转速及有无预冷器的空调系统性能进行了仿真模拟。主要结论有:处理空气风量越大、入口温度越高、入口湿度越小、转轮转速越低则空调系统的除湿量越小;处理空气风量越大、入口温度越高、入口湿度越大、转轮转速越高,则蒸发温度越高,制冷COP越大;发动机转速越大,系统的再生温度越高、送风温度越低、冷凝温度越高、蒸发温度越高、除湿量越大;太阳光照强度越强,系统的除湿量就越大;有预冷器的空调系统除湿量更大。     

基于高压雾化的溶液除湿性能实验研究

采用高压雾化将除湿液雾化成细小颗粒,可增大溶液除湿的接触面积,从而提高除湿效率。基于高压雾化的原理,搭建高压雾化溶液除湿系统实验台,研究空气量、溶液流量、空气状态对雾化除湿性能的影响。结果表明:高压雾化溶液除湿系统的除湿量随空气量、进口空气含湿量以及溶液流量的增加而增加;在进口空气温度为29.5℃,含湿量为21.44 g/kg,液气比为0.19的情况下,实验系统单位溶液除湿量可达15.78 g/kg;实验过程中,单位溶液的平均除湿量为10.39 g/kg;在相同除湿量下,雾化溶液除湿的单位溶液除湿量比传统填料式除湿器高2倍以上;拟合出除湿量的经验公式,可知实验值与测量值吻合得较好。     

新风和回风对液体除湿空调系统的影响

采用十字正交实验法对液体除湿新风处理机组在高温高湿工况下的除湿量进行了测定分析,结果表明：除湿量受新风含湿量、风量影响较大,受新风温度和回风温度、风量影响较小;并随着进口空气流量、含湿量、温度和回风量的增加而增大,随回风温度的升高而降低。     

小型液体除湿空调系统实验研究

对小型液体除湿空调系统,从居住建筑除湿负荷及经济性角度出发,采用CaCl2溶液进行液体除湿实验,研究CaCl2除湿和再生的动态特性。研究发现除湿与再生的3个重要因素为溶液温度、溶液浓度和空气进口含湿量。在实验工况下,CaCl2溶液的除湿量为32 g/kg,再生性能优于除湿性能,约为除湿的1.3～9倍。对实验进行总结后,认为CaCl2作为除湿剂进行液体除湿还有很大改进空间和推广潜力。     

溶液除湿用泡沫陶瓷填料性能的实验研究

使用耐腐蚀的10PPI氧化铝(Al2O3)陶瓷泡沫作为溶液除湿填料并对其进行了实验研究.采用氯化锂的水溶液作为除湿剂.实验在人工环境舱中进行,研究了在溶液和空气处于逆流的情况下,进口空气流量、干球温度、含湿量以及进口溶液温度、浓度、流量对除湿量和除湿效率的影响.除湿效率和除湿量最高分别可以达到62.69％和0.819g/s.进口空气流量、含湿量,进口溶液流量、浓度的增加对除湿量增加起促进作用,但是进口空气干球温度、进口溶液温度的增加时除湿量是减少的.进口空气流量、干球温度以及进口溶液温度的逐渐增加时,除湿效率呈现下降趋势.进口溶液浓度对除湿效率的影响很小.利用实验结果拟合出了除湿效率和除湿量的表达式.     

夏热冬冷地区民用建筑除湿方式的适用性分析

本文对常见的几种空气除湿的原理进行了分析,针对夏热冬冷地区的建筑气候特点,比较了冷冻除湿、通风升温除湿、被动除湿、干式除湿和复合式除湿等各自的特点和适用场合。分析了该地区空气处理设备实现温湿度独立控制的必要性,强调了空调设备设计选型时不能只考虑设备显热冷负荷,说明了湿度控制对空气处理设备设计选型的要求,提出了独立新风系统集中除湿和室内空气湿度独立控制的重要途径,并从室内环境质量综合控制角度指出了民用建筑空气除湿技术和该地区空气湿度控制方式的发展趋势。     

固体转轮除湿与冷凝除湿的适用性研究

针对不同工况,对固体除湿转轮进行吸湿与再生的性能实验;根据实验结果,采用空气源热泵作为冷热源,通过理论计算得出不同条件下固体转轮除湿与冷凝除湿两种方式的性能。结果表明,相同工况除湿量相同时,转轮除湿相对于冷凝除湿功耗大、效率低;随着室内空气湿度的增大,2种除湿系统能耗都减小,效率增大,冷凝除湿效率改善更明显;室外空气湿度增大,对冷凝除湿性能影响较小,转轮除湿功耗变大,效率降低;室外空气温度升高,冷凝除湿功耗增大,转轮除湿功耗减小,但两者的效率均增大。     

Performance of a CO2 sorbent for indoor air cleaning applications: Effects of environmental conditions,sorbent aging,and adsorption of co-occurring formaldehyde

Indoor air cleaning systems that incorporate CO₂ sorbent materials enable HVAC load shifting and efficiency improvements. This study developed a bench-scale experimental system to evaluate the performance of a sorbent under controlled operation conditions. A thermostatic holder containing 3.15 g sorbent was connected to a manifold that delivered CO₂-enriched air at a known temperature and relative humidity (RH). The air stream was also enriched with 0.8-2.1 ppm formaldehyde. The CO₂ concentration was monitored in real-time upstream and downstream of the sorbent, and integrated formaldehyde samples were collected at different times using DNPH-coated silica cartridges. Sorbent regeneration was carried out by circulating clean air in countercurrent. Almost 200 loading/regeneration cycles were performed in the span of 17 months, from which 104 were carried out at reference test conditions defined by loading with air at 25°C, 38% RH, and 1000 ppm CO₂, and regenerating with air at 80°C, 3% RH and 400 ppm CO₂. The working capacity decreased slightly from 43-44 mg CO₂ per g sorbent to 39-40 mg per g over the 17 months. The capacity increased with lower loading temperature (in the range 15-35°C) and higher regeneration temperature, between 40 and 80°C. The CO₂ capacity was not sensitive to the moisture content in the range 6-9 g/m³, and decreased slightly when dry air was used. Loading isothermal breakthrough curves were fitted to three simple adsorption models, verifying that pseudo-first-order kinetics appropriately describes the adsorption process. The model predicted that equilibrium capacities decreased with increasing temperature from 15 to 35°C, while adsorption rate constants slightly increased. The formaldehyde adsorption efficiency was 80%-99% in different cycles, corresponding to an average capacity of 86 ± 36 µg/g. Formaldehyde was not quantitatively released during regeneration, but its accumulation on the sorbent did not affect CO₂ adsorption.     

Experimental study on dehumidifier and regenerator of liquid desiccant cooling air conditioning system

A new type of air conditioning system, the liquid desiccant evaporation cooling air conditioning system (LDCS) is introduced in this paper. Desiccant evaporation cooling technology is environmental friendly and can be used to condition the indoor environment of buildings. Unlike conventional air conditioning systems, the system can be driven by low-grade heat sources such as solar energy and industrial waste heat with temperatures between 60 and 80 °C. In this paper, a LDCS, as well as a packed tower for the regenerator and dehumidifier is described. The effects of heating source temperature, air temperature and humidity, desiccant solution temperature and desiccant solution concentration on the rates of dehumidification and regeneration are discussed. Based on the experimental results, mass transfer coefficients of the regeneration process were experimentally obtained. The results showed that the mean mass transfer coefficient of the packing regenerator was 4 g/(m² s). In the experiments of dehumidification, it was found that there was maximal tower efficiency with the suitable inlet humidity of the indoor air. The effective curves of heating temperature on the outlet parameters of the regenerator were obtained. The relationships of regeneration mass transfer coefficient as a function of heating temperature and desiccant concentration are introduced.     

Condenser heat recovery with a PV/T air heating collector to regenerate desiccant for reducing energy use of an air conditioning room

This paper presents an experimental test along with procedures to investigate the validity of a developed simulation model in predicting the dynamic performance of a condenser heat recovery with a photovoltaic/thermal (PV/T) air heating collector to regenerate desiccant for reducing energy use of an air conditioning room under the prevailing meteorological conditions in tropical climates. The system consists of five main parts; namely, living space, desiccant dehumidification and regeneration unit, air conditioning system, PV/T collector, and air mixing unit. The comparisons between the experimental results and the simulated results using the same meteorological data of the experiment show that the prediction results simulated by the model agree satisfactorily with those observed from the experiments. The thermal energy generated by the system can produce warm dry air as high as 53 °C and 23% relative humidity. Additionally, electricity of about 6% of the daily total solar radiation can be obtained from the PV/T collector in the system. Moreover, the use of a hybrid PV/T air heater, incorporated with the heat recovered from the condenser to regenerate the desiccant for dehumidification, can save the energy use of the air conditioning system by approximately 18%.     

四种温度控制方法对相对湿度影响的比较

模拟比较了定风量变水量、变风量变水量、旁通型变风量、二次回风控制四种方法在部分负荷时的除湿能力.结果表明,定风量变水量控制在部分负荷时,室内相对湿度一直较高.除湿能力很差;旁通型变风量控制除湿能力较强;变风量变水量控制在潜热不变显热变化的情况下除湿能力较差,而在潜热显热都变化的情况下较好;二次回风控制只在实际显热比较小时除湿能力较差.     

不同制冷量空调器在住宅中应用的实测对比研究

通过实验测试对比了不同制冷量的定速房间空调器用于住宅卧室中时的室内温湿环境状况和空调器的耗电量情况。实验结果表明,当空调器容量过大时,空调器的除湿能力下降,室内相对湿度偏高,空调器耗电量大,实验日条件下,使用1.5 HP空调器时的室内相对湿度比使用1 HP空调器的室内相对湿度高5%,而1 HP空调器耗电量比1.5 HP空调器减少12.7%。     

关于气候分区问题的探讨

针对《全国民用建筑工程设计技术措施》暖通空调.动力篇(2009年版)中以"最湿月平均含湿量"作为气候分区判断依据一问题,探讨了含湿量(绝对湿度)和相对湿度概念的不同,指出含湿量是空气加湿或减湿的程度,而相对湿度表示的是空气接近饱和的程度,并进一步分析了湿球温度是空气接近饱和程度的一种度量,是一个独立的空气状态参数。最后笔者通过一些气候分区的举例,进一步说明了湿球温度这一参数在气候分区中的重要性。     

综合管廊通风除湿有效时长研究

为了解综合管廊通风除湿有效时长的变化规律,利用数值模拟以通风换气效率、通风除湿效率作为技术性评价指标进行比选,以最优通风形式评价6个不同影响因子作用下的综合舱通风除湿效果,判断其与通风除湿有效时长之间的相关性,基于多元回归分析搭建通风除湿有效时长预测模型。结果表明:“一端进风一端排风”通风形式的除湿表现最优;通风分区长度和通风换气次数达到一定值后除湿效果趋缓;进风温度与廊内温度初始值的差值越小除湿效果越好;对于相关性系数:进风相对湿度＞断面宽高比＞通风分区长度＞通风换气次数＞廊内相对湿度初始值＞进风温度;模型预测的通风有效时长拟合值与数值模拟结果之间的误差为0.43%,回归模型拟合效果较好。     

Theoretical study of simultaneous water and VOCs adsorption and desorption in a silica gel rotor

One-dimensional partial differential equations were used to model the simultaneous water and VOC (Volatile Organic Compound) adsorption and desorption in a silica gel rotor which was recommended for indoor air cleaning. The interaction among VOCs and moisture in the adsorption and desorption process was neglected in the model as the concentrations of VOC pollutants in typical indoor environment were much lower than that of moisture and the adsorbed VOCs occupied only a minor portion of adsorption capacity of the rotor. Consequently VOC transfer was coupled with heat and moisture transfer only by the temperatures of the rotor and the air stream. The VOC transfer equations were solved by discretizing them into explicit up-wind finite differential equations. The model was validated with experimental data. The calculated results suggested that the regeneration time designed for dehumidification may be prolonged to allow complete removal of the VOC pollutants from the rotor. The regeneration temperature designed for dehumidification provides considerable efficiency for indoor air cleaning. The application of the model in estimating the cleaning capacity of the rotor for VOC pollutants was demonstrated. PRACTICAL IMPLICATIONS: Silica gel rotors, usually used to dehumidify air, were found to be effective to remove VOCs by experiments recently. But the removal characteristics of VOCs are different from that of moisture. Therefore, the rotor structure and operating parameters for dehumidification needs to be optimized for the use of removing moisture and VOCs. This paper gives a way for the optimization.