细木工板中甲醛释放特征及规律

采用环境测试舱模拟室内环境,测量细木工板中甲醛的释放浓度,考察细木工板结构、温度、相对湿度和空气交换率对甲醛释放的影响,分析细木工板中甲醛气体扩散机理,并建立了灰色预测模型对细木工板中甲醛释放峰值后的过程进行模拟. 结果表明,细木工板中甲醛散发通道主要为端面,端面的甲醛释放量是平面的3倍;细木工板中甲醛气体扩散过程分为3个阶段(初始快速释放、稳定释放和长期缓速释放);空气交换率对细木工板中甲醛释放率影响不大;相对湿度和温度升高,细木工板中甲醛释放率也增大;预测模型的预测数据与实验数据吻合较好,平均相对误差率仅为3.717%,适合进行长期预测.     

Influence of VOC and formaldehyde emission from tile adhesives on their indoor concentrations in buildings

Volatile organic compounds (VOC) and formaldehyde emitted from building materials are considered to be one of the main causes of indoor air pollution in buildings. To reduce indoor pollutant concentrations, new installation methods for wall papers and flooring materials have been widely introduced to the construction field, including a nonadhesive floating method. However, adhesives are still widely used to install wall tiles or floor tiles on areas such as kitchens, bathrooms, and showers. The objective of this study was to investigate the influence of tile adhesive emissions on indoor air quality. The VOC and formaldehyde emission rates from two different types of tile adhesives, a conventional adhesive and a low-VOC emission adhesive, were measured using small emission test chambers. Full scale experiments were also carried out in three identical test rooms in a building. One wall of each room was finished with wallpaper in Test Room 1 and with tiles in Test Rooms 2 and 3. The other walls and ceilings were finished with wall papers in all test rooms. Wall tiles of Test Room 2 were installed with the conventional adhesive, while those of Test Room 3 were installed with the low-VOC emission adhesive. The indoor VOC concentrations in Test Room 2 were significantly higher than those in Test Room 3 due to a significantly higher VOC emission from the conventional tile adhesive. Even though the adhesives were applied under the finishing materials, investigation revealed that the adhesives were the most dominant contributor of indoor VOC concentration.     

Cold weather installation of wood flooring by adhesive bonding and its impact on indoor air quality

This study discusses the effect of installation of wood flooring by adhesive bonding under cold weather conditions on indoor air quality (IAQ) and analyzes an onsite strategy that can ensure the adhesion strength of the wood flooring and improve IAQ. To examine the temperature effects of adhesive bonding on volatile organic compound (VOC) emissions from wood flooring, the emission rates from flooring composites were compared with those from adhesive and plywood flooring as individual materials under temperature variations in a small-scale chamber. In addition, the effect of strategies, including room heating to enhance adhesion performance, and the ventilation on material emissions and indoor concentrations, were examined in onsite apartment units equipped with a radiant floor heating system. The results of the small-scale chamber test showed that VOC emissions increased notably when the temperature was elevated, particularly in the adhesive-bonded plywood flooring compared to plywood flooring alone. The results of the onsite field test showed that the flooring bonded onto the radiant floor heating system, which supplied direct heat to the flooring, caused emission of a large amount of VOCs due to the combined effects of the bonding installation and temperature-dependent characteristics. Overall, the results indicate that heating the room in conjunction with ventilation is an effective strategy to ensure adhesion strength and to improve IAQ under cold weather adhesive bonding conditions when the material temperatures can be properly maintained.     

室内环境中细木工板甲醛释放预测模型

采用环境测试舱模拟室内环境,测定其中的细木工板的甲醛释放浓度,考察环境温度和相对湿度对其释放的影响;分析细木工板中甲醛气体扩散机理,并进行实际室内环境中细木工板释放甲醛实验,与模拟室内环境对比;最后运用灰色预测模型和神经网络模型建立灰色神经网络模型,对实际室内环境中细木工板甲醛释放规律进行预测. 结果表明,随环境温度和相对湿度升高,板材释放的甲醛浓度增加,且温度对甲醛释放活跃期影响更显著,低温和低湿度时板材中甲醛释放更易达到稳定;细木工板释放甲醛浓度与室内外温差呈正相关性,热压渗风作用对室内细木工板释放甲醛浓度的变化有重要影响;灰色神经网络模型的预测与实验数据吻合较好,平均绝对误差为-0.0007 mg/m3,相对误差为0.208%~5.981%.     

相变控温调湿建筑复合材料的研究进展

相变控温调湿复合材料是近来开发的新型建筑材料,由于这种材料具有发生相变时,自动吸收或者释放热量和湿气,调节室内环境空气的温度和相对湿度的特殊性能,因此,控温调湿材料的开发和在建筑中的应用研究,已经成为国内外建筑和材料领域的研究热点。相变控温调湿复合材料应用在建筑中,可以保持室内舒适的温度和湿度,不仅有利于提高人们的工作效率和身体健康,而且节约能源、减少二氧化碳排放,保护环境。综述了各种控温调湿材料的制备技术以及主要的热湿性能,总结了控温调湿材料的热湿理论模型,概述了控温调湿材料在建筑中的应用成效,提出了未来发展中需要解决的主要问题。对国内外控温调湿相变材料的全面综述和分析将为我国的建筑和材料领域的设计和研究人员提出新的思考。     

使用环境对板式家具甲醛释放量的影响

模拟板式家具的室内使用环境,研究不同的使用环境(温度、相对湿度、通风条件)对板式家具甲醛释放量的影响。研究发现,在高温高湿的使用环境下,板式家具的甲醛释放加剧,可以使家具提前进入甲醛释放稳定期,降低使用过程中板式家具的甲醛释放量;室内使用环境的通风条件越好,越有利于家具中甲醛的释放,降低室内环境甲醛的浓度。     

相变储热技术用于被动式建筑节能的研究进展

相变潜热储能系统具有储热密度高、工作温度稳定和工艺流程简单等优点。相变材料可以通过多种方式与建筑物相结合，利用自身吸热/放热的特性对热能进行储存和释放，从而提高可再生能源的利用率。研究表明，相变储热单元能够有效地降低室内的温度波动，提高室内环境的热舒适性，减少建筑能耗。本文基于相变储热技术在建筑围护结构中的墙体、屋顶、地板以及窗户的研究现状，对近年来被动式储热建筑节能的研究现状进行了综述。阐述了适用于建筑物的相变材料的特点、优化相变材料热性能的方法、相变储热技术调控室内热环境的原理以及相变材料应用于建筑物的节能效果。文章指出，未来的研究应注重高性能相变材料的开发、复合工艺的简化以及室内热环境的综合评价。     

关于室内空气中甲醛测定方法研究

人们对自己周边的生活环境要求越来越高,想方设法改变自己的居住环境,可通过室内的陈设品和装修来改变,因此,装修成为了一股热潮,化工的涂料、木制的地板是人们装修时的首选,但是这些材料中存在甲醛这种化工原料,不仅是室内的空气受到污染,更会对人们的身体造成伤害。因此,检测空气中的甲醛存在,并及时采取消散甲醛措施非常的关键。就空气中的甲醛测定方法做了研究,并对个方法的优缺点进行了分析。     

室内空气污染物甲醛的检测及污染状况分析

以12户新装修居室为甲醛测定样本,通过对其浓度的测定和数据统计,结果表明：装修居室空气中甲醛超标严重,并分析了造成其超标的主要原因及其危害。     

室内装修后微量甲醛的检测与治理

本研究采用电化学传感器检测法对新装修室内空气质量和家具释放甲醛量进行检测。使用生物酶甲醛消除剂,对其去除室内空气和家具中甲醛性能进行了测试研究。研究结果表明,甲醛消除剂可以快速、有效地消除室内空气中的甲醛,又可以减少室内装修材料中游离甲醛的释放,是治理室内空气甲醛污染的有效手段之一。     

Influence of humidity and frequency on the energy dissipation in wood adhesives

In this paper, the frequency dependent energy dissipation of typical wood adhesive under cyclic stress was studied on film adhesive samples. Three moisture-curing one component polyurethane (1C-PUR) adhesives with relative ductile behavior, one melamine formaldehyde (MF) and one phenol formaldehyde resorcinol (PRF) adhesives both with a more brittle behavior were prepared to study the viscoelastic properties at different relative air humidities (RH). Dynamic Mechanical Analysis (DMA) in tensile mode was used to determine loss modulus, storage modulus and loss factor Tan Delta on free standing adhesive films. It has been shown that 1C-PUR adhesives dissipate proportional more of the stored energy than MF and PRF adhesives. Humidity increased the dissipative processes in all PUR adhesives, especially in the polyamide fiber filled adhesive. PRF adhesive is less influenced by humidity. While for all other tested adhesives the dissipative processes generally increased with higher humidity, humidity decreased the damping of the investigated MF adhesive. The influence of the frequency on the energy dissipation is low for all tested adhesives in the investigated frequency range. Further fatigue tests with glued wood samples are needed to confirm the results observed on the free standing adhesive films.     

LED可见光下Au/TiO2光催化氧化甲醛表观动力学

甲醛是室内空气中典型的挥发性有机化合物（VOCs）之一。等离子激元型光催化剂可吸收可见光,可在室温常压下利用太阳光驱动光催化氧化脱除室内空气中甲醛的反应,其表观反应动力学研究对设计等离子激元型光催化剂及应用于脱除VOCs等污染物具有重要意义。研究了LED可见光下等离子激元型Au/TiO₂光催化脱除气相中甲醛的表观反应动力学,考察不同波长的可见光源、光强及反应气相对湿度对表观反应动力学的影响,根据对实验数据的分析求得LED可见光催化氧化甲醛表观反应速率常数k（I,H）。结果表明,在13%相对湿度、蓝光光强为38.5 mW·cm^-2的条件下,光反应的甲醛转化率达77%,是暗反应的近5倍。在LED红、绿、蓝、白光照射下,随着光强增加,甲醛转化率快速增加后缓慢增至基本不变。相同光强（低于42 mW·cm^-2）和湿度条件下,红、绿、蓝光源的甲醛转化率相近,白光略低于其他光源。干气氛下,光反应和暗反应的甲醛转化率几乎为0。湿气氛下,光反应和暗反应均有甲醛转化率,光反应的甲醛转化率更高。不同光源条件下甲醛转化率随相对湿度变化规律相似。相对湿度为21.9%时甲醛转化率最高,而后保持不变,基本在80%左右。通过对红、绿、蓝、白光的数据拟合计算,得到表观动力学参数k（I）_H、k（H）_I、k（I,H）以及速率方程。     

Control of emission rates of chemical compounds emitted by controlling their mass transfer coefficients on the surface of the tested building material

The air change rate in the chamber, the loading factor of the materials, and the mass transfer coefficient are very important factors in the measurement of chemical compounds, because they have a decisive effect on emission rates of chemical compounds emitted from materials. Small 20-liter chambers, such as the advanced pollution and air quality chamber, are generally used in Korea and Japan for measuring the amount of released chemicals. In this study, chemical compounds released from building materials and adhesives were measured using a chamber proposed by the authors to control the mass transfer coefficient on the surface of the tested building material and we examined the distribution of chemical compounds concentrations in the chamber by means of computational fluid dynamics to confirm test reliability. The chamber was controlled and maintained at 28?°C, a relative humidity of 50%, a mass transfer coefficient of 14?m/h with an air change rate of 0.50?h^?1, and formaldehyde and total volatile organic compounds were emitted from the flooring material and adhesive. As the mass transfer coefficient on the surface of the tested building material increased, the emission rates of chemical compounds measured using the proposed chamber increased. The mass transfer coefficient on the surface of the tested building material significantly influenced the emission rates of the chemical compounds released from the building material and adhesive.     

Effect of an Ionic Air Cleaner on Indoor/Outdoor Particle Ratios in a Residential Environment

We tested a leading commercially available ionic air cleaner in a typical residential apartment to study the effect of the device on indoor/outdoor airborne particle number and mass concentration ratios. In addition, we also determined the indoor ozone and ion concentration levels. When measured during normal daily activity, the average indoor/outdoor mass concentration ratio was reduced from 1.03 to 0.73 and the number concentration ratios underwent reductions for most of the particle size fractions. However, due to a substantial inter-and intra-measurement variation in particle ratios, the observed average reductions were not statistically significant. When measurements were performed in a still room, the indoor/outdoor particle mass concentration ratio decreased from 0.9–1.4 to 0.3–0.4 in eight hours when the air cleaner was operating. Ambient ozone concentrations measured in the middle of the apartment were between 13–19 ppb during normal daily activity and the ozone levels increased to 77 ppb when measured in front of the ionic cleaner during still conditions. We also found that that there was a limited vertical diffusion of ions. The highest ion concentrations were measured at a 0.5 m height from the floor and decreased substantially with increasing measurement height. This finding may have implications for effective particle removal from a person's breathing zone. Overall, we found that the tested brand of commercially available ionic air cleaners may have the capability to remove some airborne particulate matter in actual residential settings, but its cleaning effect is reduced under normal daily activity.     

Modification of the wood-plastic composite for enhancement of formaldehyde clearance and the 3D printing application

As the formaldehyde is one of the main indoor pollutants, the purpose of this study is to effectively remove indoor formaldehyde pollution by using environmentally friendly 3D printing ornaments. The wood 3D printing filaments cellulose/polylactic acid composite (Cellu/P) was selected as the starting material, and 3-aminopropyltriethoxysilane (APTES) was used for chemical modification to obtain a series of cellulose composite materials with amino groups. The modified composite materials (APTES@Cellu/P) were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, thermogravimetric analysis, and mechanical tests, and a formaldehyde removal experiment was performed. The feasibility of 3D printing was evaluated, and the process of 3D printing-functionalized customized ornaments was proposed, and then a school emblem was used for modeling, printing, and surface modification. Compared with the commercially traditional activated carbon, 3D printing-customized ornaments of APTES@Cellu/P material has a better formaldehyde removal effect, and can even avoid the secondary pollution that is common to the activated carbon.     

Dehumidification of Moist Air with Simultaneous Removal of Selected Indoor Pollutants by Triethylene Glycol Solutions in a Packed-Bed Absorber

Abstract

A packed bed absorber-stripper system was used to remove selected indoor pollutants during the dehumidification of air by triethylene glycol solutions. Triethylene glycol concentrations of 90% and 95% by weight in water were used. Both random and structured packings were employed to provide the contact surface between the liquid and gas phases. A six-inch I. D. absorption column was operated between 50% and 80% of flooding conditions. The heights of a transfer unit for mass transfer for randomly packed 5/8-inch polypropylene Flexi rings and 1/2-inch ceramic Intalox saddles varied from 0.12 m to 0.17 m when dehumidifying air only. However, the height of a transfer unit was in the range of 0.31 m to 0.40 m for the cross corrugated cellulose and PVC structured packings. Heat and mass transfer coefficients were also calculated from the experimental data and were correlated with various process variables. The values predicted by these correlations were within ±10% of the experimental data.

Pollutants used in the study included formaldehyde, toluene, 1,1,1-trichloroethane and carbon dioxide, and their concentrations in the air were controlled to 0.02 ± 0.005 ppm, 3 ± 0.02 ppm, 24 ± 0.1 ppm, and 1000 ± 5 ppm, respectively. Although nearly 100% of the toluene and 1,1,1-trichloroethane were removed by the 95% triethylene glycol solution, only 56% of the carbon dioxide and 30% of the formaldehyde could be removed from the air stream under similar conditions. As expected, the removal of these pollutants by the triethylene glycol solution was not affected by varying the relative humidity of the air.     

寒冷地区湿传递对多层墙体热湿性能的影响

墙体的传热传湿对建筑围护结构的热工性能、建筑能耗和室内环境有十分重要的影响。以相对湿度和温度为驱动势建立多层墙体一维非稳态热、湿和空气耦合传递模型（HAM模型）,并利用有限元法进行数值求解,重点关注湿传递对传热的影响机理。结果表明：考虑传湿时墙体交界面处湿度梯度大,相变速率大;墙体内部会产生湿积累,缩短墙体的使用年限;墙体内部温度上升幅度和上升速率大,墙体交界面处局部Nusselt数变化受湿传递的影响大;相变潜热量占总传热量的26.1%,计算空调负荷时不可忽略。     

室内甲醛污染的分析调查

含有甲醛的树脂广泛应用于建材、绝热材料、家具及服装等方面,使得室内空气发生甲醛污染.通过对室内甲醛污染的调查,室内甲醛污染高于室外,污染比室外更可怕,应引起人们的高度重视.     

回路热管微通道换热器蒸发冷却实验

采用微通道换热器作为数据中心回路热管冷却换热器,在微通道冷凝器侧进行了蒸发冷却实验。实验利用焓差平台测量了不同因素对采用蒸发冷却技术的微通道冷凝器换热影响,并分析了室内外不同温差、室外不同湿度条件下采用蒸发冷却的微通道冷凝器及蒸发器的进出口空气温差。实验结果表明：采用蒸发冷却可使冷凝器入口空气温度实现大幅温降,并增加冷凝器及蒸发器的进出口空气温度差值,喷淋后可使流经热管空气降温0.3～1.9℃,增大2%～20%的系统换热量,冷凝器换热效率得以提升,并可扩大回路热管换热器使用地区,延长回路热管年利用时间。     

溶剂型木器涂料中挥发性有机化合物释放规律

小型气候箱模拟典型室内空气条件，不同时间用椰子壳活性炭吸附管收集一定体积硝基、多组分聚氨酯清漆涂膜释放出的VOC与空气的混合气体，气相色谱法测定二硫化碳提取液中VOC组分浓度的实验方法，研究了溶剂型木器涂料成膜后VOC的气相浓度由迅速衰减、过渡和缓慢衰减三个过程构成并受液-气界面压力差和解吸的控制，基于数据分析建立定量描述涂料涂装后气相浓度与涂膜中VOC组分量、空气交换率、实验仓容积相互关系的数学模型。气相浓度的衰减率R，可表征VOC释放特性，温度、湿度、空气交换率条件对气相浓度衰减率影响研究表明其与温度、组分的色谱保留时间存在函数关系。