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Spatial flow influence factor: A novel concept for indoor air pollutant control

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science China(Technological sciences) 2006年第1期49卷 115-128页

作者： ZHANG Yinping LI Xiaofeng WANG Xinke DENG Wei QIAN Ke Department of building science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China Department of Building Science Tsinghua University Beijing 100084 China

This paper puts forward a novel concept, the spatial flow influence factor (SFIF), which provides a new insight into the airflow structure. This concept is very helpful in the control of indoor air pollutants since: (1) for a given indoor airflow; given sources of volatile organic compounds (VOCs), the optimal arrangement of the VOC sources can easily be obtained; (2) for given positions of VOC sources; occupied regions (or target regions), the optimal indoor airflow pattern or organization can be determined; (3) the SFIF for an indoor space can also be regarded as the indoor air safety index of that space. To illustrate this concept, we present several examples of applying a SFIF to indoor air VOC control.

关键词： volatile organic compounds, indoor air quality, indoor air pollutant control, spatial flow influence factor.

How to achieve energy efficiency in buildings without compromising indoor air quality:A case study on enthalpy exchangers

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science China(Technological sciences) 2024年第9期67卷 2648-2658页

作者： LI Hao ZHANG Tao LIU XiaoHua Department of building science Tsinghua UniversityBeijing 100084China

As a representative heat recovery device,the fixed-plate enthalpy exchanger possesses the advantages of high recovery effectiveness,low pressure drop,and small space ***,indoor contaminants may transfer to fresh air through the enthalpy exchanger simultaneously,causing cross-contamination ***,the cross-contamination risk of the fixed-plate enthalpy exchanger has been under-researched in previous *** a result,this study experimentally investigates the energy performance,formaldehyde and ammonia transfer rates of paper-based and membrane-based enthalpy *** results illustrate that the enthalpy recovery effectiveness of the plate exchangers ranges from 60%–85%.The formaldehyde transfer rate through the exchangers varies from 5%–23%,and the ammonia transfer rate is 0–15%.The high effectiveness and low contaminant transfer rates are conducive to the promising application of the fixed-plate enthalpy *** addition,the energy reclaimed increases with the increase of the absolute indoor-outdoor enthalpy *** formaldehyde and ammonia transfer rates and cross-contamination risk slightly decrease with increasing temperature but significantly increase with increasing ***,the experimental results demonstrate that the contaminant transfer rates through the membranebased exchanger are lower than those of the paper-based *** study provides a reference for the fixed-plate enthalpy exchanger design in practical applications.

关键词： building energy efficiency enthalpy recovery heat recovery effectiveness cross-contamination

Labeling of volatile organic compounds emissions from Chinese furniture:Consideration and practice

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Chinese science Bulletin 2013年第28期58卷 3499-3506页

作者： LIU WeiWei ZHANG YinPing YAO Yuan Department of building science Tsinghua University

Volatile organic compounds(VOCs)emitted from furniture are recognized as a main cause of bad indoor air *** European countries and the U.S.,labeling systems for furniture have been established with good effect to address this ***,there are problems with these labeling *** example,too many VOCs were targeted,and the testing time was too long(7–28 d).Aiming at solving these problems,solutions are put forward to establish furniture VOCs emissions labeling system in China and some practices are introduced in this *** are:some furniture popular in the market were tested and main VOCs emitted from these furniture were identified;furniture loading factors in residential homes were surveyed,and reference bedroom and reference living room were established according to the survey results to make emission rate thresholds of furniture;C-history method was developed and applied to testing furniture which could shorten the testing time to 3 d;a reference toluene sample for assessing the precision of the test results of chamber system was *** works are technically helpful for establishing furniture VOCs labeling system in China.

关键词：挥发性有机化合物中国家具标签系统排放量测试时间室内空气质量标签制度 VOCs

An algorithm for calculating fresh air age in central ventilation system

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science China(Technological sciences) 2003年第2期46卷 182-190页

作者：李先庭李冬宁窦春鹏 Department of building science School of Architecture Tsinghua University

Fresh air age is an important index to evaluate indoor environment. The conventional method for measuring or calculating fresh air age is only suitable for simple ventilation systems and not for central ven-tilation systems. In this paper, an algorithm for calculating fresh air age in central ventilation system is pre-sented, which is based on the analysis of air flow in duct and air mixing. An example is given to illustrate the algorithm. The fresh air age in every ventilated room and duct can be acquired after all rooms and duct are directly calculated in turn without iteration. The algorithm is suitable for different central ventilation sys-tems.

关键词： ventilation, indoor air quality (IAQ), fresh air age, algorithm.

Numerical Study of Thermal Performance of Phase Change Material Energy Storage Floor in Solar Water Heating System

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湖南大学学报（自然科学版） 2009年第S1期36卷 141-145页

作者： ZENG Ruo-lang,WANG Xin,ZHANG Yin-ping,DI Hong-fa,ZHANG Qun-li(Department of building science,Tsinghua University,Beijing 100084,China) Department of building science Tsinghua University Beijing 100084 China

The conventional solar heating floor system contains a big water tank to store energy in the day time for heating at night,which takes much building space and is very *** order to reduce the water tank volume even to cancel the tank,a novel structure of integrated water pipe floor heating system using shape-stabilized phase change materials(SSPCM)for thermal energy storage was developed.A numerical model was developed to analyze the performance of SSPCM floor heating system under the intermittent heating condition,which was verified by our experimental *** thermal performance of the heating system and the effects of various factors on it were analyzed *** factors including phase transition temperature,heat of fusion,thermal conductivity of SSPCM and thermal conductivity of the decoration material were *** results show that tm and kd are the most import influencing factors on the thermal performance of SSPCM floor heating system,since they determine the heat source temperature and thermal resistance between SSPCM plates and indoor air,*** should be large to store enough thermal energy in the day time for nighttimes *** effects of kp can be ignored in this *** SSPCM floor heating system has potential of making use of the daytime solar energy for heating at night efficiently in various climates when its structure is properly designed.

关键词： phase change material energy storage solar water heating

Progress of entransy analysis on the air-conditioning system in buildings

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science China(Technological sciences) 2016年第10期59卷 1463-1474页

作者： ZHANG Tao LIU XiaoHua TANG HaiDa LIU Jun Department of building science Tsinghua University School of Aerospace Tsinghua University

It is of great importance to improve the energy performance of the air-conditioning system for building energy conversation. Entransy provides a novel perspective to investigate the losses existing in the air-conditioning system. The progress of entransy analysis in the air-conditioning system is comprehensively investigated in the present study. Firstly missions and characteris- tics of the air-conditioning system are analyzed with emphasis on heat or mass transfer process. It is found that reducing the temperature difference, i.e. reducing the entransy dissipation helps to improve the performance. Entransy dissipations and thermal resistances of typical transfer processes in the air-conditioning system are presented. Characteristics of sensible heat transfer process and coupled heat and mass transfer processes are researched in terms of entransy dissipation analysis. Reasons leading to entransy dissipation are also clarified with the help of unmatched coefficient 4. Principles for reducing the entransy dissipation and constructing a high temperature cooling system are summarized on the basis of case studies in typical handling processes. It＇s recommended that reducing mixing process, improving match properties are main approaches to reduce the entransy dissipation. The present analysis is beneficial to casting light on the essence of the air-conditioning system and proposing novel approaches for performance optimization.

关键词： air-conditioning system temperature difference entransy dissipation thermal resistance performance optimization

Dispersion stabilization of antimony-doped tin oxide(ATO)nanoparticles used for energy-efficient glass coating

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Particuology 2014年第6期12卷 49-53页

作者： Ning Li Qinglin Meng Nan Zhang State Key Laboratory of Subtropical building science Building Environment Energy Laboratory(BEEL)South China University of Technology

Nano-antimony-doped tin oxide（ATO） was synthesized using the sol-gel method.A colloidal dispersion of ATO nanoparticles in distilled water was achieved using a milling process in which different dispersants were *** this paper,different factors that affect the stability of ATO nanoparticles were discussed,such as zeta potential,dispersant,and pH *** polyphosphate was a suitable dispersant for stabilizing ATO nanoparticles in distilled water.A stable dispersion of ATO nanoparticles in distilled water was *** stable dispersion of ATO nanoparticles was used to prepare nano-thermal insulation glass paint to block near-infrared rays of sunlight.

关键词： Nano-ATO dispersion Zeta potential Stabilization Energy-efficient glass coating

Experimental study on the shear behavior of the interface between cushion materials and the concrete raft

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Earthquake Engineering and Engineering Vibration 2018年第1期17卷 165-178页

作者： Li Yaokun Han Xiaolei Khaled Galal Ji Jing State Key Laboratory of Subtropical building science South China University of Technology Department of building Civil and Environmental EngineeringConcordia University

Cushion is a layer of granular materials between the raft and the ground. The shear behavior of the interface between the cushion and the raft may influence the seismic performance of the superstructure. In order to quantify such influences, horizontal shear tests on the interfaces between different cushion materials and concrete raft under monotonic and cyclic loading were carried out. The vertical pressure P_v, material type and cushion thickness h_c were taken as variables. Conclusions include： 1） under monotonic loading, P_v is the most significant factor; the shear resistance P_（hmax） increases as P_v increases, but the normalized factor of resistance μ_n has an opposite tendency; 2） for the materials used in this study, μ_n varies from 0.40 to 0.70, the interface friction angle δ_s varies from 20° to 35°, while u_（max） varies from 3 mm to 15 mm; 3） under cyclic loading, the interface behavior can be abstracted as a ＂three-segment＂ back-bone curve, the main parameters include μ_n, the displacement u_1 and stiffness K_1 of the elastic stage, the displacement u_2 and stiffness K_2 of the plastic stage; 4） by observation and statistical analysis, the significance of different factors, together with values of K_1, K_2 and μ_n have been obtained.

关键词： cushion/raft interface shear behavior monotonic test cyclic test "three-segment" back-bone curve

3D Dynamic Response of Layered Unsaturated Soils to Harmonic Loads

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Journal of Donghua University(English Edition) 2010年第3期27卷 407-411页

作者：徐明江魏德敏 State Key Laboratory of Subtropical building science South China University of Technology Guangzhou Institute of building science

Considering compression of solid grain and pore fluids,viscous-coupling interactions and inertial force of fluids,dynamic governing equations for unsaturated soils are established by adopting an exact constitutive formula of *** equations are highly versatile and completely compatible with Biot's wave equations for the special case of fully saturated *** governing equations in Cartesian coordinates are firstly transformed into a group of state differential equations by introducing the state *** the transfer matrix for layered media are derived by means of a double Fourier *** the transfer matrix followed by boundary and continuity conditions between strata,solutions of steady-state dynamic response for multi-layered unsaturated soils are *** examples show that the echoes generated by boundary and stratum interfaces make the displacement amplitude of the ground surface fluctuate with distance;the relative position of soft and hard strata has a significant influence on displacement.

关键词： unsaturated soils dynamic response wave equations double Fourier transform transfer matrix