In situ measuring and evaluating the thermal resistance of building construction

This paper introduces an in situ measuring method for the thermal resistance of buildings, including the test chamber, measuring points’ arrangement, and measurement results, in Nanjing during 2000 and 2001. Three methods for the analysis of in situ data are also presented to determine the thermal resistance of buildings although the R-values evaluated by these methods have smaller values than those of design due to the limitation of field conditions. The synthetic temperature method only requires measuring the heat flow rate on the inside surface of the building construction and both the synthetic indoor and outdoor temperatures. And the surface temperature method just requires testing the heat flow rate on the inside surface of building envelopes and both the inside and outside surface temperatures of building construction. However, the frequency response method introduced in this paper only relates to the mean synthetic indoor and outdoor temperatures and the average inside surface temperatures of the building envelopes. In other words, it is not involved with the heat flow rate, which is difficult to measure. Thus, on this point, the frequency response method is better than the other two methods to evaluate the in situ R-value of buildings.     

建筑围护结构传热系数现场检测装置研制

建筑围护结构传热系数检测是建筑节能检测中的重要项目,为在现场准确测量围护结构的传热系数,将用于实验室测试围护结构传热系数的热箱法与用于现场测试的热流计法结合起来,设计并制作了现场检测围护结构传热系数的实验装置.热箱能够人为控制室内检测环境,使室内外温度差达到检测要求,弥补了热流计法只能在采暖季节测试的不足,提高了检测效率及准确度.通过对某建筑物墙体进行了现场检测,实验结果表明该现场检测装置测试时间短、准确度高.现场检测得到的传热系数比理论计算值高约55％,建议将建筑围护结构的现场检测结果和理论计算值作为评价其节能效果的综合指标.     

New equipment for testing steady and transient thermal performance of multilayered building envelopes with PCM

Thermal properties of the different building envelopes, such as thermal transmittance in steady state, heat storage capacity and dynamic thermal responses, must be taken into account during the design phase of buildings. The evaluation and measurement of these parameters in multilayered samples are difficult because of the irregular morphology of the used materials and the difficulty in providing the well-controlled environment needed for the measurements. A new equipment has been designed to measure the thermal response and heat capacity of composite walls of different materials simulating real building envelopes.The equipment presented in this paper was used to test the improvement in the thermal response of a building envelope due to the incorporation of PCM. This study is focused on wood structural panels attached to a gypsum board, which is either impregnated or not with PCM. The four edges of the composite sample are properly insulated to ensure one-dimensional heat flow. The two faces of the sample are exposed to controlled environments heated and cooled by copper coils with thermo stated water supplied by water baths. The measured surface heat fluxes at both surfaces of the sample and temperature distribution in the sample provide accurate assessment to thermal mass and dynamic response of the composite wall, while the steady state measurements provide an accurate estimate of its effective thermal transmittance.     

地源热泵地埋管换热器热响应测试分析

通过对某地源热泵现场测试孔的热物性测试,由热响应测试仪器测得现场埋置岩土中U形换热器循环介质的进出水温度、流量等相关参数,并利用线热源模型计算了岩土综合导热系数、钻孔内热阻相关参数,为该地区地源热泵系统设计提供正确的设计参数。     

锚杆锚固体与土体界面特性室内测试新方法

为了更真实地反映锚杆受拉时锚固体与土体界面的特性,较准确地获得包含界面剪切残余段的剪应力–位移(?–s)全过程曲线,自行研发了一种锚–土界面摩阻性能测试仪及相应的锚杆拉拔试样制作装置和方法。该测试仪器和测试方法简便易行,可成批模拟多种环境条件进行室内锚杆拉拔试验。利用该仪器完成了4批次27个不同条件的锚固体拉拔试验,深入研究了锚固体养护龄期、拉拔速率等因素对锚–土界面剪切强度特性的影响,提出了一种锚–土界面?–s全过程本构模型。研究结果表明:界面剪切强度在锚固体养护14 d后增长缓慢;锚杆以0.1~2.5 mm/min拉拔时,速率对剪切强度的影响不大;提出的锚–土界面模型计算曲线与试验曲线吻合良好。     

钢筋混凝土结构火灾损伤的红外热像-电化学综合检测技术与应用

根据红外热成像及电化学检测原理 ,采用红外热成像与电化学等检测方汉匹配组合 ,由表及里地检测分析火灾钢筋混凝土结构的受火温度、强度损失及损伤深度 ,并综合评价其损伤等级。现场检测实践表明 :钢筋混凝土结构火灾损伤的红外热像 -电化学综合检测与评估可快速获取比较全面翔实的建筑物火灾损伤资料 ,从而为修复加固工程提供科学可靠的依据     

基于温度-应力试验机的水工混凝土抗裂性试验方法

目前水工混凝土采用极限拉伸值和绝热温升来评判抗裂性的方法未能客观反映混凝土实际的抗裂表现。重大水利工程对混凝土的抗裂性提出了更高的要求,迫切需要一种科学、综合的试验方法来客观评价混凝土的抗裂性。作为一种先进的设备,温度-应力试验机能够克服目前混凝土抗裂性试验方法的缺陷,可以实现以下功能:测量半绝热及模拟实际坝体温度历程下混凝土力学及变形性能的发展规律、监测不同约束状态下的应力应变发展、测量混凝土的真实开裂温度以及早期拉徐变性能。因此,该试验方法能够为重大工程的混凝土配合比设计及优化提供试验依据,客观地评价不同配合比混凝土的开裂风险。     

真空玻璃保温性能检测技术研究及应用

传热系数是衡量真空玻璃保温性能的关键技术指标。本文采用标定热箱法和热流计法对不同尺寸真空玻璃传热系数进行测试,通过两种检测方法的结果对比,研究真空玻璃传热系数测试方法与样品尺寸之间的匹配度,得到真空玻璃保温性能检测技术的适用性,确保了检测数据的准确性,以实现真空玻璃在建筑节能产品市场的推广和应用。     

空调送风口送风量的测试方法

指出了传统的送风口送风量测试方法的不足，提出了一种新的送风口送风量测试方法，给出了新的送风口送风量测试装置的设计方法。新的送风口送风量测试装置不需标定，操作方便，可提高测试速度和测试精度，既可应用于实验室中测试送风口送风量，也可应用于实际工程实测送风口送风量。     

土壤热导率测试系统研究

介绍了土壤热导率的测试方法,根据传热模型反解法设计了土壤热导率测试系统。结合工程实例,应用土壤热导率测试系统对北京某地区的土壤热导率进行了测试。测试系统采用的恒热流密度法可以获得最恶劣工况下土壤的热导率,从而确保了地源热泵的可靠性且测试误差较小,但恒热流密度法对电源的稳定性要求较高。     

一种用于饱和土的热固结试验装置及其应用

介绍一种用于饱和土圆柱形试样的热固结试验的温控固结压力室系统，可用来测定变化温度荷载和外力荷载耦合作用下试样的热固结变形量。该试验装置压力室内温度可在17℃～100℃范围内变化，同时可承受较高的等向周围固结压力（0～3 MPa）。分析了该试验装置的基本原理和测试方法。此外，针对一种典型的黏性土，研究了温度诱致的饱和黏性土的热固结变化规律，对试样的温度演化过程、孔隙水压力变化以及热体积应变的测定等问题进行了分析。     

土的热导率

本文简要论述了土的热导率研究的重要性，介绍了土的热导率的测试方法及土的热导率的变化规律。     

墙体热工缺陷及传热系数现场检测技术研究

对建筑工程建成后的实际节能效果进行评价应结合现场检测获得的相关结果开展。结合红外热像法确定广西新型墙材节能建筑示范项目围护结构的热工缺陷,同时,利用温控箱-热流计法测试围护结构的传热系数,结果表明,在合理控制现场条件的情况下,红外热像法和温控箱-热流计法的配合使用,可以有效反应实际建筑工程围护结构的节能效果,检测结果较为可靠。     

CFG桩的几种方法综合检测

采用CFG桩处理的地基,具有承载力提高幅度大、工后地基变形小以及施工方便快捷等特点。本文通过比较几种检测方法的适用性,提出了几种方法的检测次序、侧重点和局限性,从而总结出,几种方式配合起来,综合使用,可以对CFG桩进行经济、有效且准确的检测。     

相变储能石膏板导热系数2种测试方法的研究

相变储能石膏板导热系数的测试多采用单一的非稳态测试方法,为更好表征相变储能石膏板导热系数的变化规律,分别采用稳态测试方法（防护热板法）和非稳态测试方法研究了相同配合比相变储能石膏板的导热系数.分析比较发现：随着相变材料掺量的增大,石膏基相变储能构件的导热系数降低;2种测试方法均能反映相变储能石膏板导热系数的变化规律,初始温度在相变温度区间时,试件的导热系数值最大;非稳态测试得到的导热系数值较大.     

水工混凝土多项配合比联合设计试验方案探讨

本文依据工作实践提出了水工混凝土多个配合比联合设计时试验方案的制定方法,除了技术指标的归集和原材料的测试外,强调了共性测试和分组测试应进行的试验内容,并在分组测试环节,着重描述了"分线"和"借线"的概念及应用。     

虚拟仪器技术在检测混凝土早期开裂敏感度试验中的应用

混凝土的开裂敏感度受很多因素影响 ,而传统的试验方法只能进行单因素检测 ,不能很好地评价混凝土早期的开裂敏感度。温度 -应力试验适用于评价多种因素 ,如温度、应力、变形、约束和弹性模量的综合影响 ,通过对开裂温度和室温应力的检测评价混凝土的开裂敏感度。介绍计算机虚拟仪器技术在混凝土早期温度 -应力试验中的应用 ,包括各组成部分的设计原理和设备主要部件 ,介绍了虚拟仪器检测混凝土温度应力的一个实例。     

Assessment of uncertainties for the GHP apparatus in determining U-value of double-glazed window with inter-pane blinds

This paper describes a procedure for determining the component uncertainties for the guarded heater plate apparatus – developed to compute from the measured thermal resistance – the ‘Unit heat loss rate’ of a double-glazed window with inter-pane venetian blinds. An example for computation of such uncertainties as per full-factorial design (162 trial runs) is also presented. The overall uncertainty for determining this U-value was determined to vary from 1.2% to 2.6% for the identified design. It was concluded that the fabricated apparatus has the advantage of getting an acceptable level of accuracy without using the complex and specifically designed equipment.     

Experimental Studies on the Fire Behaviour of High Performance Concrete Thin Plates

In recent decades, the use of structural high performance concrete (HPC) sandwich panels made with thin plates has increased as a response to modern environmental challenges. Fire endurance is a requirement in structural HPC elements, as for most structural elements. This paper presents experimental investigations on the fire behaviour of HPC thin plates (20 or 30 mm thick) being used in lightweight structural sandwich elements. Tests were undertaken using a standard testing furnace and a novel heat-transfer rate inducing system (H-TRIS), recently developed at the University of Edinburgh. The parametric assessment of the specimen performance included: thickness of the specimen, testing apparatus, and concrete mix (both with and without polypropylene fibres). The results verified the ability of H-TRIS to impose an equivalent thermal boundary condition to that imposed during a standard furnace test, with good repeatability, and at comparatively low economic and temporal costs. The results demonstrated that heat induced concrete spalling occurred 1 to 5 min earlier, and in a more destructive manner, for thinner specimens. An analysis is presented combining the thermal material degradation, vapour pore pressure, stress concentrations, and thermo-mechanical energy accumulation in the tested specimens. Unexpectedly, spalling at the unexposed surface was observed during two of the tests, suggesting a potentially unusual, unwanted failure mode of very thin-plates during fire. On this basis it is recommended to favour 30 mm thick plates in these applications, since they appear to resist spalling better than those with 20 mm thickness.     

对《家用燃气灶具》国家标准中热效率测试方法的研究

本文主要介绍了《家用燃气灶具》新国家标准GB16410—2007与旧国家标准GB16410—1996在热效率测试方面的不同之处．并通过试验测试比较新旧国家标准测试计算得到的热效率值之间的偏差．并结合实际使用燃气灶具的情况和试验测试方法所产生的偏差,对热效率的测试方法提出建议。