scholarly journals Experimental investigation of thermal bridges in building at real conditions

2018 ◽  
Vol 70 ◽  
pp. 03013
Author(s):  
Robert Smusz ◽  
Michał Korzeniowski
Keyword(s):  
Building Materials ◽  
Thermal State ◽  
Building Envelope ◽  
Heat Losses ◽  
Additional Heat ◽  
In Situ Ir ◽  
Thermal Bridges ◽  
Modern Technologies

In recent time the energy consumption of buildings may be reduced by the application of modern technologies in the construction industry. Modern building materials ensure a reduction of heat losses. However, studies show that thermal bridges may cause up to 30% of the additional heat losses through the building envelope. Therefore, a one key aspect in assessing the real thermal state of buildings is the identification of the heat losses through thermal bridges. The analytical, experimental and numerical methods are used for the assessment of thermal transmittance value of building. In the paper the authors present the experimental research on heat losses through the building under real winter conditions. Infrared thermovision technique has been used to the thermal bridges assessment in situ. IR thermography technique allowed the determination of the influence of thermal bridges on the additional heat losses. For the obtaining the surface emissivity the measurements have been also performed with the use of thermocouples system. Numerical validation of the experimental results has been performed.

scholarly journals Determination of the Lewis acidity of amide–AlCl3 based ionic liquid analogues by combined in situ IR titration and NMR methods

RSC Advances ◽  
2018 ◽  
Vol 8 (24) ◽  
pp. 13248-13252 ◽  
Author(s):  
Pengcheng Hu ◽  
Wei Jiang ◽  
Lijuan Zhong ◽  
Shu-Feng Zhou
Keyword(s):  
Ionic Liquid ◽  
Lewis Acidity ◽  
Nmr Analysis ◽  
In Situ Ir ◽  
Nmr Methods

The Lewis acidic strength and amount of amide–AlCl3 IL analogues are determined by the combination of in situ IR titration and NMR analysis.

In Situ Measurement of Thermal Resistance of Building Envelope at the Residential Occupancy in Indonesia

2015 ◽  
Vol 771 ◽  
pp. 191-194 ◽  
Author(s):  
Wahyu Sujatmiko ◽  
Hermawan Kresno Dipojono ◽  
F.X. Nugroho Soelami ◽  
Soegijanto
Keyword(s):  
Thermal Resistance ◽  
High Performance ◽  
Building Materials ◽  
Precast Concrete ◽  
Green Building ◽  
Building Envelope ◽  
Building Wall ◽  
Ashrae Standards ◽  
Building Walls

Abstract. This paper presents the measurement results of three building wall materials which are commonly used for residential housings in Indonesia, namely clay brick, batako (concrete brick), and precast concrete. In-situ measurement of the steady state thermal flow (heat flux) at building walls (envelopes) is conducted in order to determine the thermal resistance of building wall according to ASTM C1155. The results show that all three building materials having a thermal resistance values are far below the energy conservation provisions of ASHRAE 90.1 and especially when compared to the provision of high performance green building ASHRAE 189.1 It is found that precast concrete has higher thermal resistance (or has lower thermal conductivity) than that of other two materials, hence a better compliance to the ASHRAE standards.

Possible Solutions for Ground Slabs of Energy Efficient Buildings

2014 ◽  
Vol 1041 ◽  
pp. 105-108
Author(s):  
Anna Sedláková ◽  
Pavol Majdlen ◽  
Ladislav Ťažký
Keyword(s):  
Energy Efficiency ◽  
Heat Flow ◽  
Thermal Comfort ◽  
Energy Efficient ◽  
Direct Contact ◽  
Thermal State ◽  
Building Envelope ◽  
Heat Losses ◽  
Internal Environment ◽  
Energy Efficient Buildings

The building envelope is a barrier that separates the internal environment from the effects of weather. This barrier ought to facilitate the optimal comfort of the interior environment in winter as well as summer. It has been shown in practice that most building defects occur within the building envelope. This includes external walls, roofs and floors too, and is impartial to new or renovated buildings. Heat losses of buildings through external constructions – roof, external walls, ground slabs are not negligible. It is therefore important to pay more attention to these construction elements. Basementless buildings situated on the ground are in direct contact with the subgrade and its thermal state. An amount of heat primarily destined for the creation of thermal comfort in the interior escapes from the baseplate to the cooler subgrade. The outgoing heat represents heat losses, which unfavourably affect the overall energy efficiency of the building. The heat losses represent approximately 15 to 20 % of the overall heat losses of the building. This number is a clear antecedent for the need to isolate and minimalize heat flow from the building to the subgrade.

scholarly journals ALTERNATIVE METHOD FOR ON SITE EVALUATION OF THERMAL TRANSMITTANCE

2017 ◽  
Vol 15 (2) ◽  
pp. 341 ◽  
Author(s):  
Aleksandar Janković ◽  
Biljana Antunović ◽  
Ljubiša Preradović
Keyword(s):  
Heat Flow ◽  
Thermal Characteristics ◽  
Building Envelope ◽  
Heat Losses ◽  
Flow Meter ◽  
Simple Method ◽  
Building Element ◽  
Thermal Transmittance ◽  
Heat Flow Meter

Thermal transmittance or U-value is an indicator of the building envelope thermal properties and a key parameter for evaluation of heat losses through the building elements due to heat transmission. It can be determined by calculation based on thermal characteristics of the building element layers. However, this value does not take into account the effects of irregularities and degradation of certain elements of the envelope caused by aging, which may lead to errors in calculation of the heat losses. An effective and simple method for determination of thermal transmittance is in situ measurement, which is governed by the ISO 9869-1:2014 that defines heat flow meter method. This relatively expensive method leaves marks and damages surface of the building element. Furthermore, the final result is not always reliable, in particular when the building element is light or when the weather conditions are not suitable. In order to avoid the above mentioned problems and to estimate the real thermal transmittance value an alternative experimental method, here referred as the natural convection and radiation method, is proposed in this paper. For determination of thermal transmittance, this method requires only temperatures of inside and outside air, as well as the inner wall surface temperature. A detailed statistical analysis, performed by the software package SPSS ver. 20, shows several more advantages of this method comparing to the standard heat flow meter one, besides economic and non-destructive benefits.

scholarly journals Evaluation of Thermal Bridges Using Online Simulation Software

2020 ◽  
Vol 172 ◽  
pp. 08010
Author(s):  
Ligia Moga ◽  
Ioan Moga
Keyword(s):  
Finite Difference Methods ◽  
Building Envelope ◽  
Simulation Software ◽  
Heat Losses ◽  
Modelling And Simulation ◽  
Zero Energy ◽  
Online Simulation ◽  
Thermal Bridge ◽  
Thermal Bridges ◽  
The Impact

In order to reach nearly Zero Energy Buildings, a thorough design must be given in designing proper junctions, which will overall reduce the impact of the thermal bridges on the thermal performance of the building envelope. It is well-known that a thermal bridge is a weak thermal area of the building envelope through which increased heat losses occur. For the thermal bridges' evaluation, several numerical simulation software exist on the market, but their usage implies knowledge regarding the numerical modelling and simulation using various numerical methods (i.e. finite element method, finite difference methods, and others). Due to time constraint, designers use thermal bridges atlases that provide values for the linear heat transfer coefficient for several types of thermal bridges. Nevertheless, the multitude of existing thermal bridges requires more and more atlases which are not feasible in elaborating, due to time constraints. In order to respond to this demand, the authors developed a software for the modelling and simulation of thermal bridges that can be easily accessed by practitioners. The paper presents the software its components and the way that the user can interact with it.

Pre-Decommissioning Radiological Characterization of Concrete

2007 ◽  
Author(s):  
Sven Boden ◽  
Eric Cantrel
Keyword(s):  
Building Materials ◽  
Gamma Spectroscopy ◽  
Cost Minimization ◽  
Field Tests ◽  
Building Structures ◽  
Naturally Occurring Radionuclides ◽  
Non Destructive ◽  
Activation Depth

The decommissioning of the BR3 (Belgian Reactor 3) approaches its final phase, in which the building structures are being decontaminated and either denuclearized for possible reuse or demolished. Apart from the presence of naturally occurring radionuclides in building materials, other radionuclides might be present due to contamination or activation. The overall process of the BR3 building structure D&D (Decontamination & Decommissioning) consists of the following steps: • make a complete inventory and preliminary categorize all elements based on historical data; • characterize and determine the contamination or activation depth; • determine the decontamination method; • perform the decontamination and clean up; • a possible intermediate characterization followed by an additional decontamination step; and • characterize for clearance. A good knowledge of the contamination and activation depth (second step) is fundamental in view of cost minimization. Currently, the method commonly used for the determination of the depth is based on core drilling and destructive analysis. Recently, we have introduced a complementary non destructive assay based on in-situ gamma spectroscopy. Field tests at BR3, both for contamination and activation, showed promising results.

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

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