scholarly journals Effect of Cavity Vacuum Pressure Diminution on Thermal Performance of Triple Vacuum Glazing

2018 ◽  
Author(s):  
Saim Memon ◽  
Farukh Farukh ◽  
Karthikeyan Kandan
Keyword(s):  
Element Model ◽  
Vacuum Pressure ◽  
Cavity Pressure ◽  
Existing Buildings ◽  
Zero Energy ◽  
Mathematical Methods ◽  
Thermal Transmittance ◽  
U Value ◽  
Vacuum Glazing

Long-term durability of the vacuum edge-seal plays a significant part in retrofitting triple vacuum glazing (TVG) to existing buildings in achieving towards zero-energy buildings (ZEB) target. Vacuum pressure decrement with respect to time between panes affect the thermal efficiency of TVG. This study reports a 3D finite element model, with validated mathematical methods and comparison, for the assessment of the influence of vacuum pressure diminution on the thermal transmittance (U value) of TVG. The centre-of-pane and total U values of TVG calculated to be 0.28 Wm−2K−1 and 0.94 Wm−2K−1 at the cavity vacuum pressure of 0.001 Pa. The results suggests that a rise in cavity pressure from 0.001 Pa to 100 kPa increases the centre-of-pane and total U values from 0.28 Wm−2K−1 and 0.94 Wm−2K−1 to 2.4 Wm−2K−1 and 2.58 Wm−2K−1, respectively. The temperature descent on the surfaces of TVG between hot and cold sides’ increases by decreasing the cavity vacuum pressure from 50 kPa to 0.001 Pa. To maintain the cavity vacuum pressure of 0.001 Pa for over 20 years of life span in the cavity of 10 mm wide edge sealed triple vacuum glazing, non-evaporable getters will maintain the cavity vacuum pressure that will enable the long-term durability to TVG.

scholarly journals Effect of Cavity Vacuum Pressure Diminution on Thermal Performance of Triple Vacuum Glazing

2018 ◽  
Vol 8 (9) ◽  
pp. 1705 ◽  
Author(s):  
Saim Memon ◽  
Farukh Farukh ◽  
Karthikeyan Kandan
Keyword(s):  
Element Model ◽  
Vacuum Pressure ◽  
Cavity Pressure ◽  
Existing Buildings ◽  
Zero Energy ◽  
Mathematical Methods ◽  
Zero Energy Building ◽  
U Value ◽  
Vacuum Glazing

Long-term durability of the vacuum edge seal plays a significant part in retrofitting triple vacuum glazing (TVG) to existing buildings in achieving progress towards a zero-energy building (ZEB) target. Vacuum pressure decrement with respect to time between panes affects the thermal efficiency of TVG. This study reports a 3D finite element model, with validated mathematical methods and comparison, for the assessment of the influence of vacuum pressure diminution on the thermal transmittance (U value) of TVG. The centre-of-pane and total U values of TVG are calculated to be 0.28 Wm−2 K−1 and 0.94 Wm−2 K−1 at the cavity vacuum pressure of 0.001 Pa. The results suggest that a rise in cavity pressure from 0.001 Pa to 100 kPa increases the centre-of-pane and total U values from 0.28 Wm−2 K−1 and 0.94 Wm−2 K−1 to 2.4 Wm−2 K−1 and 2.58 Wm−2 K−1, respectively. The temperature descent on the surfaces of TVG between hot and cold sides increases by decreasing the cavity vacuum pressure from 50 kPa to 0.001 Pa. Nonevaporable getters will maintain the cavity vacuum pressure of 0.001 Pa for over 20 years of life span in the cavity of 10-mm wide edge-sealed triple vacuum glazing, and enable the long-term durability of TVG.

scholarly journals Hygrothermal Behaviour of Ventilation Cavities in Highly Insulated Envelopes

2020 ◽  
Vol 172 ◽  
pp. 07003
Author(s):  
Klaus Viljanen ◽  
Xiaoshu Lü ◽  
Jari Puttonen
Keyword(s):  
Heat Flux ◽  
Relative Humidity ◽  
Experimental Studies ◽  
Thermal Transmittance ◽  
The Future ◽  
U Value ◽  
Hygrothermal Behaviour

This article presents long-term experimental studies on the moisture safety in the ventilation cavities of highly insulated (HI) structures. The tested HI-walls had thermal transmittances of 0.11-0.13 W/m2K. A wall with a thermal transmittance of 0.23 W/m2K represented the baseline wall in the test. In addition to walls, an HI-roof of a newly built house with a U-value of 0.08 W/m2K was measured. The results indicate that, in the ventilation cavity, the relative humidity of an HI-wall exceeds 1-7% of the humidity measured from the baseline wall during winter, which coincides with the 0.4-1.5ºC lower temperatures observed in the HI-walls. The mold risk in the ventilation cavities of the walls is low, as the value of the mold index (MI) remains below one, which indicates small amounts of microscopic mold only on surfaces. However, at the bottom of the cavity, the MI value reaches 1.4 due to lower temperatures. In the HI-roof, the MI values are between 1.0 and 2.0 in the middle of the cavity in winter. The reasons for the higher mold risk of the roof are the humid weather, the built-in moisture of the roof and the low heat flux from inside. The study confirms that, in the future, warmer weather and increased humidity can increase moisture risks in the ventilation cavities. The results support the use of materials that are more resistant to mold in the outer parts of structures.

Using distributed lag models to predict regional budget revenues

2020 ◽  
Vol 19 (6) ◽  
pp. 1154-1172
Author(s):  
Yu.V. Granitsa
Keyword(s):  
Unemployment Rate ◽  
Consumer Price Index ◽  
Mathematical Methods ◽  
Distributed Lag ◽  
Key Indicator ◽  
Distributed Lag Models ◽  
Regional Budget ◽  
The Impact ◽  
Financial Result

Subject. The article addresses projections of regional budget revenues, using distributed lag models. Objectives. The purpose is to review economic and statistical tools that are suitable for the analysis of relationship between the revenues of the regional budget system and regional macroeconomic predictors. Methods. The study draws on statistical, constructive, economic and mathematical methods of analysis. Results. In models with quantitative variables obtained under the Almon method, the significant predictors in the forecasting of regional budget revenues are determined mainly by the balanced financial result, the consumer price index, which characterizes inflation processes in the region, and the unemployment rate being the key indicator of the labor market. Models with quantitative variables obtained through the Koyck transformation are characterized by a wider range of predictors, the composition of which is determined by the peculiarities of economic situation in regions. The two-year forecast provides the average lag obtained during the evaluation of the models. The exception is the impact of unemployment rate, which is characterized as long-term. Conclusions. To generate forecasts of budget parameters, the results of both the Koyck method and the Almon method should be considered, though the former is more promising.

Nearly Zero-Energy Buildings & Buildings Built with Industrialized Technology: The Case of Hungary

2016 ◽  
Vol 824 ◽  
pp. 469-476
Author(s):  
Attila Talamon ◽  
Viktória Sugár ◽  
Ferenc Pusztai
Keyword(s):  
Economic Structure ◽  
Financial Resources ◽  
Existing Buildings ◽  
Ghg Emission ◽  
Zero Energy ◽  
Building Stock ◽  
Central European ◽  
The Past ◽  
The Eu ◽  
Zero Energy Buildings

There is an urgent need nowadays to reduce current levels of GHGs emissions. On the other hand the EU countries are largely dependent on energy imports and are vulnerable to disruption in energy supply which may in turn threaten the functioning of their current economic structure. The EU imported 54% of its energy sources in 2006 and this value was projected to increase even further by 2030. Reducing its import dependency is one of the EU’s main goals of the 20-20 by 2020 target – this legislative package is believed to reduce the expected imports of energy by 26% compared to the development before the 20-20 initiative.One of the most important environmental problems is the energy consumption of the buildings. Current paper shows that buildings built with industrialized technology can deliver large energy and GHG emission reductions at low costs.Only 1-2% part of the building stock is exchanged every year, so it is very important to increase the energy efficiency of the existing buildings, too.Present paper focuses on the buildings built with industrialized technology only, and their potential in nearly zero-energy buildings sector. Up till now the Central European support schemes concentrated most financial resources on buildings built with prefabricated technology. Present paper explains the past and present of the “panel” problem in Hungary with a short outlook to some other countries.

scholarly journals Data Pruning of Tomographic Data for the Calibration of Strain Localization Models

2018 ◽  
Author(s):  
William Hilth ◽  
David Ryckelynck ◽  
Claire Menet
Keyword(s):  
Model Updating ◽  
Element Model ◽  
Sampled Data ◽  
Model Free ◽  
Reduction Techniques ◽  
Long Term Storage ◽  
X Ray Computed ◽  
Tomographic Data ◽  
Data Pruning

The development and generalization of Digital Volume Correlation (DVC) on X-ray computed tomography data highlight the issue of long term storage. The present paper proposes a new model-free method for pruning the DVC data. The size of the remaining sampled data can be user-defined, depending on the needs concerning storage space. The data pruning procedure is deeply linked to hyper-reduction techniques. The DVC data of a resin-bonded sand tested in uniaxial compression is used as an illustrating example. The relevance of the pruned data is tested afterwards for model calibration. A new Finite Element Model Updating (FEMU) technique coupled with an hybrid hyper-reduction method is used to successfully calibrate a constitutive model of the resin bonded sand with the pruned data only.

scholarly journals Case Study and Numerical Simulation of Excavation beneath Existing Buildings

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hua-feng Shan ◽  
Shao-heng He ◽  
Yu-hua Lu ◽  
Wei-jian Jiang
Keyword(s):  
Finite Element ◽  
Case Reports ◽  
Measurement Data ◽  
Element Model ◽  
Existing Buildings ◽  
Related Case ◽  
Finite Element Software ◽  
Curing Period ◽  
Cutting Sequences ◽  
Bearing Behavior

Excavation beneath existing buildings may cause the superstructure to tilt and crack, which seriously affects the normal use of the superstructure. Due to the new working conditions of excavation beneath existing buildings, related case reports are rare and limited. In the case of No. 3 section basement construction project of Ganshuixiang, we monitored the excavation construction by burying test instruments at the designated location. Afterwards, Plaxis 3D finite element software was used to establish an underpinning pile-cap-excavation model, which can analyze the influence of different pile cutting sequences on the bearing behavior of new basement structural pillars. By comparing the in situ measurement data with the finite element model, it can be concluded that when the excavation depth rises, the axial force of the underpinning pile gradually increases, and the pile skin friction is slowly exerted from top to bottom. Different cutting sequences will influence the bearing behavior of the structural pillar. Moreover, the pile cutting process also significantly impacts its bearing behavior and the settlement behavior of the superstructure. Compared with the clockwise pile cutting sequence, the symmetrical pile cutting is more advantageous. In the whole process of the storey adding and reconstruction, the superstructure settlement is related to the working condition of digging and adding layers. In the stage from soil excavation to the concrete curing period of the structural pillar, it increases slowly with time and tends to be stable in the concrete curing period. However, in the pile cutting stage, the superstructure settlement increases sharply, and after pile cutting, it becomes stable.

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