Theoretical Calculation of Thermal Transmittance

2016 ◽  
Vol 820 ◽  
pp. 212-217
Author(s):  
Adela Palková ◽  
Milan Palko
Keyword(s):  
Computer Simulation ◽  
Theoretical Calculation ◽  
Window Frame ◽  
Thermal Transmittance ◽  
Heat Engineering ◽  
Technical Requirements ◽  
Plastic Profile ◽  
Frame Construction ◽  
Theoretical Assessment ◽  
Window Frames

The article is focused on the theoretical calculation of thermal transmittance for new plastic window frame. Constant making the thermos-technical requirements stricter lays higher demands on improvement of window frames which the weakest element from the point of heat engineering. One important part of the window, which is needed to be improved, is a frame profile. Assessment of newly proposed window profile system is realised based on currently effective technical norms and regulations. The main aim of the theoretical assessment and computer simulation is to define the coefficient of passage of heat of the frame construction of a new plastic profile system.

Design of Turning Area for LNG Terminal Base on Computer Simulation

2012 ◽  
Vol 215-216 ◽  
pp. 1236-1240
Author(s):  
Yao Tian Fan
Keyword(s):  
Computer Simulation ◽  
Theoretical Calculation ◽  
Cost Effective ◽  
Major Axis ◽  
Minor Axis ◽  
Computer Simulator

Design of turning area for sea port is generally done according to the outcome of theoretical calculation or real-ship trial. However, these methods only take into account some limited respects for planning a port or are not so cost-effective. In this paper, computer simulator is used for optimizing the size of turning area for Yangshan LNG terminal. The outcome indicates that the major axis and minor axis of the turning area can meet the requirement of Q-Max LNG carrier berthing operation and it is suggested to do such maneuvering in some given conditions related to wind, current, tide, visibility and wave.

Numerical Analysis of Window Structure Seating Depth Effects on Surface Temperature and Linear Thermal Transmittance

2014 ◽  
Vol 1057 ◽  
pp. 53-60 ◽  
Author(s):  
Marek Zozulák ◽  
Marián Vertaľ ◽  
Dušan Katunský
Keyword(s):  
Computer Simulation ◽  
Numerical Analysis ◽  
Numerical Experiment ◽  
Coupling Coefficient ◽  
Thermal Field ◽  
Thermal Coupling ◽  
Thermal Transmittance ◽  
Surface Temperatures ◽  
Deformation Amount ◽  
Depth Effects

The paper deals with effect of window structure seating depth in window lining on the deformation of thermal field represented by the change in surface temperatures and thermal coupling coefficient. Alternative depths of window structure seating are analysed by the numerical experiment using the computer simulation of thermal field. The objective of analysis is to optimize the window structure seating depth in the existing experimental wall. The effect of deformation amount of thermal field of analyzed contact on the course of surface temperatures and thermal coupling coefficient of the binding has also been analysed.

scholarly journals Two-dimensional heat transfer analysis of timber structure walls filled with hemp-lime composite

2019 ◽  
Vol 252 ◽  
pp. 05015 ◽  
Author(s):  
Przemysław Brzyski ◽  
Sylwia Duda ◽  
Andrzej Raczkowski
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Timber Structure ◽  
Heat Transfer Analysis ◽  
Two Dimensional ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Thermal Insulating ◽  
Frame Construction ◽  
Industrial Hemp

Hemp-lime composite is a thermal insulating material used as a filling in timber frame construction walls. It is a material based on the wooden part of industrial hemp stalk (hemp shives) and lime binder. In practice, different wall thicknesses, composites with different thermal properties and various configurations of timber structure are used. These factors affect the temperature distribution in the wall. In the thermally weaker areas of walls, there is a greater risk of condensation and mould growth. This issue is important while designing walls based on organic materials. The paper presents the two-dimensional (2D) heat-transfer analysis based on the finite-element method, using THERM software. Several variants of external walls were adopted for the analysis. Thermal parameters of hemp-lime composites used in the analysis were obtained from our own research. The results of the analysis were presented as the values of the thermal transmittance coefficient and linear thermal transmittance equivalent to timber construction. The temperature distribution for an exemplary wall was also shown graphically in the form of isotherms and colour-flooded isotherms.

Simulation of a Cyclone Separator to Improve the Efficiency of Gas Purification from Mechanical Impurities

2021 ◽  
Author(s):  
Khasan Abrorov
Keyword(s):  
Computer Simulation ◽  
Theoretical Calculation ◽  
Gas Flow ◽  
Granulometric Composition ◽  
Suitable Method ◽  
Solid Model ◽  
Cyclone Separator ◽  
Gas Purification

Abstract This paper provides an overview of methods for dealing with mechanical impurities, justifies the choice of a suitable method and prototype for the conditions of the field. A methodology for designing cyclone separators of JSC "NIIOGAS" is presented, in accordance with which a theoretical calculation of the design of a cyclone separator was carried out. A solid model of a computational cyclone separator in the SolidWorks software was created, a computer simulation of a gas flow with the presence of mechanical impurities of various granulometric composition was carried out, based on the results of which conclusions were made.

scholarly journals Hibernation of Flies in a Lincolnshire House

Parasitology ◽  
1918 ◽  
Vol 11 (1) ◽  
pp. 81-82 ◽  
Author(s):  
G. S. Graham-Smith
Keyword(s):  
Very Old ◽  
Window Frame ◽  
Large Numbers ◽  
Window Frames

In the autumn of 1917 the writer received several letters from Mr L. C. Peters describing his experiences with flies hibernating in a large and very old house, situated in a large park at Frampton, near Kirton, Boston, Lincolnshire. Mr Peters' attention was directed first to the matter towards the end of October. On removing the window sashes the frames were found “black with flies.” After fumigation a bucketful of dead flies was removed from a single window frame, and about six bucketfuls from other infested windows. Only one side of the house was affected, but on that side the flies were found in the window frames on all three stories. “Ladybirds” were also present in large numbers.

Material Properties of Windows in the Building Energy Concept

2013 ◽  
Vol 855 ◽  
pp. 116-119 ◽  
Author(s):  
Adela Palková ◽  
Milan Palko
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Building Energy ◽  
Material Base ◽  
Thermal Transmittance ◽  
Technical Requirements ◽  
Exposed Part ◽  
The Heat Transfer Coefficient

The window is an exposed part of the external cladding. Assessment of windows regarding the heat transfer coefficient. Categorization of thermo-technical requirements for windows. Experimental measurement and determination of heat transfer coefficient. Calculation and determination of linear thermal transmittance. Material base of windows for passive energy building standard.

scholarly journals Analysis of the Occurrence of Thermal Bridges in Several Variants of Connections of the Wall and the Ground Floor in Construction Technology with the Use of a Hemp–lime Composite

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2392 ◽  
Author(s):  
Brzyski ◽  
Grudzińska ◽  
Majerek
Keyword(s):  
Heat Transfer ◽  
Construction Technology ◽  
Floor Level ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Surface Condensation ◽  
Thermal Bridges ◽  
Almost All ◽  
Frame Construction ◽  
Temperature Factors

This article analyses the connection of the two types of floors on the ground (floors on joists and self-supporting floors), with the external wall made of a hemp–lime composite for the occurrence of thermal bridges. Several factors that may affect the heat transfer in the junction were taken into account: the level of the floor on the ground, the wall thickness, the thermal conductivity of the composite, and the location of the timber frame construction. The technology of using hemp and lime is relatively new, and there is a lack of such analyses in the literature. The two-dimensional (2D) heat-transfer in the described construction joints was analyzed based on the finite-element method with the use of the THERM 7.4 software. The results were presented as averaged and linear thermal transmittance coefficients dependent on the above mentioned factors. The possibility of surface condensation was also checked. The differences in the values of the thermal transmittance of the junction between the two variants of ground floors reached around 0.13%–1.67% and the values of linear thermal transmittance factor reached approximately 2.43%–10.13%. The junctions with the highest floor level showed a decrease in the thermal transmittance value by about 3.00%–5.77% and in the linear thermal transmittance, by about 21.98%–53.83%, compared to the junctions with the lowest floor level. Calculations showed that almost all analyzed junctions are free from surface condensation causing mould growth, because the minimum temperature factors f0.25 were higher than 0.78 (except for junctions with the lowered floor levels). The junction with a floor on the timber joists showed better thermal parameters than the junction with a self-supporting floor in each of the analyzed variants. By increasing the level of floor insulation, it is possible to limit the thermal bridges and improve the thermal properties of the junction.

scholarly journals Influence of Window Details on the Energy Performance of an nZEB

2019 ◽  
Vol 24 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Kristo Kalbe ◽  
Targo Kalamees
Keyword(s):  
Energy Efficient ◽  
Energy Demand ◽  
Energy Performance ◽  
Optimal Placement ◽  
Design Decision ◽  
Single Family ◽  
Window Frame ◽  
Remarkable Effect ◽  
Thermal Transmittance ◽  
Heat Demand

One of the largest sources of heat loss in buildings are the windows. However, windows are alsoimportant to increase solar heat gain and provide daylight. It is necessary to understand how windowdetails influence the energy performance of very energy efficient houses. This is valuable informationfor the design decision making process and may lead to further research or product development. Thispaper examines the influence of window frame thermal transmittance, window frame width and windowinstallation depth on the energy demand of the building. A single-family prefabricated timber nZEBlocated in Estonia was used as a reference building for this study. The results show that decreasing thethermal transmittance and width of the window frame have a remarkable effect on the energy demandof the nZEB (a variation of 42% and 25% respectively). The effect of optimising window installation depthis insignificant (ca 3% variation of heat demand on most of the window placement range and up to 10%of increase in heat demand when comparing the optimal placement to the least effective one). However,it can further improve the energy performance.

scholarly journals The The Occurrence of Thermal Bridges in Hemp-Lime Construction Junctions

2019 ◽  
Author(s):  
Magdalena Grudzińska ◽  
Przemysław Brzyski
Keyword(s):  
Energy Efficient ◽  
Composite Structures ◽  
Building Materials ◽  
Thermal Transmittance ◽  
Timber Frame ◽  
Energy Efficient Buildings ◽  
Moisture Condensation ◽  
Thermal Bridges ◽  
Frame Construction ◽  
Insulating Properties

Thermal bridges increase heat losses in buildings and reduce the temperature of the internal envelope surface, causing moisture condensation and mould growth. This is an important issue for building materials based on organic components such as a hemp-lime composite, as they are particularly susceptible to biological degradation.The hemp-lime composite is used as a filling in timber frame construction. The increased cross-section of wooden elements together with the geometry change in the construction joints can form thermal bridges. The paper presents numerical analyses of temperature distribution in the area of construction elements connections, taking into account several variants of junctions: external walls, corners, and window placement in a wall. The thermal parameters of hemp-lime composites used in the analyses were obtained from the authors’ own research.Despite relatively good insulating properties, timber elements have a noticeable influence on the local increase of the heat transfer in hemp-lime composite structures, forming thermal bridges in the partitions themselves and in the construction nodes. However, the linear thermal transmittance coefficients in the presented joints were not very significant (in the range of 0.026 ÷ 0.092 W/(m·K) depending on the type of connection), proving the usefulness of this type of construction in energy-efficient buildings.

scholarly journals Sensitivity Analysis of Window Frame Components Effect on Thermal Transmittance

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2957
Author(s):  
Giorgio Baldinelli ◽  
Agnieszka Lechowska ◽  
Francesco Bianchi ◽  
Jacek Schnotale
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Sensitivity Analysis ◽  
Surface Heat ◽  
Transfer Coefficients ◽  
Window Frame ◽  
Surface Heat Transfer ◽  
Thermal Transmittance ◽  
Heat Transfer Coefficients ◽  
Definition Of

Standard ISO 10077-2 gives the procedure to calculate thermal transmittances of window frames in 2D numerical simulations. It also introduces some examples of frame geometrical models with all necessary input data and the solutions so as to perform validation of the applied numerical tools. In the present paper, the models prepared with a commercial finite volume software of a PVC window frame were first positively validated with the results given in the Standard. An experimental test was then implemented to confirm the simulated data, with satisfactory agreement. The numerical code was used on one of the frames provided by the Standard to perform a sensitivity analysis of all the components and boundary conditions playing a role on the definition of the frame thermal transmittance, such as surface heat transfer coefficients, values of the solid thermal conductivity, emissivity and insulation properties of air gaps. Results demonstrate that the air gap properties represent the most influential parameters for the definition of the PVC window frames thermal transmittance, followed by the surface heat transfer coefficients and the PVC thermal conductivity. The rubber and the steel properties show a negligible effect on the whole frame performance. This procedure could constitute a design tool to guide the efforts of window manufacturers for the achievement of high performance products.

Sign in / Sign up

Export Citation Format

Share Document