Selection of the Optimal Window Type and Orientation for the Two Cities in Serbia and One in Slovakia

The necessity of having windows on any building’s façade is not questionable. However, not every window is suitable for any building. The selection of an adequate window must include the analysis of various factors—the most important ones are the type of window (e.g., single or double glazing); filling gas in cavities (e.g., air, argon or some other gas); and placing, i.e., orientation of a window on a façade (facing north, south, or east, etc.). The research presented in this paper is dealing with the calculation of the window thermal loading for the cities of Kragujevac and Bor in Serbia and Žilina in Slovakia. These three cities were selected because they belong to different climate regions, according to the Köppen–Geiger climatic classification. The first two cities in Serbia belong to the same region Cf with difference only in the category of summer—Kragujevac Cfa and Bor Cfb—while the third city—Žilina in Slovakia—belongs to the Dfb region. The calculated thermal loading through the window was obtained as a sum of the thermal loading due to the heat conduction and thermal loading due to the solar radiation. The objective was to find the optimal window construction and orientation of a building’s façade for each of these cities, by varying the type of the window, its frame material and the filling gas. The results show that for the first two cities in Serbia, there is a difference in the window frame material in the optimal window construction, while for the third city (Žilina in Slovakia), the results are the same as for the second city (Bor in Serbia) despite the fact that they belong to different climate regions (Cfb and Dfb, respectively). These results support the fact that the climate affects the optimal window construction for any city/region in the world.

Bending Stiffness of Hybrid Wood-Metal Composite Beams: An Experimentally Validated Numerical Model

This paper presents an experimentally validated model for the computational analysis of metal-reinforced wooden composites. The model can be used in both research and in industry to effectively estimate how much a certain composite design improves the bending stiffness and strength of a hybrid metal-reinforced wooden component. A model based on computer simulations allows the prediction and analysis of the mechanical behaviour of a hybrid composite material consisting of several interconnected components made of different base materials. The model for different boundary conditions and parameters provides the correct data on stiffness, especially bending, and the associated maximum displacements. It allows for a variation of the mechanical and geometrical properties, and makes it possible to observe the initiation of irreversible change in the window-frame member. The model enables parametrical simulations to find the optimum layout of reinforcements in the window-frame member, as well as to make estimations of the maximum performance of certain designs.

Investigating thermal bridging in window systems insulated with monolithic silica aerogel.

Windows typically account for 30% to 50% of heat losses through building envelopes. Monolithic silica aerogel has thermal properties and physical characteristics which make it an attractive material for high performance glazing. Optimizing the thermal performance of individual window components can improve the thermal performance of windows insulated with monolithic silica aerogel. It is important to consider how the thermal properties can be sustained, especially when in contact with other window components such as edge and intermediate spacers and the window frame. The purpose of this research paper is to analyze French style windows insulated with four panes of monolithic silica aerogel and investigate the thermal bridging of edge and intermediate spacers and window frame in order to assess how they collectively affect the centre of glass and edge of glass regions. The research aims to determine the spacer geometry, materials, and window frame that guarantee the best performing window system.

Investigating thermal bridging in window systems insulated with monolithic silica aerogel.

Windows typically account for 30% to 50% of heat losses through building envelopes. Monolithic silica aerogel has thermal properties and physical characteristics which make it an attractive material for high performance glazing. Optimizing the thermal performance of individual window components can improve the thermal performance of windows insulated with monolithic silica aerogel. It is important to consider how the thermal properties can be sustained, especially when in contact with other window components such as edge and intermediate spacers and the window frame. The purpose of this research paper is to analyze French style windows insulated with four panes of monolithic silica aerogel and investigate the thermal bridging of edge and intermediate spacers and window frame in order to assess how they collectively affect the centre of glass and edge of glass regions. The research aims to determine the spacer geometry, materials, and window frame that guarantee the best performing window system.

Design and Analysis of Composite Window Frame for a Regional Aircraft

This work presents the design and analysis of a thermoplastic composite window frame for integration into a regional aircraft. The main parameters which are investigated include buckling, damage and failure loads of a composite window frame subjected to shear loads repesentative of fuselage skin stress distribution due to flight loads. The attachment of such thermoplastic window frame to a thermoset fuselage skin was investigated including both adhesively bonded interface as well as riveting. Even though the bonded frame did meet the design criteria, its failure was very sudden, and the riveted assembly showed a considerably higher strength and structural integrity. The numerical simulation resulted in failure loads which matched very closely to experimental results.

Thermal Characteristics of Window Junctions to Brick and Reinforced Concrete Walls of Civil Buildings in the Kirovograd Region

Existing design standards require that the temperature of the inner surface of the enclosure in the zones of high thermal conductivity should not fall below the temperature of the dew point. This phenomenon can occur in a place of window framing to the wall of residential and public buildings, which were massively produced in the second half of the twentieth century. Condensation can be avoided by raising the surface temperature of the inner window jamb extensions. This can be done by adding an additional insulation or displacement of the block frame window inside the building. The aim of the work is to calculate the appropriate values of the displacement of the block frame window inside the wall of different types for the climatic conditions of the Kirovograd region. The framing of metal-plastic windows to the walls of various structures that were produced in the second half of the twentieth century are analyzed. The insulation is performed in accordance with DBN B.2.6-31-2016. The lowest design temperature of the coldest five-day period within the territory of the Kirovograd Region is -24 °С. As a safety margin, the dew point temperature for residential and public buildings for various purposes is taken to be +11 °C. Finite element modeling in the THERM program environment made it possible to construct the temperature fields of the framing of metal-plastic windows to the walls of various structures and to obtain the very temperature of the inner window jamb extensions at various positions of the window frame within the wall. For each of the nodes examined, the possibility of condensation on the inner surfaces of the walls was established taking into account the position of window frame within the wall. As a result of the studies, it was found that the nodes of the side framing of the windows to the brick and panel walls of civil buildings without additional facade insulation do not meet the requirements for thermal reliability according to the condensation criterion. Facade insulation of existing or new walls, made in accordance with the requirements of DBN B.2.6-31-2016 "Thermal insulation of buildings", in almost all cases guarantees the absence of condensation on the internal surfaces of window jambs.

Sensitivity Analysis of Window Frame Components Effect on Thermal Transmittance

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.

Multi-Sensor Orientation Tracking for a Façade-Cleaning Robot

Glass-façade-cleaning robots are an emerging class of service robots. This kind of cleaning robot is designed to operate on vertical surfaces, for which tracking the position and orientation becomes more challenging. In this article, we have presented a glass-façade-cleaning robot, Mantis v2, who can shift from one window panel to another like any other in the market. Due to the complexity of the panel shifting, we proposed and evaluated different methods for estimating its orientation using different kinds of sensors working together on the Robot Operating System (ROS). For this application, we used an onboard Inertial Measurement Unit (IMU), wheel encoders, a beacon-based system, Time-of-Flight (ToF) range sensors, and an external vision sensor (camera) for angular position estimation of the Mantis v2 robot. The external camera is used to monitor the robot’s operation and to track the coordinates of two colored markers attached along the longitudinal axis of the robot to estimate its orientation angle. ToF lidar sensors are attached on both sides of the robot to detect the window frame. ToF sensors are used for calculating the distance to the window frame; differences between beam readings are used to calculate the orientation angle of the robot. Differential drive wheel encoder data are used to estimate the robot’s heading angle on a 2D façade surface. An integrated heading angle estimation is also provided by using simple fusion techniques, i.e., a complementary filter (CF) and 1D Kalman filter (KF) utilizing the IMU sensor’s raw data. The heading angle information provided by different sensory systems is then evaluated in static and dynamic tests against an off-the-shelf attitude and heading reference system (AHRS). It is observed that ToF sensors work effectively from 0 to 30 degrees, beacons have a delay up to five seconds, and the odometry error increases according to the navigation distance due to slippage and/or sliding on the glass. Among all tested orientation sensors and methods, the vision sensor scheme proved to be better, with an orientation angle error of less than 0.8 degrees for this application. The experimental results demonstrate the efficacy of our proposed techniques in this orientation tracking, which has never applied in this specific application of cleaning robots.