In situ U g-value measurement on three different glazing types

This study presents in situ monitoring data of three different glazing systems over a period of one year. An insulated glass unit (IGU), a Vacuum Insulated Glass hybrid unit (VIG-hybrid) and an opaque architectural insulation module (AIM) were monitored under the equivalent environmental condition in this study. Different issues were observed and analyzed. It was found that the Ug-value cited by the manufacturers agrees with the Ug-values derived from the measured data, to within less than 5 % for the IGU and the VIG-hybrid. The consistency of the Ug-value of each glazing types one year after the start of monitoring was validated for similar environmental conditions. Depending on the magnitude of the resistance to heat flow, an increasing Ug-value was observed for a higher temperature difference between the inside and outside environments. The effect is much more significant for the glazing type with the largest Ug-value (IGU) and less significant for the glazing types with a high thermal resistance (VIG-hybrid, AIM).

RESEARCH OF POSSIBILITY OF ARMOURING A CABIN OF TYPE Mi-8A HELICOPTER

Given an urgent need to protect a crew of the type Mi-8 helicopter from firearms in the course of combat missions and lack of transparent armor for this type of helicopter in the Armed Forces of Ukraine, it was decided to conduct a theoretical and experimental research with regard to armouring a cabin of type Mi-8 helicopter. The first stage of experimental research was laboratory (bench) research. Samples of bulletproof glass measuring 500x500 mm and 12 and 18 mm thick were provided for testing. The purpose of research bench tests was to determine the degree of protection of the armored glass unit. The samples were fired at with 9 mm pistol bullets, ind. 57-H-181c (Makarov pistol), bullets 7.62 mm pistol cartridge, ind. 57-H-134c (Tokarev pistol) and 5.45 mm bullets, ind. 7H6 (AK-74 assault rifle). The next stage of experimental research was to conduct research ground tests of armored glass of a Mi-8 helicopter crew cabin. The purpose of research ground tests was to evaluate the protective properties of armored glass samples, based on the results of their firing with a single 5.45 mm bullet shots, ind. 7H6 (AK-74 assault rifle) at the shooting range. Samples of armoured glass of the on-board technician and sight (right) glass intended for protection of the flight crew, systems and units of the cabin were presented for ground research tests. The final stage of experimental research was the stage of research flight tests of the Mi-8MSB-B helicopter with 18 mm thick armored glass. The purpose of research flight tests was as follows: to determine changes in the main technical and operational characteristics of Mi-8MSB-B helicopter after installation of 18 mm thick armored glass; to determine the possibility of using 18 mm thick armored glass on Mi-8 helicopters; to assess the effectiveness and safety of armored glass for armouring Mi-8 helicopters’ cabins; to determine peculiarities of using 18 mm thick armored glass on Mi-8 helicopters and peculiarities of Mi-8 helicopter operation with armored glass installed; to obtain initial data for elaboration of tactical and technical (general) requirements for helicopters Mi-8 (particularly concerning the installation of armored glass), approved by Testing Program and Procedure for research flight tests of Mi-8MSB-B helicopter.

The Changes in Thermal Transmittance of Window Insulating Glass Units Depending on Outdoor Temperatures in Cold Climate Countries

Windows, which have a U-value that is governed by an insulating glass unit (IGU) U-value, must be a building’s only enclosure element, which has no design value concept. The declared U-value, which is calculated or measured with 0 °C of external ambient temperature, is used instead of the design value. For most of a building’s elements, its thermal transmittance with a decrease in the external temperature diminishes a little, i.e., improves. However, for modern window IGUs with Low-E coatings, it is the opposite: the thermal transmittance with a lowering external temperature increases. Therefore, for calculating the peak power for the heating of buildings it is necessary to pay attention to this phenomenon and, therefore, it would be wise to introduce the concept of design U-value for windows, recalculation rules, or affix their declared U-values. This is especially the case in modern times with the prevailing architectural tendencies for enlargement of transparent building elements. For IGUs with Low-E coatings and inert gas fillers, the thermal transmittance depends on the temperature difference between warm and cold environments. When the external temperature is −30 °C instead of 0 °C, the thermal transmittance of the IGU can increase by up to 35%. This study presents the thermal properties of windows’ IGUs depending on the changes in outdoor temperatures by using guarded a hot box climate chamber and presents the proposed simplified methodology for determining the thermal properties of windows’ glass units. The accuracy of the composed simplified methods, comparing the calculated thermal transmittances of IGUs with those measured in the “hot box”, were up to 1.25%.

Experimental and numerical investigation of thermal improvement of window frames

In this article are presented experimental and numerical determinations of thermal transmittance performed on three different types of window frames (vinyl, aluminium and wooden) within the same insulated glass unit. Good agreement between experimental and numerical results was attained. Using the numerical models, thermal improvement techniques of the frames and their influence on thermal transmittance of frames were studied. The first thermal improvement technique was using the insulation materials inserted inside large air cavities. By filling the cavity of vinyl frame with the polyurethane foam, thermal transmittance of vinyl frame was lowered by 10%. The second technique was based on repeating the procedure with materials installed inside frames with the materials that have lower thermal conductivity. This technique can be applied on thermal breaks and on steel profiles inside cavities. The result of this thermal improvement (attained by replacing thermal break material with material that has lower thermal conductivity) was certain reduction of the thermal transmittance of frames, by 9%. Using stainless steel instead of the oxidized steel was reduction of the thermal transmittance of vinyl frame by 3%. For the case of wooden frames was analysed the influence of shifting glazing unit deeper into profile upon the thermal transmittance of the frame. Installing the glass unit by 5 mm deeper into the wooden frame reduced glass thermal transmittance by 5%.