Heat Transfer through Double-Chamber Glass Unit with Low-Emission Coating

Abstract

The numerical modeling of radiation and convective heat transfer through a double-chamber glass unit was carried out to substantiate the increase in the heat transfer resistance of this unit via the application of low-emission coatings to glass surfaces. In the space between the panes of a window without low-emission coatings, the amount of heat transferred via radiation exceeds the amount of heat transferred via thermal conductivity and convection. The question of the effect of low-emissivity coatings on reducing heat loss through a window has not yet been sufficiently studied. This problem is also not sufficiently reflected in the literature. In this regard, this paper presents the results of numerical simulation aimed at studying the effect of low-emissivity coatings on heat transfer through a double-chamber glass unit. Simulation is carried out by numerically solving a system of equations of fluid dynamics and energy for the air gap and glass. Boundary conditions of the fourth kind are set on the internal surfaces of the chambers, taking into account the radiation and conduction components of the total heat flux emanating from the glass. The results of modeling heat transfer through a glass unit with ordinary glass show that about 60% of the heat is transferred by radiation. Therefore, an effective measure to reduce heat loss through windows is to reduce the radiation component of the total heat flux by applying a low-emissivity coating to the internal surfaces of the glass unit. This allows for the reduction of the overall heat flux (and, accordingly, heat loss to the environment) by 20–34%, depending on the number of glass surfaces with such a coating.

The Thermophysical Aspects of the Transformation of Porous Structures in Versatile Nanostructured Materials

“…Preliminary experiments involving plates constructed from nanostructured aerogels, supplemented with low-emission coatings, corroborate their potential to significantly enhance the energy efficiency of cutting-edge window structures [56]. Concurrently, this approach leads to notable reductions in heat dissipation from buildings to the environment, thereby offering a tangible contribution towards mitigating global warming stemming from the energy sector [57].…”