The Infra-red Spectra of Complex Molecules.

Double-layer nanoparticle-based coatings for efficient terrestrial radiative cooling

From the thermal point of view, windows represent the weak link between the internal and external ambients of a room. In cold climates, they are responsible for 10–25% of the heat lost from the heated ambient to the external atmosphere. In hot climates, the excessive solar radiation entering the internal ambient through the windows leads to increasing the cooling load of the refrigeration system. The use of absorbing gases filling the gap between glass sheets appears to be an alternative solution for thermally insulated glass windows. The other options one may incorporate filling materials such as silica aerogel or a PCM. In this work, a comparison between the thermal efficiency of two glass windows one filled with an absorbing gas and the other with a PCM and exposed to solar radiation in a hot climate is done. To model double glass window filled with infrared absorbing gases, a CW real gas model is used. A radiative convective conductive model and a radiative conductive model were investigated. Three mixtures of gases were used; a strongly absorbing gas mixture, an intermediate absorbing gas mixture and a transparent to infrared radiation mixture. To model the double glass window filled with a PCM, a relatively simple and effective radiation conduction one dimensional formulation is used. Heat transfer through the window is calculated and the total heat gain coefficients are compared and discussed.

Comparison between PCM filled glass windows and absorbing gas filled windows

Solar energy materials for thermal applications: A primer

A comparative study of naturally ventilated and gas filled windows for hot climates

Transparent thermal insulation with infrared-absorbing gases

We investigate the radiative heat transfer between blackbody-like surfaces confining an infrared-absorbing gas layer. Spectrophotometric measurements on selected gases lead us to optimized compositions with sulfur hexafluoride, propyne, and different freons. Theoretically, the gas is able to diminish the radiative heat flux across a 1 cm thick slab by a factor - 0.7 in comparison with the case of a non-absorbing medium. Infrared-absorbing gases seem to offer interesting possibilities for improved transparent thermal insulation of windows.

J. Karlsson

Papers

Transparent thermal insulation with infrared-absorbing gases

Transparent Thermal Insulation With Infrared-Absorbing Gases