Transparent insulation materials: An overview on past, present and future developments

Abstract

Transparent Insulation (TI) systems are regarded as one of the most promising technologies for providing thermal insulation along with transmission of solar energy. TI systems have a wide range of applications in energy conservation and harnessing solar energy. This paper provides an overview of TI systems and TI materials (TIM), by characterising TI systems on the basis of geometry, material used and general heat losses in these geometrical layouts. Evolution of TI applications is presented with the introduction of new materials. Two new types of TIM (polypropylene and cellulose acetate) are reported in this paper in contrast to previous reviews on TIM. A systematic survey of past literature was carried out to present latest research works and development on TI geometrical layouts and applications. An explicit study of TIM and TI system manufacturers has been carried out to show existing trends in TI applications and geometry. In the last decade, aerogels are most frequently used as TIM for providing insulation and daylighting in buildings. It is concluded that in existing TIM technologies, TI systems incorporating aerogel have the lowest thermal transmittance (U-value) and better solar transmittance (g-value) at lower thickness compared with TI systems incorporating other types of TIM. This paper highlights the availability of TIM geometry with desirable applications and TI systems for energy conservation.

Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System

“…Therefore, in order to utilize the solar selective properties of SATIS in 1D simulation tools, a simplified computational methodology is required. The basis of the developed methodology is the extension of the one-dimensional transient conduction differential equation by the heat source term (Q V ) as defined in Equation (3).…”

“…Alternatively, transparent insulation materials (TIMs) are characterized by good thermal insulation combined with high light transmission and can be used in various shapes and applications [1,2]. The main applications of such systems comprise solar collectors for process heat generation, solar collectors for domestic hot water storage, long-term thermal energy storage, daylighting and space heating systems via facades or roofs [3,4]. When TIMs are used as passive facade heating systems, not only the transmission heat losses can be further reduced, but also additional solar gains can be obtained to compensate for other energy losses (ventilation, windows, etc.)…”

“…This often leads to summer overheating effects when applying TIMs to south-facing facades [1,15,18], which shall be avoided by the solar selective properties of SATIS. In addition, most TIMs are made of glass or plastic [3], which have significantly higher thermal conductivities than the insulating material used for SATIS.…”

Energy Efficiency of a Solar Wall with Transparent Insulation in Polish Climatic Conditions

“…The reduction of excessive solar gains can also be achieved by using appropriate selective absorbers [15][16][17] and thermotropic layers integrated with transparent insulation, which reversibly reduce the total solar energy transmittance, becoming opaque after heating [10]. Works [3,[18][19][20] provide an overview of insulation systems based on transparent materials, as well as the materials which transparent insulations are made of.…”

Thermal performance evaluation of a passive building wall with CO2-filled transparent thermal insulation and paraffin-based PCM

“…To achieve this thermal reduction, the authors had to add an insulation layer with thermal conductivity of 0.035 W/mK and thickness of 20 mm between the catalytic layer and the wall. Paneri et al (2019) described a modular set of TTI system and PCM (GLASSX AG-products). This architectural application considered a cavity filled with inert gas and a cavity with PCM plate (Calcium chloride hexahydrate).…”