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Title: A novel translucent insulation material (TIM) for daylighting with low thermal transmittance
Author: Paneri, Anshul
ISNI:       0000 0004 7655 5803
Awarding Body: Glasgow Caledonian University
Current Institution: Glasgow Caledonian University
Date of Award: 2018
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Transparent/Translucent insulation materials (TIM) are regarded as one of the most promising technologies for providing thermal insulation along with transmission of solar radiations. This ability of TIM grants them an exceptional advantage over conventional materials for harnessing solar energy in a wide range of applications such as window glazings, transparent/translucent walls, roof cover systems, solar water heaters and other solar applications (Wong et al., 2007). TIMs have shown plenty of potential in harnessing solar energy and provide thermal insulation but are yet to be commercialised on a large scale. Only a few manufacturers have taken a bold step of using TIM to create transparent insulation (TI) systems for solar applications. The manufacturing complexities have discouraged manufacturers to produce TIM subsequently slowing down the commercialisation of this technology. Considering the factors associated with the practical realisation of TIM, this research aims to develop a novel TIM geometry for TI systems. The primary objective of this research was to investigate a new geometrical layout for TIM, produce the TIM and validate it with experimental measurements for optical and thermal properties. A systematic survey of past literature was conducted to establish a deep understanding of TIM. The study provided an overview on TIM, by characterising TIM on the basis of geometry, the material used and general heat losses in these geometrical layouts. An explicit study of TIM and TI system manufacturers has been carried out to show existing trends in TI applications and geometry. It was concluded that in existing TIM technologies, aerogels are the best TIM because of their high optical transparency and very low thermal conductivity. However, manufacturing of silica aerogels is a complicated and expensive procedure, where production of large crack-free monolithic silica aerogels is not straightforward in comparison to granular silica aerogels. Additionally, these materials are very fragile to use alone and thus need a protective cover. The current research trends observed in the systematic survey presents the enhancement of insulating property of polymers by adding lower thermal conductivity materials in the polymer during production. On the basis of these findings, it was concluded to cast a novel composite polymer by incorporating granular silica aerogels in the polymer to protect the fragile structure of silica aerogels while enhancing the insulating property of the polymer. Enova aerogel impregnated polyurethane composite samples with increasing silica aerogel percentage were prepared successfully. The impact of adding aerogels in polyurethane was demonstrated with the help of experimental measurements of optical and thermal properties of the prepared samples. The thermal conductivity measurements provided affirmation of enhancement in the thermal insulation properties with the addition of Enova aerogels in polyurethane. The results showed a 7.8% reduction in the thermal conductivity with the addition of 2.73% Enova aerogel in a polyurethane matrix. The optical measurements exhibited no drastic reduction in the total solar energy transmission with the addition of aerogels in the polyurethane. On the other hand, there is a significant improvement in the protection factors with the addition of Enova aerogels. The solar material protection factor (SMPF) has improved by 158.3%, and solar skin protection factor (SSPF) has improved by 39.13% with the addition of 2.73% Enova aerogel in a polyurethane matrix. Aerogel impregnated polyurethane samples with bigger granular silica aerogels (Lumira) were also prepared. However, more significant size of these aerogels made it impossible to suspend them homogeneously in the polyurethane resin. Additionally, the cured samples had many cracks in places where aerogels were present. To understand the effect of these cracks in the cured samples thermal conductivity measurements were conducted, which provided a better understanding of the crack occurrence. The thermal conductivity measurements from these samples were then used to compare the impact of the Lumira aerogels arrangement with the Enova aerogels arrangement in polyurethane samples. This research project contributed to knowledge in five ways. Firstly, the successful impregnation of Enova aerogel in polyurethane provides a novel TIM composite. Secondly, the novel TIM with lower thermal conductivity is beneficial for TI structures. Furthermore, it presents possibilities of a significant enhancement in thermal insulation when the percentage of Enova aerogel is increased further than the presented value. The substantial reduction in thermal conductivity due to the arrangement of Lumira aerogels in polyurethane encourages further research to develop a crack-free sample. Finally, the optical and thermal performance of the Enova aerogel impregnated polyurethane samples exhibit a novel composite with reduced thermal transmittance and good total solar energy transmittance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available