Sol, CWO;
Schläfer, J;
Parkin, I;
Papakonstantinou, I;
(2018)
Mitigation of hysteresis due to a pseudo-photochromic effect in thermochromic smart window coatings.
Scientific Reports
, 8
, Article 13249. 10.1038/s41598-018-31519-x.
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Abstract
The aim of thermochromic window coatings is to reduce the energy consumption in the built environment by passively switching between a high solar transmitting state at low temperatures and low solar transmitting state at high temperatures. Previous studies have highlighted the negative impact of phase transition hysteresis on the performance of refection based thermochromic flms. However in the literature, the best reported results have depended on vanadium dioxide nanoparticle composites and anti-refective structures that modulate light via changes in absorption rather than refection. In light of these factors, this work aims to demonstrate theoretically, how the efects of phase transition hysteresis and gradient difer between absorbing and non-absorbing thermochromic flms. To quantify and compare the performance of flms with diferent transition characteristics, we defne a metric based on the varying net energy fux through the window over the course of a year, including thermal energy re-radiated into the building from the flm. Specifcally, and importantly for the feld, we demonstrate that a pseudo-photochromic efect in absorbing thermochromic flms mitigates the detrimental efects of phase transition hysteresis and gradient that have been reported for refection based thermochromic flms. We fnd that for moderate hysteresis widths of 15°C, the performance of the non-absorbing case drops to ~60% of its initial value whilst the performance of the absorbing flm only drops to ~95%. As a result we fnd that the absorbing case outperforms the nonabsorbing case when hysteresis widths are greater than 8°C.
| Type: | Article |
|---|---|
| Title: | Mitigation of hysteresis due to a pseudo-photochromic effect in thermochromic smart window coatings |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/s41598-018-31519-x |
| Publisher version: | http://dx.doi.org/10.1038/s41598-018-31519-x |
| Language: | English |
| Additional information: | This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10055619 |
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