Experimental and numerical investigations of the optical and thermal aspects of a PCM-glazed unit

Gowreesunker, B. L., Stankovic, S. B., Tassou, S. A. & Kyriacou, P. A. (2013). Experimental and numerical investigations of the optical and thermal aspects of a PCM-glazed unit. Energy and Buildings, 61, pp. 239-249. doi: 10.1016/j.enbuild.2013.02.032

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Abstract

This paper reports on the thermal and optical characterisation of PCM (phase change material) RT27 using the T-history method and spectrophotometry principles, respectively, and the experimental and numerical performance evaluation of a PCM-glazed unit. Various relationships describing the variations in the extinction, scattering and absorption coefficients within the phase change region were developed, and were validated in a numerical CFD model. The results show that: (i) during rapid phase changes, the transmittance spectra from the PCM are unstable, while under stable conditions visible transmittance values of 90% and 40% are obtained for the liquid and phases, respectively; (ii) the radiation scattering effects are dominant in the solid phase of the PCM, while radiation absorption dominates in the liquid phase; (iii) the optical/radiation performance of PCM can be successfully modelled using the liquid fraction term as the main variable; (iv) the addition of PCM improves the thermal mass of the unit during phase change, but risks of overheating may be a significant factor after the PCM has melted; (v) although the day-lighting aspects of PCM-glazed units are favourable, the change in appearance as the PCM changes phase may be a limiting factor in PCM-glazed units.

Item Type: Article
Subjects: Q Science > QC Physics
T Technology > TH Building construction
Divisions: School of Engineering & Mathematical Sciences > Engineering
URI: http://openaccess.city.ac.uk/id/eprint/2215

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