Transmission performances of solar windows exposed to concentrated sunlight

Application of phase change material (PCM) in the glazing structure can improve its thermal performance by enhancing its thermal energy storage capacity. In this study, the effect of thermophysical parameters of PCM on thermal performance of a PCM-filled double-glazing unit was investigated. The results show that the temperature time lag of the PCM-filled double-glazing unit increases and the temperature decrement factor decreases with the increase of density, thermal conductivity, specific heat capacity, latent heat, and melting temperature of PCM. Increasing density, latent heat, and melting temperature of PCM are effective to enhance the thermal performance of PCM-filled double-glazed units; however, enhancing thermal conductivity and specific heat capacity are ineffective when thermal conductivity is beyond 2.1 W/(m•K) and specific heat capacity is <4460 J/(kg•K).

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“…The interface reflectances are calculated based on Fresnel's relations (Wang et al, 2014(Wang et al, , 2013(Wang et al, , 2015Dai et al, 2014) as…”

Section: Fig2 Layout Of Double-glazing Unit Filled With Pcmmentioning

confidence: 99%

Thermal performance of a PCM-filled double-glazing unit with different thermophysical parameters of PCM

Zheng

et al. 2016

Solar Energy

120

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“…Dai et al [85] studied an integrated sunlight transfer model that was constructed by a dish concentrator connected to convex window. The performance of window transmission was also investigated by Monte Carlo ray tracing (MCRTM) approach.…”

Section: Fig 45mentioning

confidence: 99%

“…The light reaches at aperture and then centered on dish. When the light hits the window, then a part of the light reflects, the part is absorbed, and the part is transmitted to the receiver cavity [85]. Concentrated light effects depend on geometry, tracking error in dish and slope errors.…”

Section: Fig 45mentioning

confidence: 99%

“…Semi-Minor axis and Window Thickness) on transmission performance is negligible. The geometry of window is mostly determined by the requirements of mechanical strength [85]. The absorption coefficient and refractive index of sapphire are higher than the quartz glass index, and the transmissibility of the sapphire window is about 12.0% less than quartz glass window.…”

Section: Fig 45mentioning

confidence: 99%

“…The input angle between incoming sunlight and normal window direction can be increased by increasing the inclination errors and the errors in the tracking angle. They have shown that the slope error reduction and the tracking error angle are useful for improving the transmission characteristics of the solar window [85].…”

Section: Fig 45mentioning

confidence: 99%

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Building integrated solar concentrating systems: A review

Xuan

Akram

et al. 2020

Applied Energy

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In the building sector, concerns towards the vast energy consumption has promoted the development of renewable energy technologies. In this regards, the solar concentration devices show a promising concept for building applications. However, the solar concentrators for application in buildings have many restrictions, which are different from the traditional solar concentrators. The main objective of this paper is to present a concise review on the building integrated concentrating devices, that have their own characteristics and multiple functions. This paper made a classification based on device's functions, i.e. building integrated concentrated photovoltaic systems (BICPV), building integrated concentrating solar thermal (BICST) and building integrated concentrating solar daylighting (BICSD) and the combination of functions, i.e. BICPV/T, BICPV/D, BICST/D and BICPV/T/D. At the same time, this paper presented an elaborate introduction of the demands, types and applications of the building integrated concentrating devices and prospects/ directions/ policies about these technologies around the world. The review would provide important information for the actual engineering of building integrated concentrating devices.

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Investigations on thermal and optical performances of a glazing roof with PCM layer

Liu

et al. 2017

Int J Energy Res

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Summary The thermal and optical performances of a roof in a building containing phase change material (PCM) were investigated in this paper. The glazing roof model consists of two layers of glass and one layer of PCM. The purpose of filling the roof structure with PCM is to utilize the solar energy efficiently. The effectiveness of thermal and optical performances of the roof PCM system was determined by analyzing the heat flux and temperature at the indoor surface with different absorption coefficients and refractive index of PCM in solid and liquid states. The results show that the absorption coefficients and refractive index of solid and liquid PCMs have both effects on thermal performance in the roof PCM system. Of all the thermal performances, the effect on internal temperature, temperature lag, and total transmitted energy is smaller and the effect on solar transmittance and transmitted solar energy is bigger. The absorption coefficients have the opposite effect with the refractive index on interior temperature lag. Considering the indoor daylight, increasing the refractive index and absorption coefficient of liquid PCM is a better method to better the thermal performance of a roof PCM system. Copyright © 2017 John Wiley & Sons, Ltd.

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Transmission performances of solar windows exposed to concentrated sunlight

Cited by 21 publications

References 17 publications

Thermal performance of a PCM-filled double-glazing unit with different thermophysical parameters of PCM

Thermal performance of a PCM-filled double-glazing unit with different thermophysical parameters of PCM

Building integrated solar concentrating systems: A review

Investigations on thermal and optical performances of a glazing roof with PCM layer

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