scholarly journals Smart window for angular selective filtering of solar radiation

2019 ◽  
Vol 124 ◽  
pp. 01002
Author(s):  
R. Zakirullin ◽  
I. Odenbakh
Keyword(s):  
Solar Radiation ◽  
Light Transmission ◽  
Slope Angle ◽  
Optical Filter ◽  
Angular Range ◽  
Smart Window ◽  
New Approach ◽  
Direct Radiation ◽  
Daily Change ◽  
Parallel Strips

A new approach to angular selective filtering of the solar radiation without using the sunlight redistribution devices is proposed. Parallel strips of chromogenic materials on two surfaces of the pane(s) form an optical filter having angular selective light transmission. Clarified methods to calculate the optimum slope angle of the strips on the pane(s), their widths and relative position on two surfaces considering the seasonal and daily change in the solar radiation, the location of the building and the window’s azimuth are presented. Such a smart window blocks the direct radiation in a preset angular range and transmits the scattered and reflected radiation that is provides comfortable daylighting indoors.

A Smart Window for Angular Selective Filtering of Direct Solar Radiation

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Rustam S. Zakirullin
Keyword(s):  
Solar Radiation ◽  
Light Transmission ◽  
Slope Angle ◽  
Optical Filter ◽  
Time Of Day ◽  
Direct Solar Radiation ◽  
Smart Window ◽  
Smart Windows ◽  
Solar Radiation Intensity ◽  
Parallel Strips

Thin-film grating coatings are proposed for smart windows to angular selective filtering of solar radiation. The gratings are formed by absorptive, reflective, or scattering parallel strips (made of chromogenic or other materials) alternating with directionally transmissive strips (untreated surface of pure glass) on two surfaces of the window pane(s). The smart window with grating optical filter has angular selective light transmission and partially or completely blocks the direct solar radiation in a preset angular range and transmits the scattered and reflected radiation without using the daylight redistribution devices. The results of numerical simulation and experimental confirmation of optimum slope angle of the strips on the pane(s), their widths, and relative position on two surfaces to minimize the directional light transmission of the window at the preset date and time of day taking into account orientation of the window to the cardinal, the latitude of the building, and the seasonal and daily distribution of the solar radiation intensity are demonstrated.

A Study on the Different Components of Solar Radiation in Order to Calculate the Optimum Solar Angles and the Gain of Solar Energy Using Genetic Algorithm

2011 ◽  
Author(s):  
P. Talebizadeh ◽  
M. A. Mehrabian ◽  
M. Abdolzadeh
Keyword(s):  
Genetic Algorithm ◽  
Solar Radiation ◽  
Solar Energy ◽  
Slope Angle ◽  
Computation Time ◽  
Azimuth Angle ◽  
Energy Gain ◽  
Direct Radiation ◽  
Save Energy ◽  
Independent Parameters

In this paper, the genetic algorithm is applied to calculate the optimum slope and surface azimuth angles for receiving maximum solar radiation in an area of Iran. Different components of solar radiation are employed in order to calculate the solar optimum angles. At first, the optimum angels are calculated in different days, months, seasons and the whole year and the energy gain is calculated. Then, this process is redone with considering different component of solar radiation. These conditions are direct, direct and ground reflect, direct and diffuse, and all together. The results showed that maximum solar energy in different days of a year is received at different slope angels; however, the optimum azimuth angle is zero for receiving maximum solar energy. In addition, adjusting the collector at the daily optimum slope angle can only save energy very little compared with the case at the monthly optimum slope angle. Furthermore, the results of analyzing different components of solar radiation show that the optimum slope angles are mostly related to the direct radiation, however, the gain of energy is considerably different. It is worth mentioning that genetic algorithm is more effective when the independent parameters are numerous and in this case, the optimum angles are easily determined, however, the computation time is reduced.

scholarly journals Diffraction in grating optical filters with angular-selective light transmission

2020 ◽  
Vol 44 (3) ◽  
pp. 343-351 ◽  
Author(s):  
R.S. Zakirullin
Keyword(s):  
Light Transmission ◽  
Incidence Angle ◽  
Slope Angle ◽  
Optical Filters ◽  
Time Of Day ◽  
Light Transmittance ◽  
Smart Windows ◽  
Input And Output ◽  
Parallel Strips ◽  
Complex Movement

The effect of diffraction on the directional light transmittance of grating optical filters designed for smart windows is studied. The filter has an angular selective light transmission due to two thin-film gratings formed by "non-transmissive" (absorptive, reflective or scattering) parallel strips on the surfaces of a single or double glazed window. Methods are considered for calculating the op-timal slope angle of two filter’s gratings, their relative position on the opposite window surfaces and the widths of the strips of both gratings to minimize light transmission on a specific date and time of day for a given latitude and longitude of the building and azimuth of the window. A meth-od has been developed for calculating the diffraction at the input and output gratings of the filter with regard for a complex movement of the Sun relative to the window and a corresponding change in the incidence angle of the solar beams on the gratings. To evaluate a decrease in the light transmittance of the filter due to diffraction, an additional factor is introduced into the calcu-lation equation. Geometric parameters of the filters and diffraction are calculated. The values of the diffraction factor are 0.9999992 and 0.9999998 for single or double glazed windows, respec-tively, i.e., the influence of diffraction on the light transmittance of the grating filter can be ne-glected.

Daylighting Dynamic Control by Smart Window with Grating Optical Filter

2021 ◽  
pp. 27-32
Author(s):  
Irina A. Odenbakh
Keyword(s):  
Solar Radiation ◽  
Dynamic Control ◽  
Optical Filter ◽  
Thermal Conditions ◽  
Working Hours ◽  
Time Of Day ◽  
Light Transmittance ◽  
The Sun ◽  
Smart Window ◽  
Solar Radiation Intensity

A smart window with a novel grating optical filter is proposed, which supplies dynamic daily and annual control of window transmission without the use of blinds and similar devices. The filter attenuates direct solar radiation, letting in diffused and reflected radiation, thus creating more comfortable conditions for daylighting, insolation, and sun protection in rooms. A method for calculating the grating filter is changed and numerical modelling is conducted to show the capabilities of the new method of dynamic control of transmission. The optimal geometric parameters of the filter for a single-glazed smart window at a given azimuth of the window orientation are determined. The hourly values of the light transmittance of the filter during daylighting hours are calculated for the 15th day of each month from April to September, and the theoretical angular characteristics of the transmission of the filter, corrected for reflection and absorption, are constructed. The average monthly values of the theoretical and corrected light transmittance of a smart window are obtained, based on the results of calculations every hour compared to the time of day when the azimuths of the Sun and the window are equal. It is shown that the smart window with the built-in grating optical filter provides the minimum transmission at a given time of the day, taking into account the azimuth of the window, the geographic coordinates of the building, the seasonal and daily distribution of the solar radiation intensity on the calculated day of the year, and in the rest of the time, with the most demanded protection from solar radiation, the filter functions within acceptable limits. It is stated that the smart window with the built-in optical filter is most suitable for rooms with a long stay of people during daylight hours that is for office, educational, industrial, etc. rooms, in order to provide comfortable daylighting and the required insolation and thermal conditions during working hours.

scholarly journals Manipulation of light transmission from stable magnetic microrods formed by the alignment of magnetic nanoparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2390-2396
Author(s):  
Yoon Ji Seo ◽  
Hyung Gyu Lee ◽  
Jun Seok Yang ◽  
Hwanyeop Jeong ◽  
Jeonghun Han ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Light Transmission ◽  
Smart Window ◽  
Light Valve

Magnetic microrods were synthesised from magnetic nanoparticles by alignment using a magnetic field. The transparency difference was maximised and the anisotropic features of the rods were used as a light valve to control the transparency of a smart window.

scholarly journals Characteristics of solar radiation at Xiaotang, in the northern marginal zone of the Taklimakan Desert

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12373
Author(s):  
Lili Jin ◽  
Sasa Zhou ◽  
Qing He ◽  
Alim Abbas
Keyword(s):  
Solar Radiation ◽  
Scattered Radiation ◽  
Weather Conditions ◽  
Taklimakan Desert ◽  
Observation Data ◽  
Total Radiation ◽  
Direct Radiation ◽  
Northern Margin ◽  
Monthly Total ◽  
Atmospheric Transmittance

The characteristics of solar radiation and the influence of sand and dust on solar radiation in the northern margin of Taklimakan Desert were analyzed using radiation observation data from 2018. The results showed that the annual total radiation, direct radiation, and scattered radiation at Xiaotang were 5,781.8, 2,337.9, and 3,323.8 MJ m−2, respectively. The maximum monthly total radiation, direct radiation, and scattered radiation were observed in July (679.8 MJ m−2), August (317.3 MJ m−2), and May (455.7 MJ m−2), respectively. The aerosol optical depth corresponded well with the scattered radiation, and the maximum value was in May. Further analysis showed a significant correlation between the total radiation and solar height angle under different weather conditions. Under the same solar height angle, total radiation was higher during clear days but lower on sandstorm days. Calculation of atmospheric transmittance showed that the average atmospheric transmittance on a clear day was 0.67; on sand-and-dust days, it was 0.46. When the atmospheric transmittance was 0.5, the increase in scattering radiation by aerosol in the air began to decrease. Probability analysis of radiation indicated the following probabilities of total radiation <500 W m−2 occurring on clear, floating-dust, blowing-sand, and sandstorm days: 67.1%, 76.3%, 76.1%, and 91.8%, respectively. Dust had the greatest influence on direct radiation; the probabilities of direct radiation <200 W m−2occurring on clear, floating-dust, blowing-sand, and sandstorm days were 44.5%, 93.5%, 91.3%, and 100%, respectively, whereas those of scattered radiation <600 W m−2were 100%, 99.1%, 98.1%, and 100%, respectively. Therefore, the presence of dust in the air will reduce scattered radiation.

scholarly journals Preparation and Properties of Thermoresponsive P(N-Isopropylacrylamide-co-butylacrylate) Hydrogel Materials for Smart Windows

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Jae-Hyung Park ◽  
Ji-Won Jang ◽  
Jae-Hak Sim ◽  
Il-Jin Kim ◽  
Dong-Jin Lee ◽  
...  
Keyword(s):  
Light Transmission ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Light Transmittance ◽  
Solar Light ◽  
Solution Temperature ◽  
Smart Window ◽  
Thermoresponsive Polymers ◽  
Smart Windows ◽  
Hydrogel Films

Thermoresponsive polymers that exhibit phase transition in response to temperature change can be used as material for smart windows because they can control solar light transmission depending on the outside temperature. The development of thermoresponsive polymers for a smart window that can be used over a wide temperature range is required. Therefore, to obtain smart window materials that can be used at various temperatures, three-dimensional thermoresponsive P(NIPAm-co-BA) hydrogels were prepared by free radical polymerization from main monomer N-isopropylacrylamide, comonomer butyl acrylate, and crosslinking agent N,N′-methylenebisacrylamide (MBAm) in this study. This study examined the effect of BA content on the lower critical solution temperature (LCST) and the solar light transmittance of crosslinked P(NIPAm-co-BA) hydrogel films. The LCST of hydrogel films was found to be significantly decreased from 34.3 to 29.5°C with increasing BA content from 0 to 20 mol%. It was found that the transparent films at T=25°C (T<LCST) were converted to translucent films at a higher temperature (T=45°C) (T>LCST). These results suggested that the crosslinked P(NIPAm-co-BA) hydrogel materials prepared in this study could have high potential for application in smart window materials.

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