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Electrically switchable polymer stabilised broadband infrared reflectors and their potential as smart windows for energy saving in buildings.

Khandelwal H, Loonen RC, Hensen JL, Debije MG, Schenning AP - Sci Rep (2015)

Bottom Line: Simulations predict that a significant amount of energy can be saved on heating, cooling and lighting of buildings in places such as Madrid by using this switchable IR reflector.We have also fabricated a switchable IR reflector which can also generate electricity.These polymer based switchable IR reflectors are of high potential as windows of automobiles and buildings to control interior temperatures and save energy.

View Article: PubMed Central - PubMed

Affiliation: 1] Functional Organic Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven, University of Technology, Den Dolech 2, 5600 MB Eindhoven, the Netherlands [2] Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands.

ABSTRACT
Electrically switchable broadband infrared reflectors that are relatively transparent in the visible region have been fabricated using polymer stabilised cholesteric liquid crystals. The IR reflectors can change their reflection/transmission properties by applying a voltage in response to changes in environmental conditions. Simulations predict that a significant amount of energy can be saved on heating, cooling and lighting of buildings in places such as Madrid by using this switchable IR reflector. We have also fabricated a switchable IR reflector which can also generate electricity. These polymer based switchable IR reflectors are of high potential as windows of automobiles and buildings to control interior temperatures and save energy.

No MeSH data available.


Related in: MedlinePlus

Comparison of energy use intensity for a normal double glazed window (DG), static IR reflector (StIR) and the switchable (responsive) infrared reflector (R-IR) for three different climates.
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f5: Comparison of energy use intensity for a normal double glazed window (DG), static IR reflector (StIR) and the switchable (responsive) infrared reflector (R-IR) for three different climates.

Mentions: Three different climates were chosen to understand the relation between environmental conditions and energy savings in buildings by using a switchable IR reflector: (1) Abu Dhabi, United Arab Emirates (2) Amsterdam, the Netherlands and (3) Madrid, Spain. The results are compared to a reference configuration employing normal double glazing (DG) for a south facing office. We have also compared the results of the switchable IR reflector (R-IR) with the static permanent broadband IR reflector (StIR) in the ‘off’ state. This evaluation demonstrates the potential impact a switchable system may have in comparison to static IR reflectors. The window properties that were used in the simulations were obtained using the calculation methods in the software Optics-5, 2013 (Supplementary Table S2). Our simulations suggest that the impact of switchable infrared reflectors in office buildings depends on the local environmental conditions. In Abu Dhabi, which has warm and sunny climate throughout the year, the application of a switchable IR reflector (R-IR, 178.1 kWh/m2/yr) leads to cooling energy savings of >15% compared to a normal double glazing window (DG, 211.2 kWh/m2/yr). However, in such locations, the demand for cooling is high throughout the year, which makes non-visible solar gains unwanted at all times. Given the current window switching control strategy, the window would be in the transparent state for only 23 hours of the year. Hence, similar energy savings are achieved with static broadband IR reflection (Fig. 5, StIR versus R-IR). In contrast, in the Amsterdam environment the window would be switched from the reflective state to the transmissive state for a considerable amount of time (1684 hours). The simulation results reveal that in heating-dominated climates such as Amsterdam, there is no need for either switchable or static IR reflectors. The decrease in warming of building interiors by solar heat gains would lead to an increase in demand of energy required for heating, offsetting any energy savings for heat rejection in warmer seasons.


Electrically switchable polymer stabilised broadband infrared reflectors and their potential as smart windows for energy saving in buildings.

Khandelwal H, Loonen RC, Hensen JL, Debije MG, Schenning AP - Sci Rep (2015)

Comparison of energy use intensity for a normal double glazed window (DG), static IR reflector (StIR) and the switchable (responsive) infrared reflector (R-IR) for three different climates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487232&req=5

f5: Comparison of energy use intensity for a normal double glazed window (DG), static IR reflector (StIR) and the switchable (responsive) infrared reflector (R-IR) for three different climates.
Mentions: Three different climates were chosen to understand the relation between environmental conditions and energy savings in buildings by using a switchable IR reflector: (1) Abu Dhabi, United Arab Emirates (2) Amsterdam, the Netherlands and (3) Madrid, Spain. The results are compared to a reference configuration employing normal double glazing (DG) for a south facing office. We have also compared the results of the switchable IR reflector (R-IR) with the static permanent broadband IR reflector (StIR) in the ‘off’ state. This evaluation demonstrates the potential impact a switchable system may have in comparison to static IR reflectors. The window properties that were used in the simulations were obtained using the calculation methods in the software Optics-5, 2013 (Supplementary Table S2). Our simulations suggest that the impact of switchable infrared reflectors in office buildings depends on the local environmental conditions. In Abu Dhabi, which has warm and sunny climate throughout the year, the application of a switchable IR reflector (R-IR, 178.1 kWh/m2/yr) leads to cooling energy savings of >15% compared to a normal double glazing window (DG, 211.2 kWh/m2/yr). However, in such locations, the demand for cooling is high throughout the year, which makes non-visible solar gains unwanted at all times. Given the current window switching control strategy, the window would be in the transparent state for only 23 hours of the year. Hence, similar energy savings are achieved with static broadband IR reflection (Fig. 5, StIR versus R-IR). In contrast, in the Amsterdam environment the window would be switched from the reflective state to the transmissive state for a considerable amount of time (1684 hours). The simulation results reveal that in heating-dominated climates such as Amsterdam, there is no need for either switchable or static IR reflectors. The decrease in warming of building interiors by solar heat gains would lead to an increase in demand of energy required for heating, offsetting any energy savings for heat rejection in warmer seasons.

Bottom Line: Simulations predict that a significant amount of energy can be saved on heating, cooling and lighting of buildings in places such as Madrid by using this switchable IR reflector.We have also fabricated a switchable IR reflector which can also generate electricity.These polymer based switchable IR reflectors are of high potential as windows of automobiles and buildings to control interior temperatures and save energy.

View Article: PubMed Central - PubMed

Affiliation: 1] Functional Organic Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven, University of Technology, Den Dolech 2, 5600 MB Eindhoven, the Netherlands [2] Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands.

ABSTRACT
Electrically switchable broadband infrared reflectors that are relatively transparent in the visible region have been fabricated using polymer stabilised cholesteric liquid crystals. The IR reflectors can change their reflection/transmission properties by applying a voltage in response to changes in environmental conditions. Simulations predict that a significant amount of energy can be saved on heating, cooling and lighting of buildings in places such as Madrid by using this switchable IR reflector. We have also fabricated a switchable IR reflector which can also generate electricity. These polymer based switchable IR reflectors are of high potential as windows of automobiles and buildings to control interior temperatures and save energy.

No MeSH data available.


Related in: MedlinePlus