uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Evaluation of control strategies for different smart window combinations using computer simulations
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
2010 (English)In: Solar Energy, ISSN 0038-092X, Vol. 84, no 1, 1-9 p.Article in journal (Refereed) Published
Abstract [en]

Several studies have shown that the use of switchable windows could lower the energy consumption of buildings. Since the main function of windows is to provide daylight and visual contact with the external world, high visible transmittance is needed. From an energy perspective it is always best to have the windows in their low-transparent state whenever there are cooling needs, but this is generally not preferable from a daylight and visual contact point of view. Therefore a control system, which can be based on user presence, is needed in connection with switchable windows. In this study the heating and cooling needs of the building, using different control mechanisms were evaluated. This was done for different locations and for different combinations of switchable windows, using electrochromic glazing in combination with either low-e or solar control glazing. Four control mechanisms were investigated; one that only optimizes the window to lower the need for heating and cooling, one that assumes that the office is in use during the daytime, one based on user presence and one limiting the perpendicular component of the incident solar irradiation to avoid glare and too strong daylight. The control mechanisms were compared using computer simulations. A simplified approach based on the balance temperature concept was used instead of performing complete building simulations. The results show that an occupancy-based control system is clearly beneficial and also that the best way to combine the panes in the switchable window differs depending on the balance temperature of the building and on the climate. It is also shown that it can be beneficial to have different window combinations for different orientations.

Place, publisher, year, edition, pages
2010. Vol. 84, no 1, 1-9 p.
Keyword [en]
smart windows, energy simulations, control strategies, user presence, solar energy, building simulations
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Engineering Science with specialization in Solid State Physics
URN: urn:nbn:se:uu:diva-110699DOI: 10.1016/j.solener.2009.10.021ISI: 000274082400001OAI: oai:DiVA.org:uu-110699DiVA: diva2:278011
Available from: 2009-11-23 Created: 2009-11-23 Last updated: 2010-12-16Bibliographically approved
In thesis
1. Optical Characterization and Energy Simulation of Glazing for High-Performance Windows
Open this publication in new window or tab >>Optical Characterization and Energy Simulation of Glazing for High-Performance Windows
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Optisk karakterisering och energisimulering av smarta fönster
Abstract [en]

This thesis focuses on one important component of the energy system - the window. Windows are installed in buildings mainly to create visual contact with the surroundings and to let in daylight, and should also be heat and sound insulating. This thesis covers four important aspects of windows: antireflection and switchable coatings, energy simulations and optical measurements.

Energy simulations have been used to compare different windows and also to estimate the performance of smart or switchable windows, whose transmittance can be regulated. The results from this thesis show the potential of the emerging technology of smart windows, not only from a daylight and an energy perspective, but also for comfort and well-being. The importance of a well functioning control system for such windows, is pointed out.

To fulfill all requirements of modern windows, they often have two or more panes. Each glass surface leads to reflection of light and therefore less daylight is transmitted. It is therefore of interest to find ways to increase the transmittance. In this thesis antireflection coatings, similar to those found on eye-glasses and LCD screens, have been investigated. For large area applications such as windows, it is necessary to use techniques which can easily be adapted to large scale manufacturing at low cost. Such a technique is dip-coating in a sol-gel of porous silica. Antireflection coatings have been deposited on glass and plastic materials to study both visual and energy performance and it has been shown that antireflection coatings increase the transmittance of windows without negatively affecting the thermal insulation and the energy efficiency.

Optical measurements are important for quantifying product properties for comparisons and evaluations. It is important that new measurement routines are simple and applicable to standard commercial instruments. Different systematic error sources for optical measurements of patterned light diffusing samples using spectrophotometers with integrating spheres have been investigated and some suggestions are made for how to avoid such errors.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2009. 77 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 692
energy simulations, antireflection coatings, dip-coating, optical measurements, spectrophotometer, integrating spheres, low-e windows, solar control windows, smart windows, control strategies, U value, g-value
National Category
Other Engineering and Technologies
Research subject
Engineering Science
urn:nbn:se:uu:diva-110716 (URN)978-91-554-7667-0 (ISBN)
Public defence
2010-01-08, Polhemssalen, Ångström Laboratory, Uppsala University, 10:15 (English)
Available from: 2009-12-17 Created: 2009-11-23 Last updated: 2009-12-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Jonsson, AndreasRoos, Arne
By organisation
Solid State Physics
In the same journal
Solar Energy
Other Engineering and Technologies not elsewhere specified

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 469 hits
ReferencesLink to record
Permanent link

Direct link