Review
Fenestration of today and tomorrow: A state-of-the-art review and future research opportunities

https://doi.org/10.1016/j.solmat.2011.08.010Get rights and content

Abstract

Fenestration of today is continuously being developed into the fenestration of tomorrow, hence offering a steadily increase of daylight and solar energy utilization and control, and at the same time providing a necessary climate screen with a satisfactory thermal comfort. Within this work a state-of-the-art market review of the best performing fenestration products has been carried out, along with an overview of possible future research opportunities for the fenestration industry. The focus of the market review was low thermal transmittance (U-value). The lowest centre-of-glass Ug-values found was 0.28 and 0.30 W/m2 K, which was from a suspended coating glazing product and an aerogel glazing product, respectively. However, the majority of high performance products found were triple glazed. The lowest frame U-value was 0.61 W/m2 K. Vacuum glazing, smart windows, solar cell glazing, window frames, self-cleaning glazing, low-emissivity coatings and spacers were also reviewed, thus also representing possibilities for controlling and harvesting the solar radiation energy. Currently, vacuum glazing, new spacer materials and solutions, electrochromic windows and aerogel glazing seem to have the largest potential for improving the thermal performance and daylight and solar properties in fenestration products. Aerogel glazing has the lowest potential U-values, ∼0.1 W/m2 K, but requires further work to improve the visible transmittance. Electrochromic vaccum glazing and evacuated aerogel glazing are two vacuum-related solutions, which have a large potential. There may also be opportunities for completely new material innovations, which could revolutionize the fenestration industry.

Highlights

► Review of fenestration of today and tomorrow. ► State-of-the-art market review of the best performing fenestration products. ► Overview of possible future research opportunities for the fenestration industry.

Introduction

Currently, saving energy and carbon emissions is a top priority for buildings and constructions. With up to 60% [1] of the total energy loss of a building coming from its windows, fenestration products have a huge potential to provide large energy savings. Hence, windows with a low thermal transmittance, or U-value, can substantially reduce energy losses and save costs. In recent years building codes have been requiring lower U-values for new windows, e.g. the Norwegian Building Codes recently restricted the U-value for new windows to 1.2 W/m2 K [2], and this trend is set to continue as governments seek to save energy and reduce emissions.

This work aims to cover all main types of fenestration products, including multilayer glazing [3], vacuum glazing [4], [5], frames [1], [6], electrochromic windows [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], solar cell glazing [18], aerogels [19], [20], low-emissivity (low-e) coatings [21], [22] and spacers [23]. However, mechanically operated fenestration parts, e.g. blinds, shades and awnings, are not part of this study. The focus is on low U-values and solar radiation glazing factors. The first part will be a market review of the best performance state-of-the-art fenestration products available now, while the second part is a review of the research and development being performed and a look at the possible research opportunities and the potential products of the future. The definition of solar radiation glazing factors, e.g. visible solar transmittance (Tvis), solar transmittance (Tsol), ultraviolet solar transmittance (Tuv), solar reflectance (Rsol), solar factor (SF), solar material protection factor (SMPF) and solar skin protection factor (SSPF), may be found in Jelle et al. [14] and Jelle and Gustavsen [24]. When calculating U-values the method used must be noted as there can be up to a 3% difference between the North American (ASHRAE) and European (ISO) methods [25]. For further information on thermal transmittance values and their calculation see works by Gustavsen et al. [1], Gustavsen et al. [26] and Blanusa et al. [25]. Earlier review works on advanced glazing technology [27], advances in window technology [28] and zero energy windows [29] are noted.

This work gives many tables with a lot of information, e.g. manufacturers, product names and various properties, both in the main text and in the appendices. Some of these properties are very important and even crucial to the performance of the various products. Hence, the tables provide the readers with valuable information concerning these products. However, unfortunately it is often hard to obtain all the desired information (e.g. product properties) from all the manufacturers. In general, many property values are often not available at the manufacturers' websites or other open information channels, which is then seen as open spaces in the tables within this work. Hopefully, our addressing of this fact could act as an incentive for the manufacturers to state all the important properties of their products at their websites and other information channels, and also as an incentive and reminder for the consumers and users to demand these values from the manufacturers.

Section snippets

Glazing

Glazing can be considered as the most important part of fenestration products. This is especially true when calculating the U-value of a window as the glazing nearly always has the largest area of the constituent parts, and this greatly affects the overall window Uw-value [26]. Presented within this section are examples of multilayer and vacuum glazing. Multilayer glazing is the most popular commercially available glazing and therefore constitutes the majority of products reviewed. The focus

Future research opportunities

This section aims to outline the research currently being doing into improving fenestration products and creating new innovations. Conclusions will also be drawn on what are regarded as the best solutions for the future of the industry.

Conclusions

This work shows that there are many high performance fenestration products on the market today. With regard to glazing the majority are triple glazed multilayer products, but the vacuum glazing and aerogel solutions are growing and produce competitive U-values. Aerogels in particular have a large potential. They are already in use for translucent applications, and if their clarity could be improved for transparent applications, together with large production cost reductions, the aerogels could

Acknowledgements

This work has partly been funded by the Research Council of Norway, Lian Trevarefabrikk and Lawrence Berkeley National Laboratory (LBNL) through the NTNU and SINTEF research project “Improved Window Technologies for Energy Efficient Buildings” (EffWin), and the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, Building Technologies Program of the U.S. Department of Energy under Contract no. DE-AC02-05CH11231.

References (89)

  • C.M. Lampert

    Smart switchable glazing for solar energy and daylight control

    Solar Energy Materials and Solar Cells

    (1998)
  • C.M. Lampert

    Chromogenic smart materials

    Materials Today

    (2004)
  • R. Baetens et al.

    Aerogel insulation for building applications: a state-of-the-art review

    Energy and Buildings

    (2011)
  • J.M. Schultz et al.

    Super insulating aerogel glazing

    Solar Energy Materials and Solar Cells

    (2005)
  • K. Chiba et al.

    Low-emissivity coating of amorphous diamond-like carbon/Ag-alloy multilayer on glass

    Applied Surface Science

    (2005)
  • M. Reidinger et al.

    Low-emitting transparent coatings based on tin doped indiumoxide applied via a sol–gel routine

    Thin Solid Films

    (2009)
  • S.-Y. Song et al.

    Evaluation of inside surface condensation in double glazing window system with insulation spacer: a case study of residential complex

    Building and Environment

    (2007)
  • P. Blanusa et al.

    Comparison between ASHRAE and ISO thermal transmittance calculation methods

    Energy and Buildings

    (2007)
  • M. Del Re et al.

    Study of the optical properties of AlN/ZrN/AlN low-e coating

    Surface and Coatings Technology

    (2004)
  • E. Hammarberg et al.

    Antireflection treatment of low-emitting glazings for energy efficient windows with high visible transmittance

    Thin Solid Films

    (2003)
  • A. Chabas et al.

    Behaviour of self-cleaning glass in urban atmosphere

    Building and Environment

    (2008)
  • K. Guan

    Relationship between photocatalytic activity, hydrophilicity and self-cleaning effect of TiO2/SiO2 films

    Surface and Coatings Technology

    (2005)
  • N.P. Mellott et al.

    Commercial and laboratory prepared titanium dioxide thin films for self-cleaning glasses: photocatalytic performance and chemical durability

    Thin Solid Films

    (2006)
  • A.S. Bahaj et al.

    Potential of emerging glazing technologies for highly glazed buildings in hot climates

    Energy and Buildings

    (2008)
  • M. Reim et al.

    Silica-aerogel granulate—structural, optical and thermal properties

    Journal of Non-Crystalline Solids

    (2004)
  • M. Reim et al.

    Silica aerogel granulate material for thermal insulation and daylighting

    Solar Energy

    (2005)
  • M.M. Farid et al.

    A review on phase change energy storage: materials and applications

    Energy Conversion and Management

    (2004)
  • S.M. Hasnain

    Review on sustainable thermal energy storage technologies, Part I: Heat storage materials and techniques

    Energy Conversion and Management

    (1998)
  • R. Baetens et al.

    Phase change materials for building applications: a state-of-the-art review

    Energy and Buildings

    (2010)
  • A.M. Khudhair et al.

    A review on energy conservation in building applications with thermal storage by latent heat using phase change materials

    Energy Conservation and Management

    (2004)
  • K.A.R. Ismail et al.

    Thermally effective windows with moving phase change material curtains

    Applied Thermal Engineering

    (2001)
  • P.W. Griffiths et al.

    Fabrication of evacuated glazing at low temperature

    Solar Energy

    (1998)
  • Y. Fang et al.

    Low emittance coatings and the thermal performance of vacuum glazing

    Solar Energy

    (2007)
  • H. Manz et al.

    Triple vacuum glazing: heat transfer and basic mechanical design constraints

    Solar Energy

    (2006)
  • S. Papaefthimiou et al.

    Development of electrochromic evacuated advanced glazing

    Energy and Buildings

    (2006)
  • Y. Fang et al.

    Thermal performance analysis of an electrochromic vacuum glazing with low emittance coatings

    Solar Energy

    (2010)
  • A. Jonsson et al.

    Visual and energy performance of switchable windows with antireflection coatings

    Solar Energy

    (2010)
  • R. Prado et al.

    Development of multifunctional sol–gel coatings: anti-reflection coatings with enhanced self-cleaning capacity

    Solar Energy Materials and Solar Cells

    (2010)
  • K. Duer et al.

    Monolithic silica aerogel in superinsulating glazings

    Solar Energy

    (1998)
  • A. Rigacci et al.

    Structural investigation in monolithic silica aerogels and thermal properties

    Journal of Non-Crystalline Solids

    (1998)
  • A. Rigacci et al.

    Improvement of the silica aerogel strengthening process for scaling-up monolithic tile production

    Journal of Non-Crystalline Solids

    (2004)
  • J.M. Schultz et al.

    Evacuated aerogel glazings

    Vacuum

    (2008)
  • R. Baetens et al.

    Vacuum insulation panels for building applications: a review and beyond

    Energy and Buildings

    (2010)
  • R. Baetens et al.

    Gas-filled panels for building applications: a state-of-the-art review

    Energy and Buildings

    (2010)
  • Cited by (438)

    • Environmental durability of soft low-e coatings: A review

      2024, Solar Energy Materials and Solar Cells
    View all citing articles on Scopus
    View full text