Quadruple glazing

Last updated
Standard quadruple glazed window - openable QGU1.jpg
Standard quadruple glazed window - openable
The quadruple glazing, Q-Air, on Deg 8 building in Oslo, Norway (2020). Renovation brings Ug value of 0,29 W/(m K) [R-value 20 Renovation with quadruple-pane in Oslo.jpg
The quadruple glazing, Q-Air, on Deg 8 building in Oslo, Norway (2020). Renovation brings Ug value of 0,29 W/(m K) [R-value 20

Quadruple glazing (quadruple-pane insulating glazing) is a type of insulated glazing comprising four glass panes, commonly equipped with low emissivity coating and insulating gases in the cavities between the glass panes. Quadruple glazing is a subset of multipane (multilayer) glazing systems. Multipane glazing with up to six panes is commercially available. [1]

Contents

Multipane glazing improves thermal comfort (by reducing downdraft convection currents adjacent to the windowpane), and it can reduce greenhouse gas emissions by minimising heating and cooling demand. Quadruple glazing may be required to achieve desired energy efficiency levels in Arctic regions, [2] or to allow for higher glazing ratios in curtain walling without increasing winter heat loss. Quadruple glazing allows building glazing elements to be designed without modulated external sun-shading, given that the low thermal transmittance of having four or more glazing layers enables solar gain to be adequately managed directly by the window glazing itself. [3] In Nordic countries, some existing buildings with triple glazing are being upgraded to glazing with four or more layers. [4]

Features

Measured and clear-sky calculated seasonal dependence of the direct solar energy transmittance in multipane glazing. Quadruple angular dependent diagram.jpg
Measured and clear-sky calculated seasonal dependence of the direct solar energy transmittance in multipane glazing.
Cold downdraught analysis in multipane glazing. Cold downdraught analysis multipane glazing.jpg
Cold downdraught analysis in multipane glazing.

With quadruple glazing, the center-of-panel U-value (Ug) of 0.33 W/(m2K) [R-value 17] is readily achievable. [5] With six-pane glazing, a Ug value as low as 0.24 W/(m2K) [R-value 24] was reported. [1] This brings several advantages, such as:

Energy efficient buildings without modulated sun shading
The desired overall window thermal transmittance value of lower than about 0.4 W/(m2K) is possible without having to depend on modulated external shading. A study by Svendsen et al. showed that at such low window U-values, glazing with moderate solar gain performs comparably to glazing of comparable U-value with variable external shading and high solar gain. [3] This is so because with improved overall U-values, a building's heating demand diminishes, to the point that wintertime solar heat gain alone may be enough to heat the building.


Pronounced seasonal-dependence of the solar gain
Due to incidence-angle-dependent Fresnel reflections, the optical characteristics of multipane glazing, also notably vary seasonally. As the sun's average elevation varies throughout the year, the effective solar gain tends to be meaningfully less in the summer. [1] The effect is also visible to an extent to the naked eye.


Comfort for occupants
When compared to traditional double-pane or triple-pane windows with mechanical or structural shading arrangements, multipane glazing enables easier viewing between indoor and outdoor environments. A low U-value maintains inside glass temperatures at a more uniform level throughout the year. During the winter, downwards convection currents (downdrafts) are very small, thereby enabling people seated near such a multipane window to feel as comfortable adjacent to the window as they would feel if they were seated adjacent to a solid wall. [1] However, occlusion or shading might still be wanted for purposes of privacy.


Nearly zero heating building
In 1995, it was predicted that with a glazing U-value of 0.3 W/(m2K) zero-heating building could be attained. [6] It has also been shown [3] that the heating demand might be decreased to nearly zero for glazed buildings with system U-values as low as 0.3 W/(m2K). Theoretically, in the summer, the remaining cooling demand could be satisfied by photovoltaic generation alone, with the greatest need for cooling nearly coinciding with the strongest sunlight incident on solar panels. [1] However, in practice, temporal lags between cooling demand and the output from solar panels could occur due to factors such as ambient humidity and the need for dehumidification, as well as the thermal inertia of the building and its contents.

Engineering

Peak solar radiation heating induced temperature profile of the triple- and quadruple-pane glazing comprising low-E coatings and argon gas fill. TGU QGU Tplot ANG.png
Peak solar radiation heating induced temperature profile of the triple- and quadruple-pane glazing comprising low-E coatings and argon gas fill.

Multipane glazing is often designed with thinner intermediate glass panes in order to save weight. [7] To prevent intermediate panes from thermal stress cracking it is sometimes required to use heat-strengthened glass. [7] [5] With more than three glass panes, special care must be taken of the spacer and sealant temperatures as intermediate glass panes in contact with these glazing elements can readily exceed design temperature limits of respective materials due to solar radiation (irradiance) heating. [8]

Angle-dependent view through the quad glazing from inside of the Deg 8 building in Oslo. Quadruple angular dependent 2020.jpg
Angle-dependent view through the quad glazing from inside of the Deg 8 building in Oslo.

Solar irradiance heating of intermediate glass panes increases substantially with an increased number of glass panes. [1] [9] Multipane glazing must be carefully designed to account for the expansion of the insulating gases that are placed between the glass layers, because such gaseous expansion becomes an increasingly important consideration as the number of glass panes is increased. Special breather vents, as well as small vents communicating between the layer spaces, can be incorporated in order to manage this glass-bulging effect. [10] [1] Finite element analysis is often used to calculate appropriate glass sheets' strengths. Calculating static equilibrium with thin glass panes used in multipane glazing may involve nonlinear plate mechanics. [11]

Performance

Double-pane windows have been the industry standard for decades. They represent a vast improvement over single-pane windows but the potential for even greater energy savings with more highly insulating windows has been elusive. Recent price reductions in the thin glass used in both smartphones and flat-screen TVs, as well as in the krypton gas used in halogen lights, however, have made it possible to build lighter, high- efficiency quad-pane windows at a lower cost. Researchers from the National Renewable Energy Laboratory evaluated two configurations of Alpen High Performance (an American manufacturer) quad-pane windows at an office building at the Denver Federal Center. Both configurations have the same thickness and a comparable weight as a standard commercial double-pane window—one model uses two layers of film suspended between two panes of standard glass, the other replaces the film with two panes of ultra-thin glass. Researchers found that on average, quad-pane windows saved 24% heating and cooling energy compared with a high-performing double- pane window. For new construction and window replacements, the quad-pane windows have payback between one and six years, depending on climate zone and utility rates. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Window</span> Opening to admit light or air

A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation, or closed to exclude inclement weather. Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts.

A Trombe wall is a massive equator-facing wall that is painted a dark color in order to absorb thermal energy from incident sunlight and covered with a glass on the outside with an insulating air-gap between the wall and the glaze. A Trombe wall is a passive solar building design strategy that adopts the concept of indirect-gain, where sunlight first strikes a solar energy collection surface in contact with a thermal mass of air. The sunlight absorbed by the mass is converted to thermal energy (heat) and then transferred into the living space.

<span class="mw-page-title-main">Passive solar building design</span> Architectural engineering that uses the Suns heat without electric or mechanical systems

In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and electrical devices.

<span class="mw-page-title-main">Thermal mass</span> Use of thermal energy storage in building design

In building design, thermal mass is a property of the matter of a building that requires a flow of heat in order for it to change temperature. In scientific writing the term "heat capacity" is preferred. It is sometimes known as the thermal flywheel effect. The thermal mass of heavy structural elements can be designed to work alongside a construction's lighter thermal resistance components to create energy efficient buildings.

<i>R</i>-value (insulation) Measure of how well an object, per unit of area, resists conductive flow of heat

The R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat, in the context of construction.. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The measure is therefore equally relevant for lowering energy bills for heating in the winter, for cooling in the summer, and for general comfort.

<span class="mw-page-title-main">Window film</span> Film installed on glass surfaces

A window film, sometimes called tint, is a thin laminate film that can be installed on the interior or exterior of glass surfaces in automobiles and boats, and as well as on the interior or exterior of glass in homes and buildings. It is usually made from polyethylene terephthalate (PET), a thermoplastic polymer resin of the polyester family, due to its clarity, tensile strength, dimensional stability, and ability to accept a variety of surface-applied or embedded treatments.

<span class="mw-page-title-main">Low-energy house</span> House designed for reduced energy use

A low-energy house is characterized by an energy-efficient design and technical features which enable it to provide high living standards and comfort with low energy consumption and carbon emissions. Traditional heating and active cooling systems are absent, or their use is secondary. Low-energy buildings may be viewed as examples of sustainable architecture. Low-energy houses often have active and passive solar building design and components, which reduce the house's energy consumption and minimally impact the resident's lifestyle. Throughout the world, companies and non-profit organizations provide guidelines and issue certifications to guarantee the energy performance of buildings and their processes and materials. Certifications include passive house, BBC—Bâtiment Basse Consommation—Effinergie (France), zero-carbon house (UK), and Minergie (Switzerland).

<span class="mw-page-title-main">Passive house</span> Type of house

Passive house is a voluntary standard for energy efficiency in a building, which reduces the building's carbon footprint. Conforming to these standards results in ultra-low energy buildings that require less energy for space heating or cooling. A similar standard, MINERGIE-P, is used in Switzerland. Standards are available for residential properties and several office buildings, schools, kindergartens and a supermarket have also been constructed to the standard. Energy efficiency is not an attachment or supplement to architectural design, but a design process that integrates with architectural design. Although it is generally applied to new buildings, it has also been used for refurbishments.

Storm windows are windows that are mounted outside or inside of the main glass windows of a house. Storm windows exist in North America, but are uncommon in continental Europe, where double, triple or quadruple glazing is prevalent. Storm windows can be made of glass, rigid plastic panels, or flexible plastic sheets; and may be permanently or temporarily mounted. They function similarly to insulated glazing. The term may also refer to a small openable flap found in the side window on light aircraft.

<span class="mw-page-title-main">Architectural glass</span> Building material

Architectural glass is glass that is used as a building material. It is most typically used as transparent glazing material in the building envelope, including windows in the external walls. Glass is also used for internal partitions and as an architectural feature. When used in buildings, glass is often of a safety type, which include reinforced, toughened and laminated glasses.

<span class="mw-page-title-main">Building insulation</span> Material to reduce heat transfer in structures

Building insulation is material used in a building to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation. Often an insulation material will be chosen for its ability to perform several of these functions at once.

<span class="mw-page-title-main">Solar gain</span> Solar energy effect

Solar gain is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total incident solar irradiance and of the ability of any intervening material to transmit or resist the radiation.

Window insulation film is a plastic film which can be applied to glass windows to reduce heat transfer. There are two types in common use designed to reduce heat flow via radiation and convection respectively.

Window insulation reduces heat transfer from one side of a window to the other. The U-value is used to refer to the amount of heat that can pass through a window, called thermal transmittance, with a lower score being better. The U-factor of a window can often be found on the rating label of the window.

<span class="mw-page-title-main">Double-skin facade</span>

The double-skin façade is a system of building consisting of two skins, or façades, placed in such a way that air flows in the intermediate cavity. The ventilation of the cavity can be natural, fan supported or mechanical. Apart from the type of the ventilation inside the cavity, the origin and destination of the air can differ depending mostly on climatic conditions, the use, the location, the occupational hours of the building and the HVAC strategy.

<span class="mw-page-title-main">Glazing (window)</span> Part of a wall or window, made of glass

Glazing, which derives from the Middle English for 'glass', is a part of a wall or window, made of glass. Glazing also describes the work done by a professional "glazier". Glazing is also less commonly used to describe the insertion of ophthalmic lenses into an eyeglass frame.

<span class="mw-page-title-main">Insulated glazing</span> Construction element consisting of at least two glass plates

Insulating glass (IG) consists of two or more glass window panes separated by a space to reduce heat transfer across a part of the building envelope. A window with insulating glass is commonly known as double glazing or a double-paned window, triple glazing or a triple-paned window, or quadruple glazing or a quadruple-paned window, depending upon how many panes of glass are used in its construction.

<span class="mw-page-title-main">Skylight</span> Window in the ceiling-roof

A skylight is a light-permitting structure or window, usually made of transparent or translucent glass, that forms all or part of the roof space of a building for daylighting and ventilation purposes.

<span class="mw-page-title-main">David and Lucile Packard Foundation Headquarters</span> Office in California, United States

The David and Lucile Packard Foundation Headquarters is the corporate headquarters of the David and Lucile Packard Foundation, located in Los Altos, California. The Packard Foundation was created in 1964 by David Packard and his wife Lucile Salter Packard, one of the top 100 grant-making foundations in the United States, with the goals of improving the lives of children, enabling the creative pursuit of science, advancing reproductive health, and conserving and restoring the Earth’s natural systems. The David and Lucile Packard Foundation Headquarters is designed by EHDD to be the largest net zero energy building in California, and it has successfully reduced the energy use by 65% over conventional buildings.

<span class="mw-page-title-main">Zero heating building</span> Building without heating demand

Zero-heating building or nearly zero-heating building (nZHB) is a building having essentially zero heating demand, defined as having heating demand, Q’NH, less than 3 kWh/(m2a). The zero-heating building is intended for use in heating-dominated areas. The purpose of the zero-heating building is to supersede net-zero energy buildings as a way to bring building-related greenhouse gas emissions to zero in the EU. Zero-heating buildings address flawed net-zero energy buildings: the requirement for seasonal energy storage, in some cases poor comfort of living and narrow design options.

References

  1. 1 2 3 4 5 6 7 8 9 10 Kralj, Aleš; Drev, Marija; Žnidaršič, Matjaž; Černe, Boštjan; Hafner, Jože; Jelle, Bjørn Petter (May 2019). "Investigations of 6-pane glazing: Properties and possibilities". Energy and Buildings. 190: 61–68. doi: 10.1016/j.enbuild.2019.02.033 . hdl: 11250/2589488 .
  2. Krick, Benjamin. "Optimum glazing in the regions of Europe considering the embedded energy" (PDF). Passive House Institute. Retrieved 3 May 2019.
  3. 1 2 3 Vanhoutteghem, Lies; Skarning, Gunnlaug Cecilie Jensen; Hviid, Christian Anker; Svendsen, Svend (September 2015). "Impact of façade window design on energy, daylighting and thermal comfort in nearly zero-energy houses" (PDF). Energy and Buildings. 102: 149–156. doi:10.1016/j.enbuild.2015.05.018. S2CID   38055509.
  4. Kristiansen, Øyvind Meyer. "Höegh Eiendom først i Norge med innovativ fasadeløsning". Enova. Retrieved 23 May 2019.
  5. 1 2 Chmúrny, Ivan (January 2016). "Triple or Quadruple Glazing?". Applied Mechanics and Materials. 820: 242–247. doi:10.4028/www.scientific.net/AMM.820.242. S2CID   111693176.
  6. Feist, Wolfgang (1995). Erfahrungen mit Häusern ohne aktives Heizsystem. Darmstadt: IBK-Institut für das Bauen mit Kunststoffen.
  7. 1 2 "Quadruple insulated glass unit". MEM4WIN. Retrieved 16 Feb 2020.
  8. Starman, Bojan; Maček, Andraž; Rus, Primož; Obid, Štefan; Kralj, Aleš; Halilovič, Miroslav (19 February 2020). "Primary Seal Deformation in Multipane Glazing Units". Applied Sciences. 10 (4): 1390. doi: 10.3390/app10041390 .
  9. Grynning, Steinar; Jelle, Bjørn; Gustavsen, Arild; Gao, Tao; Time, Berit (2016). Multilayer Glazing Technologies: Key Performance Parameters and Future Perspectives. Aalborg, Denmark: CLIMA 2016 - Proceedings of the 12th REHVA World Congress, Vol. 2. pp. Article no. 187. Retrieved 3 May 2019.
  10. Anderson, Martin; Simon, Nilsson (2014). "Bulging of Insulating Glass Units - Numerical and Experimental Analysis". TVSM-5000. Lund, Sweden: Lund University.
  11. Halilovič, Miroslav; Maček, Andraž; Mole, Nikolaj; Koc, Pino; Plešnik, Filip; Rus, Primož; Žnidaršič, Matjaž; Kralj, Aleš (1 December 2023). "Accurate determination of the static equilibrium in insulating glass units under climatic loading". Journal of Building Engineering. 80. doi: 10.1016/j.jobe.2023.107955 . hdl: 20.500.12556/RUL-152298 .
  12. https://www.gsa.gov/cdnstatic/Applied_Research/GPG%20048-Findings-Quad%20Pane%20Windows.pdf [ bare URL PDF ]