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Smart, lightweight, cost-effective and energy efficient windows based on novel material combinations

Final Report Summary - WINSMART (Smart, lightweight, cost-effective and energy efficient windows based on novel material combinations)

Executive Summary:
WINSMART is an inter-European research and development project aiming at creating the windows of the future - low U-value, fully sustainable, lightweight, Smart Windows – by combining vacuum insulation glazing (VIG) with suitable optical transmission control schemes. The project is a co-operation between eight recognized European partners – all experts within their respective fields – and is supported by the European Commission through FP7. The project ended September 2016.

The WINSMART project took a three-way approach to developing the window of the future by targeting significant technological advancements within both glazing production technology, frame manufacturing, and optical control mechanisms.

A cornerstone of the WINSMART project was to make use of vacuum to produce thin, lightweight glazing with very low u-values. The WINSMART project succeeded in developing a new production technology for vacuum insulation glazing (VIG) by laser welding glass panes together in vacuum to achieve flexible, lightweight, highly insulating, and thin glazing for the WINSMART window. The welding together of the VIG in vacuum eliminates the use of the pump-out-valve present on current state-of-the-art VIGs.

The special geometry of the developed WINSMART vacuum glazing required the design and development of a unique sash and frame. This frame should match the super insulating nature of the VIG. The WINSMART sash and frame solution consists of a compartmented 3D printed shell which can be filled up with insulation material according to preferences. 3D-printer technology was chosen to allow more degrees of freedom in the development phase. For minimizing the WINSMART window U-value, the sash and frame was filled with highly insulating aerogel material.

Last but not least, WINSMART developed and incorporated optical transmission control technologies into the glazing. Substantially improved indoor environment can be gained by incorporation of smart optical transmission control technologies into windows to avoid overheating of buildings. Currently, Smart window technologies are divided into three broad categories: chromic, liquid crystals and suspended particle devices. WINSMART significantly advanced developments within photochromic and electrochromic materials technology. In addition, Winsmart developed a procedure for integration of Microshade™ solar-shading technology with the developed vacuum insulated glazing.

Project Context and Objectives:
Currently, saving energy and reducing carbon emission are top priorities for buildings and the construction industry. With up to 60 % of the total building energy loss coming from windows the potential for providing large energy savings and substantial reductions in greenhouse gases deriving from buildings, is huge. Highly insulating windows with a low U-value can substantially reduce energy losses and save costs. In recent years, national building codes in many European countries have been requiring lower U-values for new windows, down to around 1.2 W/m2K, and this trend is expected to spread around Europe. This is especially so in the context of the Energy Performance of Buildings Directive (EPBD 2010/31/EU) published in June 2010. The directive states that EU member states shall ensure that by the end of 2020, all new buildings are nearly zero energy buildings. As the weak point (insulation wise) of the building envelope, windows and window development have a huge part to play in reaching the objectives of the EPBD.

The overarching objectives for the WINSMART project have been to: (i) Develop the enabling technologies for realisation and eventual production of a revolutionary, low U-value, fully sustainable, lightweight Smart Window by combining vacuum insulation glazing with suitable optical transmission control schemes. (ii) Up-scale and synergistically combine the production technologies for vacuum insulation glazing and optical transmission control in different, selected configurations. (iii) Rigorously test and validate the developed solution combinations. (iv) Deliver the “best case design blueprint” for a new generation of lightweight, durable and energy efficient Smart Windows for the future with proven substantial impact on the energy performance of buildings.

Project Results:
The overarching project objectives have been fulfilled and all project deliverables have been concluded. The main project results were:

• Development of the flexible VIG edge seal technology by anodic bonding. The developed samples represent the worlds largest ever specimens produced by anodic bonding.
• Production of a VIG with a U-value < 0.48 W/m2K.
• Development of the necessary technology for the production of a photochromic prototype device – the worlds first photochromic single layer window pane with multi-layered structure.
• Development of an electrochromic prototype device with redox electrolyte offering high optical contrast.
• Development of a highly insulating sash and frame to fit the developed VIG edge seal solution.
• Construction and testing of a demonstrator window having a tested U-value of 0.53 W/m2K incorporating the developed technologies with the potential to reach 0.3 W/m2K during commercial optimization such as diminishing the width of the metal foil in the VIG.
• Life cycle analysis report evaluating sustainability aspects.
• Dissemination activities such as scientific writing (4 peer reviewed publications), conference and workshop presentations (24), newspaper articles, trade fair participation (GlassTech, World Sustainable Energy Days, Building Green).

Six commercially exploitable results were identified in the project:

1. New edge seal solution for Vacuum Insulation Glazing
2. Photochromic device
3. Electrochromic device with redox electrolyte
4. New materials for counter electrodes
5. New design for sash and frame
6. Enhanced manufacturing process for Microshade™

Of these, one (#6) progressed to the level of full commercialization (Technology Readiness Level (TRL) 9). The others progressed to TRL 4-5 i.e. prototype level.

Potential Impact:
The WINSMART window has a large potential impact on reducing carbon emissions and energy savings in the European building sector. WINSMART technologies enables the construction of windows with U-values down to 0.3 W/m2K at a 50% weight reduction compared to state-of-the-art technology. It is clear that with up to 60% of the total energy loss from buildings coming from windows, the potential impact from window solutions like the WINSMART project on energy savings is enormous both for Europe as a whole and for the individual consumer.

The economic and environmental sustainability of the Winsmart window system was evaluated by LCC and LCA analysis. The pay-back time of the window investment in a scenario where existing windows in a building (U-value 2.50 W/m2K) were exchanged with Winsmart windows (0.3 W/m2K) was calculated to 8 years in a Northern European scenario based on the real costs of saved energy resulting from the low U-value. Additionally there are potentially huge environmental benefits to be gained as well by using Winsmart windows. The environmental impacts of the Winsmart window solution was evaluated by Life Cycle Analysis (LCA) and compared to current state of the art. The results showed that the Winsmart window resulted in a 50% reduction in Green House Gas (GHG) emissions and Global Warming Potential (GWP) over a 25 years period when comparing to a state-of-the-art window in a Northern European scenario. Although the Winsmart window had a slightly higher Global Warming Potential (GWP) than the state of the art reference for the production phase (Cradle-to-gate) – the difference was paid back already after 2 years when considering the use phase, due to the energy savings and lower Green House Gas (GHG) emissions gained by the low U-value.

List of Websites:
Winsmart Coordinator:
Dr. Niels Morsing
Dansih Technological Institute
Gregersensvej 3
DK-2630 Taastrup
Mob: +45 7220 2312