Windows that preheat and cool themselves A European consortium of manufacturers and suppliers is developing a high-performance self-regulating window which looks set to dramatically reduce heat loss from buildings. Climate Change and Environment © CLIMAWINDA CLIMAWINDA is developing an intelligent ventilation window that can preheat and cool itself to minimise energy loss and optimise ventilation. The CLIMAWIN unit works as a natural heat recovery ventilation system in cooler climates and as a daylighting (self-cooling) device in hotter climates. It is targeted at the retrofitting market, but could also suit new build situations. The revolutionary window includes integrated vents for controlled air intake and an integrated PV power system – innovations which cannot be found on existing ventilation systems. It also features air filters, integrated electronics, and wireless communication between windows and rooms. Energy lost by conduction through the CLIMAWIN window is regained from the incoming air, raising its temperature to improve the level of comfort. South-facing windows benefit from a net heat gain making the window, in effect, a passive heat recovery ventilation system. The consortium has made significant progress in developing the CLIMAWIN manufacturing process. Key, bespoke components – including electronics, valves and controllers – are now in manufacture and ready for potential customers to order. In addition, commissioning processes have been automated, and a web/telephone application has been developed that allows for the remote control of vents and blinds from a distance. New window profiles and designs in aluminium clad timber (aluclad), wood and other combinations of materials have been tested and perfected. This has led to both manufacturing partners developing frame profiles specifically for CLIMAWIN, which are currently in production and ready to order. Now, monitoring of the completed window units is taking place at five pilot sites – two in Germany, two in Scandinavia and one in Ireland. The most important test-bed has been installed at the Fraunhofer Institute in Stuttgart, where the window is being monitored on a minute-by-minute basis. Guides to installing, monitoring and commissioning the new windows have been completed and the CLIMAWINDA interim website is up and running. A computer animation explaining the windows is available, and sales brochures have been published in six languages. Homes fitted with CLIMAWIN intelligent windows are expected to benefit from annual energy savings of up to 15 % to 20 % and around 50 % preheating of incoming ventilation air. As a result, homeowners can look forward to improved levels of comfort and indoor air quality together with associated health benefits. Brian O’Brien, CIMAWINDA’s project coordinator, commented: ‘CLIMAWIN is perhaps the most exiting innovation in low energy design since the LED. It combines improvements in energy performance with health and comfort benefits that can’t be found in other ventilation solutions. I’ve no doubt it will go on to become standard issue in the nearly-zero energy buildings (NZEBs) and passive houses of the future.’ Keywords CLIMAWIN, CLIMAWINDA, smart windows, energy efficiency, ventilation, insulation, window profiles
