Transparent Insulation Materials (TIMs) have been developed for application to building facades to reduce heating energy demands of a building. This research investigates the feasibility of TI-applications for high-rise and low-rise office buildings in London, UK, to reduce heating energy demands in winter and reduce overheating problems in summer. The energy performance of these office building models was simulated using an energy simulation package, Environmental Systems Performance-research (ESP-r), for a full calendar year. The simulations were initially performed for the buildings with conventional wall elements, prior to those with TI-systems (TI-walls and TI-glazing) used to replace the conventional wall elements. Surface temperatures of the conventional wall elements and TI-systems, air temperature inside the 20mm wide air gaps in the TI-wall, dry-bulb zone temperature and energy demands required for the office zones were predicted. Peak temperatures of between 50 and 70C were predicted for the internal surface of the TI-systems, which clearly demonstrated the large effect of absorption of solar energy flux by the brick wall mass with an absorptivity of 90% behind the TIM layer. In the office zones, the magnitude of temperature swings during daytime was reduced, as demonstrated by a 10 to 12 hours delay in heat transmission from the external façade to the office zones. Such reduction indicates the overheating problems could be reduced potentially by TI-applications. This research presents the scale and scope of design optimisation of TI-systems with ESP-r simulations, which is a critical process prior to applications to real buildings.Keywords: Transparent Insulation System; temperature profiles; energy simulation; building façades; London climate; energy demand
IntroductionThe installation of opaque insulation with thickness of up to 50cm to building façades to reduce heat loss has been an issue for many building designers due to the resulting reduction of occupied space. The development of Transparent Insulation Materials (TIMs) for application to building façades not only responds to this issue, but also reduces heating energy demands of buildings. TIMs are small-celled honeycomb structures, made of highly transparent films, such as, Corresponding author; Tel: +44(0)1413313864; Fax: +44(0)1413313370 2 polypropylene, polycarbonate, polymethylmethacrylate (PMMA), translucent foam, and aerogels. Depending on the geometrical layout of the materials, TIMS can be classified into four generic types, such as, absorber-parallel, absorberperpendicular, cavity and quasi-homogeneous structures . Each has a unique pattern of solar transmission and physical behaviour. Absorber-parallel and absorber-perpendicular structures, which comprise of multiple glazing elements or transparent plastic films parallel or perpendicular to the absorber surface, result in an increase in optical reflection or transmission. Cavity structures are the combination of absorber-parallel and absorberperpendicular structures. ...