The development of novel window systems towards low carbon buildings

Buildings are responsible for over 70% of the average city’s greenhouse gas emissions. As the key component of buildings, window serves very important role in architecture. In current energy efficient building practice, windows are considerably less well insulating component than other parts of the building envelope. Therefore improving windows thermal performance is an important issue to develop energy efficiency building design. This research is carried out from the case studies of zero/low carbon buildings, in which windows were found the weakest part of building envelope. Within this work state-of-the-art window glazing types, latest best performing fenestration products in the market and advanced window technologies are reviewed. Vacuum window technology using evacauted tube pannels will be presented in this research work, as well as Thermoelectric (TEC) window system and Thermoelectric power generation window system. The objectives of the development of novel window systems are: (1) to develop the first-of-its-kind window technology using evacuated tube panels, its thermal transmittance (U-value) will be studied; (2) In order to compare U-values data with high performance windows, thermal performance of novel designed Aerogel and argon window system will be investigated; (3) to develop novel window system by combining evacuated tube panels and thermoelectric modules, which is functioned as a heat pump device; (4) to develop window system as a power generation device by interating thermoelectric generator. Novel windows technologies would meet the requirements of the Code for Sustainable Homes and those of commercial buildings. The study on development of novel window systems is carried on from the current window technologies and includes: (1) Computer modelling results show U-values about 0.59 W/m2K for double wall vacuum tube window, 0.61 W/m2K for single wall vacuum tube window. Laboratory measurements are carried out to validate theoretical results. The test results show that 1.0 W/m2K and 1.1 W/m2K for double and single wall vacuum tube window respectively. Economic and environmental assessments are also analysed. (2) Numerical model and laboratory tests have illustrated the U-values of different thickness of aerogel, argon and combination of both filled window. Comparing to standard double glazed window unit with 20mm air gap (U-value of 2.8 W/m2K), the U-value result of 6mm Aerogel-Argon window can be improved by 45% in theory and 30% according to the laboratory measurement results. (3) Advanced glazing will become “Energy Suppliers” as well as “Energy Managers”. Novel design of thermoelectric window system may function as “a heat pump” contributing buildings’ heating load in winter. Laboratory and outdoor tests investigate the amount of heat supply under various voltage regimes and weather conditions. (4) The electric power output of thermoelectric generator device combined with vacuum tube is examined under different experimental thermal conditions. The use of TEM has advantages of its maintainance free and can operate from any heat source. Window unit (sized1m×1m) installed such device can generate electricity approximately 70~180W