A DESIGN PROPOSAL FOR A BUILDING INTEGRATED SOLAR THERMAL VERTICAL COLLECTOR (BIST) AS A DYNAMIC SELF-ACTIVATED SHADING DEVICE

The extensive use of glass façades has recently become a design trend in architecture. Several researches on high-performance glazed technologies and systems have being developed, but few of them focus on the exploitation of the surface extension of glazed-facades actively working as a renewable solar energy systems with a passive “defensive” action against overheating toward visual and thermal comfort. BIST (Building Integrated Solar Thermal) systems show great potential for architectural integration of solar energy conversion devices. The paper aims to show a viable way to provide the exploitation of wide transparent surface area in high-rise buildings for solar energy conversion, the reduction of indoor heat gains, the control of visual comfort through a dynamic self-activated shading system, as well as the reduction of primary energy demand. An innovative solar thermal collector integrated in vertical transparent facades’ panels, working as a dynamic shading device, is then proposed. It consists of a water-filled triple-glazed system with a water stream able to exploit the heat absorbed within the window as a preheating device supporting combined space heating/cooling and water heating systems, reducing the building overall energy demand. Opaque shapemorphing 4D-printed smart items are immersed within the water cavity to enhance water solar absorption and pre-heating efficiency. They provide dynamic solar shading against overheating through their self-activation and deactivation when solar rays no more hit the window, enhancing daylight. Adaptive facades and responsive building envelope components, featured by dynamic performance, show greater energy efficiency, being able to deal with contradictory requirements, such as thermal and visual comfort needs. A preliminary study of the system applications highlights high-rise commercial/residential buildings with stable heat water demand as the most suitable building uses and that the integration on East/West façades in warm temperate climates allows higher energy efficiency.