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Title: Passive seasonally responsive thermal actuators for dynamic building envelopes
Author: Leung, C.
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2014
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It is desirable for a glazed façade to have a variable performance to moderate a building’s energy-balance from seasonal variations in solar gains (Davies, 1981). A novel actuator mechanism is developed that self-regulates a façade by physically reconfiguring its movable elements into different environmental control functions. Its practical feasibility is explored with a proprietary thermal actuator that exploits the expansion of wax during melting from its absorption of heat energy. This provides a means to operate a mechanism solely by its response to passive energy exchanges given prevailing weather conditions. An advance is needed for thermal actuators to respond differently to the seasonal intensity of sunlight. A means to overcome this obstacle is explored through the possibility of linking multiple heat-motors into thermal comparators. A methodology is adopted to iteratively develop virtual models of mechanisms and energy-flows, complemented by practical machines for testing in controlled climate-chambers and observation on uncontrolled sites. The possibility of differentiating the energy-balance between actuators by amplifying seasonal differences in the daily intensity of sunlight under clear-skies is investigated using hot-boxes. Simulations predict the possibility of a well-differentiated annual repertoire of responses that reconfigures façade elements for daylight access, solar shading and night-time insulation. Practical thermal actuators in hot-boxes arranged with differentiated exposure to sunlight were observed through a cycle of seasons. The results demonstrate the feasibility of a seasonal difference in actuator responses from daily cycles of accumulated and rejected heat-energy. The development of a passive means to seasonally marshal the state of wax in response to sunlight and use linked thermal actuators to mechanically express it has shifted the conceptual ground away from environmental control that is abstracted. Architects can move towards the design of dynamic building façades that can literally reconfigure in and of itself by virtue of the embodied state of its material components.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available