High-resolution analysis for the coupling of thermal systems with lightweight structures

This thesis investigates combining a set of building components into a multifunctional element. These elements can perform many functions simultaneously, such as energy, structural and architectural aspects. This method is in contrast to traditional sequential design in which, each component satisfies a single purpose. The starting point is an existing concrete structure that has been optimised geometrically to reduce embodied energy. The component is then thermally activated to supply space heating and cooling from a renewable geothermal source. Operational energy performance is further enhanced by using a passive thermal mass resource that leverages the thermal properties of the exposed concrete with a mixed ventilation strategy. This challenge is tackled with the application of high-resolution modelling in three steps, which are focused on progressing the development of thermally active structural elements. The nature of the construction industry makes it difficult for innovation to be accepted due to government regulation and market forces. Therefore, in step one a building design phase is used to define the critical issues for the product development. The building includes two multifunctional elements and a connection to a renewable district scale geothermal source. This work provides a framework for the integration of the multifunctional element analysis with a dynamic building model and the performance factors of a district energy network. The next steps involve two multifunctional elements with different design constraints and modelling requirements. Step two examines an internal multifunctional element based on a structural form that is optimised by a vault and fin method. With this method, a significant volume of concrete is replaced by expanded polystyrene insulation at locations that improve the structural and thermal performance of the element. Improvements to operational energy are provided by an active hydronic heating and cooling system and a passive thermal mass resource. The main advantage is a reduction in thermal losses by minimising the connection between the radiant panel and the structural supports. This method increases the heat flow density, resulting in a lower supply medium temperature and an improved system efficiency of the active panel. Further, the modelling strategy includes a high-resolution method for analysing thermal comfort within the conditioned zone. Finally, the third step examines a thermally activated concrete shell that is exposed to external weather conditions. High-resolution analysis is used to solve building physics issues and to provide the initial system performance. A parametric geometry model is used to apply the hydronic pipework to a complex roof shape. With input from the previous two tasks, a reduced resolution method is used to add the characteristics of the system to an industry standard whole building simulation model. This final step allows for the development of initial control strategies for the novel multifunctional element. The implications of the research findings are discussed in the context of possible alternations to the building design process due to the influence of digital fabrication