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- PublicationDevelopment and testing of a sandwich panel with UHPC and PCM concrete layersPrecast concrete sandwich panels provide a thermally efficient alternative to conventional brick and mortar construction and improve the energy efficiency of existing buildings. This project comprised the design and testing of a sample re-cladding panel composed of a phase change material (PCM) in the concrete inner wythe (for thermal efficiency) and a thin ultra-high performance concrete (UHPC) outer wythe, joined compositely using a C-grid shear connector. Six different concrete mixes were prepared and structurally tested in compression and flexure. A concrete sandwich panel was cast using two of the best performing mixes and subsequently tested in three-point bending to investigate its flexural performance. The strongest PCM and UHPC concretes had average compressive and flexural strengths of 25MPa and 5.1MPa, and 121MPa and 9.2MPa respectively. The 900mm span panel tested in flexure reached its serviceability limit at 10kN, with ultimate peak load occurring at 97kN. Post-peak behaviour illustrated the role of the shear connector in allowing composite action to occur.
- PublicationFinite Element Analysis of Thin Precast Concrete Sandwich PanelsThe purpose of this study is to numerically investigate the performance of a thin Precast Concrete Sandwich Panel (PCSP) proposed for building retrofit. Standard precast concrete sandwich panels, constructed of steel reinforced concrete, are physically heavy and have significant thicknesses. A thin precast concrete over-cladding sandwich panel is presented in this paper which combines the state-of-the-art in ultra-high-performance concrete, carbon fibre shear reinforcement and vacuum insulation to allow for a slimmer design while abiding by thermal and structural constraints. Another precast concrete re-cladding sandwich panel is also referred to in this paper which uses phase change materials (PCM) in a thicker inner wythe to enhance the thermal storage properties of the concrete. The panels are modelled, and their structural integrity is investigated, using finite element techniques. The aim of the analysis is to provide an insight into the limiting parameters of these thin precast concrete claddin elements. The analysis has highlighted the concrete wythe thickness and the insulation stiffness as two important performance parameters.
- PublicationDesign and manufacture of a precast PCM enhanced concrete cladding panel for full scale performance monitoringThe overall aim of this study is to develop innovative precast cladding panels for the renovation of Europe’s existing building stock thereby improving their energy performance. Using the mass of a building to store heat and/or cold can reduce the demand on the auxiliary heating and/or cooling systems and hence reduce the overall energy demand of the building. Previous laboratory research has shown that the incorporation of phase change materials (PCMs) into concrete enhances its thermal storage capacity by up to 50%. However in a real application where a PCM-concrete composite material is used in a building to store thermal energy, the effectiveness of the PCM depends on many variables including the form of construction and local climate conditions. In this research study a precast cladding panel formed with PCM enhanced concrete has been developed and manufactured. In order to observe the performance of the PCM-concrete composite panels in a full scale scenario, three demonstration huts have been constructed and instrumented to record internal thermal behaviour. Monitoring of the data is ongoing and shows that the effectiveness of the PCM varies with the seasons. Data recorded during the summer period highlighted that the internal temperature may not drop low enough during the night to solidify the PCM and discharge the stored heat. A further test in which passive ventilation was provided during the night proved to be an effective method of addressing this issue. It is expected that this long term study will enable recommendations to be made on the seasonal benefits of using PCM-concrete to enhance the energy performance of buildings located in climate conditions similar to Ireland. The results of the data analysis will inform a refinement of the panel design prior to installing the panels at a school in the UK which currently has an overheating problem.