Department of Civil Engineering

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Browsing Department of Civil Engineering by Subject "3DPC"

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    Thermal performance of cavities in 3DPC building facades using DesignBuilder
    (Stellenbosch : Stellenbosch University, 2022-11) Moelich, Migael; Van Zijl, Gideon P. A. G.; De Villiers, Wibke; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: The lack of research done on improving the thermal comfort for occupants of low-income Reconstruction and Development Programme (RDP) buildings in South Africa are problematic seeing that there is a great improvement that can be achieved through 3DPC construction evident in this research. Typical RDP buildings are constructed using traditional masonry methods which are unproductive in terms of labour and time. Three dimensional printed concrete (3DPC) construction and the rapid shift to three-dimensional building information modelling (BIM) mitigates these problems by the high precision and versatile nature of construction from digital models that inherits all construction details. This can be seen as the fourth industrial revolution for construction. The research aims to evaluate and improve the thermal performance of 3DPC high-density buildings using commercial three-dimensional simulation software, DesignBuilder, to contribute to and facilitate the development of 3DPC building construction and the thermal comfort for the occupants. The Department of Human Settlements in South Africa noted a need for improved living conditions for occupants of the RDP and informal settlements and launched a new approach for sustainable housing delivery under the Integrated Reconstruction and Development Programme (IRDP) initiative. The third phase of the Joe Slovo project in Langa, Western Cape, is the flagship of this initiative with 2886 subsidised homes on 27 hectares. Each building consists of six double story apartments, each comprising of a living area, kitchen, and bathroom downstairs, and two bedrooms upstairs, constructed to comply with the National Home Builders Registration Council (NHBRC) regulations of South Africa. The construction drawings with all necessary construction specifications were made available by JSA-Architects. Conclusions from a case study by the department reports that the optimised thermal design of the building creates a more comfortable internal environment of temperature measurements up to 3 °C cooler in summer and 6 °C warmer in winter compared to a typical RDP building. DesignBuilder has predetermined transmittance values for typical wall types in buildings, like solid concrete walls of various density classes, and typical masonry cavity wall assemblages, but not for non-standard wall types like 3DCP walls with intricate cross-sectional shapes. Hence, the thermal transmittance is determined by simulating the Hot Box procedure according to ASTM C1363:2005 using a Finite Element Analyses (FEA). This value effectively quantifies the amount of thermal energy that is transferred through the section. A few alternative facade wall geometries are analysed to determine the most thermally effective geometry for 3DPC wall facades. The thermal transmittance of the existing hollow concrete block facades can be reduced by 71.5 % from 5.6 to 1.57 W/m2 if replaced with the proposed 3DPC facade of similar thickness. A validation on a physical tested element was performed by comparing temperatures of the same nodes in the FEA. The calculated Pearson correlation coefficient for the last 24 hours averaged over all nodes is 0.83. The proposed 3DPC facade adheres to recommendations made by SANS 10400-XA:2021 and proves to have a similar thermal transmittance to typical masonry cavity walls with a 50 mm airspace and 13 mm thick plaster.