Design Transition of Emirati Public Housing from Urban Sprawl to Vertical Urban Forms: Impacts on Energy and Ecological Performances

The United Arab Emirates has adopted environmental sustainability agendas for urban development and housing levels. In response, the urban design of public housing has been transformed from a low-rise urban sprawl housing typology into more compact urban forms and recently into vertical urban forms. While the social aspects related to Emirati families have been carefully preserved in the designs of all these public housing typologies, the environmental sustainability aspects have not been rigorously assessed in these designs, especially at the urban scale. To address this, this study was aimed at assessing the energy and ecological performance of a recent pioneering vertical public housing project in comparison with two case studies representing the most-compact low-rise urban form and the conventional low-rise urban sprawl public housing. The assessments of the three cases were compared with local benchmarks to evaluate how close their environmental performance was to these benchmarks, especially for the vertical housing design. As for the research method, these assessments were performed by calculating the expected average annual operational energy and embodied environmental impacts using the Urban Modeling Interface design tool for reliable simulations. The simulation results for the three urban housing case studies revealed that the average annual operational energy per square meter [energy use intensity (EUI)] for the pioneering vertical housing project, with its high urban compactness floor-area ratio (FAR) of 1.34, reached 104 kWh/m². By comparison, the most-compact form of low-rise urban public housing, with a FAR of 0.41, had an EUI value of about 120 kWh/m², with the urban sprawl case study having an EUI value of about 157 kWh/m². The estimated average total embodied energy per square meter over 50 years was 1,070.79 kWh/m² in the vertical residential building, a decrease from the 1,331 kWh/m² for the compact low-rise housing and the much higher 1,527.67 kWh/m² for the urban sprawl public housing. In addition, the recorded average annual carbon dioxide (CO₂) emissions per square meter over 50 years significantly decreased, from 147.37 kgCO₂/m² in the conventional urban sprawl and 129.83 kgCO₂/m² in the compact low-rise housing to only 105.35 kgCO₂/m² in the vertical public housing project. Despite the notable enhancement in energy performance in the vertical public housing when compared with the low-rise urban forms, there is still a desperate need for more-efficient and sustainable design strategies for the vertical public housing typology to make it comply with the local benchmark for sustainable residential buildings.