A survey of building design practitioner perceptions of ventilative cooling in their building design processes

Buildings account for 40% of EU energy consumption and 36% of the energy related greenhouse gas emissions at present. Consequently, the net zero target set by Energy Performance of Building’s Directive by 2050 for building stock is ambitious to achieve. The often default design choice to adopt mechanical cooling in non-domestic buildings highlights the lack of robust decision support tools or frameworks available to designers to properly evaluate ventilative cooling as a realistic alternative. Recent research suggests that the initial or concept design stage of a building project is a high leverage point in the design cycle to properly influence a building’s design to avoid ‘locking in’ vulnerability at later stages due to retrospective value engineering efforts. Properly accounting for the potential of ventilative cooling solutions to mitigate risks against external disturbances to the indoor thermal environment such as heat waves as a result of climate change, as well as other performance limiting factors (i.e. air and noise pollution, power outages etc), is important to avoiding the selection of emissions intensive alternatives. A critical review of existing design processes followed by architects in practice completed as part of this study suggests that the pre-design phase and the schematic design phase of any building are the two crucial phases in any architectural design process. In these two stages, the information about a building’s purpose, site, local micro-climate, client’s expectations, and local legislations influences the building’s overall shape, internal layout and morphology. This paper presents initial findings from a survey of industry experts about their design practices and experienced based approaches to designing ventilative cooling in low energy buildings at the concept design stages. The survey data was analysed through a mixed-methods approach (quantitative for closed-ended questions and qualitative for open-ended questions). This survey informed the ongoing development of the conceptual design framework within the Technical committee (TC) within the European Committee for Standardization (CEN Technical Bodies - CEN/TC 156/WG 21, n.d.; CEN/TC 156/WG 21 - Revision of Calculation Standards EN15241, 15242 and 15243, n.d.) scope. The framework which would be developed as an outcome of the completed study would have the potential to significantly improve the operational performance of ventilative cooling systems through early-stage interventions in building design that lead to more robust strategies that limit the need for mechanical cooling.