Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

Rijal, Hom B. and Tuohy, Paul Gerard and Humphreys, Michael A. and Nicol, J. Fergus and Samuel, Aizaz (2012) Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings. Architectural Science Review, 55 (1). pp. 35-48. ISSN 0003-8628 (

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A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS).


Rijal, Hom B., Tuohy, Paul Gerard ORCID logoORCID:, Humphreys, Michael A., Nicol, J. Fergus and Samuel, Aizaz ORCID logoORCID:;