Visual thermal landscaping (VTL) model : a qualitative thermal comfort approach based on the context to balance energy and comfort

Shahzad, Sally and Calautit, John Kaiser and Hughes, Ben Richard and BK, Satish and Rijal, Hom B. (2019) Visual thermal landscaping (VTL) model : a qualitative thermal comfort approach based on the context to balance energy and comfort. Energy Procedia, 158. pp. 3119-3124. ISSN 1876-6102 (

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The Visual Thermal Landscaping (VTL) model provides a practical solution to balance energy and comfort tailored for the context and the immediate needs of individual occupants in that context through a thermal visualisation analysis. The aim is to provide a solution to the limitations of current tools employed in practice which do not account for the richness of thermal experience, which is never neutral. This disconnect between analysis tools and experience results in buildings using more energy than they should and leaves occupants dissatisfied with their environment. The capabilities of the approach were demonstrated through a field survey in an open plan office building, which was naturally ventilated and very energy efficient, as is reflected in its BREEAM excellence award. The model demonstrated the complexity of thermal comfort through contextual analysis. It illustrated individual differences in perceiving the thermal environment and the dynamic aspect of thermal comfort (i.e. occupants change their mind). Hence, a particular room temperature cannot satisfy everyone all the time. This holistic qualitative approach enables to provide comfort for every individual as well as a strategy to lower the overall energy consumption of the building. The immediate results of the model can be used by facilities management systems and the future development of the model can be used to predict areas and periods of thermal discomfort, provide additional support for the use of energy efficiency measures, and promote the use of thermal diversity in buildings.