Evaluation of comfort conditions in airport terminal buildings

This paper presents findings from extensive field surveys in three airport terminal buildings in the UK, where the indoor environmental conditions were seasonally monitored and simultaneous structured interviews were conducted with 3087 terminal users. Moving beyond the recent work which brought to light the significantly differentiated requirements for thermal comfort between passengers and staff, this paper expands on the investigation of thermal and lighting comfort needs for the entire spectrum of terminal users under the scope of energy conservation. The results demonstrate the influence of the thermal environment on overall comfort and reveal consistent discrepancies, up to 2.1 °C, between preferred and experienced thermal conditions. Outdoor temperature dictated the clothing levels worn indoors, where the preferred thermal state was other than neutral. Terminal users demonstrated high levels of thermal tolerance and wide acceptability temperature ranges, averaging 6.1 °C in summer and 6.7 °C in winter, which allow for heating energy savings through the fine-tuning of indoor temperature set-points. Lighting comprises an additional field for energy savings through the maximisation of natural light. Bright rather than dim conditions were preferred and a preference for more natural light was evident even in cases where this was deemed to be sufficient, while the preference for more daylight was found to be time-dependent suggesting a link with the human circadian rhythm. The findings from this study can inform strategies aimed at reducing energy use in airport terminals without compromising comfort conditions as well as the design and refurbishment of new and existing terminals respectively.