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Future of thermal comfort in an energy-constrained world
thesisposted on 2023-05-26, 01:00 authored by Law, TO
In the context of global warming the sum of current trajectories, known as the 'business as usual' scenario, is generally compared unfavourably to alternative low-carbon scenarios. One of these trajectories sees the continuation of an unabated demand for air-conditioning with its inevitable increase in energy consumption. This thesis proposes strategies to ameliorate this problem in the difficult context of a knowledge-based economy in an equatorial climate. It begins by retracing the emergence of thermal comfort standards in consumer societies, typified by the pursuit of individualistic interests. It identifies a gap that can explain why the scientifically valid adaptive comfort standard has not stemmed the continuous growth in air-conditioning demand, especially in knowledge-based economies. It is proposed that the nexus is brain cooling and while some studies have acknowledged, it has been too complex to quantify in existing comfort models. With the high variability of individual comfort demands, this thesis argues that future provisions of thermal comfort will be achieved by facilitating personal control over the microclimate. A number of innovations are explored through cycles of action research, and the underlying problems are then crystallised. A successful innovation has to appeal to the business interests of key decision makers, conform to consumer interests of improved thermal comfort and address the need to conserve energy. This has led to the development of a whole building solution (the Rain Tower), a floor-by-floor approach (a desiccant wheel AHU) and finally, cooling by means of a personal air-conditioning system called the Ductless Task Air-Conditioning (DTAC) system. The DTAC technology, meeting the criteria for commercialisation, was subsequently prototyped and its performance measured. Further refinements were made before undertaking a pilot study to field trial the system in naturally ventilated offices and a climate controlled room. The results are analysed statistically to quantify its improvement to sensation and comfort. Whilst this thesis emerges from an architectural science platform with a primary interest in thermal comfort, it draws on the disciplines of engineering, sociology, physiology and business to frame and propose viable solutions to this complex real world problem. This thesis studies the behaviours that persist in the business-as-usual scenario and the reasons for the difficulties in changing attitudes. Technologies are then developed to reduce the environmental impact of air-conditioning whilst conforming to current and future expectations of thermal comfort. The results of the research demonstrate that thermal comfort, with reduced carbon emissions compared with conventional air-conditioning, can be provided for workers in knowledge-based economies in hot humid equatorial climates.
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