Evaluating local and overall thermal comfort in buildings using thermal manikins

Ehab Foda

    Research output: ThesisDoctoral ThesisCollection of Articles

    Abstract

    Evaluation methods of human thermal comfort that are based on whole-body heat balance with its surroundings may not be adequate for evaluations in non-uniform thermal conditions. Under these conditions, the human body's segments may experience a wide range of room physical parameters and the evaluation of the local (segmental) thermal comfort becomes necessary. In this work, subjective measurements of skin temperature were carried out to investigate the human body's local responses due to a step change in the room temperature; and the variability in the body's local temperatures under different indoor conditions and exposures as well as the physiological steady state local temperatures. Then, a multi-segmental model of human thermoregulation was developed based on these findings to predict the local skin temperatures of individuals' body segments with a good accuracy. The model predictability of skin temperature was verified for steady state and dynamic conditions using measured data at uniform neutral, cold and warm as well as different asymmetric thermal conditions. The model showed very good predictability with average absolute deviation ranged from 0.3-0.8 K. The model was then implemented onto the control system of the thermal manikin 'THERMINATOR' to adjust the segmental skin temperature set-points based on the indoor conditions. This new control for the manikin was experimentally validated for the prediction of local and overall thermal comfort using the equivalent temperature measure. THERMINATOR with the new control mode was then employed in the evaluation of localized floor-heating system variants towards maximum energy efficiency. This aimed at illustrating a design strategy using the thermal manikin to find the optimum geometry and surface area of a floor-heater for a single seated person. Furthermore, a psychological comfort model that is based on local skin temperature was adapted for the use with the model of human thermoregulation. The latter combination was used with a virtual thermal manikin on a CFD code for the evaluation of indoor thermal conditions and was experimentally validated using human subjects' tests. The results showed that these two approaches with the physical and virtual thermal manikins, using the introduced control mode, can produce a very reasonable predictability of the local and overall thermal comfort for sedentary activities. The average absolute deviation from subjective data for these two approaches was in a range from 0.25-0.5 on the thermal comfort scale. The thermal manikin with the new control mode may be used to optimize the design of HVAC systems towards energy-efficiency along with thermal comfort.
    Translated title of the contributionPaikallisen ja kokonaislämpöviihtyvyyden arviointi rakennuksissa lämpönuken avulla
    Original languageEnglish
    QualificationDoctor's degree
    Awarding Institution
    • Aalto University
    Supervisors/Advisors
    • Sirén, Kai, Supervising Professor
    Publisher
    Print ISBNs978-952-60-4814-7
    Electronic ISBNs978-952-60-4815-4
    Publication statusPublished - 2012
    MoE publication typeG5 Doctoral dissertation (article)

    Keywords

    • thermal comfort
    • thermoregulation
    • skin temperature
    • thermal manikin
    • equivalent temperature

    Fingerprint

    Dive into the research topics of 'Evaluating local and overall thermal comfort in buildings using thermal manikins'. Together they form a unique fingerprint.

    Cite this