The Energy Saving Potential and the Associated Thermal Comfort of Displacement Ventilation Systems Assisted by Personalised Ventilation

Abstract

This study examined the effect of assisting displacement ventilation (DV) systems with personalised ventilation modules on the segmental and overall comfort of the human body during transient load variations and the associated energy saving of the combined system. A transient thermal space model has been developed for the DV system aided by the personalised task ventilator. The model was coupled with a human bioheat model to predict the segmental skin and core temperature and to assess segmental and overall thermal comfort. A case study of a typical office including six occupants was considered to assess the energy savings associated with operation of the DV system with and without personalised ventilation for the same comfort level. Higher room air temperatures in the occupied zone of the order of 26℃ (78.8°F) were found acceptable for the combined system resulting in a thermal comfort of 1.4 on a scale of −4 (very uncomfortable) to +4 (very comfortable). The DV system aided by the personalised ventilator used 27% less energy over nineteen hours of daily operation when compared to a standalone DV system providing the same level of comfort. Higher room temperatures exceeding the limit of 26℃ were found not to be beneficial in terms of energy saving.