Micro-environmental control for efficient local heating: CFD simulation and manikin test verification

Micro-environment control system has been proved to be able to provide local thermal comfort control. It also has the potential to save building energy by relaxing the control on the unoccupied space. This work aims at designing an efficient heating delivering device (HDD) to locally warm the person to restore thermal comfort when the unoccupied space temperature is reduced from 70.0 °F to 66.0 °F to save the energy. A three-stage approach was developed for designing the HDD including the initial stage of developing by CFD simulation, the second stage of manikin test verification and final stage of human subject test confirmation. The results of the first two stages were presented and discussed in this work. It was shown that convective heating was not efficient enough unless a confinement box was used to hold the hot air around the legs and feet. A more ergonomically friendly design of using a foot warmer was finally proved to be a better solution for individually heating by both simulation and experiments since it can heat the occupant sufficiently. The ability of using CFD to predict heat loss from the clothed human body and its limitation was also investigated. It was found that with proper clothing insulation, the CFD can give a reasonable prediction, although simulating the clothing as a layer of certain thermal resistance might be problematic regarding the structure and permeability of the clothing material. A more appropriate method for simulating the clothing was needed for better prediction in the future.