A study on the parameter ranges of the locally supplied air in a task ambient conditioning system with chest exposure

摘要

The benefits of task ambient conditioning in improving thermal comfort and indoor air quality have been demonstrated in recent studies. The potential use of task ambient conditioning for improving thermal comfort when the room air temperature is beyond the suggested range in mixing ventilation; however, has not been fully explored. A newly developed task ambient conditioning with chest exposure was, therefore, suggested at the room air temperature of 28 degrees C (82.4 degrees F), which is higher than the normally set temperature under cooling conditions in mixing ventilation. The present study aims to explore the appropriate air parameter ranges of the local airflow, but not to develop the practical system. Assessments of the thermal environment were performed by subjective questionnaires under nine distinct conditions with task ambient conditioning with chest exposure as well as the ambient environment in a climate chamber. The thermal sensations under the nine conditions with task ambient conditioning with chest exposure were nearly thermal neutral or slightly cool, while a slightly warm sensation was experienced in an ambient environment. Thermal sensation votes indicated cooler sensations with a decrease in the temperature of the locally supplied air, and with an increase in the velocity of locally supplied air, as well as in the vent diameter. The locally supplied airflow of task ambient conditioning with chest exposure obviously improved thermal comfort, the percentage of discomfort was reduced to 20% or less. Furthermore, the appropriate ranges of airflow parameters (air temperature, air velocity, and vent diameter) of task ambient conditioning with chest exposure were demonstrated, to aid the practical development of task ambient conditioning with chest exposure systems.