Energy saving and indoor thermal comfort evaluation using a novel local exhaust ventilation system for office rooms

Abstract

Energy saving, indoor thermal comfort and inhaled air quality in an office are strongly affected by the flow interaction in the micro-environment around the occupants. The local exhaust ventilation system, which aims to control the transmission of contaminant and extract contaminant air locally, is widely used in industrial applications. In this study, the concept of the local exhaust ventilation system is developed for use in office applications. Consequently, a novel local exhaust ventilation system for offices was combined with an office work station in one unit. Energy saving, thermal comfort and inhaled air quality were used to evaluate the performance of the new system. Experimental data from published work are used to validate the computational fluid dynamic model of this study. The performance of the new system for three different amounts of recirculated air (35%, 50%, and 65% of the total mass flow rate) was investigated numerically in an office room with and without using the new system to show its impact on energy saving, thermal comfort and inhaled air quality. The result shows that the new local exhaust ventilation system can reduce the energy consumption by up to 30%, compared with an office not using this system. Furthermore, this system was able to reduce the contaminant concentration in a micro-environment area by up to 61% and improve the human thermal comfort in the occupied zone. It can be concluded that using the local exhaust ventilation concept can make significant improvements to the quality of inhaled air and produce extra energy saving with an acceptable thermal comfort.