Optimization of airflow pattern for indoor ventilation

Abstract

In the recent decade, more research and interest has been on air conditioning design and implementation. With the basis to understand and optimize airflow pattern for an office space, this paper looks at the heat transfer and air flow of a three dimensional model of a typical single office space. This space incorporated a simple geometry block to model a human and has two other heat sources from a desktop computer and window (solar heat). It is simulated through advance computational fluid dynamics (CFD) software, Ansys FLUENT. Main cooling conditions were inherited from ASHRAE endorsed studies and guidelines - cooling conditions of mean air temperature of 24oC and air velocity of less than 0.18 m/s.

Three major air distribution systems (ceiling, underfloor, desktop cooling) were compared together to see which was the most efficient cooling mechanism. Additionally an investigation was carried out to see if the position of diffuser to the body had any effect on cooling. Lastly, each type was individually optimised and an annual cost estimation was carried out.

Interestingly, the underfloor air distribution systems seemed to be the best method amongst all three types, meeting cooling standards with just a supply temperature of 292K (19oC) and inlet velocity of 0.47 m/s. This method proved to incur the lowest annual cost (estimated fan motor power) of SGD194.98, about 40~45% savings compared to a ceiling mounted and desktop cooling mechanism.