Experimental and numerical study of air temperature distribution of anunderfloor air distribution system

A numerical model of an underfloor air distribution system was created to aid future research on the system's environmental performance. A validated numerical model can serve to minimize the need for costly experimental setups. This paper presents theresults of an experimental and numerical study 1. INTRODUCTIONof the air temperature distribution of anunderfloor air distribution system. A full scalemock up of an interior office space (26.75 m2)was constructed for the experiment andcomputational fluid dynamics (CFD) wasutilized for the numerical portion of the study.The numerical model was based onexperimental data collected from four test casesinvolving supply air temperature of 18.3 C andvariations in supply air volume (56.6 Lls and37.8 Lls) and diffuser throw angle (63 and 90).The findings of the study revealed a closematch in air temperature measurements andvertical temperature distribution profilesbetween the experimental and numerical cases.The overall difference between measured andsimulated values of temperature was 2.30percent. That is a total difference of 4.60percent which is much less than the 10 percentto 20 percent differences noted by Lemaire (1993), Heiselberg (1997), Roos (1999), andBartak et al. (2001) in their reports on indoor airflow measurements and simulations. Overall,the simulated data tended to be 0.53 C cooler than the measured data with an average difference of 0.95 C. Considering the accuracy between measured and simulated results was 4.60 percent on average, less than the differences reported by other researchers by almost half or more, it is reasonable to conclude that the accuracy of this numerical model is sufficient enough to rely upon for future studies involving this underfloor air distribution system.