TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesslats. Hence the cases of the cavity closed (Step 4) and open (Step 5) areconsidered separately.6.1 Step 1 – Inside circulation (Airflow modes [1]-[2])Five experiments were conducted on August 1, 2007 (System 2). The samplingtime was 1 second, and the number of data points is 1,912(System 1) and1,440(System 2). Table 3 shows the estimated unknown parameters in Eq. (17).Table 3: Unknown parameters in inside circulationSystem 1 System 2eq.(17ξ160 0)ucaξ17 12.73 0.5024f 6.683 0.3044Simulation 13.61 15.58Measurement 14.48 14.40Table 3 indicates that for both systems, ξ 17 is the dominant for determination of f .There are significant differences in the values of f between system 1 and 2. This isdue to the fact that the friction loss, affecting the airflow in the cavity, isinfluenced by the height and width of the cavity. The higher and deeper the cavity,the less friction loss. Moreover, the form loss factor is also influenced by pressuredrop through the ventilation dampers, e.g. entrance type and opening geometry ofthe dampers. Thus, the difference in the damper shape between the two systemshas also influenced the form loss factor. For these reasons, the two systems havedifferent form loss factors ( f ).The average differences between simulated and measured airflow velocity incavity are 6.89cm/s (System 1) and 4.73cm/s (System 2). Fig 6 shows thecomparison between simulated and measured values.506