Question 5

A certain fan system has a seasonal airflow requirement as shown inFigure 1. For four months of the year, the demand is almost double that of the other eight months.

Average air flow rates (monthly) 12 10 8 Flow rate (m3/s) 4 2 O Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MonthDuration diagram 12 10 8 6 Flow rate (m3/s) 4 T O Nov Jan Feb Dec Jun May Sep Apr Jul Mar Oct Aug MonthDuration diagram (power) (approximated) 120 100 80 Fan output power (KW) 60 40 20 1 2 3 4 5 6 7 8 9 10 11 12 Month