• The supply fan power relationships in Figure 10 suggest the VAVR system's horsepower is reduced in proportion to the cube of the airflow reduction. The only way this can be achieved is for the fan to "ride the system curve," meaning no dampers ever move. This would never happen in an actual system in a building. If the overall fan airflow reduction were 40%, yet one zone still required 80% of its design airflow, the static pressure requirement of that zone would limit the system static pressure reset. Applying the fan laws to that specific zone, the static pressure requirement for that terminal could only be reduced by 36%. Using Table 1 data, a 40% system airflow reduction combined with a 36% reduction in the fan static pressure would result in a fan break horse power变风量再热与主动冷却梁和DOA