GOC665945 - Consultant (3) - EWA-Installing VFD on Supply and Return Fan

The main AHU in the penthouse mechanical room currently has inline axial supply and return fans
moving air to and from the VAV box zones spread throughout the JD Higinbotham building. Both supply
and return fans have variable inlet vanes which modulate open and closed to adjust the system airflow
to meet the variable building cooling and ventilation demand loads.These inlet vanes work well in
adjusting to the changes in building demand loads however they are considered in-efficient and older
technology by current standards. With this type of pressure control design the fan motors run at
constant speed and near to full load at all times whether or not the actual building demand load drops
dramatically. It is recomned to install VFD's on the supply and return fans (SF-1, RF-2) not currently
controlled by VFD. Both fans have been intalled in penthouse mechanical room and provide services for
1-4th floor. A separate occupancy schedule in the BAS for the existing motorized dampers between the
2nd and 3rd floor, and between the 3rd and 4th floor.