DOE-2 Energy Modeling Summary - Courthouse
Page 16 of 26
Ventilation air through the primary air handler follows the schedules described in Section B,
Building Occupancy Patterns. When no ventilation is required, 2% of the rated fan flow is
assumed to leak through the outside air damper.
The secondary air handler provides 100% outside air at 25% of the minimum ventilation rate
during occupied hours. The system cools the air to 55F for humidity control and reheats to the
occupied space temperature. When the outside air temperature is below 55F no mechanical
cooling occurs.
Ventilation System Fans
Efficiency
50% (combined fan and motor efficiency)
Static pressure drop 1.75 in. W.C.
Exhaust Fans
Efficiency
65% (combined fan and motor efficiency)
Static pressure drop
2 in. W.C.
Schedule
follows AHU fan schedule
Air Distribution
Basement AHUs
The basement floor is served by two (2) variable volume air handling units (AHUs) per floor
with a hot water preheat coil, a chilled water coil, and variable speed supply and return fans.
Supply air is overhead and return air is via ceiling plenum.
Operating Parameters:
C
Proportional zone thermostats for heating and cooling; throttling range 1.5F
Minimum cfm ratio is 0.4 cfm/ft2
C
C
Supply fan static pressure 2.0" H2O
C
Return fan static pressure 0.6" H2O
C
Fan efficiencies (combined: fan and motor): Supply - 50%; return - 25%
C
Cooling deck temperature reset to satisfy the cooling load to the warmest zone
Access Floor AHUs (Floors one through five)
Each floor is served by two (2) variable volume air handling units (AHUs) with a hot water
preheat coil, a chilled water coil, and variable speed supply and return fans. Airflow distribution
is via an access floor for all spaces except public lobbies, restrooms and utilitarian areas in
basement. Return air is via ceiling plenum. Perimeter spaces have baseboard hot water radiant
heat. Ventilation air control and delivery is described above in "Ventilation and Exhaust Air".
Operating Parameters:
C
Proportional zone thermostats for heating and cooling; throttling range 1.5F
C
Minimum cfm ratio is 0.4
C
Supply fan static pressure 1.75" H2O
C
Return fan static pressure 0.6" H2O
C
Fan efficiencies (combined: fan and motor): Supply - 50%; return - 25%
C
Cooling deck temperature reset to satisfy the cooling load to the warmest zone
APPENDIX I - GSA LEED COST STUDY
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