DOE-2 Energy Modeling Summary - Office Building
Page 10 of 21
Air Distribution
AHUs for perimeter and core office spaces (Floors one through nine)
Two variable volume air handling units (AHUs) with a hot water preheat coil, a chilled water
coil, and variable speed supply and return fans at each floor. Airflow distribution is ceiling air
supply with ceiling return air plenum. Perimeter spaces have series fan-powered boxes with hot
water reheat coils.
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 3.0" H2O
C
Return fan static pressure 1" 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
AHUs for corridor, toilet rooms and elevator lobbies (Floors one through nine)
One variable volume air handling unit (AHUs) with a hot water preheat coil, a chilled water coil,
and variable speed supply and return fans at each floor. Airflow distribution is ceiling air supply
with ceiling return air 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 3.0" H2O
C
Return fan static pressure 1" 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
A computer room is served by a single constant volume system.
Mechanical rooms are served by unit ventilators with hot water heating coils. The parking area is
served by a separate constant volume ventilation system with no heating or cooling capability.
Cooling Plant
Two (2) 330-ton water cooled, centrifugal chillers (6.1 COP @ 100%), and one (1) 135-ton
water cooled screw chiller (4.45 COP @ 100%). Two (2) cooling towers with two speed fans to
cool condenser water. Chilled water economizer via strainer cycle with a heat exchanger
between chilled water and tower water.
Operating Parameters
Chiller:
Chilled water supply temperature 44F; throttling range 1.25F
Chilled water return temperature 56F (temperature rise 12F)
Design condenser water temperature rise 10F
Condenser water flow rate 3 gpm/ton
APPENDIX J - GSA LEED COST STUDY
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