# Bevel Damper Static Pressure Red_savings by liuqingyan

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```									 HPCBS
High PerformanceCommercial Building Systems

Functional Testing Guide for Air Handling
Systems
Appendix C.2.4 Example 1 - Energy Savings Associated with Airfoil Blade Smoke Isolation Dampers Instead of the Conventional Desig

Horsepower Savings Calculation for a 20,000 cfm system

Assumptions:
        Q  PSaved                
Horsepower  
 6,356  


           FanStatic   Motor    
Where :
Horsepower  The horsepower saved at the terminals of the motor (includes motor efficiency losses)
Q  The flow rate which is experienci ng the reduction in static pressure in cubic feet per minute (cfm)
PSaved  The static pressure reduction associated with the improvemen t in inches water column (in.w.c.)
6,356  A units conversion constant
 FanStatic  The fan static efficiency
 Motor  The motor efficiency

Pressure drop through the conventional damper =                       0.065 inches w.c. @ 2,000 fpm
Pressure drop through the airfoil blade damper =                      0.170 inches w.c. @ 2,000 fpm
Savings associated with airfoil blades =                   0.105 inches w.c.
System flow rate =               20,000 cfm

Calculation:

Flow rate =            20,000 cfm
Static pressure reduction =                    0.11 in.w.c.
Assumed fan efficiency =                    75% (estimated)
Assumed motor efficiency =                     89% (from energy efficient motor performance data in file)
Fan horse power reduction =                     0.50 hp.
kW =                0.37 kW

File name = e112b1e0-f3b8-48e2-bfe2-a5c145c0841f.xls,
Calculations are subject to the assumptions and inputs. PIER, LBNL, and PECI assume no responsibility thier application and use.
HPCBS
High PerformanceCommercial Building Systems

Functional Testing Guide for Air Handling
Systems
Appendix C.2.4 Example 1 - Energy Savings Associated with Airfoil Blade Smoke Isolation Dampers Instead of the Conventional Design

Energy Savings Calculation for a 20,000 cfm system
Assumptions:

Constant volume system operation
Current system operating hours =                   2,860 hr/yr (5 days at 10 hr./day and 1 day at 5 hr./day, 52 wk/yr)
Operating hours after the first year =                   8,760 hr/yr
Current electrical rate =            \$0.0900 \$/kWh
kW savings per hour at design flow =                    0.37 per hour (from previous calculation)

Calculation:

Annual savings at current operating schedule =                     1,062 kWh
=              \$96 per year
Annual savings at future operating schedule =                    3,253 kWh
=             \$293 per year

File name = e112b1e0-f3b8-48e2-bfe2-a5c145c0841f.xls,
Calculations are subject to the assumptions and inputs. PIER, LBNL, and PECI assume no responsibility thier application and use.
HPCBS
High PerformanceCommercial Building Systems

Functional Testing Guide for Air Handling Systems

Appendix C.2.4 Example 1 - Energy Savings Associated with Airfoil Blade Smoke Isolation Dampers Instead of the Conventional Design

Horsepower Savings Calculation for a 14,000 cfm system

Assumptions:

2
Q      

P New  POld   New  
 Q Old 
Where :
P New  The static pressure at the new flow condition to be evaluated.
POld  The static pressure at the old or original flow condition, usually th e design condition.
Q New  The flow at the new flow condition to be evaluated.
Q Old  The flow at the old or original flow condition, usually th e design condition.

        Q  PSaved                     
Horsepower  
 6,356  


              
FanStatic     Motor   
Where :
Horsepower  The horsepower saved at the terminals of the motor (includes motor efficiency losses)
Q  The flow rate which is experienci ng the reduction in static pressure in cubic feet per minute (cfm)
PSaved  The static pressure reduction associated with the improvemen t in inches water column (in.w.c.)
6,356  A units conversion constant
 FanStatic  The fan static efficiency
 Motor  The motor efficiency

Pressure drop through the conventional damper =                        0.065 inches w.c. @ 2,000 fpm
Pressure drop through the airfoil blade damper =                       0.170 inches w.c. @ 2,000 fpm
Savings associated with airfoil blades =                   0.105 inches w.c.
System flow rate =             20,000 cfm
Average flow rate as a percentage of design =                       70% (from the load profile we generated with the engineer's data)
Flow rate to be used for the evaluation =                 14,000 cfm

Calculation:
Pressure drop for the evaluation based on the reduced flow rate using the square law

Design flow rate =         20,000 cfm
Static pressure reduction at the design flow rate =                         0.11 in.w.c.
Reduced flow rate =             14,000 cfm
Static pressure reduction at the reduced flow rate =                         0.05 in.w.c.

Horsepower savings to be used for the energy calculation based on the reduced flow rate

Flow rate =         14,000 cfm
Static pressure reduction =                  0.05 in.w.c.
Assumed fan efficiency =                75% (estimated)
Assumed motor efficiency =                    89% (from energy efficient motor performance data in file)
Fan horse power reduction =                    0.17 hp.
kW =              0.13 kW

File name = e112b1e0-f3b8-48e2-bfe2-a5c145c0841f.xls,
Calculations are subject to the assumptions and inputs. PIER, LBNL, and PECI assume no responsibility thier application and use.
HPCBS
High PerformanceCommercial Building Systems

Functional Testing Guide for Air Handling
Systems
Appendix C.2.4 Example 1 - Energy Savings Associated with Airfoil Blade Smoke Isolation Dampers Instead of the Conventional

Energy Savings Calculation for a 14,000 cfm system

Assumptions:

Variable volume operation
Current system operating hours =                    2,860 hours per year
Operating hours after rennovation =                    8,760 hours per year
Current electrical rate =            \$0.0900 \$/kWh
kW savings per hour at design flow =                     0.13 per hour (from previous calculation)

Calculation:

Annual savings at current operating schedule =                       364 kWh
=               \$33 per year
Annual savings at future operating schedule =                      1,116 kWh
=              \$100 per year

File name = e112b1e0-f3b8-48e2-bfe2-a5c145c0841f.xls,
Calculations are subject to the assumptions and inputs. PIER, LBNL, and PECI assume no responsibility thier application and use.
HPCBS
High PerformanceCommercial Building Systems

Functional Testing Guide for Air Handling Systems

Appendix C.2.4 Example 1 - Energy Savings Associated with Airfoil Blade Smoke Isolation Dampers Instead of the Conventional Design
Deriving a Load Profile from Project Engineering Data
Interior Office - Interior cubicle served by AHU 2, Typical of 50 served by the unit

Summer

Scheduled        Scheduled        Scheduled        Scheduled        Scheduled
and              and              and              and              and
observed         observed         observed         observed         observed
occupancy        occupancy        occupancy        occupancy        occupancy
(off when        (off when
unoccuppied) unoccuppied)
Total            Percentage       In terms of      Percentage       Average
Hours            Btu/Hr           of peak          CFM              of peak          Percentage

1              304              9%               16                0%               0%
2              266              8%               14                0%               0%
3              233              7%               12                0%               0%
4              204              6%               10                0%               0%
5              178              5%                9                0%               0%
6              156              5%                8                0%               0%
7              137              4%                7                0%               0%
8              120              4%                6                4%               0%
9             1483             45%               76              45%              70%
10            2255              68%            116                68%              70%
11             1989             60%            102                60%              70%
12             2171             66%            112                66%              70%
13             1946             59%            100                59%              70%
14            2392              72%            123                72%              70%
15             3301             100%           170                100%             70%
16            2590              78%            133                78%              70%
17            2628              80%            135                80%              70%
18              930             28%               48                0%               0%
19              758             23%               39                0%               0%
20              633             19%               33                0%               0%
21              538             16%               28                0%               0%
22              462             14%               24                0%               0%
23              401             12%               21                0%               0%
24              349              11%              18                0%               0%

Peak Load                  3301                                                                       Peak load / [1.08 x (space temp - supply temp)]
Max CFM            #DIV/0!
Average CFM over 24 hours                                     57
Average as a percentage of the peak                        42%
Average CFM over occuppied hours                           119
Average as a percentage of the peak                        88%

Space temperature design point                       74                    °F
Space humidity design point               50%                       RH
(from psychrometric chart)
Average sensible heat ratio               0.95
(from psychrometric chart)
Coil discharge air temperature                     53                    °F               (from fan and duct gains)
Estimated temperature rise                    3                     °F
Supply air temp at grill                56                    °F

Minimum flows assume:
20 cfm per person
30% Outdoor air setting at the AHU

File name = e112b1e0-f3b8-48e2-bfe2-a5c145c0841f.xls,
Calculations are subject to the assumptions and inputs. PIER, LBNL, and PECI assume no responsibility thier application and use.
Typical Interior Office Air Handling System Load Profile

120%                                                               160%

140%
100%
Load as a Percentage of the Peak

Flow as a Percentage of the Peak
120%

80%
100%                                      Load as a Percentage of Peak

Flow as a Percentage of Peak
60%                                                                80%

Average Flow for the Fan Operating
60%                                       Hours
40%

40%

20%
20%

0%                                                                0%
0   2   4   6   8   10   12   14   16   18   20   22   24
Hour of Day

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