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ASHRAE Rocky Mountain Chapter
Fan Efficiency Grades and System Effect and Their Effects
on HVAC Systems
Matt Spink, P.E. Greenheck Fan Corporation
ASHRAE Rocky Mountain Chapter
Learning Objectives
• Understanding Fan Efficiency Grades (FEG) • Selection of fans within acceptable efficiency
tolerances • System Effect: Understanding their impact on
performance/energy
ASHRAE Rocky Mountain Chapter
Background • US total energy consumption for 2010…
98 Quadrillion BTUs! (1.0 quadrillion = 1,000,000,000,000,000 BTUs)
• According to the DOE US fans consume:
– 0.9 quads of electricity in industrial applications – 1.6 quads of electricity in commercial applications (2.5 quads is about 2.5% of total) * Sources: DOE and LLNL
ASHRAE Rocky Mountain Chapter
Background
Source: AMCA International
Fan Efficiency
Drive Efficiency
Fan Selection
System Effects
System Leakage
Savings Potential in HVAC Systems
ASHRAE Rocky Mountain Chapter
Background
2007 2008 2009 2010 2011 2012 2013
• DOE suggests 65% fan efficiency.
• ASHRAE & AMCA collaborate on AMCA 205 – Fan Efficiency Grades.
AMCA 205-10 Fan
Efficiency Classification
For Fans
ASHRAE 90.1 adopted
– FEG 67
• AMCA begins certifying FEGs
• 2012 IgCC adopts FEG 71
• DOE publishes intent to regulate fan energy efficiency
ASHRAE Rocky Mountain Chapter
Fan Energy Consumption
Power Input (Electrical)
Power Output (Flow and Pressure)
Power Loss !
ASHRAE Rocky Mountain Chapter
Fan Energy Consumption
Electrical Power
In
Motor Loss
(10%)
Drive Loss (3% -10%)
Bearing Loss (3%)
Aerodynamic Loss
(10% to 20%)
Fan Power
Out
Fan Efficiency
ASHRAE Rocky Mountain Chapter
What is Fan Efficiency?
Power Output Efficiency = Power Input
CFM x Pressure Fan Efficiency = BHP
ASHRAE Rocky Mountain Chapter
What is Fan Efficiency? CFM x Ps Static Efficiency = x 100% 6343.3 x BHP
PT = PS + PV
CFM x Pt Total Efficiency = x 100% 6343.3 x BHP
ASHRAE Rocky Mountain Chapter
Fan Curves
0.0
2.0
4.0
6.0
8.0
10.0
0 2 4 6 8 10 12 CFM x 1000
Ps
Ps vs. CFM
BHP vs. CFM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
BH
P Surge Area
ASHRAE Rocky Mountain Chapter
Fan Curves
0
20
40
60
80
100
0 2 4 6 8 10 12 CFM x 1000
Ps
Ps vs. CFM
Static Efficiency vs. CFM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Eff
icie
ncy Peak 75%
ASHRAE Rocky Mountain Chapter
Fan Selection for Efficiency
0.0
2.0
4.0
6.0
8.0
10.0
0 2 4 6 8 10 12 CFM x 1000
Ps
0.0
1.0
2.0
3.0
4.0
5.0
6.0
BH
P
Ps
BHP Surge Area
High Efficiency, Low Sound
Low Efficiency, High Sound
ASHRAE Rocky Mountain Chapter
CFM
Ps
Fan Selection for Efficiency
Design Duty 27
24
22
20
18
30
ASHRAE Rocky Mountain Chapter
% CFM
Fan Selection for Efficiency
% Ps
Static Efficiency
Peak
SE
High Efficiency, Low Sound
Actual Selections
ASHRAE Rocky Mountain Chapter
Fan Efficiency Grades
• ANSI/AMCA Standard 205-10 – Energy Efficiency Classifications for Fans
• ISO 12759:2010 Fans – Efficiency Classification for Fans
ASHRAE Rocky Mountain Chapter
Fan Efficiency Grades AMCA 205
85
ASHRAE Rocky Mountain Chapter
Fan Efficiency Grades AMCA 205
Airfoil Centrifugal
Backward Inclined
Forward Curved
ASHRAE Rocky Mountain Chapter
AMCA 205
AMCA 205, Annex A: In order to achieve the goals in energy savings by
operating fans it is important that the fan is selected in the system close to the peak of the fan efficiency. The fan operating efficiency at all intended operating point(s) shall not be less than 15 percentage points below the fan peak total efficiency (see figure).
ASHRAE Rocky Mountain Chapter
Fan Efficiency Grades
0
20
40
60
80
100
0 2 4 6 8 10 12 CFM x 1000
Ps
Ps vs. CFM
Total Efficiency vs. CFM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Eff
icie
ncy Peak 75%
ASHRAE Rocky Mountain Chapter
Fan Curves
0
20
40
60
80
100
0 2 4 6 8 10 12 CFM x 1000
Ps
Ps vs. CFM
Total Efficiency vs. CFM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Eff
icie
ncy
60% Minimum within 15 points of
peak efficiency
ASHRAE Rocky Mountain Chapter
ASHRAE 90.1 Addendum u 6.5.3.1 Fan System Power and Efficiency Limitation 6.5.3.1.3 Fan Efficiency. Fans shall have a Fan Efficiency Grade (FEG) of 67
or higher based on manufacturers’ certified data, as defined by AMCA 205. The total efficiency of the fan at the design point of operation shall be within 15 percentage points of the maximum total efficiency of the fan.
Exceptions: a. Single fans with a motor of 5 hp or less. b. Multiple fans in parallel or series that have a combined motor power of 5
hp or less and are operated as the functional equivalent of a single fan. c. Fans that are part of equipment listed under 6.4.1.1 Minimum Equipment
Efficiencies – Listed Equipment – Standard Rating and Operating Conditions.
d. Fans included in equipment bearing a third-party-certified seal for air or energy performance of the equipment package.
e. Powered wall/roof ventilators (PRV) as defined by ANSI/AMCA-99-2010.
ASHRAE Rocky Mountain Chapter
International Green Construction Code 2012 IgCC
CHAPTER 6 607.2.2.3 Minimum fan efficiency. Stand-alone supply, return and exhaust fans designed for operating with motors over 750 watts (1hp) shall have an energy efficiency classification of not less than FEG71 as defined in AMCA 205. The total efficiency of the fan at the design point of operation shall be within 10 percentage points of either the maximum total efficiency of the fan or the static efficiency of the fan.
ASHRAE Rocky Mountain Chapter
“Things are not always as they seem; the first appearance deceives many.”
- Phaedrus (Roman Poet)
ASHRAE Rocky Mountain Chapter
60”
49”
54”
54”
54”
Impeller Dia
6.8
13.4
6.87
8.30
7.11
BHP
90
90
75
67
56
FEG
6.1
3.8
4.4
1.7
1.0
$ Cost
Housed Centrifugal
Housed Centrifugal
Vane Axial
Tube Axial
Sidewall Prop
Model
Fan Types 40,000 CFM at 0.25” Ps
ASHRAE Rocky Mountain Chapter
Fan Types
28
Adhering to codes that require minimum Fan Efficiency Grades will result in replacing this:
ASHRAE Rocky Mountain Chapter
Fan Types
29
With this:
ASHRAE Rocky Mountain Chapter
12.0
12.5
13.6
16.2
19.0
24.5
Oper BHP
78%
75%
70%
58%
50%
38%
Static Eff
83%
82%
79%
70%
64%
55%
Total Eff
78%
78%
78%
74%
74%
75%
Peak Static
Eff
83%
83%
83%
79%
79%
79%
Peak Total Eff
85
85
85
85
85
85
FEG
36
33
30
27
24
22
SW Airfoil Centrifugal
I
I
II
II
III
III
Fan Class
Fan Selections 15,000 CFM at 4” Ps
ASHRAE Rocky Mountain Chapter
Summary
• New standards are going to require Fan Efficiency Grades
• FEGs are an indicator of Peak Total Efficiency, not of Fan input power
• For fan comparison and selection, use the actual Fan BHP
• Future standards will likely start to look at installed systems, not just individual components
ASHRAE Rocky Mountain Chapter
System Effects
34
ASHRAE Rocky Mountain Chapter
Design Airflow
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 2 4 6 8 10 12 14 CFM x 1000
Ps
Catalog Fan Curve
Design System Curve
ASHRAE Rocky Mountain Chapter
Fan Curves • Show how a fan will operate in any system (installation) • Based on standardized tests
– AMCA 210
• Tested under ideal conditions
ASHRAE Rocky Mountain Chapter
ASHRAE Rocky Mountain Chapter
System Effects Defined:
•Anything you place in close proximity before or after the fan that effects the cataloged performance.
38
ASHRAE Rocky Mountain Chapter
System Effects
ASHRAE Rocky Mountain Chapter
Actual Airflow
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 2 4 6 8 10 12 14 CFM x 1000
Ps
Catalog Fan Curve
System Curve
Actual Fan Curve
ASHRAE Rocky Mountain Chapter
Why System Effect is Important
• Can decrease performance
• Can cause excess vibration
• Can cause excess noise
• Can require more energy (HP) to achieve rated performance
• Takes time to determine and understand
41
ASHRAE Rocky Mountain Chapter
Three most common causes of deficient performance of a fan/system are:
• Improper outlet connections
• Swirl at the inlet
• Non-uniform inlet flow
42
ASHRAE Rocky Mountain Chapter
Fan Outlet Velocity Profiles
43
Blast Area Cut off
25%
50%
75%
100% Effective Duct Length
Outlet Area
Discharge Duct
Centrifugal Fan
Axial Fan
Adapted from AMCA Publication 201-202, Fans and Systems.
ASHRAE Rocky Mountain Chapter
Effective Duct Length
Effective Duct Length = 2.5 Duct Diameters for 2,500 FPM or less
Add 1 duct diameter for each additional 1,000 FPM
44
For rectangular ducts, the equivalent duct diameter is
(4 x width x length / 3.14) ^ 0.5
ASHRAE Rocky Mountain Chapter
System Effect
Curve
45
1
2
3
2 Adapted from AMCA Publication 201-202, Fans and Systems.
ASHRAE Rocky Mountain Chapter
System Effect Curves for Outlet Ducts - Centrifugal Fans
46
1 0 0 % E f f e c t i v e D u c t L e n g t h
B l a s t A r e a
N o D u c t
1 2 % E f f e c t i v e
D u c t
2 5 % E f f e c t i v e
D u c t
5 0 % E f f e c t i v e
D u c t
1 0 0 % E f f e c t i v e
D u c t
B l a s t A r e a D i s c h a r g e D u c t
O u t l e t A r e a C u t o f f
U W - -
S y s t e m E f f e c t C u r v e
U W - - U - V W - X - - W - X - - - -
X - - - -
- - - - - -
0 . 4 O u t l e t A r e a
0 . 5 0 . 6 0 . 7
0 . 8
0 . 9 1 . 0 - - - - - -
P R - S P R - S R - S S - T S U
T - U V W
W - W W - X - - - -
Adapted from AMCA Publication 201-202, Fans and Systems.
ASHRAE Rocky Mountain Chapter
System Effect
Curve
47
1
2
3 +0.45 in w.g.
Adapted from AMCA Publication 201-202, Fans and Systems.
ASHRAE Rocky Mountain Chapter
ASHRAE Rocky Mountain Chapter
Thank you for your time.
Questions?
49
ASHRAE Rocky Mountain Chapter
-+
50
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