Description
Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.
Training Session on Energy Equipment
Fans & Blowers
Presentation from the “Energy Efficiency Guide for Industry in Asia” www.energyefficiencyasia.org
1 © UNEP 2006
Training Agenda: Fans & Blowers
Introduction Types of fans and blowers Assessment of fans and blowers Energy efficiency opportunities
2 © UNEP 2006
Introduction
1. Fan components 2. System resistance 3. Fan curve 4. Operating point 5. Fan laws
3 © UNEP 2006
Introduction
Fan Components
Provide air for ventilation and industrial processes that need air flow
Turning Vanes (typically used on short radius elbows)
Outlet Diffusers
Baffles Filter
Heat Exchanger
Inlet Vanes Motor Controller
(US DOE, 1989)
Centrifugal Belt Drive Fan
Variable Frequency Motor Drive
4 © UNEP 2006
Introduction
System Resistance
• Sum of static pressure losses in system
• Configuration of ducts, pickups, elbows • Pressure drop across equipment
• Increases with square of air volume
• Long narrow ducts, many bends: more resistance
• Large ducts, few bends: less resistance
5 © UNEP 2006
Introduction
System Resistance
System resistance curve for various flows
Actual with system resistance calculated
(US DOE, 1989)
6 © UNEP 2006
Introduction
Fan Curve
Performance curve of fan under specific conditions
• Fan volume • System static pressure • Fan speed • Brake horsepower
(US DOE, 1989)
7 © UNEP 2006
Introduction
Operating Point
Fan curve and system curve intersect
Flow Q1 at pressure P1 and fan speed N1
Move to flow Q2 by closing damper (increase system resistance)
(BEE India, 2004)
Move to flow Q2 by reducing fan speed
8 © UNEP 2006
Introduction
Fan Laws
9
(BEE India, 2004)
© UNEP 2006
Training Agenda: Fans & Blowers
Introduction Types of fans and blowers Assessment of fans and blowers Energy efficiency opportunities
10 © UNEP 2006
Types of Fans & Blowers
Types of fans
• Centrifugal • Axial Types of blowers • Centrifugal • Positive displacement
11 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans
• Rotating impeller increases air velocity • Air speed is converted to pressure • High pressures for harsh conditions
• High temperatures • Moist/dirty air streams • Material handling
• Categorized by blade shapes
• Radial • Forward curved • Backward inclined
12 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans – Radial fans
• Advantages
• • • • • High pressure and temp Simple design High durability Efficiency up to 75% Large running clearances
(Canadian Blower)
• Disadvantages
• Suited for low/medium airflow rates only
13 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans – Forward curved
• Advantages
• Large air volumes against low pressure • Relative small size • Low noise level
• Disadvantages
• Not high pressure / harsh service • Difficult to adjust fan output • Careful driver selection • Low energy efficiency 55-65%
( Canadian Blower)
14 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans - Backward-inclined
• Advantages
• Operates with changing static pressure • Suited for high flow and forced draft services • Efficiency >85%
• Disadvantages
• Not suited for dirty airstreams • Instability and erosion risk
( Canadian Blower)
15 © UNEP 2006
Types of Fans & Blowers
Axial Fans
• Work like airplane propeller:
• Blades create aerodynamic lift • Air is pressurized • Air moves along fan axis
• Popular with industry: compact, low cost and light weight • Applications
• Ventilation (requires reverse airflow) • Exhausts (dust, smoke, steam)
16 © UNEP 2006
Types of Fans & Blowers
Axial Fans – Propeller fans
• Advantages
• High airflow at low pressure • Little ductwork • Inexpensive • Suited for rooftop ventilation • Reverse flow
• Disadvantages
• Low energy efficiency • Noisy
(Fan air Company)
17 © UNEP 2006
Types of Fans & Blowers
Axial Fans – Tube axial fans
• Advantages
• High pressures to overcome duct losses • Suited for medium-pressure, high airflow rates • Quick acceleration • Space efficient
• Disadvantages
• Expensive • Moderate noise • Low energy efficiency 65%
(Canadian Blower)
18 © UNEP 2006
Types of Fans & Blowers Axial Fans – Vane axial fans
• Advantages
• Suited for medium/high pressures • Quick acceleration • Suited for direct motor shaft connection • Most energy efficient 85%
• Disadvantages
• Expensive
(Canadian Blower)
19 © UNEP 2006
Types of Fans & Blowers Blowers
• Difference with fans
• Much higher pressures
Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.
Training Session on Energy Equipment
Fans & Blowers
Presentation from the “Energy Efficiency Guide for Industry in Asia” www.energyefficiencyasia.org
1 © UNEP 2006
Training Agenda: Fans & Blowers
Introduction Types of fans and blowers Assessment of fans and blowers Energy efficiency opportunities
2 © UNEP 2006
Introduction
1. Fan components 2. System resistance 3. Fan curve 4. Operating point 5. Fan laws
3 © UNEP 2006
Introduction
Fan Components
Provide air for ventilation and industrial processes that need air flow
Turning Vanes (typically used on short radius elbows)
Outlet Diffusers
Baffles Filter
Heat Exchanger
Inlet Vanes Motor Controller
(US DOE, 1989)
Centrifugal Belt Drive Fan
Variable Frequency Motor Drive
4 © UNEP 2006
Introduction
System Resistance
• Sum of static pressure losses in system
• Configuration of ducts, pickups, elbows • Pressure drop across equipment
• Increases with square of air volume
• Long narrow ducts, many bends: more resistance
• Large ducts, few bends: less resistance
5 © UNEP 2006
Introduction
System Resistance
System resistance curve for various flows
Actual with system resistance calculated
(US DOE, 1989)
6 © UNEP 2006
Introduction
Fan Curve
Performance curve of fan under specific conditions
• Fan volume • System static pressure • Fan speed • Brake horsepower
(US DOE, 1989)
7 © UNEP 2006
Introduction
Operating Point
Fan curve and system curve intersect
Flow Q1 at pressure P1 and fan speed N1
Move to flow Q2 by closing damper (increase system resistance)
(BEE India, 2004)
Move to flow Q2 by reducing fan speed
8 © UNEP 2006
Introduction
Fan Laws
9
(BEE India, 2004)
© UNEP 2006
Training Agenda: Fans & Blowers
Introduction Types of fans and blowers Assessment of fans and blowers Energy efficiency opportunities
10 © UNEP 2006
Types of Fans & Blowers
Types of fans
• Centrifugal • Axial Types of blowers • Centrifugal • Positive displacement
11 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans
• Rotating impeller increases air velocity • Air speed is converted to pressure • High pressures for harsh conditions
• High temperatures • Moist/dirty air streams • Material handling
• Categorized by blade shapes
• Radial • Forward curved • Backward inclined
12 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans – Radial fans
• Advantages
• • • • • High pressure and temp Simple design High durability Efficiency up to 75% Large running clearances
(Canadian Blower)
• Disadvantages
• Suited for low/medium airflow rates only
13 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans – Forward curved
• Advantages
• Large air volumes against low pressure • Relative small size • Low noise level
• Disadvantages
• Not high pressure / harsh service • Difficult to adjust fan output • Careful driver selection • Low energy efficiency 55-65%
( Canadian Blower)
14 © UNEP 2006
Types of Fans & Blowers
Centrifugal Fans - Backward-inclined
• Advantages
• Operates with changing static pressure • Suited for high flow and forced draft services • Efficiency >85%
• Disadvantages
• Not suited for dirty airstreams • Instability and erosion risk
( Canadian Blower)
15 © UNEP 2006
Types of Fans & Blowers
Axial Fans
• Work like airplane propeller:
• Blades create aerodynamic lift • Air is pressurized • Air moves along fan axis
• Popular with industry: compact, low cost and light weight • Applications
• Ventilation (requires reverse airflow) • Exhausts (dust, smoke, steam)
16 © UNEP 2006
Types of Fans & Blowers
Axial Fans – Propeller fans
• Advantages
• High airflow at low pressure • Little ductwork • Inexpensive • Suited for rooftop ventilation • Reverse flow
• Disadvantages
• Low energy efficiency • Noisy
(Fan air Company)
17 © UNEP 2006
Types of Fans & Blowers
Axial Fans – Tube axial fans
• Advantages
• High pressures to overcome duct losses • Suited for medium-pressure, high airflow rates • Quick acceleration • Space efficient
• Disadvantages
• Expensive • Moderate noise • Low energy efficiency 65%
(Canadian Blower)
18 © UNEP 2006
Types of Fans & Blowers Axial Fans – Vane axial fans
• Advantages
• Suited for medium/high pressures • Quick acceleration • Suited for direct motor shaft connection • Most energy efficient 85%
• Disadvantages
• Expensive
(Canadian Blower)
19 © UNEP 2006
Types of Fans & Blowers Blowers
• Difference with fans
• Much higher pressures