“Compressed Air System Design for Energy Efficiency” · “Compressed Air System Design for Energy Efficiency ... • ITC Limited, ... Rule of Thumb 34 Energy Efficiency

“Compressed Air System Design for Energy Efficiency”

Chennai – 3rd to 5th September 2010

•Understanding the Context•Need for EnCon•Saving Potential

Contents

Energy Efficiency Summit 20102

• Designing Energy Efficient Compressed Air System

•Supply•Distribution•Demand

Understanding the Context

• What is “Compressed Air System”?• Why ENCON in Compressed Air System ?• Where do I Save Cost in “Compressed Air System”?


• Where do I Save Cost in “Compressed Air System”?

Understanding the Context

What is Compressed Air System ?


• As Fourth Utility has one of the widest industry usage .

• By far the most Energy Intensive

Understanding the ContextWhy ENCON in Compressed Air System ?


• By far the most Energy Intensive

• Scope of Energy Conservation spans right from point of generation to point of use.

Compressed air energy

16%

Heat of

Ratio: 8:1

Understanding the ContextWhy ENCON in Compressed Air System ?


Heat of compression

84%

Compressed Air – Energy Utilization

Leaks5%

End users9%

Pressure drop2%

Heat of compression

84%

• CAPEX• Cost of energy to operate the driver• Space cost• Installation cost• Routine maintenance cost

Understanding the ContextWhere do I Save Cost in Compressed Air System ?


• Routine maintenance cost• Repair cost• Overhaul cost• Supervisory cost

•Understanding the Context•Need for EnCon•Saving Potential

Contents


• Designing Energy Efficient Compressed Air System

•Supply•Distribution•Demand

• Supply– Compressor– System

Controls– Air Dryer– Aftercoolers

Designing Energy Efficient “CAS”• Distribution

– Air piping– Filters– Lubricators


– Aftercoolers– Air Filters– Primary

Storage– Flow controls

All elements of Compressed Air System provide opportunity for energy savings

•Demand–Pneumatic tools–Mechanical drive–Blowers–Vacuum generators–Etc . . .

Ten Questions You Should Ask Before Purchasing Air


Ask Before Purchasing Air Compressor

1. Do I Need a Compressor ?

2. Can I Not eliminate the usage of Compressed Air?

3. What Air Quality Do I Need ?

4. Where will compressor be located?

5. How much pressure (PSI) is needed?

Designing Energy Efficient “CAS”Supply Side


4. How much air flow (CFM) is needed?

5. What horsepower is required?

6. What type and size tank is needed?

7. What are the electrical requirement?

8. What Compressor Features Are Needed?

9. Do I Need a dryer?

• Pressure• Capacity• Horsepower

Remember The Three Main Parameters?

Three Parameters Are Directly Related

Air Basics

Designing Energy Efficient “CAS”Supply Side


• Horsepower

• Capacity Or Flow Determines How Much Work Is Done.

• Pressure Determines How Fast The Work Is Done.• Horsepower Is The Energy Input Required To Get

The Work Done.

Horsepower = Pressure x Flow x Constant

Three Main Parameters As A Formula

Air Basics


The Three Are Directly Related


The Three Main Parameters As A Formula

Air Basics




The Three Main Parameters As A FormulaThe Three Main Parameters As A Formula

Air Basics



“ Think, Learn, Apply”



Air Basics



Can you Increase Horsepower Of An Electric Motor??




Air Basics



Or



• Centrifugal Air compressors with Heat recovery units. (Capacity >1500 cfm)

• Two stage Rotary screw compressors. (Capacity < 1500 cfm)

• Single Stage rotary screw compressors with integrated VFD (5 to 50 hp), Refrigerated Dryer & Air receiver

Designing Energy Efficient “CAS”Supply Side – Selection of Compressor - Guidelines


• Screw Compressors with Hybrid Permanent Magnet motors (50hp to 350 hp)

• Skid packaged Reciprocating Air compressors for Oil free Air (50 to 1000 cfm)

• Properly sized air receivers & Air Treatment Components (Variable capacity ref dryer & Heat of compression dryers)

A Paper mfg manufacturing company

• Replacement of old & inefficient multiple reciprocating compressors with

one Centrifugal air compressor

• 4 # 1000CFM Base Load & 1 # 1000CFM trimming reciprocating air

compressors.

• Power consumption - 700kW for 3500CFM@100PSIG

• Investment - Rs.75Lacs.

Case Study


• Centrifugal air compressor - 560kW for 3500CFM

• Energy Savings – 140 kW

• Payback period less than 2 years.

Benefits Achieved:• High efficiency, highly reliable, auto control, low maintenance prone

compressors

Centrifugal Compressor


The most Cost-effective SolutionMajor IR CENTAC Customer in Pulp & Paper Industries• Hyundai Motors India Limited• Ford India• Maruti• CPCL,MRPL,GGSR,BPCL• ITC Limited, HNPL,HPCL,BILT and more

Centac with Heat Recovery Unit


Save upto 40% of the power consumption using Heat recovered thru the water (intercooler & after cooler)

Two stage screw compressors

⇒ Air is compressed in two stages, which allows “More Flow/ Unit Power”

⇒ Optimization of power usage–ability to upgrade existing systems by replacing with 2-

2 Stage Energy Savings


systems by replacing with 2-stage and getting more flow (increased value)

⇒ This increases the overall compression efficiency up to 15% of the total full load power consumption.

• VFD provides the ability to exactly match the compressors’ output to the capacity required by a plant air system.

Screw Compressors with Integrated VFD

� Provides constant system pressure +/- 2psi� Significant energy savings.� Precise pressure control.


� Prolonged life of the compressor.

Hybrid Permanent Magnet motors for Rotary Screw Com pressors

Cylindrical Roller Bearing

Triple Lip Shaft Seal

Duplex Tapered Roller Bearing

Direct drive – Motor stator mounted on primary rotor shaft


Airend Discharge Connects directly to Separator Tank

Triple Lip Shaft SealAspirated, Scavenged

Bearing Coolant Dam

95% efficiency, .96 power factor

Hybrid Permanent Magnet Motors

Induction MotorInduction Motor HPM MotorHPM Motor


PDP = Class 1 or 2

Compressed Air Quality ISO 8573.1

QualityClass

1 -100.0 -702 -40.0 -403 -4.0 -20

WaterPressure Dewpoint (°F / °C)

Designing Energy Efficient “CAS”Supply Side – Selection of Dryer - Guidelines


PDP = Class 1,2 or 3

PDP = Class 4, 5 or 6

3 -4.0 -204 37.4 35 44.6 76 50.0 10

Common findings with un-managed systems:

o More compressors are running than required

–Higher energy

–Higher maintenance

–Lower reliability, less standby capacity

Why System Control?

System Automation


–Lower reliability, less standby capacity

o System pressure is much higher than required

–Higher energy

–Higher maintenance

–Lower quality and repeatability

As much as 20%-60% of the energy used to operate typical compressed air

systems…is wasted!

Control Objective

• Manage Compressors

• Base load & trim

• Single point pressure control

• Stabilize Pressure

System Automation


• Stabilize Pressure

• Prioritize Sequences

• Operate only as needed

Fully Loaded and Standby Compressors

Control Philosophy:

Base Load- Trim Load…

System Automation


Variable Speed Trim Compressors

• Pipe System-the compressed air distribution system that carries the air from compressor discharge to the point of use (tools or equipment).

Designing Energy Efficient “CAS”Distribution System


• 2 basic types– Loop– Grid

Loop Systems

• Loop systems – Compressor/s located centrally– Air to point of use from two directions– Pressure droop is cut in HALF

� How….think of it as doubling the pipe size

•


• What’s good about them– Good pressure distribution– Good flow distribution– Great for high usage/production facilities– Easy to expand/add drops later (and more cost

effective)

Grid Systems

• Grid Systems– Simply a main trunk line with several branches serving

points of use/drops.– Compressor/s located at one end of trunk line– Not as efficient as the loop/unit loop systems


• What’s good about them– Might be cheaper to install than a loop/unit loop system– Simple & intuitive

Materials

• Typical materials– Stainless Steel

� Clean, expensive– Aluminum

� No scale rust, cost– Black iron

� Cheap, high labor

• Connection types– Thread– Flange– Compression– Crimp– Sweat (solder),


� Cheap, high labor – Galvanized

� Cheap, dirty– Copper

� Little scale, cost– Brass (fittings)

� Tough, expensive

– Sweat (solder), – Twist lock– Press fit

• For every 2 psi increase in pressure approximately 1% more power is

required.

• Compressors capacity to horsepower or specific powe r ratio is

approximately 4 to 5 cfm-fad per hp .

• The typical oil consumption for rotary screw compre ssors per 100 cfm-

fad at a rated 4 ppm is approximately 1/2 gallon for every 2000 hours of

Rule of Thumb


fad at a rated 4 ppm is approximately 1/2 gallon for every 2000 hours of

operation .

• On a typical 75 deg F day with 75% RH a compressor can introduce 18

gallons of water in the form of condensate/vapor for every 100 cfm-fad .

• Every 20 deg F rise in operating temperature cuts lubricant life by 50%.

• Every 20 deg F reduction of air temperature cuts the moisture cont ent by

50%.

“Air is Free but Compressed Air is not !”

Thank you!

If you require any assistance in your Air system au dit & analysis, pl email us at [email protected]

Documents

“Compressed Air System Design for Energy Efficiency” · “Compressed Air System Design for Energy Efficiency ... • ITC Limited, ... Rule of Thumb 34 Energy Efficiency