Deep Dive Into Process EfficiencyAEP November 14, 2017

Kelly Kissock Ph.D., P.E. Department of Mechanical and Aerospace Engineering / Renewable and Clean Energy

University of Dayton, Dayton Ohio, U.S.A.

jkissock1@udayton.edu

Three Steps To Energy Efficiency

1.

2.

3.

Three Steps To Energy Efficiency

1. Develop Baseline

2. Identify and Quantify Savings Opportunities

3. Sustain Efforts Using Sustainable Investment Strategies

Baseline

1. …

2. ….

Baseline

• Graph Your Data

• Estimate Electricity and Fuel Use by Equipment

Interpret Electricity Billing Data

0

2,000

4,000

6,000

8,000

10,000

12,000

Jan-

00

Feb-

00

Mar-

00

Apr-

00

May-

00

Jun-

00

Jul-

00

Aug-

00

Sep-

00

Oct-

00

Nov-

00

Dec-

00

De

ma

nd

(k

W)

Identify and correct anomalies

Interpret Electricity Billing Data

Identify billing errors

Interpret Electricity Billing Data

0

20

40

60

80

100

120

140

160

180

200

12/22/1

994

2/24

/1995

4/26

/1995

6/26

/1995

9/26

/1995

11/22/1

995

1/25

/1996

3/26

/1996

5/24

/1996

7/26

/1996

9/25

/1996

11/22/1

996

Dem

an

d (

kW

)

0

200

400

600

800

1,000

1,200

1,400

1,600

En

erg

y (

kW

h/d

ay)

Actual Demand (kW) Billed Demand (kW) Energy (kWh/day)

Seasonal demand charge

Interpret Electricity Billing Data

0

500

1,000

1,500

2,000

6/6/

1995

8/7/

1995

10/6/1

995

12/6/1

995

2/6/

1996

4/4/

1996

6/6/

1996

8/6/

1996

10/7/1

996

12/6/1

996

2/6/

1997

4/7/

1997

Dem

an

d (

kW

)

0

5,000

10,000

15,000

20,000

25,000

En

erg

y (

kW

h/d

ay)

Demand (kW) Energy (kWh/day)

Demand relatively constant but energy use driven by production

Graph Electricity vs Production

Interpret Fuel Billing Data

Fraction for production = 310 / 430 = 72% Fraction for space heating =

Graph Fuel Use Versus Temperature

• High Data Scatter = Poor Control•Observation: heating energy varies by 3x at same temp•Discovery: didn’t close shipping doors

Estimate Electricity and Fuel Use by Equipment

Equipment Rated Power Frac Loaded Oper Hours Elec Use

(hr/yr) (kWh/yr)

AC #1 50 hp 90% 5,000 187,500

Lights 10 kW 100% 6,000 60,000

… … … … …

Other 10,000

Utility Bill Total = 257,500

Equipment Rated Input Frac Loaded Oper Hours Gas Use

(Btu/hr) (hr/yr) (MBtu/yr)

Boiler 1 1,000,000 70% 5,000 3,500

Make Up #1 500,000 100% 2,000 1,000

… … … … …

Other 500

Utility Bill Total = 5,000

1) Estimate energy use from:

• rated power• frac loaded• operating hours

2) Calibrate sum against measured total energy use

Graph Electricity And Fuel Use by Equipment

0% 12% 24% 36% 48% 60%

Vacuum Pumps

Process Blowers/Fans

Lighting

Dust Collectors

Sanders

Other Process Motors

Air Compressors

Process Heating

Other

20%

18%

17%

12%

12%

8%

6%

5%

2%

Estimated Electrical Use Breakdown

0% 10% 20% 30% 40% 50% 60%

Other Fuel Using Equipment

Gas Fired Heater

Endo Generators

Sterlco Water Heater

Potable Water Heater

51%

13%

12%

11%

1%

Estimated Natural Gas Use Breakdown

Identify and Quantify Savings Opportunities

1. .

2. .

3. .

Identify and Quantify Savings Opportunities

1. List energy systems in your facility

2. Look for savings in conversion, distribution and

end-use of each system

3. Improve part-load efficiency of each system

HVAC Systems with Savings Opportunities

• Lighting

• Zone temperature

• Outdoor air

• Fan system

• Pumping system

• Cooling system

• Boiler system

Ask Two Questions

1) Is system working as intended?

2) Can control be improved?

Industrial Systems with Savings Opportunities

Components of Energy Systems

Conversion Distribution UseEnergy

Supply

Energy

Use

Inside-Out Analysis Approach

Name an Energy Saving Opportunity

in Each Component of Some Energy System

1 Conversion

2 Distribution

3 End use

Inside-out Approach to Compressed Air:

Reduce Blow-off with Solenoid Valves

Flow from open tube (scfm) = 11.6 (scfm/lbf) x [Diameter (in)] 2 x Pressure (psia)

ExampleInstall solenoid to shut-off blowoff from

3/8-in pipe at 100 psig 80% of timeFlow Savings = 11.6 (scfm/lbf) x [3/8 (in)]2 x

115 psia x 80% = 150 scfmCost Savings = 150 scfm / (4.2 scfm/hp x

0.90) x 0.75 kW/hp x (1-0.50) x 6,000 hr/yr x $0.10 /kWh = $8,933 /yr

Cost of 3/8-inch solenoid valve = $100

Plant manager taking charge!

Reduce Blow off with Air-Saver Nozzles

Nozzles maximize entrained air and generate same flow and force with ~50% less compressed air

ExampleAdd nozzle to 1/8-in tube at 100 psigFlow Savings = 11.6 (scfm/lbf) x [1/8 (in)]2

x 115 psia x 50% = 10.4 scfmCost Savings = 10.4 scfm / (4.2 scfm/hp x

0.90) x 0.75 kW/hp x (1-0.50) x 6,000 hr/yr x $0.10 /kWh = $620 /yr

Nozzles cost about $10 each

Inside-out Approach to Compressed Air:

Identify Leaks Using Ultrasonic Sensor

Automatic Sequencer Control:

VSD Always Trim

VSD compressor IS always trim compressor

Reduce Excess Electric Lighting

Known

• Measured = 50 fc

• Required = 30 fc

Action

• Disconnect (1- fcreq/fcmea)

% of fixtures

Savings

• Disconnect

= (1 – fcreq / fcmea)

= (1 – 30 / 50)

= 40% of fixtures

Position Task Lighting Above Work Areas

Reposition Lights Below Scaffolding

Paint Ceilings White

Replace Metal Halide

with High Bay Fluorescent Lights

High bay fluorescent (HBF) lights:

• Reduce energy use by 50% or more

• Improve CRI

• Reduce maintenance costs

• Stabilize light level

• Improve light distribution

• Can be turned on/off as needed, w/ occupancy or w/photocells

Replace Fluorescent with LED

LEDs use 25% less energy than fluorescents,

but biggest advantage may be dimming.

Control Opportunities:

1) Dimming increases sky lighting savings.

Working hour savings potential from

LightSim:

On/Off control: 86%

Dimming control: 93%

2) Dimming perimeter lights

77 W 55 W

Reduce Steam Demand

• Insulate hot

surfaces at end

use

• Cover

uninsulated

tanks

Fix Steam Traps

• Steam traps are automatic valves that discharge condensate from a steam line without discharging steam.

• If trap fails open, steam by-passes heat exchanger and releases heat in condensate return system

• If trap fails closed, condensate fills the heat exchanger and chokes-off heat to process.

• Fixing failed steam traps is highly cost-effective.

Insulate Pipes and Tanks

• Insulate

– Steam pipes

– Condensate return pipes

– Condensate return tanks

– Deaerator tank

– Valves

Reduce Excess Air by Adjusting Air/Fuel Linkage

• Most boilers use mechanical linkages

between natural gas supply valves and

combustion air inlet dampers.

• Unfortunately, linkages seldom hold air/fuel

ratio constant over firing range.

• Adjust linkages so smallest excess air is

10%.

Which Component Has the

Biggest Bang for the Buck?

1. Conversion

2. Distribution

3. End use

Savings Multiply From Inside-Out

Inside-out Efficiency Savings (kWh)

Reduce pipe friction - 1.00

Pump 70% 1.43

Drive 95% 1.50

Motor 90% 1.67

Transmission and distribution 91% 1.83

Power plant 33% 5.55

Think About Control at Part Load

• Engineers design systems for

maximum load

• Systems seldom (never) operate

at maximum load

• Energy efficiency at part load

varies widely

• Thus, pay attention to part load

control

Control (Part-load) Efficiency

Fraction

Energy

Input

Fraction Useful Output

100%

100%

Worst

Bad

Good Excellent

Inefficient Flow Control

By-pass loop(No savings)

By-pass damper (No savings)

Valve/damper/vanes(Small savings)

Intermittent Flow(Small savings)

By-pass Valve

Efficient Flow Control

Trim impellor for constant-volume

pumps

Slow fan for constant-volume

fans

VFD for variable-volume pumps

or fans

Close By-pass Valve

VFD

dP

VFD Fan/Pump Control Strategies

For 50% Flow

B: Fan/pump outlet

C: Supply duct/pipe

D: Critical zone/valve

reset

DP

V

AB

V2 = V1 / 2 V1

C

D

Pset,outlet

Pset,duct

Pset,zone = 0

Air Compressor Control

Savings if

FC = 25%

Savings if

FC = 75%

Savings from improving control are biggest on under-loaded (trim) compressors

Part-load Control Determines

Operating Strategy for Multiple Units

Air Compressor Efficiency Increases With Load

Run Minimum Number of Compressors

Boiler Efficiency Decreases with Load

Efficiency highest at LOW EXCESS AIR and LOW STACK TEMPERTURES

– Reduce excess air by improving combustion air control

– Reduce stack temperature by operating at lower firing rate or cleaning heat exchanger surfaces

70%

75%

80%

85%

90%

0 10 20 30 40 50 60 70 80 90 100

Excess Air (%)

Eff

icie

ncy

Ts=300F

Ts=400F

Ts=500F

Run Maximum Number of Boilers

Efficiency highest at low-fire

Run multiple boilers at mid-fire to increase efficiency

– Run 1 boiler at high fire: Eff = 81%

– Run 2 boilers at mid-fire: Eff = 82%

Chiller Efficiency Varies with Load

Constant-speed: efficiency decreases as load decreases

Variable-speed: efficiency increases as load decreases

Stage Constant-Speed Chiller LWT Setpoints

to Run Fewest Possible Chillers

Running 1 chiller at (60% load and 0.30 kW/ton) instead of

2 chillers at (30% load and 0.37 kW/ton) saves 19%.

Stage Variable-Speed Chiller LWT Setpoints

to Run Maximum Possible Chillers

Running 2 chillers at (40% load and 0.22 kW/ton) instead of

1 chiller at (80% load and 0.27 kW/ton) saves 19%.

If Variable and Constant-Speed Chillers

Employ Controller So Variable is Always Trim

Size VS 125% bigger than next biggest chiller to avoid control gaps.

Depending on load, controllers save 5-10%

List 2 Part-Load Control Opportunities to

Investigate in Your Facility

1.

2.

Sustain Efforts Using

Sustainable Investment Strategies

Reinvest Part of Savings to Achieve

Net-zero Co2 At Net-zero Cost

Energy

savings pays

for renewable

energy

Net CO2 zero at

net zero cost!

Sustainable Manufacturing and Buildings

Summary

Develop BaselineGraph data

Estimate energy use by equipment

Identify and Quantify Savings OpportunitiesThink in terms of energy systems

Break down energy systems into end use, distribution and conversion

Pay attention to part load control

Maximize Efficiency Using Sustainable Investment StrategiesReinvest part of savings into more savings and renewable energy

What’s New?

• Data analytics

• Advanced rules-based controls

• Machine-learning control

Temperature-Based Economizer Control

Data Analytics: Plot MAT-RAT vs OAT-RATWorking Economizer

Integrated

Hours –

37%

Modulating

Hours –

27%

Cooling

Hours –

22%

Heating

Hours –

14%

Data Analytics: Malfunctioning Economizer

Source: Hourly logged data. 10/21/2016 – 11/15/2016

Advanced Rules-based Control:

Use CO2 Sensor in Return Air to Reset Foa,min

Foa,min,CO2 = (ppm,return - ppm,outdoor)

(ppm,upper limit – ppm,outdoor)

CO2

Sensor

When Foa,min reduced by 50% for 20% of time

when Toa>Tr, outdoor air cooling savings = 10%

Data Analytics + Advanced Rules Based Controls:

If Mean Damper Position < 70% Open,

Reduce Static Set Point

Baseline:

Pset = 1.5” Dampers 65% Open

Post Baseline:

Pset = 1.0” Dampers 67% Open

Savings From Reducing Pset from 1.5” to 1.0”

Savings: 26%

Fan Outlet Control to Turkur/Ma Reset Control

51% fan energy savings

Zone CO2 Sensor

Duct Static Pressure Reset

Duct Static Pressure Before and After Reset Vmin

Measured Savings

Machine-Learning Control

• Run efficiently through coaching or learning

• Rules-based control requires explicit knowledge

about systems

• Machine learning control uses neural networks,

clustering techniques + classical optimization to

learn optimum behavior

Machine-Learning Control Example

Global optimization analyzes all possible pumping

combinations and chooses the combination closest to

the cost optimized value.

Industrial Assessment Center Program

Goals

Help industry be more resource-efficient and cost-competitive

Train new energy engineers

Advance practice and science of energy efficiency

Sponsored by U.S. Department of Energy (DOE)

Began during 1970’s “energy crisis”

24 centers at universities throughout the U.S.

20 no-cost assessments per year for mid-sized manufacturers

Qualifying For A Free IAC Assessment

To qualify for a free assessment, you must:

Be a water utility or a manufacturer with SIC code between 2000 –3999

Have total annual energy costs between $100,000 - $2.5 million

Ohio Lean Buildings Program

Sponsored by Ohio Development Services Agency

4 universities and 6 consulting companies

Goals

Make Ohio’s buildings more energy-efficient and cost-competitive

Train new energy engineers

Advance practice and science of energy efficiency

Qualifying for an OLB Assessment

To Qualify for a Building Assessment, you must:

Commercial and institutional buildings larger than 10,000 ft2

State of Ohio pays for 50% of assessment

Client qualifies for low-interest loan for implementation

go.udayton.edu/iac

(937) 229-3343

udayton.iac@gmail.com

University Of DaytonIndustrial Assessment Center &Ohio Lean Buildings Program U.S. Department of Energy and State of Ohio Sponsored Programs