University of Dayton Industrial Assessment Center

1
University of DaytonIndustrial Assessment Center

• Debriefing Manual

2
Energy Costs and CO2
3
Natural Gas Price Trends
Source U.S. Dept. of Energy, Annual Energy
Review 2005, Report No. DOE/EIA-0384(2005)
4
Natural Gas Price Volatility

• Source Canada National Energy Board,
  http//www.neb.gc.ca/energy/EnergyPricing/HowMarke
  tsWork/NG_e.htm

5
Electricity Price Trends
Source U.S. Dept. of Energy, Annual Energy
Review 2005, Report No. DOE/EIA-0384(2005)
6
Electricity Price Volatility

• Residential electricity prices will increase 2.6
  in 2007, compared to 2.2 over the last 10 years
• Those regions with States undergoing market
  restructuring may experience more price
  volatility.  For example, residential prices in
  the East North Central region are projected to
  rise by nearly 6 percent in 2007, compared to the
  last 10-year average of only 1 percent.

Source U.S. Dept. of Energy, Short Term Energy
Outlook, May 2007, http//www.eia.doe.gov/emeu/ste
o/pub/contents.html
7
Inside Out Method
8
Traditional Outside-In Approach To Energy
Efficiency
Traditional Analysis Sequence for Reducing Energy
Use
Traditional Analysis Sequence for Reducing Waste
Result Incremental improvement at high cost
9
Preferred Inside-out Approach To Energy
Efficiency
Inside-Out Analysis Sequence for Reducing Energy
Use
Inside-Out Analysis Sequence for Reducing Waste
Result Significant improvement at minimal cost
10
Inside-out Approach to Energy Efficiency

• Reduce end-use loads
• Reduce distribution losses and loads
• Improve primary energy conversion equipment

11
Electrical System
12
Power Factor and Phase Lag

• Inductive loads such as AC motors cause phase lag
  between voltage and current, which converts some
  supplied power (kVA) into un-useable reactive
  power (kVAr) and decreases useable power (kW)
• Thus, supplied power (kVA) increased by utility
  to deliver required useable power (kW)

13
Power Factor, kVA and kW

• One week of
• kVA, kW, PF

14
Power Factor

• Inductive loads such as AC motors cause phase lag
  between voltage and current, which converts some
  supplied power (kVA) into un-useable reactive
  power (kVAr) and decreases useable power (kW)
• Thus, supplied power (kVA) increased by utility
  to deliver required useable power (kW)
• PF is ratio of useable power (Pa) and supplied
  power (Ps)
• Low PF has three adverse effects
• Utilities charge for low PF
• Increased supplied power (kVA) increases line
  losses, line size, transformer size
• May cause sensitive electrical equipment to
  malfunction.
• Good practice to maintain PF at 90 or more by
  right-sizing under-loaded motors and adding
  capacitors

15
Reduce Peak Demand by Moving Electrical Operation
to Light Shift
Even shifts moving operation increases demand
Uneven shifts moving operation decreases demand
16
Stagger Startup of Barrel Heaters
Sunday barrel pre-heat, with hydraulic motors
off, does not generally set peak demand
17
Lighting
18
Inside-out Approach for Lighting Efficiency

• End-Use
• Deliver required quantity of lighting
• Maximize daylighting
• Distribution System
• Position lights effectively
• Improve luminaire efficiency
• Primary Equipment
• Install high-efficiency lighting

19
Paint Ceilings White

• White ceilings reflect more light onto the work
  plane.
• Lighting levels under identical lights were
• 30 fc under white ceiling
• 10 fc under black ceiling
• Use 1/3 as many lights under white ceilings

20
Replace Colored / Fiberglass Windows with
Corrugated Polycarbonate
Corrugated polycarbonate costs about the same as
and is installed just like corrugated fiberglass,
but lets in about 10 times more light.

21
Employ Skylighting

• Skylights
• Highest quality light
• Reduce lighting energy costs
• Increase heating/cooling costs
• To maximize cost-effectiveness
  
• Analyze competing costs
• Identify optimum skylight / floor area ratio

http//www.sprung.com/Product/Images/SkylightsSqua
re
22
Light Levels vs. Skylight Area
23
Total Cost Savings vs. Skylight Area
24
Recommended Skylighting Areas

• Optimum skylight/floor area ratio
• Ranges from 1 to 6
• Increases with target lighting level
• Decreases as lights are more efficient
• Energy cost savings
• Range from 1 to 25 cents per ft2 floor area-year
• Increase with target lighting level
• Decrease as lights are more efficient

Wallmart with 5 skylight/floor ratio and lights
turned off
25
Replace / Modify Inefficient Luminaires

• Acrylic to aluminum MH luminaires
• Add reflectors to fluorescent strip lighting

• Known
• Fluorescent strip lights with CU .65
• Action
• Add reflectors so CU 0.75
• Savings
• Fraction luminaires removed (1/CU1 1/CU2)
• Fraction luminaires removed 1/.65 1/.75 20

26
Install Reflectors on T12 Fixtures without
Reflectors

• Reflectors push light downward onto the work
  plane rather than allowing it to escape upward
  onto the ceiling.
• 63 fc under fixtures with reflectors and 20 fc
  under fixtures without reflectors.
• Installing reflectors on half of current fixtures
  would provide same lighting and cut energy use in
  half.

27
Replace Incandescent with Compact Fluorescent
Lamps

• CF lamps
• Use 75 less energy
• Last 8-10 times longer

• Known
• 100 100-W I lamps, life 1,000 hours, cost
  1, operating 6,000 h/yr
• Action
• Replace with 23-W CF lamps, life 10,000 hours,
  cost 5
• Savings
• 100 lamps x (.100 - .023) kW/lamp x 6,000 h/yr
  46,200 kWh/yr
• 46,200 kWh/yr x 0.10 /kWh 4,620 /yr
• 100 lamps x 6,000 h/yr x (1/1,000 5/10,000)
  (h-lamp)-1 300 /yr
• 4,620 /yr 300 /yr 4,920 /yr

28
Replace T12 Lamps Electro-magnetic
Ballastswith T8 Lamps Electronic Ballasts

• T8 lamps with electronic ballasts
• Use 25 less energy
• Improve CRI and eliminate flicker

• Known
• 100 fixtures with four 34-W T12 lamps and
  electro-magnetic ballasts operating 6,000 h/yr
• Action
• Replace with four 32-W T8 lamps and electronic
  ballasts
• Savings
• 100 fix x (.144 - .112) kW/fix x 6,000 h/yr
  19,200 kWh/yr
• 19,200 kWh/yr x 0.10 /kWh 1,920 /yr

29
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

30
Metal Halide to High Bay Fluorescent
31
Light Output vs. Temperature

• Metal Halide
• Constant output
• T8
• Max at 77 F
• 80 at 50 F and 112 F
• T5
• Max at 93 F
• 80 at 64 F and 131 F

Source http//www.ruudlighting.com
32
Replace High Pressure Sodium with High Bay
Fluorescent Lights

• Photos of lighting under HPS and HBF lights in
  same facility taken with same camera.

33
Motors
34
Turn Off Motors When Not in Use

• Stamping press motors
• 65 of power dissipated as heat due to friction
• Use 65 of power required during stroke part of
  cycle while idle
• Hydraulic system motors
• Use 40 of full load power even while idle.
• Motor startup too brief to influence peak demand.

35
Replace Smooth with Notched V-belts

• Example
• Notched belts are
• 3 more efficient than smooth belts
• Last 50 to 400 longer than smooth belts
• Cost only about 30 more than smooth belts
• Estimated Savings
• 25-hp motor, 91 efficient, 75 loaded
• 25 hp x 0.75 kW/hp x 75 loaded / 91 x 3 0.5
  kW
• 0.5 kW x 6,000 hours/yr 3,000 kWh/year
• 3,000 kWh/year x 0.10 /kWh 300 /year
• Implementation Cost
• Negligible
• Simple Payback
• Immediate

36
Replace V-belt with Synchronous Belt Drive

• Example
• Synchronous belt drives are
• 5 more efficient than v-belt drives
• Last 24,000 hours
• Estimated Savings
• 100-hp motor, 91 efficient, 75 loaded
• 100 hp x 0.75 kW/hp x 75 loaded / 91 x 5 3.1
  kW
• 3.1 kW x 6,000 hours/yr 18,600 kWh/year
• 18,600 kWh/year x 0.10 /kWh 1,860 /year
• Implementation Cost
• 12 /hp x 100 hp 1,200
• Simple Payback
• 1,200 / 1,860 /yr 8 months

37
Under-loaded Motors Efficiency Declines

• Example
• Estimated Savings
• 75-hp motor is 15 loaded. Operates at an
  efficiency of about 50. The power requirement
  is about
• (75 hp x 15 x .746 kW/hp) / 50 16.8 kW
• 15-hp motor would be 75 loaded and 86
  efficient. The power requirement would be about
• (15 hp x 75 x .746 kW/hp) / 86 9.8 kW
• Total electricity savings would be about
• 16.8 kW - 9.8 kW 7 kW
• 7 kW x 48 hr/wk x 50 wk/yr 16,800 kWh/yr
• 16,800 kWh x 0.10 /kWh 1,680 /yr
• Estimated Implementation Cost and Simple Payback
• Cost of straight drive, 15-hp motor and labor
  would be about 500. Simple payback would be
  about
• SP 500 / 1,680 /yr x 12 months/yr 4 months

38
Under-loaded Motors Power Factor Declines
39
Power Factor

• Inductive loads such as AC motors cause phase lag
  between voltage and current, which converts some
  supplied power (kVA) into un-useable reactive
  power (kVAr) and decreases useable power (kW)
• Thus, supplied power (kVA) increased by utility
  to deliver required useable power (kW)
• PF is ratio of useable power (Pa) and supplied
  power (Ps)
• Low PF has three adverse effects
• Utilities charge for low PF
• Increased supplied power (kVA) increases line
  losses, line size, transformer size
• May cause sensitive electrical equipment to
  malfunction.
• Good practice to maintain PF at 90 or more by
• Right-sizing under-loaded motors
• Adding capacitors

40
Motor Efficiency and Costs
Source US DOE Motor Master 2.0
41
Motor Lifecycle Cost Dominated by Energy

• Consider
• 20 hp motor, 93 efficient, 80 loaded, 6,000
  hr/yr, 10 years
• Cost of electricity
• 20 hp x 80 x 0.75 kW/hp / 0.93 x 6,000 hr/yr
  77,500 kWh/yr
• 77,500 kWh/yr x 10 yr x 0.10 /kWh 77,500
• Cost of motor
• Purchase cost 1,000
• Ratio of energy to purchase cost
• 77,500 / 1,000 77 to 1
• Thus,
• Use efficient motors!

42
1 Improvement in Efficiency Equals Purchase Cost

• Consider
• 20 hp motor, 93 efficient, 80 loaded, 6,000
  hr/yr, 10 years
• Cost of electricity
• If efficiency 93, then 10 year electricity
  cost 77,500
• If efficiency 94, then 10 year electricity
  cost 76,600
• Savings 77,500 - 76,600 900
• Cost of motor
• Purchase cost 1,000
• Thus,
• Purchase premium efficiency motors!

43
Replace Rather than Repair Old Motors
Assuming 80 loaded, 6,000 hr/yr, 0.10 /kWh
44
Fluid Flow
45
Fluid Flow Systems

• Inside is work required to move fluid
• Reduce friction
• Smooth pipes/ducts (PVC, Copper, Steel)
• Large diameter pipe/ducts (P k D5)
• Low pressure drop fittings /valves (long radius
  elbows)
• Maintain proper inlet/outlet conditions
• Unrestricted flow for 6 duct diameters
• Pump slow, pump long

46
Minimize Pipe Friction

• Use large diameter pipes
• DP headloss C / D5
• Doubling pipe diameter reduces pumping costs by
  97
• Use smooth plastic pipes
• fsteel 0.021 fplastic 0.018
• Pumping savings from plastic pipe
• (0.021 0.018) / 0.018 17
• Less friction reduces pumping costs and cooling
  load

47
Employ Energy-Efficient Flow Control

• Most pump and fan systems
• Sized for peak flow, but
• Operate at lower flows
• Or require variable flows
• Use energy-efficient methods to control flow

48
Old Inefficient Flow Control
By-pass loop (No savings)
By-pass damper (No savings)
Outlet valve/damper (Small savings)
Inlet vanes (Moderate savings)
49
New Efficient Flow Control
Trim impellor for constant-volume pumps
Slow fan for constant-volume fans
VFD for variable-volume pumps or fans
50
Inefficient and Efficient Flow Control
51
Install VFD on Process Cooling Loop Pump

• W2 W1 (V2/V1)3
• Reducing flow by 50 reduces pumping costs by 87

52
Variable Frequency Drive Costs
53
Variable-Speed Cooling Tower Fans
Variable speed cooling tower fans save the most
energy on year-round loads with high set-point
temperatures characteristic of industrial process
cooling applications.
54
Compressed Air
55
Inside-out Approach to Compressed Air Efficiency

• End use
• Install solenoid valves to shut off air
• Install air saver nozzles
• Install differential pressure switches on bag
  houses
• Use blower for low-pressure applications
• Distribution
• Fix leaks
• Starve leaks
• Install no-loss drains
• Decrease pressure drop in distribution system
• Compressor System
• Compress outside air
• Use refrigerated dryer
• Direct warm air into building during winter
• Use load/unload control with auto shutoff or VSD
  for lag compressor
• Stage compressors with pressure settings or
  controller
• Add compressed air storage to increase auto
  shutoff

56
Eliminate Continuous Blowoff with Solenoid Valves

• Known
• Open tube air loss V (scfm) 11.6 x ID (in)2
  x P (psia)
• Solenoid valves cost between 30 - 350
• Operate up to 600 cycles per minute from 50-150
  psig
• Controlled by process machines, photo sensors,
  etc.
• Action
• Replace continuous blowoff from 100 psig, 3/8-in
  pipe with solenoid valve open 20 of time
• Savings
• V tube 11.6 x 3/8 (in)2 x 115 (psia) 188
  scfm
• 188 scfm x 80 x 0.75 kW/hp / (4.2 scfm/hp x
  0.90) 30 kW
• 30 kW x 6,000 hr/yr x 0.10 /kWh 18,000 /yr
• If load/unload at 60 6,200 /yr x 40 7,200
  /yr

57
Reduce Blow-off with Air-Saver Nozzles

• Known
• Open tube air loss V (scfm) 11.6 x ID (in)2
  x P (psia)
• 3/8-in tube, 100 psig, 2000 hr/yr, 4.2 scfm/hp
  comp
• 3/8-in vortex nozzle consumes 31 scfm
• Action
• Add nozzle to tube
• Savings
• V tube 11.6 x 3/8 (in)2 x 115 (psia) 188
  scfm
• V nozzel 31 scfm
• (188 31) scfm x 0.75 kW/hp / (4.2 scfm/hp x
  0.90) 31 kW
• 31 kW x 2,000 hr/yr x 0.10 /kWh 6,200 /yr
• If load/unload at 60 6,200 /yr x 40 2,480
  /yr

58
Control Bag House Air Pulses with Differential
Pressure Sensor

• Known
• Timed pulse uses 34 scfm at peak production
• Production is currently 60 of peak
• Action
• Install differential pressure control
• Savings
• 34 scfm x 40 x 0.75 kW/hp / (4.2 scfm/hp x
  0.90) 2.7 kW
• 2.7 kW x 6,000 hr/yr x 0.10 /kWh 1,620 /yr
• If load/unload at 60 1,620 /yr x 40 648
  /yr

59
Use Blower For Low-pressure Applications

• Known
• Air compressor at 100 psig 4.2 scfm/hp
• Low-pressure blowers at 20 psig 7.2 scfm /hp
• Tank currently uses 140 scfm of comp air
• Action
• Install low-pressure blower
• Savings
• 140 scfm x 0.75 kW/hp x (1/4.2 1/7.2) hp/scfm
  / 0.90 11.6 kW
• 11.6 kW x 6,000 hr/yr x 0.10 /kWh 6,960 /yr
• If load/unload at 60 6,960 /yr x 40
  2,780 /yr

60
Purchase Ultrasonic Sensor and Fix Leaks

• Known
• Most compressed air systems lose between 5 and
  20 of compressed air to leaks.
• To find leaks
• listen with the unaided ear or ultrasonic
  sensor.
• monitor compressor power when all production
  machinery is off.
• Inspect system for leaks once a week
• Action
• Fix single 1/32-inch leak
• Savings
• 1 scfm x 0.75 kW/hp / (4.2 scfm/hp x 0.90) 0.2
  kW
• 0.2 kW x 6,000 hr/yr x 0.10 /kWh 120 /yr
• If load/unload at 60 120 /yr x 40 48 /yr

61
Starve Leaks in Unoccupied Areas by Shutting Off
Branch Headers

• Known
• Total plant leak load 200 cfm
• Half of plant operates 6,000 hr/yr and half of
  plant operates 2,000 hr/yr
• Action
• Install solenoid valve to shut off air to unused
  area
• Savings
• 200 scfm x 50 x 0.75 kW/hp / (4.2 scfm/hp x
  0.90) 20 kW
• 20 kW x 4,000 hr/yr x 0.10 /kWh 8,000 /yr
• If load/unload at 60 8,000 /yr x 40 3,200
  /yr

62
Replace Timed Solenoid with No-loss Drains

• Known
• 3/8-inch drain with timed solenoid opens 3
  seconds every 30 seconds to discharge condensate.
• 3/8-inch no-loss float-type drains eliminates
  90 of air losses.
• 3/8-inch no-loss float-type drains costs about
  600
• Action
• Replace timed solenoid drain with no-loss drain
• Savings
• V drain 11.6 x 3/8 (in)2 x 115 (psia) 188
  scfm
• Fraction time open (3 sec / 30 sec) 10
• 188 scfm x 10 x 0.75 kW/hp / (4.2 scfm/hp x
  0.90) 3.7 kW
• 3.7 kW x 90 x 6,000 hr/yr x 0.10 /kWh 2,000
  /yr
• If load/unload at 60 2,000 /yr x 40 800
  /yr

63
Use Looped Piping to Decrease System Pressure
Drop

• Use looped rather than linear design
• Main line size from average cfm to get DP 3
  psi
• Branch line size from cfm peak to get DP 3psi
• Feed lines size from peak cfm to get DP - 1 psi
• Hose can generate DP 4 to 5 psi (proper
  selection of hoses is important!)
• Total DP lt 10 psig

64
Avoid Deadhead Connections
65
Properly Size Supply Piping / Hoses
66
Properly Size and Maintain Filters and Dryers

• Place filter upstream of dryer to protect dryer
• DP filter lt 1 psid
• DP refrigerated dryer lt 5 psid ( 90 F inlet and
  40 F outlet)

67
Reduce Compressor Operating Pressure
Fractional Savings
0.5 per psi

• Known
• Compressor draws 20 kW while producing 120 psig
  air
• Action
• Reduce pressure setting to from 110 to 100 psig
• Savings
• (P2high/P1)0.286 (110 psig 14.7 psia) / 14.7
  psia0.286 1.84
• (P2low/P1)0.286 (100 psig 14.7 psia) / 14.7
  psia0.286 1.80
• Frac savings (1.84 1.80) / (1.84 1) 4.8
  
• 20 kW x 4.8 x 6,000 hr/yr x 0.10 /kWh 580
  /yr

68
Compress Outdoor Air

• Known
• Compressing cooler outside air reduces
  compressor work
• Fractional Savings (Thi - Tlow) / Thi 2 per
  10 F
• Compressor draws 20 kW, Tin 80 F, Tout 50 F
• Action
• Install PVC piping to duct outside air to
  compressor
• Savings
• Frac Savings ((80 460) - (50 460)) / (80
  460) 5.5
• 20 kW x 5.5 x 6,000 hr/yr x 0.10 /kWh 660
  /yr
• If load/unload at 60 660 /yr x 40 264
  /yr

69
Replace Desiccant Dryer with Refrigerated Dryer

• Known
• Refrigerated dryer cools to Tdew-point 35 F,
  and use 4-6 W/scfm
• Desiccant dryer cools air to Tdew-point -40 F,
  but use 15 of compressed air for purging
• Current use 840 scfm from compressor at 4.2
  scfm/hp
• Action
• Install refrigerated dryer
• Savings
• Purge power
• 840 scfm x 15 x 0.75 kW/hp / (4.2 scfm/hp x
  90) 25 kW
• Refrigerated dryer power
• (840 scfm x 85 x 0.006 kW/scfm 4.3 kW
• (25 kW 4.3 kW) x 6,000 hr/yr x 0.10 /kWh
  12,420 /yr

70
Direct Warm Air Into Plant During Winter
Winter

• Known
• gt75 of compressor input power lost as heat
• Compressors draws 105 kW, heating system 80
  efficient, operates 2,000 hours per year
• Action
• Change ventilation or add duct work to direct
  warm air into plant during winter
• Savings
• 105 kW x 75 x 3,413 Btu/kWh x 2,000 hours/year
  540 mmBtu/yr
• 540 mmBtu/year / 80 x 10 /mmBtu 6,750 /year

71
Compressor Power vs Capacity By Control Mode
FP (FC x (1 FPNL) FPNL
72
Power Characteristics of Load/unload and
Modulation Control
73
Modulation vs Load/Unload with Auto Shutoff
74
Modulation to Load/Unload with Auto Shutoff
Savings

• Known
• Power draw measured at 79 kW in modulation 51 kW
  in load/unload with auto shutoff
• Action
• Switch from modulation to load/unload with auto
  shutoff
• Savings
• (79 51) kW x 6,000 hr/yr x 0.10 /kWh
  16,800 /yr

75
Stage Compressors

• If the same load/unload pressures for two
  compressors are the same, both compressors will
  operate at part-load.

• Stage compressors into a lead and lag
  compressor by setting the load/unload pressures
  of the lag compressor 5 psi less than the lead
  compressor.

• Staging allows the Lead compressor to run fully
  loaded and the Lag compressor to turn off or run
  at minimal load, increasing efficiency.

76
Stage Compressor Savings

• Known
• Two 100-hp, compressors operating between 95
  105 psig at 70 capacity
• FP (FC x (1 FPNL) FPNL
• Action
• Set base between 95 105 psig and lag between
  90-100 psig
• Savings
• Current
• FP (.7 x (1 .6) .6 .88
• Power 2 x 100 hp x .88 / .90 x .75 kW/hp 147
  kW
• Proposed
• Base 100 hp x 1.00 / .90 x .75 kW/hp 83 kW
• Lag FP (.2 x (1 .6) .6 .68 P 100 hp
  x .68 / .90 x .75 kW/hp 57 kW
• Base Lag 83 kW 57 kW 140 kW
• Savings (147 140) kW x 6,000 hr/yr x 0.10
  /kWh 4,200 /yr
• Savings if auto shutoff (147 100) kW x 6,000
  hr/yr x 0.10 /kWh 28,200 /yr

77
Add Compressed Air Storage
Minimal storage causes frequent cycling
Adding storage decreases cycling and enables
auto-shutoff

• Savings
• Add 500 gallons of storage
• Average power draw from 17 to 14.5 kW after
  adding storage
• (17 14.5) kW x 6,000 hr/yr x 0.10 /kWh
  1,500 /yr

78
Add Local Storage w/ Valve and Reduce Compressed
Air Pressure
79
Summary of Key Equations and Relations

• Input power (kW) Voltage (V) x Current (A) x
  1.73 x Power factor (kW/kVA) / 1,000 VA/kVA
• Peak input power (kW) Rated motor power (hp) x
  Service factor x 0.75 kW/hp / Motor efficiency
• Annual energy use (kWh/yr) Input power (kW) x
  Operating hours (hr/yr)
• Annual electricity cost (/yr) Annual energy
  use (kWh/yr) x Unit electricity cost (/kWh)
• Flow from open tube (scfm) 11.6 (scfm/lbf) x
  Pressure (psig) x Diameter (in) 2
• Input power from flow (kW) Flow (scfm) x 0.75
  kW/hp / (Specific output (scfm/hp) x Motor
  efficiency)
• Typical compressor/blower specific output 4.5
  scfm/hp at 100 psig 7.2 scfm at 20 psig
• Savings from reducing operating pressure 0.5
  per psi
• Savings from reducing intake air temperature 2
  per 10 F
• Refrigerated dryer electricity use 0.006
  kW/scfm Unheated desiccant dryer air use 15
  of flow
• Recoverable heat from air compressors 75 of
  electrical power (kW) x 3,412 (Btu/kWh)
• Fraction Power (Fraction Capacity x (1
  Fraction Power at No Load) Fraction Power at
  No Load
• Typical Fraction Power at No Load (Modulation
  Control) 0.70
• Typical Fraction Power at No Load (Load/unload
  Control) 0.50 - 0.60
• Typical Fraction Power at No Load (Variable Speed
  Drive) 0.10
• Typical Fraction Power at No Load (On/Off) 0.0

80
Process Cooling
81
Match Cooling Source to End Use
Near order of magnitude difference in costs!
82
Cooling Tower

• 500 ton tower delivers 7.5 mmBtu/hr
• Ppump 18 kW Pfan 20 kW Water 120
  gal/mmBtu
• Unit cost of cooling 1.22 /mmBtu

83
Water-Cooled Chiller

• E/Q 0.8 kW/ton 67 kWh/mmBtu
• Unit cost of cooling 6.70 /mmBtu

84
Air-Cooled Chiller

• E/Q 1.0 kW/ton 83 kWh/mmBtu
• Unit cost of cooling 8.30 /mmBtu

85
Absorption Chiller

• E/Q 1 Btu-heat / Btu-cooling Eff-boiler 80
• Unit cost of cooling 12.50 /mmBtu

86
Open-Loop Water Cooling

• DT 10 F V 12,000 gallons / 1 mmBtu
• Unit cost of cooling 72 /mmBtu

87
Compressed Air Cooling

• Vortex cooler uses 150 scfm at 100 psig to
  produce 10,200 Btu/hr cooling
• 4.5 scfm per hp
• Unit cost of cooling 272 /mmBtu

88
Add Heat Exchanger in Continuous Process with
Sequential Heating and Cooling
89
Add Heat Exchanger When Cooled Tank is Warmer
than Heated Tank
T 145 F Requires Cooling
T 120 F Requires Heating
90
Avoid Mixing
Separate hot and cold water tanks
91
Cooling Tower Performance
92
Use Cooling Tower Instead of Chiller When
Possible
Fraction of year cooling tower can deliver water
at Tc (Assume Tr 10 F in Dayton OH)
93
Air-Cooled Chiller

• E/Q 1.0 kW/ton 83 kWh/mmBtu
• Unit cost of cooling 8.30 /mmBtu

94
Water-Cooled Chillers

• E/Q 0.8 kW/ton 67 kWh/mmBtu
• Unit cost of cooling 6.70 /mmBtu

95
Air-Cooled Chiller Performance
96
Water-Cooled Chiller Performance
97
Process Heating
98
Heat Balance on Furnace
99
Energy Saving Opportunities From Heat Balance

• Reduce flue losses
• Reduce wall losses
• Reduce opening losses
• Reduce cooling losses
• Reduce storage losses
• Reclaim heat from flue to
• Pre-heat combustion air
• Pre-heat load

100
Natural Gas Combustion with Stoichiometric Air
CH4 2 (O2 3.8 N2) CO2 2 H2O 7.6
N2
HEAT

• Oxygen breaks CH4 into CO2 and H2O
• Nitrogen doesnt react
• Heat absorbed by products CO2, H2O and N2

101
Natural Gas Combustion with Excess Air
CH4 3 (O2 3.8 N2) CO2 2 H2O 7.6
N2 02 3.8 N2
HEAT

• With excess air, heat absorbed by excess O2 and
  N2
• Lowers flame temperature, heat transfer and
  efficiency.

102
Natural Gas Combustion with Correct Amount of
Excess Air
CH4 2.2 (O2 3.8 N2) CO2 2 H2O
7.6 N2 0.2 02 0.8 N2
HEAT

• About 10 excess air, insures complete
  combustion
• 10 excess air 2 O2 in exhaust gasses

103
Natural Gas Combustion Products
104
Fraction Heat Available to Furnace(Combustion
Efficiency)
105
Fraction Heat Lost Up Stack
106
Natural Gas Combustion with Oxygen
HEAT
CH4 2 (O2) CO2 2 H2O

• Oxygen doesnt contain N2
• Heat absorbed by less product gasses CO2, H2O
• Increases flame temperature, heat transfer,
  efficiency

107
Flame Temperature with Oxygen Enhancement
108
Available Heat (Combustion Efficiency) with
Oxygen Enhancement
109
CO Formation
7000
6000
No Air Leakage into furnace
5000
4000
CO - PPM
3000
2000
1000
0
0
1
2
3
4
5
Oxygen
110
0.5 Oxygen
1 Oxygen
2 Oxygen
4 Oxygen
111
Insulate Injection Molding Barrels and Heads
112
Turn Off Heat to IMM Barrels When Not in Use
113
Minimize Air Leakage Into Furnaces
Heat in Flue Gases
Air Leaks
Combustion Air
Fuel
114
Seal Furnace Openings

• Openings
• Usually enable air leakage into furnace
• Always enable radiation loss

115
Use Draft Control to Balance Pressure
116
Reduce Air Leakage in Continuous Ovens By
Modifying Entrance/Exit
117
Cover Charge Wells

• 2 ft x 4 ft open charge well radiates and
  convects heat
• Cover charge well with mineral fiber insulation
  75 of time
• Savings 1,500 /yr

118
Preheat Combustion Air with Recuperator
119
Preheat Combustion Air with Tubein-Tube Heat
Exchanger
120
Preheat Combustion Air with Regenerators
121
Preheat Load with Preheating Shed
122
Preheat Continuous Load with Counter-flow Heat
Exchange
123
Recover Flue Gas Heat with Waste Heat Boiler
124
Boilers and Steam
125
Inside Out Approach to Boiler/Steam Efficiency

• End use
• Insulate hot surfaces
• Cover open tanks
• Distribution system
• Fix leaky steam traps
• Insulate steam and condensate pipes
• Boiler system
• Reduce excess air
• Switch from On/Off to Modulate control
• Run multiple boilers at part load
• Add recuperator to preheat feed water

126
Insulation Properties
Rule of thumb insulate all surfaces over 120 F
127
Insulate Open Tanks

• Heat loss from open tanks occurs via convection,
  radiation and evaporation
• Losses reduced by covering surface or adding
  floats.

128
Steam Traps

• Inverted Bucket Traps Condensate discharged
  intermittently.
• Float and Thermostatic Traps Condensate
  discharged continuously
• Thermostatic Traps Condensate discharged
  continuously
• Thermodynamic Traps Condensate discharged
  intermittently
• Intermittent traps detect leaks by listening for
  continuous discharge with ultrasonic sensor
• Continuous traps detect leaks by measuring
  temperature on both sides

129
Steam Trap Orifice Size and Leakage Rate

• Orifice size is function of design pressure and
  pipe diameter (NPT)

• Steam flow (lb/hr) 24.24 lb/(hr-psia-in2) x P
  psia x D inch2 x FracOpen

130
Fix Leaky Steam Traps

• Known
• Failed 0.5-inch inverted bucket trap rated at 180
  psi, actual steam pressure is 120 psig.
• Savings
• From table orifice size is 1/32-inch. Assuming
  that the orifice is 50 open, the steam loss
  through the leaking trap is about
• 24.24 lb/(hr-psia-in2) x 135 psia x 3/32 inch2
  x 50 14.5 lb/hr
• The latent heat of steam at 120 psig is about 872
  Btu/lb and the saturation temperature is about
  350 F. Assuming that 100 of the condensate is
  returned at 200 F, and that the boiler is 80
  efficient, the natural gas savings from fixing
  the steam trap would be about
• 14.5 lb/hr x 872 Btu/lb 1 Btu/lb-F x (350
  200) F x 6,000 hr/yr / 80 111 mmBtu/yr
• 111 mmBtu/yr x 10 /mmBtu 1,110 /yr
• Implementation Cost and Simple Payback
• Inverted-bucket steam traps for ½-inch pipe
  connections with a max operating pressure of 125
  psig cost about 92 each with installation cost
  of 30 per trap. If so, the cost of replacing
  the trap would be about 122.
• Simple Payback 122 / 1,110 /yr x 12 months/yr
  1 month

131
Insulate Steam and Condensate Return Pipes

• Known
• Insulate 100 ft x 6-in steam pipe carrying 100
  psig
• Savings
• 125,870 Btu/hr x 8,000 hr/yr / 80 1,260
  mmBtu/yr
• 1,260 mmBtu/yr x 10 /mmBtu 12,600 /yr
• Implementation Cost
• 1,800
• Simple Payback
• 1,800 / 12,600 /yr 0.15 years

132
Close Condensate Return System
Open system
Closed System
Open systems lose 25 of steam energy as flash,
return colder condensate
133
Close Condensate Return System

• Known
• Closed system returns 100 lb/hr at 200 F compared
  to 150 F for open system
• Boiler is 80 efficient
• Savings
• 100 lb/hr x 1 Btu/lb-F x (200 150) F x 8,000
  hr/yr / 80 50 mmBtu/yr
• 50 mmBtu/yr x 10 /mmBtu 500 /yr

134
Excess Air and Boiler Efficiency

• Combustion air generally controlled by dampers
• Simple recalibration of dampers can reduce excess
  excess air

135
Combustion with 10 Excess Air Guarantees
Complete Combustion
136
Boiler Control

• Most boilers have
• Modulating burners
• Single-point positioning control
• Inconsistent excess air levels over firing range
• Typically greater at low fire than high fire by
  30 or more
• Excess air calibrated at high fire, then too much
  at reduced firing

137
Single-Point Positioning Control

• Controls based on signals from steam or hot water
  gauge
• Combustion controls are usually calibrated by
  technicians at high fire

Burner with Single-Point Positioning
Burners Linking Mechanism
138
O2 Trim System

• Can be programmed to maintain a desired excess
  air level (10).
• Eliminates the need to calibrate to slightly
  higher levels than desired.
• System should be calibrated 3 to 4 times per
  year, which results in a 1,500 - 2,000 annual
  maintenance cost.
• Purchase cost is 20,000 - 30,000 per system.

139
Preheat Water With Economizer

• Air-to-water heat exchangers called economizers
• Forces water through finned tubes in exhaust
  stack
• Best pay-backs for full-year heating with low
  condensate return

140
HVAC
141
Inside-out Approach to HVAC Efficiency

• Minimize heating/cooling load
• Improve distribution system
• Improve efficiency of heating/cooling plant

142
Use Programmable Thermostats

• Lower/increase interior set-point temp during
  unoccupied periods
• Important because heating/cooling load
  proportional to (Tia Toa)
• Example If Toa 50 F, then reducing Tia from
  70 F to 60 F decreases heating load by 50
• However, thermal mass limits temperature drop
  and reduces savings

143
Close Doors and Openings

• Install garage-door openers on lift-trucks
• Observation Heating energy varies by 3X at same
  temp!
• Discovery Didnt close shipping doors!

144
Turn Off Dust Collectors When Not Needed

• Reduce ventilation load with
• VAV
• On/off control
• Filter air with HEPA filter if both heating and
  cooling

145
Balance Supply / Exhaust Air
146
Employ DP Control to Balance Plant Air

• Manometer measures DP between inside and outside,
  and adjusts air flow of MAU
• Good choice if ventilation requirements change
  frequently
• Paint booths
• Large combustion air demands

147
Reverse Direction of Exhaust Fan During Winter
Months

• Exhausting air drives infiltration and internal
  heat gains dont displace space heating
• Supplying air eliminates infiltration and
  internal heat gains displace space heating

148
Insulate Under-insulated Walls / Ceilings

• Example Add 3.5-in fg batt insulation (R 3.2
  /inch) to R 3 brick wall
• Qh,sav (1/R1 1/R2) x A x (Tbal Toa)
• Qh,sav (1/3 1/13) Btu/hr-ft2-F x (65 30) F
  9 Btu/hr-ft2
• Qng,sav 9 Btu/hr-ft2 x 4,000 hr/yr / 0.80 x 10
  /mmBtu 0.45 /ft2-yr
• Cost 3-in fiberglass batt insulation 0.35 /ft2
• SP 0.35 / 0.45 /yr
• SP 0.8 yr

Diminishing returns for adding R-10 insulation
149
Insulate Under-insulated Walls / Ceilings

• 4 inches of spray on cellulose
• 1.30 per ft2

150
Deliver Heat Effectively

• Problems
• Warm air pulled out of facility by exhaust fans
  or openings
• Excess temperature stratification
• Solutions
• Install radiant heaters in high ventilation areas
• Install destratification fans

151
Use Outside Air Requirement to Select Unit
Heater or MAU

• Unit heaters
• 80 efficient
• Recirculate inside air
• Make-up air units
• 100 efficient
• Supply outside air
• Selection
• If dont need outside air, use unit heaters to
  avoid heating cold outside air
• If need outside air, use makeup air units for
  high efficiency

152
Convert from CAV to VAV Systems

• Constant-Air-Volume (CAV) system, air supply
  constant and zone temperature regulated with
  reheat
• Variable-Air-Volume (VAV) system, air supply to
  zones is varied and reheat is minimized
• Thus, VAV systems use less fan, cooling and
  heating energy

153
Reheat/VAV Box Control

• CAV
  VAV

154
CAV-VAV Whole Building Electric Savings
155
CAV to VAV Cooling Savings
156
CAV to VAV Heating Savings