Potential Energy Savings Using Variable Speed Drives Presented by: Darryl Whitley
Our Rules
A Dollar not Spent on Energy Is a Dollar of NET PROFIT No consumption of manufacturing capacity No consumption of logistical support A company generating 5% Return on Net Assets (RONA) has to sell $ in products to generate $50,000 in profit? $1 Million Dollars If your solution saves just $10,000.00 in Energy Cost How much is that really worth? $200,000.00 in Top Line Revenue (savings in dollars) x (1/(RONA % provided by Management) Energy Costs are Rising in Motors are the Largest Consumers of Energy in North America
Basic Electrical Costs Demand Power Factor Kilowatt Hours Consumed
Hard to Justify Demand Charge Peak Usage in 15 Minute Average Staggered Starts Soft Starts Variable Speed Drives
Easier to Justify Power Factor Charge or credits (depending on the power factor) Decreases efficiency even if Ameren doesn t bill you extra if power factor is below 85% May be credited dif power factor is above 95%
Power Factor as a Cost Lagging PF Your Apparent Consumption +20% IE: Required Generation Capacity +10% Standard -10% (In phase with line voltage) -25% Unity PF Real Work Power Factor Billed KWh
Power Factor as a Cost Your Apparent Consumption IE: Required Generation Capacity Lagging PF +20% +10% Standard -10% (In phase with line voltage) -25% Unity PF Real Work Power Factor Billed KWh
Power Factor as a Cost Your Apparent Consumption IE: Required Generation Capacity Lagging PF +20% +10% Standard -10% (In phase with line voltage) -25% Unity PF Real Work Power Factor Billed KWh
Variable Speed Drives Electrically Located at Motor To the Distribution System the VFD Looks Like a Power Factor Correction Capacitor
Capacitor Location? Metering Service Entrance Distribution Infrastructure Utility MCC
Simple & Easy Justification Consumed KW Reducing true consumption provides the quickest paybacks and are the easiest to Justify. Tools eliminate the guess work
VFD are the Big Payoff Exponential Reduction in Consumed kw Variable Torque Fans & Pumps Variable Load Characteristics Systems that Cycle Injection Molders Throttled Loads Restricted Flows Dampers, p, Control Valves, Recirculation
The Affinity Laws The Affinity Laws Apply to All Centrifugal Devices Reduce Flow 100% (Q) Speed to Pressure 80% speed (P) on is a 25HP fan/pump Power (HP) is Changes Proportional to the Proportional to the Linearly with Square of 3 3 Speed (N) Speed Cube of (N) or Flow (Q) Speed (N) or Flow (Q) HP HP 2 1 N N 2 1 HP 25 2 80 100 HP 2 2 12.5 Q N P N HP N 2 2 2 2 2 2 Q N P N HP N 1 1 1 1 1 1 3
Affinity Law In Variable Torque Ideal Loads: Energy Increases exponentially with speed Energy Consumed = (speed) 3 Energy Consumed Speed
An Insignificant Speed Reduction Energy Consumed Insignificant Insignificant Speed Reduction Speed Reduction Speed
May Be A Good Opportunity Large Reduction In Consumed Energy Energy Consumed Insignificant Insignificant Speed Reduction Speed Reduction Speed
A Reasonable Speed Reduction Energy Consumed Reasonable Speed Reduction Speed
Is a FANTASTIC Opportunity Energy Consumed Reasonable Speed Reduction Speed
Consumption reduction =(Speed reduction ) 3 reduction p reduction 100 kw Motor @ 50% Speed: What does it Cost? E r =(1/2) 3
Pumps may have Limited Speed Ranges Due to System Constraints 100 HP Motor @ 85% Speed How much HP are you using? HP = (Motor( HP) ) x used (%( Speed) ) 3 HP = (100 HP) x (.85) 3 used
What if a Fan worked at 45 HZ? % Speed = Operating Speed / Full Speed = 45 Hz / 60 Hz = 75 HP = ( ) required (Motor HP) x (% Speed) 3 HP = (100 HP) x (.75) 3 required
Financial Justification No Magic, No Smoke & Mirrors You can make informed Decision If you provide basic data You can calculate savings» Multiple Tools Available Remember Value Exceeds Kw Hour cost What is this worth in Top Line Revenue? Does System performance justify VFD regardless of Savings Water Authority pumping just 4 hours/day Fire Main Pressure, No broken Mains, Better Management of Aquifer
Energy Savings Calculations- An Example A 25 HP fan needs to move air 3 shifts/day, /dy,5dy days a week for a year. The cost of running the fan at full speed, for the entire year would be 25HP x 0746 0.746 kw/hp x 6240 hrs x 0075 0.075 kw/hr = $ 8,728.00 Assuming that the fan does not have to run at full speed all the time: 20% of the time at 100% speed;60% of time at 80% speed;20% of time at 60% speed. The cost of running the fan with a variable frequency drive would be: 25 HP x 0.746 kw/hp x 1248 hrs x 0.075/kWhr x (1.00) 3 = $ 1,746 25 HP x 0.746 kw/hp x 3744 hrs x 0.075/kWhr x (0.80) 3 = $ 2,681 25 HP x 0.746 kw/hp x 1248 hrs x 0.075/kWhr x (0.60) 3 = $ 377 Total = $ 4,804 Potential Annual savings would be $ 8,728 $ 4,804 = $ 3,924
That s OLD SCHOOL We have tools to help you sell this to your Accounting Staff Available via download from AMEREN or AB.COM
All you have to do is fill in the Yellow blocks Project Name and Data Project Name Project Cost
Department Graphs Data A Graph that table that of show with Energy clearly the Formulas all Break the Reduction data used to do the Even Return of CO2 on Emissions Investment in demonstrates used numbers to calculate for the the impact the project CO2 of Calculations Tons related Waiting to reduction MRO to do and the project Capital Estimate in Years The savings Calculator and the expense will Generate all the extras Your Accounting Staff could ask for!
Change project information and the spreadsheet generates a New document package for you!
A Reliability Project Justified to increase Production
Where will I Find the Common Traits Fastest Payback? Long Hours of Operation Load isn t Constant Load may be Throttled Significant Downtime Cost
Design Parameters of a Typical Constant Volume HVAC System Fan Speed On 100% -20 F 100% Outside Air Temp 47 F 100 F 100% 100% 60Hz % Heating % Co ooling Fa an Speed % Fan Speed Hz 0% 68 F Space Temp 70 F { 0% 72 F 0% 0Hz Economizer Free Cooling
FanMaster TM added to your HVAC Fan Speed Varies taking based on CO2 and the demands of the building Controls -20 o F 100% % Heating Outside Air Temp 47 o F Fan Speed If Economizer Running 76 F (RTU3-3) Minimum Fan Speed 100 o F % Coolin ng 100% 54% (RTU 3-3) 100% 60Hz Fa an Speed % Fan Speed Hz 33% 20Hz 0% 68 o F Space Temp 70 o F { 0% 72 o F 0% 0Hz Economizer Free Cooling
Resources http://www.ab.com/drives/energy_savings/index.html g http://www.angelfire.com/pa/baconbacon/page2.html http://www.pupman.com/listarchives/2001/june/msg00679.html http://www.energysafe.com.au/products.html / h http://www.iserv.net/~alexx/lib/general.htm http://www.myronzuckerinc.com/docs/specification%20- p// / / p %20Trap%20Filter.pdf http://www.transcoil.com/ http://www.trane.com/ t / http://www.et-sales.com/k_factor.html http://www.ab.com/drives/energy_savings/index.html p// / / g /
For additional information or questions on the material and tools presented, please Contact: Robin Priestley Power Control Manager rspriestley@ra.rockwell.comrockwell com 563-445-6323 6323
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