ENERGY CONSERVATION IN PNEUMATIC SYSTEMS. Solutions That Save

Transcription

1 ENERGY CONSERVATION IN PNEUMATIC SYSTEMS Solutions That Save

2 Do we recognize the cost of air?

3 Should you focus on compressed air savings? Typical Plant Power Consumption (kw) Idle Mode

4 Discussion Topics 1. Plant Case Study The Ripple Effect Every change, good or bad, results in other changes 2. General Overview of Energy Conservation 1. Air Quality 2. Air Leaks 3. Non-Productive Use of Air 4. Idle Mode Demand 5. Over-Pressurization

5 Plant Case Study Here s what can happen when complacency sets in

6 Plant Case Study At Start Up 65 psi 30 CFM 65 psi 30 CFM 65 psi 30 CFM 65 psi 30 CFM Total Demand psi 2 Compressors running psi

7 Plant Case Study Six Years Later 90 psi 80 CFM 100 psi 90 CFM 105 psi 100 CFM 109 psi 105 CFM Total Demand 1, psi 9 Compressors running psi

8 What happened? The artificial over pressurization of CP #1 and CP #2 have lead to excessive flow which starves CP3 thru CP20. Other operators responded to the pressure loss by elevating their own pressure, which results in excessive flow on each machine. This leads to a plant wide pressure elevation which in turn elevates the flow on every unregulated user including leaks. The total plant demand excluding the case packers was a mere 200 CFM when the CP s were installed. The current plant demand is over 1,350 CFM, excluding the case packers.

9 Financial Ramifications Two separate negative financial impacts. Case Packers costs those associated with leaks, intermittent demand and point-of-use over pressurization. Annual total $173,585. Plant wide costs the cost of elevating plant wide pressure to meet the point-of-use elevation and the cost of inefficient compressor controls at partial load. Annual total $90,452. Total annual cost to the plant $264,037.

10 Financial Ramifications How did we get these dollar amounts? Calculations will typically use these values: 8,760 hours of operation (24 hours/day X 365 days/year = theoretical maximum) 90% electrical motor efficiency (0.90) 4 CFM per BHP (Brake Horsepower) $0.10 per Kw hour (varies per location, see page 6). The power-cost formula is: Annual Cost BHP Hoursof Operation Cost Motor Efficiency per kwh For example: The annual cost of running a 200 HP compressor: Annual Cost $ $145,221.33

11 Financial Ramifications How did we get these dollar amounts? Let s look at this another way... What is the annual cost of an air leak? We have a leak in our system and we re losing 5 CFM. Convert CFM to BHP 5 CFM / 4 CFM per BHP = 1.25 BHP Apply the formula 1.25 x x 8,760 x 0.10 / 0.90 = $908/year For another example... What is our air blow application costing us? We use 9 CFM in the application. 9 CFM / 4 CFM per BHP = 2.25 BHP The annual cost 2.25 x x 8,760 x 0.10 / 0.90 = $1,634/year

12 What was the catalyst for all this? Poor Air Quality due to lack of proper filtration Food grade oil was used in compressors: Oil easily migrated downstream (incorrect mainline filtration) Oil reacts poorly to heat - both in total life and in varnishing Direct-operated valves stick due to limited shifting force Internally piloted valves required higher pilot pressures Heat build up in valves contributed to failure (leaking & sticking). Poor filtration/valve selection for the environmental conditions. Plant addressed the symptom, not the problem.

13 Additional Ramifications Lost production due to pressure swings Additional breakdown calls related to compressed air issues Elevated ongoing compressor maintenance costs Water and oil carryover issues High scrap rate relative to other plants Increased capital budget - Significant infrastructure upgrade required Cost of compressed air was 6.2 times original value

14 How did we fix this? Address filtration issues in compressor room to minimize carryover of compressor oils Added backup filtration at point-of-use Used metal bowls which will not deteriorate from compressor oil Added service indicators Added tamper resistant regulators so that pressure would not be elevated Replaced direct-acting valves with indirect-acting valves Indirect-acting valves are less prone to sticking & generate less heat Fringe benefit: Indirect-acting valves lower power consumption from 9 watts to 1 watt Controlled pressure at point-of-use so that pressure could be restored to 90 PSI Took un-needed compressors offline, and rotated them into service periodically

15 Energy Conservation Overview Where do we go from here?

16 Energy Conservation Overview Energy efficiency is often overlooked on pneumatic systems. The point-of-use pneumatic products that are applied have a far reaching effect on energy efficiency. OEM pneumatic product selection is often based on price. Very little consideration is given to energy consumption, compressed air quality, environmental conditions or sustainability. When evaluating your compressed air system for energy inefficiency, the first and least expensive place to start is with your pneumatic point-of-use systems.

17 Areas of Energy Conservation Areas of Focus 1. Air Quality 2. Air Leaks 3. Non-Productive Use of Air 4. Idle Mode Demand 5. Over-Pressurization

18 Air Quality

19 Air Quality Sustainability Considerations Dew point and Particulate Contamination levels are managed by: Mainline Filter Point of Use Filter Dryer

20 Leaks

21 Leaks 95% of leaks occur at a pneumatic product other than the mainline plumbing. The most commonly failed components are: Fittings and tubing Air prep units i.e. filter, regulator, lubricator (FRL) Cylinders or actuators

22 Why are they leaking? Fittings and Tubing Fittings and Tubing 1. Faulty installation Accounting for 70% of failures tested during our audits. 2. Poor quality Tubing or fitting failure not caused by installation or the environment. 3. Misapplication Fittings or tubing exposed to wash down or other environments they were not manufactured to handle.

23 Why are they leaking? Air Prep Units Air Prep Units (FRL s) 1. Age and general wear Most leaking components showed failures indicative of general wear which accounted for approximately 45% of failures. 2. Internal exposure to water, Polyolester and Diester oils or rust These leaks tend to be the largest, accounting for approximately 45% of failures. 3. External damage, operator or mechanical force Accounting for 10% of failures.

24 Why are they leaking? Cylinders Cylinders 1. Internal exposure to water, Polyolester and Diester oils or rust Accounting for approximately 55% of failures. 2. Age and general wear Most leaking components showed failures indicative of general wear which accounted for approximately 25% of failures. 3. Misapplication Accounting for approximately 20% of failures.

25 Leaks Case Study Leaks by Percent of CFM 5% 6% 29% 6% 8% 13% 20% 13% Fitting FRL Valve Blowgun Cylinder Coupling Hose Other

26 Leaks Detection What a lot of work! Flow Meters Parabolic Dish and Ultrasonic Leak Detector Flow Meters tell us that leaks have developed. Now we need to know where they are!

27 Leaks Conventional Detection Compressed Air Audit Tool of Choice Ultrasonic Leak Detector Expensive Pack In, Pack Out Hassle Auditing Expensive, but Leak repair savings usually recover cost Time-consuming Auditor examines plant-wide system Conducted once or twice yearly Customer pays every time Report can be overwhelming

28 Leaks Automatic Leak Detection System Goals Decrease detection cost Fewer man hours Lower skill requirement Lower cost equipment Increased detection frequency Minimizes leak impact Rapidly pinpoint leaks Accurate leakage value (as low as.07 SCFM)

29 Leaks ALDS Concept - Implementation Hardware Flow Meter and Diverter Valve Installed in machine s main air supply line Software Written in the machine s PLC Runs leak detection subroutine

30 Leaks ALDS Advantages

31 Non-Productive Use of Air

32 Non-Productive Use of Air Air Blow Common Applications Drying Contaminate removal Part transfer Air-blow has the potential to be the most wasteful enduseapplication of compressed air. Open blow

33 Non-Productive Use of Air Air Blow Improvement Reduce pressure loss and air consumption while maintaining work surface impact. High-efficiency nozzle 100 PSI With Nozzle 100 PSI Pressure Loss is minimal Without Nozzle 100 PSI 60 PSI 20 PSI Pressure loss is great

34 Non-Productive Use of Air Air Blow Solutions Nozzle Diameter mm Pressure before nozzle PSIG Impact Pressure PSIG Air Flow Rate SCFM Distance Current 4 3 4" Improved " Improved "

35 Non-Productive Use of Air Air Blow High Pressure Solutions A great amount of money can be saved on blow-off applications by using high efficiency nozzles, regulation and effective tube to nozzle ratios, while maintaining the same impact work pressures required for the job. High-Efficiency Blow Gun The ratio of effective area and pressure

36 Non-Productive Use of Air Air-Blow Solutions Momentary positive pressure Appropriate tubing size Auto shut off when not in use Reduce to the lowest effective pressure Venturi style nozzles

37 Non-Productive Use of Air Design Alternatives Primary Considerations Cylinder Sizing Double Acting vs. Single Acting Regenerative Circuits Tubing length: Filling tube with no benefit Pressure Control

38 Non-Productive Use of Air Design Alternatives - Cylinders Pneumatic Model Selection Program Ver4.0-System Model Selection-Standard cylinder Title : Registrant : Date : Results of model selection Model Part number Quan. Fitting 1 Quan. Fitting 2 Quan. Cylinder Solenoid valve Manifold Silencer NCGB[]A50-400[] SY7240[]-[][][][]-02N AN202-N KQ2L06-U02 2 Quick exhaust valve Speed controller R AS2200-N02-[] Speed controller L AS2200-N02-[] Piping R TU0604[]-[] Piping L TU0604[]-[] Shock absorber System characteristics KQ2L06-U02 KQ2L06-U02 55 lbs. / Sliding 16 / 1 second 1 1 Pneumatic Model Selection Program Ver4.0-System Model Selection-Standard cylinder Title : Registrant : Date : Results of model selection Model Part number Quan. Fitting 1 Quan. Fitting 2 Quan. Cylinder Solenoid valve Manifold Silencer NCGT[]A32-400[] SY3240[]-[][][][]-01N AN103-N KQ2L06-U01 2 Quick exhaust valve Speed controller R AS2200-N01-[] Speed controller L AS2200-N01-[] Piping R TU0604[]-[] Piping L TU0604[]-[] Shock absorber System characteristics KQ2L06-U01 KQ2L06-U Full stroke time: Start up time: 90% Force time: Mean velocity: Max. velocity: Stroke end velocity: Max. acceleration: Max. pressure: Air consumption/ cycle: Required air flow: 1.00 s 0.07 s 1.36 s 401 mm/ s 538 mm/ s 538 mm/ s 10.1 m/ s MPa dm3(anr) dm3/ min(anr) Cushion Calculation Result Absorption energy: 3.82 J Allowable energy: 3.40 J Judgment result: Out of the allowable range Out of the allowable range: Review the operating conditions and the load conditions. Or use shock absorber. Condensation Calculation Result Condensation probability: 0 % Condensation probability is very small Input values Stroke: 400 mm Full stroke time: 1.00 s Moving direction: Push (L) Supply pressure: 0.5 MPa Ambient temperature: 20 degc Total length (R): 9.0 ft Total length (L): 9.0 ft Speed controller position (R): On cylinder 0 m Opening: 100 % Speed controller position (L): On cylinder 0 m Opening: 100 % Load mass: 55.0 lb Resistance force: N Mounting angle: 0 deg Application/ Load rate: Transfer 0.7 Friction factor: Sliding friction 0.3 Silencer opening: Quick exh. valve opening: Selection method: Optimal size priority Cushion Calculation Input Value Cushion style: Air cushion Work mounting style: Condensation Calculation Input Value Absolute humidity: kg/ kg Full stroke time: Start up time: 90% Force time: Mean velocity: Max. velocity: Stroke end velocity: Max. acceleration: Max. pressure: Air consumption/ cycle: Required air flow: 0.81 s 0.06 s 1.02 s 496 mm/ s 782 mm/ s 782 mm/ s 3.8 m/ s MPa dm3(anr) dm3/ min(anr) Cushion Calculation Result Absorption energy: 7.77 J Allowable energy: 0.91 J Judgment result: Out of the allowable range Out of the allowable range: Review the operating conditions and the load conditions. Or use shock absorber. Condensation Calculation Result Condensation probability: 0 % Condensation probability is very small Input values Stroke: 400 mm Full stroke time: 1.00 s Moving direction: Push (L) Supply pressure: 0.5 MPa Ambient temperature: 20 degc Total length (R): 9.0 ft Total length (L): 9.0 ft Speed controller position (R): On cylinder 0 m Opening: 100 % Speed controller position (L): On cylinder 0 m Opening: 100 % Load mass: 55.0 lb Resistance force: N Mounting angle: 0 deg Application/ Load rate: Transfer 0.7 Friction factor: Sliding friction 0.3 Silencer opening: Quick exh. valve opening: Selection method: Optimal size priority Cushion Calculation Input Value Cushion style: Air cushion Work mounting style: Condensation Calculation Input Value Absolute humidity: kg/ kg Comment: SMC Version: bore ~10 SCFM Comment: 1-1/4 bore ~5 SCFM SMC Version:

39 Non-Productive Use of Air Design Alternatives - Cylinders Consider Single-Acting over Double Acting Ways to save: Gravity Down? Single Acting Cylinder? Regenerative Circuits 40% Savings

40 Non-Productive Use of Air Design Alternatives - Tubing Tubing Length Consider that air used to fill the tubing on the way to the actuator does no work! The conductance of tubing decreases dramatically with an increase in length Shorten tubing as much as feasible Beware that larger diameter = larger volume Size tubing for flow required don t guess!

41 Non-Productive Use of Air Design Alternatives - Tubing The savings is a reduction of 4.14CFM or 17.3%. Of course, if you had used a cylinder with integrated valve, the savings would have been $855 Right Sizing Tubing Diameter Example 4 cylinder case erector 3/8" Tubing 1/4" Tubing Operating Pressure Bore (inch) 3 3 Stroke (inch) # of cylinders 4 4 Tubing Length (inch) Tubing I.D. (inch) # of elbow fittings 2 2 Rate: Cycle Time (sec) CFM Required Annual Cost of Operation $ 4,979 $ 4,120 ANNUAL SAVINGS $ 625

42 Non-Productive Use of Air Design Alternatives - Pressure Extend and retract strokes frequently do not require the same operating pressure. A reduction in pressure on the non-working side of the cylinder will lead to significant energy savings.

43 Idle-Mode Savings

44 Idle Mode Demand Examples Machines need to shut off when not in use Isolate during breaks, maintenance, etc. Machines typically do not operate 100%

45 Idle Mode Demand Idle Mode Demand Macro Example When reviewing a plantwide flow study, Idle Mode demand may be defined as: Compressor operation to meet a zero production demand. Idle Mode Demand Micro Example On a single piece of OEM equipment, Idle Mode demand is defined as: Equipment leaking while an operator stops production equipment from running during a product change over, preventative maintenance or scheduled operator breaks. Whether it is a macro or micro problem, Idle Mode demand during idling can be a significant draw on a compressed air system.

46 Intermittent Demand Macro Case Study Paint 6/27/06 12:00-7:00 AM CFM PSI Waste :00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 Idle flow 5,420 CFM Annual cost $145,541 90

47 Intermittent Demand Micro Case Study Current situation at snack chip manufacturer Air supply + leak CFM Leaks CFM

48 Intermittent Demand Micro Case Study Auto Drains Proposed solution to intermittent demand D Air supply + leak 60 CFM Leaks CFM Shut Off Valve Auto Drains E Shut Off Valve

49 Intermittent Demand The Cost of the Case Study The current leak load is CFM. Cost is $4,102 for leaks per packaging line $4102 * 8 lines = $32,816 per year Savings = $10,830 per year.

50 Intermittent Demand Solutions When you require a moment of positive pressure When product is present Soft-Start / Quick Exhaust Valves Auto shut off used in conjunction with equipment power or photo eye.

51 Over - Pressurization

52 Over-Pressurization Excessive pressure in a manufacturing plant often starts at the point-of-use. Plants often respond to decreasing performance at a machine by increasing regulator set pressures and often the entire plant s pressure. It s imperative to evaluate the cost of over-pressurization\ Generally, a 2 PSI increase adds about 1% more to energy costs

53 Over-Pressurization Examples Equipment operators rarely understand the relationship between flow and pressure. What leads to excessive pressurization of pneumatic systems? Misdiagnosis of equipment malfunction Flow rate increases force a droop in downstream pressure Mismanaged point-of-use filtration In each case, equipment operators respond by increasing the pressure at the regulator.

54 Excessive Pressure Case Study 120 Over Pressurization 100 psi vs. 80 psi Pressure (psi) Flow (CFM) psi CFM Time (Minutes) Statistics Pressure (psi) Flow (CFM) Annual Cost $13,069 $10,047 40

55 Excessive Pressure Solutions Use gauges with visual pressure range display

56 Locking Regulator Excessive Pressure Solutions Continued Regulators with locking adjustment knob or a pressure lock out device prevent costly over-pressurization Precision Style Regulator E/P Control Manage pressure with precision regulators Tamper Resistant Regulators Tamper Proof Regulators Restricted Regulators

57 Wrap up! Savings start in the design phase at the OEM level, however For existing systems: Evaluate your compressed air system from point-of-use backward. Reduce consumption Avoid the temptation to buy more compressors before you know for sure that this is the right energy solution Enjoy the quick return on investment!

58 If you have any questions or require additional information, please do not hesitate to contact SMC! Thank you!