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Published byDarleen Grant Modified over 9 years ago
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Diesel Generator Reliability: Lessons Learned from Storms
4/16/2017 Diesel Generator Reliability: Lessons Learned from Storms Introduce yourself. Thank the audience for attending and staying awake, etc.
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Educational facilities Government buildings Data centers
4/16/2017 In Canada many critical facilities have emergency backup power, including: Hospitals Educational facilities Government buildings Data centers Most of our orders these days are from data centers and hospital facilities.
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4/16/2017 The vast majority of emergency power is supplied by diesel generator sets:
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To operate reliably, engine-driven equipment needs:
4/16/2017 To operate reliably, engine-driven equipment needs: Good quality fuel supply Adjacent day tank Maintain steady fuel temperature Fuel system interface BAS interface You might explain why temperature monitoring is important for generator projects. You might also spell out BAS.
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Four most common causes of generator failures during the storms was:
4/16/2017 Four most common causes of generator failures during the storms was: Poor fuel quality Dead or weak starting batteries Generator coolant system failure Improper control settings This ranking is based on anecdotal evidence, not a hard survey. Improper control settings means the generators were tripped and not reset, or the controls were left in manual and did not come on automatically when the power went out. Proper system design and maintenance will prevent these failures.
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Maintenance & Inspection
4/16/2017 Maintenance & Inspection I would just read these and make any comments you have. Segway to fuel quality maintenance. “Our specialty is fuel oil system design, so I’ll talk a little bit about storing diesel fuel…”
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Additional considerations for sensitive areas:
4/16/2017 Preparedness Additional considerations for sensitive areas: Exercise generators weekly, with different facility personnel on duty each time. Perform a periodic cold start test. Review your logs & service invoices to determine when and why you call in an outside technician. (He likely won’t be available during and after a storm)
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When an event is threatening:
4/16/2017 When an event is threatening: Perform a pre-event inspection targeting all the items on the preceding list. Sample your fuel to ensure it is in good condition. Top off your fuel tanks. Have multiple suppliers lined up. Ensure you have all the recommended spare parts for your generators on hand. Schedule your best technician(s) to be on site when the storm hits. Note: after Katrina, the Houston area nursing homes reviewed their evacuation plans and discovered many of them were using the same bus company. Recognizing this one company didn’t have the capacity to handle all these nursing homes, they sought out other suppliers prior to Hurricane Rita.
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4/16/2017 Fuel Maintenance Diesel fuel is an organic product that begins to decay as soon as it is refined. Sludge formation is an organic decomposition process exacerbated by the presence of water. Water enters the tank through vents, leaks, and is often delivered with the fuel. Areas of high humidity and frequent ambient temperature changes have more problems with condensation in the fuel tanks.
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4/16/2017 Fuel Maintenance Water collects at the bottom of the fuel tank, so sludge grows mostly at the fuel-water boundary at the bottom of the tank. Filtration systems need to suck oil right off the bottom of the tank to get to where the sludge is. Add any other words of wisdom you have. Weekly generator tests will not consume enough fuel to keep the fuel fresh and turned over.
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4/16/2017 Fuel Maintenance Filtration systems are recommended for diesel generator systems where the fuel is likely to sit for long periods of time. A typical system will: Filter the sludge from the oil down to 2 microns Remove water from the fuel Add a chemical stabilizer to the fuel oil Run automatically and sequence multiple tanks. I’m still working on some sort of conclusion. You might want to mention the alternatives. In hurricane-prone regions, some generator owners keep only four hours of fuel on hand and then completely fill their tanks when a hurricane is threatening. Segway to fuel oil system design.
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Select a manufacturer with experience in Mission Critical fuel systems
4/16/2017 Fuel System Design: Select a manufacturer with experience in Mission Critical fuel systems Design for system redundancy Hold a single source supplier responsible Design for continuous fuel maintenance Too often fuel systems for mission critical facilities are designed and installed by companies with a gas station background. When the pumps don’t work at a gas station, you lose a little business. At a hospital or data center, a fuel oil system failure can be much more costly.
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4/16/2017 The shocking secret: “The diesel engine manufacturer will not design the fuel oil system for the generator.” The codes and regulations change in every state, in addition many large cities have their own local codes that impact fuel oil system design. Many architects and engineers are not familiar with these codes.
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Typical Main Storage Tank
4/16/2017 Typical Main Storage Tank High Level Alarm Emergency Vent (Typical of 2) Normal Vent Access Cover Fill Pipe Main Pump Suction Return Pipe Filtration Suction Interstitial Leak Sensor Tank Access Fill Location Fuel storage is much more complicated now than it used to be. These are the typical accessories that go into a main storage tank, whether above ground or underground… Level Transmitter
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Pump Set Controls include:
4/16/2017 Pump Set Controls include: Motor Controls Fused Circuits or Circuit Breakers Magnetic Starters & Overload Protection HOA & Run Lights Duplex Pump Operation Start/Stop Control Lead/Lag Control Automatic Alternation of Lead Pump Flow Proving Pump Set Basin Leak Detection Strainer Pressure Drop Automatic Pump Exercising For mission critical facilities, we energize a fuel oil supply pump whenever a generator is running. Many typical systems will automatically bring on a pump only when a belly tank or day tank hits low level. This is a bad time to learn you have a problem with your pumps…
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Day Tank & Return Tank Controls include:
4/16/2017 Day Tank & Return Tank Controls include: Tank Level Controls High & Low Level Alarms Fill Control Pump On/Off Control Fill Valve On/Off Control Fuel Temperature Monitoring Secondary Containment Leak Detection Motor Controls on Return Tanks Day tanks are complicated now too. Special attention needs to be paid to the sizing of fuel return system compared to supply systems to avoid an overflow situation.
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Typical Fill Box includes:
4/16/2017 Typical Fill Box includes: Volume and level indication High level alarm and horn Spill containment Soon this fill box will be available in a sidewalk box version. Plug, plug… You might mention that your going into this amount of detail because many people are unaware just how complicated fuel oil systems for generators have become. So design of the fuel oil control system is often put off until nearly the end of the project. You might mention that IUS project where we got the change order because the engineer didn’t review the pump set controls until the equipment was on site.
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4/16/2017 Centralized control of the fuel system helps ensures proper control, monitoring, and external communication. By bringing all of the system I/O into a single processor, it is easier to ensure the field devices on the main storage tank, day tanks, pump sets, and all the piping in between is coordinated to work correctly together. Once all these points are in one processor, it is easy to provide a single digital communication link the the building automation system, fire detection and suppression system, etc.
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Design Considerations:
4/16/2017 Design Considerations: Fuel systems should be contained within the Plumbing Construction Documents Wiring for fuel devices should be shown on Division 16 plans BAS points should be detailed Fuel scope should be provided by a single supplier Div. 15 & 16 scopes should be coordinated Fuel Control System specifically geared toward Mission Critical facilities Fuel oil hardware, controls, and wiring tend to be an afterthought in the system design, and poorly coordinated between trades. One supplier should be made responsible for the design, supply, and start-up of the fuel oil system.
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“When the lights go out, it’s too late.”
4/16/2017 “When the lights go out, it’s too late.” I don’t know anything about batteries or cooling systems so my focus is on the fuel.
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