Data Center Generator Maintenance & Sizing Keys To Preventing Expenses

Routine maintenance is key to smooth engine operation with a generator. Like any engine you count on, an industrial generator, should be maintained and regularly exercised. These practices ensure it’s in peak condition no matter what your industry.
 
Data centers are the top segment in our industry where generator maintenance is overlooked but needed often. Why? Data centers do not pull a large amount of load. Often, centers invest in too many or too big of a unit for what they need.

The following is an article from our friends at Kohler and some of the issues found with diesel generators when they are not properly maintained, run or load tested on a regular basis.
 
The main problem occurs at data centers when a commercial generator (or any diesel generator) isn’t run near maximum load or maintained regularly. One problem seen often is diesel generator wet stacking.
 
“Wet stacking or engine slobber is a costly and time-consuming issue that data center operators must deal with,” said Brad Meissner, Kohler product manager. “Most commonly found in generators run at 30% of capacity for extended periods of time, wet stacking is a buildup of unburned fuel in the exhaust system.

"The result is reduced engine performance and potentially a shorter lifespan," continued Meissner. "The most common solution to wet stacking is to connect an external load bank, though that comes with added fuel costs and emissions.”
 
Meissner explains the benefits of no-load exercising of diesel generators with data center operations at the forefront of this problem in a recent paper.
 
Wet stacking typically occurs when generators frequently run with little or no load because the generator is improperly sized for the power required or because adequate load is not available during an exercising period, according to Meissner.
 
Data center providers frequently have insufficient load and incur the added costs and time to connect an external load bank with resultant higher emissions and extra fuel costs, added Brad.

But is burning extra fuel and spending a small amount of money for a load bank/regular maintenance going to cost as much as replacing the generator prematurely? Definitely not! And of course, Generator Source can handle maintenance, the required load bank service and before you even make a generator purchase, size the generator more accurately.


“When generators run at less than 30% of capacity for extended periods of time, their engines are unable to sustain the optimal operating temperatures needed to burn fuel completely,” says Meissner. “Pressure inside the combustion chamber falls below crankcase pressure, and piston rings can’t expand enough to seal the space between the pistons and cylinder walls.
 
“So wet stacking occurs,” continues Brad. “Fuel injectors get fouled up, it causes excessive valve guide wear, and can lead to damaged pistons, piston liners, and rings-- among other problems with emissions.
In addition to shortened engine life and higher maintenance costs, operators may also run afoul of emissions regulations, which have grown tighter in recent years.”
 

“Wet stacking has become a more critical issue in recent years as diesel generator makers have incorporated new emissions control technologies into their products,” adds Meissner. “These include diesel oxidation catalysts (DOC), selective catalytic reduction (SCR) components, and diesel particulate filters (DPF).
 
“Such aftertreatment technologies are all negatively affected by low-load operation, which can cause emissions targets to be missed,” wrote Meissner. “SCR and DPF components, in particular, must operate within a specific exhaust temperature range.”
   
The obvious solution for wet stacking has been to exercise a generator at 30% of the rated capacity once a month to burn off unused fuel and prevent buildup, according to Meissner. “The simplest way to avoid wet stacking during monthly exercise is to run the generator at the manufacturer’s recommended minimum loading.
 
“Because data center operators do not wish to transition to building load, the monthly exercise requires use of a load bank, which can be used to supplement or perform loaded maintenance activities,” added Brad. “This load-bank testing artificially boosts the load placed on the generator to burn the accumulated buildup.
 
“Most generator operators recommend that load-bank testing be done monthly for a minimum of 30 minutes runtime,” wrote Meissner “In addition to runtime, data centers also need to consider the time it takes to set up the load bank. For a typical data center facility using between five and ten generators, that can add up to a significant time commitment by operations personnel, not to mention fuel consumption.”
 
It's time consuming to load test generators each month to ensure they are maintained and not falling victim to wet stacking. That’s where Generator Source comes in. Let our field services team deal with monthly to-dos allowing you and your team to focus on the bottom line.
 
The other big problem at data centers is they often invest in large generators, more than they need. Working closely with industry experts and electricians will give a company a more concrete idea of just how much power they need. Click here to see how sizing is calculated or call us at (877) 866-6895.

  So, there you have advice from an industry product manager about wet stacking and how to avoid driving your generator into the ground.

Our field services team can ensure your generator never miss a beat and can take the monthly, yearly generator exercising and maintenance off your plate.

Our teams operate in Colorado, Southern Wyoming, Florida, Southern Georgia and Austin, TX. Click here for more information and click here to see our current inventory of generators for sale.

Story Summary

How often should data center generators be maintained?
Data center generators should be maintained at minimum annually, but quarterly or semi-annual maintenance is recommended. Regular maintenance helps avoid issues like leaks, failures, and lack of reliability during outages.

What is Wet Stacking and what does it lead to?
A condition that occurs when generators frequently run with little or no load. It's a build up that doesn't burn off resulting in  fuel injectors get fouled up, excessive valve guide wear, and can lead to damaged pistons, piston liners, and rings-- among other problems with emissions. It leads to shortened engine life and higher maintenance costs, operators may also run afoul of emissions regulations, which have grown tighter in recent years.

What are the risks of not maintaining data center generators?
Risks of poor maintenance include:

• Engine oil and filter breakdown
• Wet stacking in diesel engines
• Leaks
• Wear on components like block heaters
• Sputtering and stalls
• Fuel tank leaks
• Reduced lifespan
• Failure during critical outages

What does generator maintenance typically include?
Key maintenance tasks include:

• Inspections of generator set, controls, and enclosure
• Topping off engine fluids
• Oil and filter changes
• Battery testing
• Lubrication service
• Cooling system checks
• Generator cleaning
• Engine exercising

How do you properly size a generator for a data center?
Factors to consider when sizing include:

• Total power load requirements
• Number of circuits to connect
• Types of loads (electrical/mechanical)
• Peripheral accessories
• Anticipated load factor
• Future growth plans
• Allowed startup limits
• Size/capacity of transfer equipment

What's the recommended generator sizing for data centers?
Generators are typically sized 1.5-2x the total connected load for proper capacity. Having multiple generators in parallel is recommended for redundancy.

What are common mistakes in generator sizing for data centers?
Common mistakes include:

• Under sizing generators
• Not accounting for future growth
• Failing to consider startup power requirements
• Overlooking peripheral loads and accessories

How does data center tier impact generator requirements?
Higher tier data centers (Tier 3-4) require more generator redundancy and capacity to ensure minimal downtime. Tier 4 centers need fully redundant systems.
 

Brian La Rue | 1/9/2024 2:30:29 PM | 0 comments
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