4 FM quick reads on data centers
1. Complexity Complicates Data Center Maintenance
The issue of complexity and computers resides within much of today's computer equipment. Just open the panels and cabinets of uninterruptible power supply (UPS) units and paralleling control cabinets, chiller control panels, paralleling switchgear, etc., and look inside. To most operating staff, this equipment has essentially become black boxes as well. So as the infrastructure has outpaced the staff's ability to troubleshoot and repair, the reliance on good maintenance practices becomes even more crucial.
Computers, programmable logic controllers, device-specific controllers, etc., are essentially "black boxes," which can complicate data center operations and maintenance. They typically don't give advance notice of pending failure, and when they do fail, the operating staff cannot make repairs or replacements. They have to call for vendor support and take manual control of the infrastructure involved.
The basic purpose of maintenance is to increase the availability of the equipment (and systems) being maintained. At the bottom of the pile is "corrective maintenance," or simply put, "fix it when it breaks." It takes the least effort from a management perspective, but results in the lowest availability and in most cases ends up costing the most in both total cost of ownership (TCO) and impact to operations.
The next rung up is preventive maintenance where you (hopefully) follow the manufacturer's recommendations to inspect and care for the equipment to extend its life and optimize its performance. In this case, you live with some planned unavailability (shutdowns) to afford the opportunity to care for the equipment (check belts, change filters, torque connections, etc.). The result is increased lifespan, more reliable performance, and lower failure rates.
The best practice is to supplement a preventive maintenance program with predictive maintenance using on-line condition-monitoring technologies. The most common and valuable on-line condition-monitoring technologies are thermography (infrared scanning) and vibration analysis. These monitoring techniques not only provide incredible insight regarding the health of the equipment, but actually require the equipment to be in operation, so the need for outages is reduced. By trending the results over time, a facility manager can see the health of the equipment start the inevitable decline towards predefined thresholds and "predict" when the equipment condition or performance will be adversely affected.
2. Determining Optimal Start Time Delays For Generators
The standby-generator start-time delay programming adjustment is driven by a number of factors.
Opinions range from 0.5 seconds to 30 seconds. One concern is that the majority of utility power bumps last less than 3 seconds. Therefore you can have quite a few unnecessary engine starts with start programming set for less than 3 seconds.
The short power bumps typically result from utility re-closers that automatically open and close quickly in an attempt to "shake loose" a problem on the lines, such as tree branches, animals, etc. Re-closers are often programmed by the utility to open and re-close quickly a couple times, resulting in power bumps of 1 second or less, then to remain open up to about 3 seconds on the third and typically final attempt. The fourth time a re-closer opens it typically stays open for many minutes or longer (awaiting manual intervention).
Another concern is that many times the utility fails, then returns, and almost immediately fails again. A generator start timer (typically located in the ATS or generator switchgear) will typically reset when power returns. For UPS backup energy storage, the recharge time is typically 10 times longer than the discharge time, so rapid short utility bumps can cumulatively draw down short-term storage (a very real concern for flywheel UPS systems). Multiple 3 to 10 second utility power failures within a short duration can leave a UPS flywheel too depleted to provide ride-through time.
Most engineers recommend programming generator start time delay settings in the 3 to 5 second range. If utility power is down for more than several seconds it will probably be down for several minutes or hours, so you might as well start your engines. It's best not to challenge UPS batteries any longer than necessary and risk the chance of a UPS failure. The longer a data center runs with no cooling while waiting for generator power, the greater the risk of the data center overheating. However, starting the generator for every light flicker takes its toll on equipment, with impacts on reliability, maintenance, and environmental emissions.
3. Strategic Perspective Guides Healthcare Facility Investment Decisions
Today's tip from Building Operating Management: A strategic perspective guides healthcare facility investment decisions at Crozer-Keystone Health System.
Crozer-Keystone is the dominant health care provider in Delaware County, just to the west of Philadelphia. Anchored by five main hospital complexes in a roughly 30-mile circuit, the system also has an ever-growing number of satellite facilities throughout the county, including more than 600,000 square feet of physician office space.
The push for innovation and efficiency in health care delivery models at Crozer-Keystone is systemic, from the medical staff's efforts at infection control to the way patient medical records are handled. And, with Brian Crimmins, vice president, facilities planning and development, at the helm, the system's facilities have played a big role.
One key is developing a strategy to deal with increasing square footage despite limited budgets. Crimmins has a seat on the hospital's capital allocations committee, where he tries to be impartial and has to make decisions that might not always be popular with his team.
Though he's the one to have to make the tough calls, Crimmins' approach is not top-down, viewing his role less as director and more as collaborator with his team.
"I try to get them to understand the priorities of the health system," Crimmins says. "They have to take ownership in their own hospital or building, but at the end of the day they have to understand that we're going to move in the direction that is in the best interest of the health system and not of the individual facility."
For example, the main data room for the health system has been maxed out in terms of the amount of power and emergency power its facility can deliver to it. So a secondary data room is being built out to relieve the pressure and create some redundancy. "Spending the money to build that data room I'm sure raised some eyebrows with some people," says Crimmins. There's always the need for capital in a hundred different directions: new patient care equipment, new roofs, etc. The new data room will be in a more remote location, isolated from where most of the hospital would see it. But it's Crimmins' job to understand the need where others don't. "With everything becoming more and more computerized, should (the data center) have a problem, it really cripples the whole system," he says.
4. How To Avoid A "Frankenstein" UPS
To reduce the risk of getting a "Frankenstein" system of mismatched components in large UPS systems for data centers, it's important for facility managers to understand the importance of selecting a vendor with a substantial and experienced U.S. sales and service organization.
These concerns with buying complex systems from marginal players in the marketplace are well-understood among industry veterans. These concerns with UPS systems are not much different than with other complex data center support equipment technologies such as redundant standby generator systems and HVAC systems, especially central plants or HVAC systems with economizing features.
One additional key factor is not always well-understood. When an order is placed with a vendor for an integrated system of components, it is up to the vendor to pull together all the correct and compatible components and see that they arrive at the jobsite, at the same time, or are otherwise sequenced as required by the construction team. A large "single module" UPS system can require the main UPS box, boxes full of batteries, sometimes a separate battery disconnect box and often a separate maintenance bypass box, sometimes all shipping from different factories and often from different sub-vendors.
Without a strong technical sales application team, the system may not get properly represented and applied with appropriate accessories or it may not get delivered correctly in accordance with customer needs. Without a strong regional service organization, routine preventive maintenance and minor issues can lead to big problems, such as excessive planned or unplanned downtime or excessive repair time.
Imported UPS units are often matched with domestically designed and assembled battery and bypass packages. Sourcing these components is often left to the domestic sales organization, which is usually different in each marketplace. Often, a buyer thinks (or hopes) all of this equipment will be integrated together or even tested as a complete system at the "main factory or assembly plant." This is rarely the case, as it would add significant cost. Getting these different components to show up correctly at the jobsite is where the marginal players often fall down on the job.
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