Power protection 00000

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Power protection 00000

  1. 1. EmersonNetworkPower.comTransformer UPS vs. Transformerless UPS Balancing high levels of availability with efficiency Click a section below Introduction ENERGY EFFICIENCY comparisons Design factors that affect AVAILABILITY MAINTAINABILITY, service and safety ToTAL CosT of ownership CRITICAL QuEsTIoNs to ask Conclusion
  2. 2. EmersonNetworkPower.com Introduction Today’s IT, facilities and data center managers face the daunting challenge of maintaining a high availability Introduction data center while simultaneously increasing energy efficiency. This challenge, coupled with the need to ENERGY EFFICIENCY quickly meet growth demands and provide an easily maintainable facility, makes selecting an uninterruptible comparisons power supply (uPs) platform a critical decision element. Design factors that affect AVAILABILITY Not all uPs platforms are alike. one such design difference being analyzed today is differences between MAINTAINABILITY, traditional transformer-based UPS to transformerless uPs technology for large enterprise data centers. service and safety This paper with embedded links and videos will highlight the most essential points IT managers need to ToTAL CosT of ownership know when evaluating the differing benefits and costs associated with transformer-based uPs compared to CRITICAL QuEsTIoNs transformerless uPs design. Topics highlighted include: to ask • Energy efficiency comparisons Conclusion • Design factors that affect availability • Maintainability, service and safety • Total cost of ownership • Critical questions to ask The right uPs design strategy should enable a data center to balance lower costs and higher efficiencies with no compromise to overall availability and ability to grow. > Click to watch “The Executive Perspective” Can’t get to YouTube at work?Emerson Network Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 1
  3. 3. EmersonNetworkPower.com ENERGY EFFICIENCY comparisons Fact: Energy efficiency is a top-of-mind concern for data center managers and transformerless uPs designs can achieve Introduction higher efficiencies by replacing the uPs transformer with solid-state circuits. ENERGY EFFICIENCY As the graph demonstrates, when comparing like-for-like operating parameters, the transformerless uPs achieves comparisons higher efficiencies compared to modern transformer uPs designs but only at loaded capacities well over 40 percent. Design factors that affect AVAILABILITY Redundant uPs are typically loaded 100% MAINTAINABILITY, Typical Enterprise Data less than 50 percent to ensure if one Center Operating Range service and safety uPs goes down, the redundant uPs 95% ToTAL CosT of ownership EffiCiEnCy can assume 100 percent of the load. CRITICAL QuEsTIoNs 90% to ask Today’s newest generation of Conclusion transformer-based uPs have been 85% engineered to optimize efficiency at less than half loads. Legacy 80% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% transformer uPs do not optimize in this operating range. Load CapaCity 750kVA Transformer UPS 750kVA Transformerless UPS Legacy Transformer UPS Continue . . . > Click to watch “White Board on Efficiency” Can’t get to YouTube at work?Emerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 2
  4. 4. EmersonNetworkPower.com ENERGY EFFICIENCY comparisons using an example of a typical large data center operation utilizing 750 kVA 2N redundant uPs, where uPs loaded at 40 Introduction percent capacity, a transformer-based uPs actually reduces energy consumption costs by roughly $2,900 over ten years. ENERGY EFFICIENCY comparisons Points to consider: Example: 750 kVA, 2N transformerless UpS transformer UpS Design factors that affect • Every data center is different, so compare kVA 750 750 AVAILABILITY uPs efficiency with actual efficiency and kW 675 675 MAINTAINABILITY, local utility rates. % Load 40% 40% service and safety kW 270 270 • Efficiency impact analysis must account ToTAL CosT of ownership Efficiency @ %Load* 91.8% 91.9% for PDu transformer losses and potential UPS Input kW-H 2,576,471 2,573,667 CRITICAL QuEsTIoNs input isolation transformers. Utility Rate ($/kwhr) 0.104 0.104 to ask Yearly Utility Cost $267,953 $267,661 Conclusion Bottom line: small differences in 1-year cost difference ($291) efficiency can have minimal impact on 10-year cost difference ($2,916) dollars saved. A transformerless uPs * Efficiencies assume like for like operating parameters (double conversion mode, fan utilization, etc.) only achieves better efficiency than transformer-based uPs at loaded capacities far greater than 40 percent. Back to Top of Article Click to watch “White Board on Energy savings” Can’t get to YouTube at work?Emerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 3
  5. 5. EmersonNetworkPower.com Design factors that affect AVAILABILITY Fact: Despite recent advances in technology, today’s transformerless uPs designs are limited to uPs modules under Introduction 300 kVA. To achieve large kW sizes or to achieve redundancy, many small transformerless modules must be paralleled ENERGY EFFICIENCY together. comparisons Design factors that affect Compare the necessary modules needed to achieve the 750 kVA 2N example under both transformer and AVAILABILITY transformerless designs: MAINTAINABILITY, service and safety tranSformErLESS tranSformEr ToTAL CosT of ownership Using 250 kVa modules Using 750 kVa modules CRITICAL QuEsTIoNs to ask 250 250 250 750 Conclusion it it Load Load 250 250 250 750 Bottom line: When sizes get large, more transformerless modules are needed, which means more opportunities for module failure and potential system failures. How many modules are needed for 1000 kVA 2N? Continue . . . Click to watch “White Board on Availability” Can’t get to YouTube at work?Emerson Network Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 4
  6. 6. EmersonNetworkPower.com Design factors that affect AVAILABILITY The number of modules greatly impacts the overall system availability. Using the reliability prediction methodolo - Introduction gies found in IEEE Std 493TM Recommended Practice for the Design of Reliable Industrial Commercial Power Systems, the ENERGY EFFICIENCY reliability of the power system can be estimated. Assuming a 10-year MTBF and performing the necessary logarithmic comparisons computations yields the following: Design factors that affect AVAILABILITY Example: 750 kVA, 2N Transformerless UPS Transformer UPS MAINTAINABILITY, Modules 3+3 1+1 service and safety Module MTBF 10 years 10 years TOTAL COST of ownership Module Failure / Yr 0.574 0.19 CRITICAL QUESTIONS Modules failing in 10 years 4 1 to ask Conclusion Bottom line: Get used to seeing the Service Technician when deploying small transformerless modules in large operations where capacity is greater than 300 kVA. With more modules come more failures. Continue . . . Reliable Design?Emerson Net work Power | Efficiency Without Compromise E-Book Series, Chapter 1 PG 5
  7. 7. EmersonNetworkPower.com Design factors that affect AVAILABILITY What if the worst case happens and all the expected module failures happen simultaneously? Introduction • The 1+1 system loses 1 module, the redundant module effectively assumes the load. No outage. ENERGY EFFICIENCY • The 3+3 system loses 4 modules, only 2 modules remain. Critical load will not be maintained. IT outage. comparisons Design factors that affect using a very conservative estimate on average financial impact of IT downtime of $108,000 and an hour of downtime, the AVAILABILITY potential business losses are significant. MAINTAINABILITY, service and safety Example: 750 kVA, 2N transformerless UpS transformer UpS ToTAL CosT of ownership Worst Case: Simultaneous Failures 4 1 Downtime Est (hours) 1 0 CRITICAL QuEsTIoNs to ask Avg cost per hr of IT downtime ($108,000) ($108,000) Expected Business Losses ($108,000) $0 Conclusion Points to consider: • Cost of IT downtime varies by industry. Losses in Telecom can be as high as $2,000,000 per hour. Losses in the Healthcare industry can be as high as $600,000 per hour. • Transformers prevent DC power from entering the critical bus, which will cause outages. Bottom line: A worst case scenario of a down data center is unacceptable for many. The more components you add to a design, the more opportunities for failures are introduced. Too many components could take down an entire data center. Back to Top of ArticleEmerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 6
  8. 8. EmersonNetworkPower.com MAINTAINABILITY, service and safety Fact: When the modules fail, they will need to be repaired. The more failures the more repairs. using the example and Introduction our expected module failures, a comparison of emergency maintenance expenses can be made: ENERGY EFFICIENCY comparisons Example: 750 kVA, 2N transformerless UpS transformer UpS Design factors that affect AVAILABILITY Module Failures in 10 yrs 4 1 Time and Material Rate ($250) ($250) MAINTAINABILITY, service and safety Mean Time to Resolution (hr) 16 16 Cost of Emergency Service Calls ($16,000) ($4,000) ToTAL CosT of ownership Billable Expense Difference $0 ($12,000) CRITICAL QuEsTIoNs to ask Points to consider: Conclusion • A transformerless UPS has the ability to pass more fault current to the critical load. A transformer UPS can clear and isolate more internal faults than a transformerless design. • Preventing arc flash explosions is a critical part of a facility manager’s duty. The impedance produced by transform­ ers will limit fault currents and arc flash energy levels. Bottom line: Transformers require fewer service calls, limit downstream fault current , isolate currents and improve arc flash safety. Click to watch “White Board on Maintainability” Can’t get to YouTube at work? Consider safetyEmerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 7
  9. 9. EmersonNetworkPower.com ToTAL CosT of ownership To properly analyze Total Cost of ownership (TCo), the compromise between efficiency and availability must be Introduction weighed against system cost. ENERGY EFFICIENCY comparisons Example: 750 kVA, 2N transformerless UpS transformer UpS 10-year difference Design factors that affect AVAILABILITY Efficiency 91.8% efficient @ 40% load 91.9% efficient @ 40% load ($2,916) Availability One 1-hour outage Zero outages ($108,000) MAINTAINABILITY, service and safety Maintainability 4 module repairs 1 module repair ($12,000) Net benefit of using Transformerless UPS ($122,916) ToTAL CosT of ownership Purchase price savings of Transformerless UPS + $122,916 = True Cost of Ownership CRITICAL QuEsTIoNs to ask There are other costs that should be factored into any TCo analysis: Conclusion • True efficiencies running under various energy optimization modes for a specific amount of hours in a year • Risk of arc flash explosions • Cost of transformers elsewhere in the power system to achieve isolation • Number of downstream faults not cleared by UPS that result in failures Bottom line: The financial impact transformer-based uPs have on Efficiency, Availability and Maintainability should be included in cost comparisons of the two designs. Continue . . .Emerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 8
  10. 10. EmersonNetworkPower.com ToTAL CosT of ownership The example used throughout the analysis, 750 kVA, 2N, is important to note. Transformerless uPs topologies, Introduction while available only in modules under 300 kVA, have many benefits that are well suited to smaller operations and ENERGY EFFICIENCY the impact to Efficiency, Availability and Maintainability will be greatly altered if the module count of the uPs is small, comparisons total power demand is low, or if the uPs is loaded far beyond 40 percent. Design factors that affect AVAILABILITY Transformerless uPs benefits that may impact TCo: MAINTAINABILITY, service and safety • Purchase Cost –Transformers are expensive components of a uPs and eliminating them will save capital costs of the uPs (but be aware, transformers will still need to be included somewhere in the data center). ToTAL CosT of ownership • Efficiency – At capacities over 40 percent, transformerless uPs efficiencies may be greater than some legacy CRITICAL QuEsTIoNs transformer-based uPs. Don’t get caught up in efficiency modes, know your typical operating mode. to ask • Footprint – Transformerless uPs have smaller footprints, so the cost of real estate needs to be included. Conclusion • Weight – By eliminating the heavy transformer, the transformerless uPs could reside on a raised floor. shipping costs will also likely be lower. • Heat Output – The need for precision cooling of the power equipment may be reduced because the heat produced by the transformerless uPs is less. IT and data center managers should evaluate how their needs and operating environment align with the capabilities and performance of the two uPs design options. Back to Top of ArticleEmerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 9
  11. 11. EmersonNetworkPower.com CRITICAL QuEsTIoNs to askWhat is my power growth plan? Introduction Why? The modular design of the transformerless uPs addresses the quickly changing power requirements of IT, but the ENERGY EFFICIENCY modularity comes at the expense of reliability when growth gets too large. If the growth path is ambiguous yet final comparisons total capacity is known to be small, transformerless uPs could be included in uPs evaluations. Design factors that affect AVAILABILITYWhat are my availability requirements and plans on UPS redundancy? MAINTAINABILITY, Why? Because of its design, the component count of transformerless uPs is high. Parts count has a direct impact on service and safety reliability. If the availability needs are high and redundancy is needed, a transformer-based uPs is the optimal design. ToTAL CosT of ownership How many components and switching devices are in my UPS design? CRITICAL QuEsTIoNs Why? Component count has a direct impact on reliability. If the system is large, a transformer-based uPs should be to ask the optimal design to reduce potential points of failure. ConclusionWhat are my real estate limitations? Why? Transformerless uPs are smaller than transformer uPs. They also weigh less, making them possible to place in the rack row. If the equipment room is not available or the uPs will reside with the IT equipment, transformerless uPs could be included in uPs evaluations. Do I have a safety requirement to reduce arc flash fault current? Why? Personal safety should always be included in IT infrastructure design. If a facility wants to limit fault current, a transformer-based uPs should be the optimal design.Emerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 10
  12. 12. EmersonNetworkPower.com ConclusionTransformer-based uPs designs are proven topologies for achieving high efficiency without compromising availability Introductionin large enterprise data center applications and midsize to small operations as well. Due to design limitations on the size ENERGY EFFICIENCYof transformerless uPs technology, their use should only be considered in low power, small and medium size operations comparisonswhere achieving the highest availability is not the top priority. Design factors that affect AVAILABILITY MAINTAINABILITY,Additional Resources service and safetyIf you’re interested in learning more about trends and topics related to powering, cooling or monitoring data centers, ToTAL CosT of ownershipcheck out these white papers from Emerson Network Power. CRITICAL QuEsTIoNsBest practice case studies of how other companies have solved data center challenges are available in narrative and video forms. to askCase studies are from small to large companies across numerous industries. ConclusionIf you have specific questions, a Liebert Representative from Emerson Network Power or a Liebert certified IT reseller can help you out.Click here to find your local contact.Finally, be sure to follow Emerson Network Power on Twitter or visit the Emerson Network Power YouTube Channel to be one of the first to knowcompany news or view new white papers and case studies.Emerson Network Power.The global leader in enabling Business-Critical ContinuityTM. EmersonNetworkPower.com AC Power Embedded Computing outside Plant Racks Integrated Cabinets Connectivity Embedded Power Power switching Controls services DC Power Infrastructure Management Monitoring Precision Cooling surge Protection While every precaution has been taken to ensure accuracy and completeness in this literature, Liebert Corporation assumes no responsibility, and disclaims all liability for damages resulting from use of this informationor for any errors or omissions. specifications subject to change without notice. ©2009 Liebert Corporation. All rights reserved throughout the world. Trademarks or registered trademarks are property of their respective owners. ®Liebert and the Liebert logo are registered trademarks of the Liebert Corporation. Business-Critical Continuity, Emerson Network Power and the Emerson Network Power logo are trademarks and service marks of Emerson Electric Co. ©2009 Emerson Electric Co.Emerson Net work Power | Efficiency Without Compromise E-Book series, Chapter 1 PG 11

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