Published on Monday, Aug 22 2011 by
Recent years has seen the importance of UPS systems grow dramatically and today they form an essential component of a data centres’ power protection, raising the question; what do users most need from their UPS? A recent survey, conducted by Uninterruptible Power Supplies Limited (UPSL), a Kohler company, investigated exactly this. Here, the company’s technical manager, Matt Henley, explains the results and provides an insight into how data centre operators should select a UPS vendor which is in tune with today’s environmental, business and technical pressures.
Decades ago, a UPS was perceived as a primitive and intrinsically ugly piece of plant room equipment, more at home amongst its generator cousins than sensitive ICT equipment. Fast forward to today, and the role of a UPS has evolved in direct correlation to the consistent advances in computer hardware – becoming an indispensable resource for the protection of critical applications. This transition to data centre essential has driven UPS systems to become more reliable, efficient, cost effective and flexible.
The growth of the data centre market especially has accelerated the development of UPS systems functionally in the areas of efficiency, availability and flexibility. As loads have grown and become more critical, electrical mains power has become, or is at least seen to be, less reliable, further contributing to the growth in UPS demand. When asked, over 75 percent of the 2000 IT professionals questioned reported that their UPS system was called upon to protect critical equipment during a power outage within the last 12 months, with 78 percent of respondents also believing the situation will only get worse over the next decade.
This opinion is certainly not without foundation. It has been predicted that up to 19 Giga Watt of UK generating capacity will be lost by 2018, as coal, oil and nuclear power stations are decommissioned and close. Timely replacement of these sources, with those compliant with ‘green’ legislation, will be ‘challenging’ according to the Department of Energy and Climate Change and will likely rely on a significant step change in the level of investment from the private sector and government sponsored renewable energy initiatives.
The rocketing price of oil, and the direct effect this has on the cost of energy, is also, unsurprisingly, of major concern to 80 percent of those questioned. Reduction of an organisation’s energy usage and carbon footprint is therefore also a growing priority, driven in large part by legislation such as the CRC Energy Efficiency Scheme. However, interestingly the survey shows that over 63 percent regard reducing overall operating costs as their main driver to reduce power consumption, compared to just 27 percent which are driven by a more altruistic desire to reduce their organisation’s carbon footprint. Furthermore, purchases of capital equipment are significantly affected, with 82 percent of respondents regarding energy efficiency as a key buying consideration. This figure includes UPSs, with nearly 54 percent of those questioned reporting that modern UPS systems – designed and manufactured with environmental considerations at their core – have significantly improved power consumption and cooling issues within their organisation.
Transformerless technology lies at the heart of modern UPS design. Its immediate impact has improved energy efficiency by around 5 percent across the UPS’s whole load span. This substantially reduces energy and cooling costs. Transformerless UPSs also present a higher and more stable input power factor, which reduces input current and sometimes electricity costs.
Transformerless implementations bring many other benefits through their reduced size and weight. A 120 kVA UPS, for example, can be implemented as a 263 Kg unit with a 0.42 m² footprint instead of an installation with a 1.32 m² footprint weighing 1,200 Kg. This has enormous implications for power protection and has enabled UPS systems to become sets of more attractive rack-mounted modules, operating in parallel, rather than monolithic floor standing units..
The modular design also increases UPS availability because a faulty module can be quickly replaced, typically within about half an hour, compared with the six hours typically needed for component level diagnosis and repair. Modules can also be ‘hot swapped’, without needing to divert the critical load onto raw mains. Availability is defined by the relationship between Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR), so reducing MTTR increases the UPS’s availability. Transformerless systems also improve battery reliability through using a DC – DC battery charger which eliminates AC ripple – a prime cause of premature battery failure.
Although these hardware improvements are welcome, users believe the overall reliability of their UPS resource is governed by the quality of the UPS supplier’s total package rather than just that of the hardware. Over 90 percent of the survey’s respondents believe that maintenance and emergency call out services are as important as the hardware itself to their business. In fact service quality becomes a factor even before the UPS hardware is selected. Vendors should be competent to advise on and offer UPS configurations efficiently matched to users’ needs rather than just selling catalogue stock products. Clearly, the UPS capacity must be adequately rated for its task, including redundancy provision. However, because modular system capacity can easily be incremented if the load grows, oversizing is unnecessary and will incur capital and operating cost penalties.
After installation, users should arrange a support package, comprising both preventative scheduled maintenance and assured emergency response. Scheduled maintenance will minimize the need for emergency callouts by spotting deteriorating components for replacement before failure. As a complete power protection installation often extends to a UPS, batteries and generator, it makes sense to use a single supplier who understands all of these, how they interact with one another and accordingly how to provide an integrated power support strategy. International standards exist to define different aspects of service quality, and it is useful to ask if prospective UPS suppliers are certified for these. BSI EN ISO 9001:2008 covers quality management, ISO 14001 covers environmental management and OHSAS 18001 is for health & safety management. These certifications not only indicate service quality; they also demonstrate that the supplier can manage the UPS user’s environmental and health & safety obligations during the equipment’s operational life and eventual disposal.
An emergency callout service – appropriate to the load’s criticality – should be negotiated. Response times for arrivals to site should be set and guaranteed, and backed by 24/7 telephone support. This service can be enhanced by remote monitoring, where key equipment parameters can be interrogated over a telephone link. This interrogation can be initiated by an alarm event to inform field response technicians about the nature of the fault before they arrive. Alarm notification of an event as it occurs allows immediate response to an emergency, while the remote diagnosis improves the rate of ‘first time’ fixes after arrival at site.
The survey has shown how UPS users’ concerns reflect our current political, business and technical environment. Inexorable growth in data centre demand, coupled with increasing concerns about UK power grid availability lead users to value reliability highly, while viewing reliability as the sum of the equipment and its support. With rising energy costs and increasingly aggressive ‘green’ legislation, energy saving is also a priority to save costs, and to a lesser but significant extent, meet carbon footprint reduction and social responsibility goals. A large majority of the respondents have carbon reduction policies and strategies to investigate product efficiencies in place. Modern UPS technologies help users to achieve these goals, but the right choice of supplier is essential as well.