Watch Your Step (down): The ideal Medium Voltage Facility
There’s a jolt of electricity traveling across businesses today. Faced with ever-shrinking corporate budgets and rising energy costs, a renewed focus has been placed on power efficiency in the data center. Just as critical individual hardware and software components, the ability to create quality, cost-effective pathways to power distribution in the data center has taken on renewed strategic significance.
There’s a jolt of electricity traveling across businesses today. Faced with ever-shrinking corporate budgets and rising energy costs, a renewed focus has been placed on power efficiency in the data center. Just as critical individual hardware and software components, the ability to create quality, cost-effective pathways to power distribution in the data center has taken on renewed strategic significance.
One of the most common practices for power distribution involves the infrastructure receiving power at medium voltage (2400 V to 35 KV) and then stepping down to distribute at 480 volts. But this “step-down” approach can be a costly mistake. There are not only inherent issues associated with efficiency loss, but costs associated with poor design. That’s why a renewed focus is being placed on the underlying power distribution infrastructure – and foundational elements, such as Uninterruptible Power Supply (UPS).
Companies must be prepared to watch their step – and ensure powering up and stepping-down happens in the most efficient means possible.
Surging Costs
Data center costs are surging – as physical footprints strive to accommodate the flood of data companies must store and manage on a daily basis. And growing infrastructures mean higher costs associated with powering the data center.
The industry analysts at Gartner Group note energy-related costs account for approximately 12 percent of overall IT infrastructure spend – making it the fastest-growing costs in the data center. And this number is only expected to grow over the next two decades. The U.S. Department of Energy estimates global demand for energy will increase nearly 60 percent during the next 20 years. The industry pundits at The Register even noted the information and technology ecosystem represents approximately 10 percent of all electricity generation today around the world. Unfortunately, companies aren’t helping with how they choose to manage and distribute power.
Recent surveys indicate companies are actually becoming less – not more – efficient in powering their infrastructures. Using the standard Power Usage Effectiveness (PUE) scale, industry firm Digital Realty Trust recently conducted a survey of IT-dependent businesses. According to the report, the typical company comes in at a PUE of 2.9 – meaning they consume 1.9 extra watts for every watt used to run servers.
But what can be done? The answer can often be found in how data centers accept and distribute power.
Going “Old School”
Typically, an “old-school” electrical distribution system mandates a series of power exchanges – meaning energy must be stepped down accordingly. Power is often received from the utility at medium voltage (2400V-35KV) and transformed to 480 V for distribution. Specifically, distribution across the infrastructure consists of several core steps:
- Utility/Power Source: Supplies power to the data center at medium voltage.
- Distribution: Power is stepped-down to “distribution voltage” (480 V) at the substation transformer.
- UPS: Power is then fed through the Uninterruptible Power Supply, which conditions the power and backs-up the infrastructure in case of an outage.
- PDU: The power is stepped-down yet again to 280/120 V by a power distribution unit (PDU), which is then stepped down to 12Vdc – the operating voltage for IT equipment.
Unfortunately, this model only adds new costs and greater inefficiencies into the power infrastructure. What’s required is a system capable of accepting and distributing energy at medium voltage.
Harnessing Medium Voltage
One obvious benefit to transitioning into a medium voltage system is found in actual physical cost savings. For example, a 480 V power distribution system mandates greater use of distribution materials – such as copper conductors. This is particularly frustrating as copper prices continue to rise exponentially. Medium voltage systems require smaller or fewer conductors, thus avoiding the extra costs of copper.
Another issue created by 480 V systems is “voltage drop”. The term describes the manner in which supplied energy of a voltage source is reduced as the current runs through a circuit. Higher voltage drops mean greater inefficiencies in lost power – as well as poor operational performance and potential damage to equipment.
Heat and its associated costs are also drawbacks to a lower voltage system. Under typical construction, a lower voltage infrastructure is comprised of conductors operating in groups. This means higher temperatures, as they act as heat sources. But medium voltage systems offer more power, meaning fewer clusters and less heat. The resulting drop in associated cost is significant.
Based on these arguments, it would only seem logical to transition into a more modern distribution infrastructure – fully leveraging the benefits of medium voltage. Unfortunately, it’s often restrictions to core infrastructure components – such as the Uninterruptible Power Supply (UPS) – that prevents this from happening.
A New Take on the UPS
A typical UPS was developed to provide emergency power to a load when the main input source fails. The system brings instantaneous protection from power interruptions by supplying stored energy. But it’s also often one of the biggest roadblocks to transitioning to a more cost effective medium-voltage model.
As a rule, typical UPS systems are static and powered with a battery offering an energy source in case of failure. But these standard UPS systems simply were not designed to handle a medium-voltage load. That’s why so many companies are increasingly turning to a Diesel Rotary Uninterruptible Power Supply (DRUPS). DRUPS devices can support the load with a diesel generator – ensuring continuous backup as needed. The system uses stored kinetic energy to bridge the diesel engine start time when there is a utility power failure.
Unlike a typical static UPS, a DRUPS unit does not need to be cooled by an air conditioning system. This results in significant energy savings and the efficiency of not running cooling equipment 24×7. There’s also no need for converting electrical energy from the utility to the critical load. These systems run in parallel with utility power, ensuring optimal use of utility supply.
The system’s ability to accept medium voltage also means it can protect even larger loads at higher levels of efficiency. In fact, the elimination of step-down and step-up transformers will provide improved efficiency of at least two percent.
And with a life expectancy of nearly 25 years, DRUPS offer a more permanent power distribution solution – ensuring lower costs, greater efficiency and quicker return on investment.
Taking the Step
As one of the fastest-rising costs in the data center, power consumption is top-of-mind for managers and executives alike. In an effort to raise efficiencies and keep costs down, an infrastructure with the ability to operate at medium voltage is increasingly becoming a viable alternative.
But to make this happen, companies must first look closely at the very backbone of these systems – the UPS. By investing in a DRUPS system, companies can remove any roadblocks and challenges imposed by step-up and step-down processes. The end result is a true medium-voltage system designed to meet data center cost and efficiency needs now – and in the future.
