| Against the backdrop of ever increasing power | | | | can be down-sized. Iron loss occurs in the cores of |
| consumption of computers and communications | | | | electrical transformers and inductors when a |
| equipment, David Bond, managing director of | | | | fluctuating magnetic field is present due to eddy |
| Uninterruptible Power Supplies Limited, explains how | | | | currents and hysterysis. Copper loss is due to the |
| the recent technological developments of modular | | | | resistance of the windings of transformers. |
| on-line double-conversion UPS systems are helping UK | | | | Transformerless UPS modules are considerably lighter |
| corporations become more energy efficient and fall in | | | | than their transformer-based counterparts. The |
| line with the UK government’s initiatives to | | | | combination of lightness and ‘hot swap’ |
| promote energy efficiency. | | | | capability (adding modules to, or removing them from |
| In this ‘information age’ we are experiencing | | | | a UPS system without disruption to the critical load) |
| exponential growth in voice and data communications | | | | to match its capacity to that of the critical load it is |
| and on-line processing for both business and pleasure. | | | | supporting, greatly simplifies ‘right-sizing’. |
| Internet surfing and transactions, VoIP, e-mail, social | | | | In a traditional example, it is common practice to |
| networking and a/v downloads, plus e-commerce and | | | | initially install a UPS system with sufficient capacity to |
| financial services on-line 24/7, present high demand | | | | support the expected maximum future loading. |
| for bandwidth and for power around the clock. | | | | However, it is invariably found that the actual load |
| Power consumption is rising rapidly for several | | | | falls a long way short of the anticipated load, resulting |
| reasons. One is that UK organizations are fulfilling | | | | in the UPS system operating well below its rated |
| expectations to provide an ever increasing number of | | | | capacity and therefore running very inefficiently and |
| IT services with consistent, reliable power, 24 hours | | | | wasting energy. |
| per day, with little or no down-time. Another reason | | | | By comparison a modern (modular hot-swappable) |
| is that they are obliged to comply with legislation | | | | UPS system in the identical scenario would fare much |
| enacted to promote improvements of corporate | | | | better. As the load grows, the UPS can be upgraded |
| accountability, which in turn requires additional, and | | | | in incremental steps by adding modules (without |
| secure, IT resources and power consumption. | | | | increasing the footprint) and the system utilization is |
| UPS systems have become commonplace in | | | | greatly improved. |
| computer rooms, data centres and server farms, and | | | | Transformerless UPS modules represent a much |
| play a vital part in maximising the availability of the | | | | lower input power factor (than their |
| systems that they support. However, their running | | | | transformer–based counterparts) to the mains |
| costs can be high, and there’s the additional cost | | | | electricity supply. That means that they draw much |
| of providing redundancy to ensure the highest levels | | | | less current (Amps), economizing on electricity |
| of power availability. Factors like the Climate Change | | | | running costs and minimizing upstream cable and |
| debate, the emergence of the low-carbon economy | | | | switchgear sizes. Transformerless UPS modules |
| and tax breaks – like the Enhanced Capital | | | | feature flat efficiency from quarter-load to full-load. |
| Allowance or ECA – and the rising cost of mains | | | | Because the modules of parallel-redundant UPS |
| electricity, collectively make energy efficiency in data | | | | systems by necessity operate at partial-load, high |
| centres a very important commercial consideration. A | | | | operating efficiency at partial load is a highly desirable |
| survey by Gartner, published in the summer of 2006, | | | | feature. |
| identified that typically sixty per cent of data centre | | | | Improved operating efficiency of UPS systems |
| budgets are concerned with delivering power and | | | | reduces the burden on air-conditioning plant in |
| expelling extraneous heat. It goes without saying that | | | | computer centres, thus making a further contribution |
| any improvements in the energy efficiency of the | | | | to energy efficiency. |
| uninterruptible infrastructure are very welcome. | | | | Incentives and technologies paving the way to more |
| Occurring during the same period, several fiscal | | | | efficient UPS systems |
| events have influenced the direction of developments | | | | More system managers and end-users expect ever |
| of UPS systems. One of them is the Climate Change | | | | higher levels of availability of business critical systems, |
| Levy (CCL), a tax on energy delivered to users in | | | | and consequently, higher levels of availability of the |
| the United Kingdom. | | | | UPS systems that support them. |
| Introduced on 1st April 2001 under the Finance Act | | | | First among EU member states to do so, the UK |
| 2000, it was forecast to cut annual emissions by 2.5 | | | | Government is publishing a draft Climate Change Bill |
| million tonnes by 2010, and forms part of the UK's | | | | for pre-legislative scrutiny and public consultation. It is |
| Climate Change Programme. It applies to energy used | | | | also publishing a strategy document that sets out |
| in the non-domestic sector (industry, commerce, and | | | | how the draft Bill fits with the Government’s |
| the public sector). The aim of the levy is to | | | | broader strategy for tackling climate change. It |
| encourage these sectors to improve energy | | | | highlights some key announcements coming up, which |
| efficiency and reduce emissions of greenhouse gases. | | | | will be central to the Government’s strategy |
| From when it was introduced, the levy was frozen at | | | | – in particular the Energy White Paper, the Waste |
| 0.43p/kWh on electricity, 0.15p/kWh on coal and | | | | Strategy and the Planning White Paper. |
| 0.15p/kWh on gas. | | | | The debate on climate change has shifted from |
| The rising price of electricity and the levy on it have | | | | whether UK citizens and corporations need to act, to |
| pushed energy efficiency to number one in the list of | | | | when, and to what extent they need to act. The |
| considerations in the procurement of a new UPS | | | | Government has expressed its commitment to |
| system. | | | | moving to a low-carbon economy and has instigated |
| Types of UPS technology | | | | several energy-saving measures that work. One of |
| Of the three types of UPS technology, off-line, | | | | them is the Enhanced Capital Allowance (ECA) |
| line-interactive and on-line, implementations of on-line | | | | scheme. Before it makes a claim for relief under the |
| double-conversion (AC-to-DC and DC-to-AC) UPS | | | | scheme, a business must obtain a certificate to |
| systems are the most popular in computer rooms | | | | confirm that its chosen system is on the Energy |
| and data centres because they protect their critical | | | | Technology List (ETL) and therefore meets the |
| loads from the full range of mains electrical supply | | | | relevant qualifying criteria. The Carbon Trust maintains |
| problems – transients, interruption, sag | | | | and publishes the ETL and manages ECA claims on |
| under-voltage, swell/over-voltage, waveform | | | | behalf of the Department for Environment, Food and |
| distortion, voltage fluctuation and frequency deviation | | | | Rural Affairs (DEFRA) and HM Revenue & |
| - and consequently deliver the highest levels of | | | | Customs. Uninterruptible Power Supplies Limited is, like |
| system availability. | | | | other UPS suppliers, lobbying the Carbon Trust for |
| Two technological developments, in particular, have | | | | static UPSs to be included in the scheme. |
| been instrumental in improving the efficiency of | | | | Five ways to improve energy efficiency |
| on-line UPS systems; they are transformerless | | | | 1. 1. Use more efficient power protection |
| double-conversion technology and parallel-redundant | | | | equipment. Invite UPS specialist firms to survey your |
| modular architecture. | | | | current UPS installation and advise on possible savings |
| Furthermore, when supplying critical loads that have | | | | to be made by using state-of-the-art equipment. |
| leading power-factors, as is the case with increasingly | | | | Today’s best-in-class UPS systems are |
| prevalent blade servers, state-of-the-art UPS system | | | | considerably more efficient at operating at partial |
| modules operate more efficiently than their traditional | | | | loads (e.g. when UPS modules operate in |
| counterparts. | | | | parallel-redundant configurations). |
| Benefits of UPS systems with parallel architecture | | | | 1. 2. Right-size your power protection |
| All parallel UPS systems comprise two or more UPS | | | | infrastructure. Considerable gains in energy efficiency |
| modules operating in parallel to feed a common critical | | | | can be made by using a modular, scalable power |
| load bus. UPS modules are paralleled for three | | | | protection system, enabling UPS to be right-sized to |
| reasons: | | | | match the critical load. |
| 1. To increase the power rating of a UPS system | | | | 1. 3. Review your server requirement/ |
| because of an increase in the size of the critical load. | | | | Review server usage Significant energy savings can |
| Such parallel systems are known as capacity | | | | be made by rationalising lightly loaded servers and |
| systems. | | | | switching off the vacated ones. |
| 2. To increase the availability of a UPS system | | | | 1. 4. Optimise the design and operation of |
| because of the importance of the critical load. Such | | | | the air-conditioning system used in the data |
| parallel systems are known as redundancy systems. | | | | centre. Invite specialist firms to survey your current |
| 3. To allow simple and cost effective system upgrade | | | | HVAC installations and propose improvements. The |
| by adding UPS modules in parallel when required, | | | | survey might uncover energy wasting scenarios such |
| known as system scalability. | | | | as restricted air paths, poor circulation around racks, |
| Transformerless UPS systems save energy | | | | inappropriate alignment of CRAC units, incorrect |
| Transformerless UPS systems are more energy | | | | location of vented floor tiles, etc. |
| efficient than their transformer-based counterparts | | | | 1. 5. Optimise the design and operation of |
| for two reasons. First, there is no iron-loss and | | | | the lighting system used in the data centre. Use |
| greatly reduced copper-loss, and consequently less | | | | more energy efficient lighting, or try installing motion |
| extraneous heat to be removed from the data | | | | sensors or lighting timers. |
| centre by the air-conditioning infrastructure, which | | | | |