Low Power, High Resilience
The new Fujitsu datacentre in North London opened this summer demonstrating that as the first Tier III accredited datacentre in Europe, it can also provide a highly resilliant facility and designed to use less energy.
There are many things about the modern world that we only really become aware of when they’re not there or not working properly. And it can seem to facilities managers that they spend the vast majority of their time providing exactly those things, from lighting to HVAC systems, toilets to running water, parking spaces to office seating. All taken for granted until people don’t have them, while their presence, unacknowledged for the most part, is testimony to the hard work and expertise of an army of unsung heroes.
While many of the services provided by facilities mangers only rarely fail, failure is not an option at all for some environments. Nowhere is this more true than it is for datacentres. According to Gary Payne of Modus Unitech, ‘In an economy reliant on technology, firms would quickly stop functioning if datacentres stopped working. Business continuity is everything. If a system becomes unavailable or insecure, then it will quickly become a problem and potentially disastrous. The datacentre must keep flawless standards for ensuring the integrity and functionality of the environment it is home to. The fact that failure is so rare, non-existent in many cases, makes the work that is done designing, building and managing datacentres so impressive. But conversely, it also means all that hard work can go largely un-credited. The users of computers may take working technology for granted a lot of the time but they have a lot of skilled and dedicated professionals to thank for it.’
Modus has just completed work on one of the most advanced datacentres in Europe, a new £44m project for Fujitsu Services in a converted 1970s warehouse at their North London centre. It’s a typically modest exterior for something that is incredibly important according to Payne, who led the Modus team responsible for the architectural design and project management of the new centre. “You would never know it at first glance, but this is one of the most advanced installations of its kind in Europe,” he says. “The brownfield development site and the redevelopment of an existing building belie the fact that what is happening inside is cutting edge, world class, offering exceptional resilience and the very best low energy credentials.” He is referring to the centre’s Tier III rating, a classification of datacentre resilience developed in the US by The Uptime Institute (TUI) but now recognised as a global standard.
The new Fujitsu datacentre is the first Tier III accredited centre in the whole of Europe As Payne explains, “It is this combination of business and economic need coupled with environmental concerns that is the most important current feature of datacentre design. What is great about the way this project has been developed is that we have been able to balance what may have been conflicting objectives — business necessity and environmental performance — and been able to meet them, without compromise.” The environmental features of the installation include the use of a carefully designed low energy cooling system including variable speed drive chillers and evaporative cooling towers coupled with variable speed fans, pumps and heat exchangers.
The cooling system is designed to maximise the use of free cooling from partial through to full free cooling, depending on ambient temperature. According to Fujitsu this system saves enough energy to power around 2,000 households every year.
The project will also run in parallel with a programme to modernise customer IT systems to save around 50 per cent of total power consumption. Fujitsu believes the new centre will allow it to save the equivalent to 10,000 tonnes of carbon dioxide emissions each year and significantly reduce the cost of IT for the business.
In technical terms, the London North centre currently achieves a Power Usage Effectiveness (PUE) of around 1.6 under full design conditions. PUE is a measure of the energy efficiency of a datacentre and is determined by dividing the amount of power entering a datacentre by the power used to run its infrastructure. So, expressed as a ratio, overall efficiency improves as the PUE decreases toward 1. In addition, Fujitsu Services is committed to looking at ways of improving the efficiency of the centre even further over time. The building’s services were designed by Red Engineering Design. At the heart of Red’s low energy design is the innovative application of tried and tested engineering principles, achieving minimum energy consumption in each area of the services. In line with TUI recommendations, the design is based on a ‘worst case’ ambient temperature of 38ºC, future-proofing the facility against the potential effects of global warming with an emphasis on using tried and tested technologies in new, sophisticated ways.
The evaporative cooling systems, for example, are well established technologies that offer a significantly more efficient alternative to traditional air cooled systems. High efficiency water cooled chillers supply chilled water at elevated temperatures to maximise opportunities for free cooling and eliminate the need for re-humidification of the air. The chillers have also been configured to minimise energy consumption at part-load. Chilled water circuits are arranged in flow and return rings, rather than the conventional flow and return circuits, allowing areas to be isolated for maintenance without disrupting chilled water flows.
Taking full advantage of the higher return temperatures, heat is recovered from the chillers by a heat pump and used to pre-heat fresh air used for ventilation. Further energy savings are achieved by the use of spray humidification, which requires considerably less energy than conventional steam humidification.
In addition, dimmable, low energy lighting in the data hall is linked to passive infra-red (PIR) occupancy detectors. When the space is unoccupied the lighting is reduced to 20 per cent of full design illuminance, sufficient for the CCTV systems. Energy consumption of lighting in other areas is also minimised through occupancy based control.
Commendable and desirable though the green performance of the new building is, it would mean nothing if the datacentre were less than totally resilient. Tier III status means that the datacentre provides 99.98 per cent site availability, ‘as near to optimum specification as you can get’ in the words of Payne. Central to this level of resilience is the provision of a diesel rotary uninterruptible power supply (DRUPS) to ensure that power failure will not disrupt service. “The provision of this specific DRUPS system was not foreseen at the outset,” explains Payne.
“It only became apparent as we developed the project that the UPS system we had originally in mind was not the optimal solution so Fujitsu worked with us to re-specify these systems to ensure the project would meet key performance criteria and give the best possible solution. We had the added challenge of ensuring that this development would not disrupt the final deadline. It has been recognised that datacentres in the south east have been approaching capacity for some time, so the provision of the new site by the middle of 2008 was considered absolutely essential. We had to hit the deadline and ensure that we met or exceeded all of our performance and environmental objectives. The only option we had was success in providing the right results on time.”
Lighting typically accounts for 40% of the total energy usage within office buildings. Consequently, leaving lighting on when it was not needed was proving to be a common cause of energy inefficiencies at 22 Whitehall – the Cabinet Office. To address this issue, FM company Ecovert FM, commissioned its preferred supplier, Setsquare Limited, to survey, design, manufacture and install a flexible presence based lighting control system which would be able to accommodate the specific requirements of this building.
A spokesperson for Ecovert FM said “The cost verses the efficiency return at 22 Whitehall was good and Setsquare’s technology provided an innovative solution to the ongoing problems relating to luminaires being continuously left on. Following the installation of their lighting controls we have experienced a 60 per cent saving in energy usage within this building, giving us an annual cost saving of £6,268, as well as a 44,9221kg reduction in carbon dioxide emissions.”
This project follows the success of Setsquare’s InfraPOD presence based lighting control installations at other Cabinet Office buildings. It required both English Heritage and local authority approval and the Cabinet Office’s architects were tasked with ensuring that it caused minimal disruption to the building’s fabric. The unobtrusive design of this innovative lighting control system and the way its installation was executed proved to be ideal for this type of application.
22 Whitehall had 488 high frequency luminaries which had been specified for their energy efficiency. 416 of these are located within the office areas, and 72 illuminated the lift lobbies. The luminaries within the offices were being left on for 19 hours per day, whilst the lift lobby luminaires were operating for a full 24 hours a day.
The InfraPOD modular range of passive infrared occupancy detection sensors provided a versatile and flexible presence-based lighting control solution in the large open plan offices and the lift lobbies. A control unit incorporates switching time delay and photocell adjustment, enabling up to 10 low profile detector heads to be linked to one controller by using low voltage 2-core screened wire. As each sensor contains a passive infrared detector, this system reacts to movement, thereby ensuring that the lighting is only on when the zone is occupied.
An adjustable timer, within the unit, maintains lighting during defined periods of inactivity. As soon as movement ceases and after a specified period of time, the luminaries will be extinguished and will not be re-energised until the system is activated by someone moving into the zone. By ensuring that lighting is only energised when body movement is sensed, or when there is insufficient natural lighting, this system has achieved substantial energy cost savings whilst also reducing the building’s carbon footprint.
The sensor heads are mounted in between the diffuser fins on the suspended mounted luminaries. As the detection sensors are positioned at a lower level than the existing ceiling height, the detection pattern within the centre of the controlled zone is more concentrated, making it sensitive enough to detect the movement of hands on a computer keyboard or mouse.
To achieve a higher level of sensitivity in the outer perimeters of the detection zone, Setsquare installed additional InfraPOD detectors. These provided the required detection capability so that where no movement was detected within a short time delay period the lighting would be automatically extinguished.
In the lift lobby areas facing a central atrium, the InfraPOD Controller takes account of the effect of natural daylight in order to further reduce energy wastage. By linking the InfraPOD control unit to a photocell detector, the system is able to utilise the dual relay to independently switch off the separate rows of lighting, as soon as the required lux level is reached. These controllers have also been used around the windows on the front elevation of the building to effectively control two rows of luminaries, automatically turning off each row as and when there is sufficient background or ambient lux levels.
This capability enables the system to switch at two independent lux levels, whilst still responding to the same movement. In doing so, it is able to use the available natural light to create a 50 per cent reduction in energy usage by simply switching off the row of lighting that is not required. The system only needs one photocell to operate up to 10 sensor heads, reducing the overall cost of installation and avoiding having to install combined sensor heads with built-in photocells and then having to undertake the cost of disabling these photocells when they are not required.
In areas where there is little or no natural daylight available to make the use of a photocell worthwhile, the system has established occupancy lighting control zones so that when a presence is detected, lighting would automatically turn on within that zone and turn off when vacated.
To suit the operational requirements of the cellular glass fronted meeting rooms, Setsquare featured its optional ‘demand button’ to enable users to override the system during visual media presentations. This switch takes the system from a presence mode, where the lighting is controlled by movement sensors, to absence mode where the lighting will need to be manually energised prior to being controlled. In absence mode it allows people to momentarily move in and out of the space without having to turn on the lighting, subject, of course, to there being sufficient ambient light.
The Ecovert FM spokesperson concluded: “Due to the flexibility of Setsquare’s lighting control technology we have been able to effectively manage the lighting requirements in the different areas of the building at 22 Whitehall.”
