The rapid adoption of digital technology and automation is driving demand for data centres, including core centres and edge computing systems that can support advanced processing. Key to fail-safe operation is a reliable energy supply – delivered by PDUs (power distribution units).
“PDUs are so much more than an energy supply component – they can also offer monitoring, switching and measurement functionality, improving the energy efficiency and performance of data centres,” adds Amanda Venter, External IT Sales, Rittal SA. “At a time when IT costs are rising, the use of intelligent PDUs to monitor and optimise energy costs and power usage effectiveness (PUE) is beneficial. The data provided by PDUs is key to overall commercial and technical planning.”
Data-driven optimisation
The first step in improving energy efficiency in data centres is recording consumption. While recording power and current throughout the data centre may be sufficient to determine energy efficiency, it doesn’t allow the administrator to identify changes in load that are caused by new applications. This is why Rittal recommends measuring current and voltage down to the rack level; it gives you useful insight into the energy-related parameters in the data centre and informs the optimisation of operating costs. “Following installation of PDUs with measurement functions on a broad basis, our customers often discover that power supplies they thought were being fully utilised actually offer a lot of untapped potential,” says Venter.
In the case of spatially and geographically dispersed edge applications, it’s particularly important to record energy consumption across all locations by integrating PDUs building or IT management systems via standard interfaces. “In large installations such as hyperscale cloud data centres, where technicians need to be able to find and resolve faults quickly, it’s wise to select high-quality PDUs tailored to the IT components in the IT rack suites. Detailed monitoring, clear labelling and optional displays are the cherry on the top, further enabling rapid resolution of faults or maintenance,” explains Venter.
Selecting the right PDU model
A number of criteria should be considered when selecting a PDU, including load capacity, as well as the number of sockets and monitoring functions required. “Compatibility with other IT components is frequently overlooked. Ideally, your PDU should be an element of a standardised modular IT kit, enabling you to carry out rapid and error-free installation, without the need for additional programming,” adds Venter.
She shares these pointers for selecting the ideal PDU model:
- Carefully consider the load capacity of the connected consumers in the IT rack as this determines the output required of the PDU. Compare the different available product models against their load capacity to save on purchasing costs.
- Since the load capacity of the PDUs represents a major cost factor, it’s important to determine the current and future loads in advance, and then select PDUs accordingly. “In general, a three-phase system with 16 amps per phase will cover almost all applications in the rack,” says Venter.
- For energy saving, use PDUs with bistable relays, as these remain current-free in their respective switching state and thus reduce their own energy consumption. “A constantly energised mechanical relay permanently consumes energy – as much as 50 watts in a fully populated PDU. Not only does this unnecessary energy consumption add to the electrical bill, it also reduces the service life of the relay device,” says Venter.
- PDUs offer several variants for energy monitoring, but optional temperature, humidity and access control sensors can be added to PDUs to monitor the physical ambient conditions in your IT rack. PDUs equipped with displays make it easy for technicians to get important information readings, at a glance. Consider setting up automatic notification of the current status via text message or e-mail. “Even without the display panel, clear labelling is essential. Look out for PDUs with colour-coded phases and clearly labelled A/B supply paths, as well as visual indicators for individual slots,” recommends Venter.
- If your data centre is staffed around the clock, it’s not necessary to have remote control options for your server’s power supply. “However, if your data centre operations include a “lights-out” operating mode, or if the centre is maintained remotely, then you’ll want a PDU with a switching function,” explains Venter.
- To avoid having to stockpile spare parts, partner with a manufacturer that can offer you not only a wide range of PDUs, but has extensive local stockholding. “Once your technicians have familiarised themselves with that manufacturer’s system, they won’t require additional training to carry out their IT management role,” adds Venter.
Modular system for maximum flexibility
The PDUs from Rittal’s extensive range set industry standards. They use a modular system that enables customised configuration, with customers being able to specify the length of the required cable, the connector plug, the position of the display and the number and type of the sockets. “This modular design ensures that the PDU controller and over-voltage protection can be replaced while the system is operational. If one component fails, it’s not necessary to replace the entire PDU,” explains Venter.
Manufactured using robust components, Rittal PDUs deliver high performance even in high waste air temperatures. “At an operating temperature of 50 degrees Celsius, the PDU continues to deliver 100% output. At 60 degrees, it maintains output with calculated derating,” says Venter.
Customers have the option to include integrated over-voltage protection using replaceable arresters and an alarm contact to protect the sensitive electronics in the IT rack from voltage peaks such as those caused by lightning strikes. Other optional features include an RC circuit-breaker and the established thermal magnetic circuit-breaker. Flat circuit-breakers (Carling type) are still integrated into the PDU housing. Almost every model in the Rittal PDU range supports the connection of additional sensors for recording environmental data (temperature, humidity and the status of switch contacts), as well as RCM type B fault current monitoring, which prevents doors from being opened when a dangerous amperage is detected in the IT rack. This gives administrators a detailed overview of the environmental conditions on site, enabling them to integrate monitoring functions into their management systems.
No additional tools are needed to install Rittal PDUs in Rittal IT racks, as they use a clip attachment in the zero-U-space on the 19-inch frame. “This installation doesn’t restrict access to the 19-inch level, meaning network and power cabling can still be carried out there and IT devices can be retrofitted while the rack is operational,” says Venter. Configuration of Rittal PDUs is made even easier with the Rittal Configuration System (RICS), which enables custom configuration of the PDU via a web browser,
“The flexibility of our PDUs makes them a solid choice for comprehensive monitoring. With integrated CMC functions such as an alarm relay, a digital input and an alarm signal transmitter, our PDUs work effectively as part of your overarching IT security system,” concludes Venter.
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"Rittal – The System." Since its foundation in 1961, Rittal has continuously evolved into the world's leading systems provider for enclosures, power distribution, climate control, IT infrastructure and software & services. Rittal offers you a perfectly coordinated system platform. It unites innovative productions, pioneering engineering solutions and global service to accommodate the most diverse requirements. It caters to a whole host of industries, from machinery and plant engineering, to the automotive industry, through to information technology. All from a single source, all in top quality.