NEWS | WATER HEATERS AND DATA CENTRES Heaters remote monitor cuts hotel energy use by 17% Whitbread to replace non-condensing water heaters at all Premier Inns A Premier Inn in Oxford has achieved a 16.7% reduction in energy use since installing a new water heater with remote monitoring. It replaced an 11-year old water heater, running at 74% efficiency, with a MAXXflo Evo model with remote monitoring. Whitbread, which owns Premier Inn, is in the process of replacing all of the non-condensing water heaters across its Premier Inn estate. The new water heater was installed before the existing unit reached the end of its life, contractors at Spie Heating replacing it in a six-hour window. The water heater is designed to be low NOx, with emissions of 39mg.kWh-1 and below, meaning it is suitable for larger commercial premises in areas with stringent air-quality policies. The diagnostic emails and alerts provided through connectivity with the BMS enables site managers to gain real-time information. Premier Inn, Oxford, energy consumption savings 1,200 1,000 800 600 400 200 0 18 20 1/ /0 1 0 Baseline consumption Installation 19 20 1/ /0 1 0 Post installation Regression model forecast The new water heater has saved 28,658kWH of energy 0 02 /2 02 / 01 Data centre moves into Nato mountain base A Nato ammunition storage facility in Norway has been converted into a data centre by site owner Green Mountain. The ex-military base in the mountains of Stavanger was selected because of the cold climate and the abundance of nearby hydroelectric power. Water for cooling is extracted from a nearby fjord at a constant temperature of 8C. Manufacturer of mechanical pipe joining systems Victaulic, and installation contractor Sig Halvorson, delivered the piping system, which cooled the server racks of the 22km2 facility. During the field trial, the service engineer could check the water heaters performance at any time including monitoring running hours, gas consumption and fault codes. Automatic fault alerts mean that any problems with hot water are now spotted by building managers rather than guests. The new water heater is running at 98% efficiency and has made savings of 28,658kWH, which is the equivalent of more than 1,300. How to specify PDUs in data centres Rittals product manager for IT power distribution outlines his principles for selecting power distribution units Energy efficiency in data centres can be improved by optimising internal power distribution systems via the PDU. 1 Does it do the job? Consider: n The overall consumption required from the PDU, which is the aggregated power consumption of all IT devices connected to it, is measured in amps for example, 3.16 or 32amps. The rating of the PDU should at least meet this aggregated figure n The use of single- or three-phase power. This depends on the total demand of the IT devices. You may need a three-phase PDU where demand exceeds 8kW per rack n The number of sockets. The socket type is typically determined by the device using it n The advantages offered by intelligent PDUs, such as remote monitoring and the ability to switch off sockets remotely 2 Efficiency rating To lower power consumption, monitor usage at the incoming supply to the PDU, to check the total power being drawn from the whole PDU. Alternatively, you can focus on an individual devices demands from a socket. PDU electronics consume power at levels that can be significant especially in a large data centre. This can range from 6 to 60 watts. If intelligent PDUs are installed in a 200-rack data centre, using dual PDUs in the rack, then the power consumption could be as little as 2.4kW or as much as 24kW. The switching function allows users to shutdown individual sockets remotely and hard boot any device connected to it. It is worth investigating what type of switch device (or relay) the PDU uses monostable or bi-stable. Monostable needs a permanent supply of power to change state and stay there; bringing it back means removing the power. Bi-stable needs to be pulsed with electricity to change state and pulsed again to come back, so it uses less power than monostable. 3 Reliability Bi-stable relays have a higher mean time between failure (MTBF) than the lower-cost monostable option in excess of 80,000 hours. Most PDUs operate at the back of the rack where ambient temperatures can exceed 40C. Metering enables users to check how close the system is getting to tripping circuit breakers as loads become too high. 4 Ease of integration Larger PDUs should not extend into the 19in space to avoid conflicting with 19in mountable equipment. You can mount PDU positions to sit in parallel with the 19in angles and this should be possible even in 600-wide racks if the PDU profile is slim. Most intelligent PDUs use SNMP protocol to communicate, so simple integration into a DCIM or NMS is easily achieved. 5 Life expectancy Users should provide additional sockets within the PDU and ensure there is spare capacity. Modular PDUs allow for additional sockets. 48 April 2020 www.cibsejournal.com CIBSE Apr20 pp47-48 Water heater News.indd 48 20/03/2020 17:19