Duty-standby rotation

One of my clients, who operates computer data centres, asked his monitoring and targeting software supplier to conduct some pilot analyses using daily data. Cusum analysis of one particular circuit, which was feeding computer-room air cooling (CRAC) units, threw up an interesting observation: energy performance had been toggling between good and bad on the first of every month. This fact had been masked by the weather and variations in the quantity of energy consumed in the equipment racks, but once revealed, it was traced to the fact that they were alternating two banks of CRACs on a monthly cycle. In situations like this, it pays to change the regime so that preference is given to the more energy-efficient plant. This has the secondary advantage that the standby set will have more maintenance life left in it when the lead set fails. Cusum analysis is very good at providing insights like this, which is why I give it prominence in my training courses on monitoring and targeting.

The other place one finds opportunities for instant savings is multi-boiler heating systems, where, too often, the firing sequence is deliberately rotated to give each boiler the lead and even out the wear. Apart from making no sense in terms of risk management (when one fails, all the survivors will be equally clapped-out) it also misses the opportunity to favour the unit with the highest combustion efficiency, and thereby consume less fuel for a given output of useful heat. Anyone unfamiliar with combustion efficiency and the opportunities that it offers can read up in the A to Z guide at www.vesma.com.

Combustion tuning is a good (and frequently-overlooked) opportunity for nearly all fuel users.

Link: Energy management training