Agile BMS — the next big thing
The effective control of building-services systems saves energy and money — but Professor David Fisk sees this capability as a revenue generator as the National Grid looks to demand-side response to match capacity to demand.
Building energy management systems could be at the door of an entirely new world where ‘agility’ counts. BMS technology came to our sector in the 1970s from industrial control. ‘Direct digital control’ revolutionised what could be measured and controlled. But nothing stands still. A teenager’s mobile phone has more computing power than a 1971 Cray Supercomputer, so it is no surprise that rapid advances are taking place in industrial control. What new drivers could pull in this technology to building services? And what is this new technology anyway?
In today’s energy market BMS technology can do a good job, given a decent budget for the system and good training for its users. But what of tomorrow’s energy market?
This autumn National Grid will hold an auction for ‘new balancing services’ to cover a possible shortage of available plant at winter peak. Some of this will be ‘demand-side response’ — about 300 MW in 2014/2015. Industry, with its superior monitoring and control capability, is likely to be the major bidder.
But time-of-use (ToU) power is not just a short term fix. With increasingly large numbers of ‘near net zero energy buildings’ passing on to everyone else the problems caused by variable generation of power from renewables, actively managing demand is going to become big business. Indeed energy suppliers are now rolling out ‘advanced meters’ capable of recording half-hourly consumption.
Ofgem has recently supported a move to half-hour settlement for customers. Over a day, half-hour prices on a wholesale power market can vary by 1:5 or more, so an ‘agile BMS’ could print money. So-called ‘demand side response’ is doing that already in many US States. If ToU tariffs are the new pull, what is the new technology?
We think of a traditional BMS as twisted pairs going back to a data bus. It might respond to a ToU tariff by switching a few easily identifiable loads. But wireless communication lets us introduce as many sensors and controls as we want without the cost of retrofitted cabling. The configuration of the monitoring and control system now looks more like a net and much less hub and spoke. Rather than dropping the monitoring system onto the plant, industrial control is edging towards embedding the monitoring and control net within the main system. Net configurations will always be more robust to lost links courtesy of a hammer drill.
One industrial example of embedded monitoring and control is the smart grid. Presumably it will not be long before these devices will be looking to communicate with any sufficiently agile BMS, offering gifts for load profiling to be totalled up in the advanced meter. But this is not just a technology for power engineers. Without as much hype, water systems controls are getting just as smart. Needless to say they are exploring ways to be rewarded for modifying their massive pumping schedules. It would be a shame if building services got left behind in the ToU market.
A disadvantage of any supervisory system is that it requires a supervisor. Since most things work most of the time, that can be a brain-numbing job, which is not improved by introducing nets and extra sensors that could increase by orders of magnitude the data flowing to the console.
The industrial approach is to avoid further bamboozling the operator by empowering ‘big data’ algorithms. We are used to entrusting the optimum start to a machine, but we can go much further. Already some building owners have explored so-called learning algorithms to predict energy requirements an hour ahead and to spot out-of-the ordinary building behaviour. Process industry, needless to say, is already there. Even Google is promising to provide big-data algorithms to enable power companies to schedule their plant to meet the (soon to be) agile demand.
We know what best practice in building management looks like, and now have the tools to deliver it. But life never stands still, and the electrical power market is changing rapidly. An ‘agile BMS’ would have a lot to offer the building owner. Borrowing its prototypes from process-control industry, its sensors and controls will be more numerous and more networked.
It is likely to make more use of algorithms (i.e. apps!) to filter out performance drift and optimise on ToU tariffs. That, of course, is the potential future. But for the owner of a good BMS, ToU tariffs are worth touting for, even with today’s technology. An operator who knows the building system well will know how to play the game. And we can thank net zero energy buildings for ensuring the game is here to stay!
CIBSE’s Building Performance Awards 2015 (now open for entries) features a new category for building control systems. This recognises the importance of integrated and automated control systems to manage and maintain optimum building performance. For more information please go to www.cibse.org/bpa
Professor David Fisk is immediate past president of CIBSE and director of the Laing O'Rourke Centre for Systems Engineering & Innovation at Imperial College London. Thanks are due for contributions to this article through some lively discussions with colleagues at Imperial College London and students on the Systems Engineering Course.