Locked in the plant room forever?
Seven years ago -in these very pages- we lamented the King Canute syndrome affecting the controls world. Not that we were bitter you understand. Frustrated? Most certainly, but not bitter. We knew the tide could not be stopped and now, 7 years on, we have seen the levee break.
In fairness the levee broke a good few years ago, and the integration industry has been enjoying the spoils (along with the hard work) that brought us. The large majority of this work has been involved in integrating and converging the plant room.
So what does this achieve? Certainly it allows devices such as variable speed drives, package chillers, boilers, pump valves and other HVAC controllers to share data across a common network with reduced (costly) hard wiring. It also allows the BMS user interface to have access to far more data about how the plant is operating. This does indeed allow the building manager to have a better understanding, and therefore improve the operation of the building.
On benefits
These are genuine benefits with short commercial pay backs; so much so, that more and more buildings are being specified this way. But does integrating the HVAC system onto one network with one protocol go any way to reducing energy usage? It could be reasonably argued that having the BMS and all devices using structured cabling will have its own positive environmental impact, in terms of reduced manufacturing and installation times. Equally the improved amounts of information available from systems can allow engineers to optimise their strategy for a more fuel efficient building. However, that doesn’t match with our experience of such projects. What often happens is the IT department quickly dismiss the idea of the HVAC systems utilising “their” structured cabling. So, more often than not a separate BMS network goes in, the BMS supplier then writes their control strategy to the consultant’s specification; and while the specification may call for full integration of all systems the forward thinking all too often stops there. So we find little benefit beyond a conventional system in terms of energy. Does that mean we should give up on integration? Certainly not, in fact we need to take this “convergence” further, as you will see.
Sadly, too much of the integration work carried out today is a red herring where energy is concerned. That isn’t to say that the benefits of an integrated HVAC system are not worthwhile, as mentioned above, they certainly are. However, where energy is concerned we need to consider the building as a whole rather than focussing solely on the plant room. We need to understand how the building is used, week to week, day to day, hour to hour. There are plenty of systems in a modern commercial building that can give us this information. More often than not the lighting system will know where people are via its occupancy detectors, the door access system will often know exactly how many people are in any given room or zone. Even the intruder system will be able to tell us some useful information. That data must be of huge benefit to the HVAC systems optimisation. So why do we ignore this valuable data?
Contractual nightmare?
Contractually the mechanical and electrical divide needs to be blurred and communications across this divide need strengthening. We have seen a new breed of consultant emerge recently; the “integrated buildings” consultants brief is as much about achieving converged networks as bridging the divide between the IT, electrical and mechanical worlds. This is to be encouraged. This cross discipline approach needs to fiulter into all areas of the contractual chain. I would suggest the contracts themselves need re-thinking to not only ease this approach but in fact to actively promote this method of partnership.
I think we all recognise that the most effective way to reduce energy usage is to simply turn things off when they are not being used. But we all know that humans are fallible, prone to forgetfulness and ultimately creatures of (often bad) habit. We won’t turn the lights off in the meeting room every time; we certainly won’t remember to adjust the air conditioning, so these functions need automating. To avoid costly duplication of occupancy sensors and building usage information we need to get the plant room and room controllers talking to the lighting and security systems that can give us this information. We also need control systems that can learn and tune themselves to patterns of usage. The BMS should monitor how and when each part of the building is used and to detect patterns.
Intelligent buildings
So we need to start thinking of the whole building as an intelligent entity that responds to need, it works out when it is used, how much it used, and services itself on demand rather than to a fixed set of timers and calendars.
We need contractors to work across disciplines more effectively and we need end clients to push consultants and contractors for more intelligent buildings. A building responding to its actual use will retain comfort levels using the minimum amount of energy. If the project is carefully specified to work in this way and early buy in is achieved from all parties – the client, consultant/s, contractors and all suppliers, then this can be achieved at minimum upfront cost.
This isn't Tomorrow's World!
The technology is out there, and not just from North. But how often do we walk past buildings at night that are fully lit? You can bet the HVAC systems are equally unresponsive too. Applying just a small amount of intelligence to buildings can be easily achieved today, and will have a huge impact on our energy demands for the future.