I recently attended the farewell reception of one of the founders of digital control technology for buildings in the Netherlands. And as we toasted his upcoming retirement together, I thought about how much knowledge he has. Important basic knowledge that over all these years has led to progressive installations based on sound hydraulic and air technology designs. But something else struck me that evening: during speeches and conversations, emphasis was placed several times on the importance of good hydraulic and air technology design for the correct and sustainable operation of climate installations in buildings. And that attention to that importance is not always self-evident in practice...
One of the reasons for this is the enormous development we have undergone in measurement and control technology. In building automation we now work with digital control computers so powerful that we could only dream of it when it was introduced in the 1980s. And modern technology offers more and more possibilities, as we experience, among other things, with the internet of things. That is of course wonderful, but it also has a downside: if we only focus on new technology and blindly rely on unprecedented computing power, we sometimes forget that the basic installation simply has to be good. Yet that idea is often dismissed: “You can correct imperfections with the control computer.” In my view that is a fallacy. Of course, almost everything is technically possible, but that does lead to waste. Only with a good hydraulic and air technical design can we guarantee optimal building comfort and minimal energy consumption.
What I notice in practice is that the control process has actually become a lot more complex. The partial load behavior of the installations is decisive for stable and accurate control. The rapid rise of speed-controlled pumps and fans only increases the challenge of creating a stable control. It is often thought that a speed-controlled fan or pump solves all capacity problems and that we therefore do not need to dimension so accurately. Anyone who thinks that forgets that the control behavior of the installation also varies continuously due to the changing flow rate. In that case, we would have to control the process with an infinite number of variables and different controllers. Usually a middle path is chosen, but that means that an installation at the top and bottom does not work optimally. This plays a particularly important role in mechanical climate installations, because we almost continuously have to deal with partial load behavior. It is therefore crucial to not only look at full load behavior during the design of the installations, but also at part load behavior.
Despite the developments, the above is actually an age-old problem. And yet I think we can solve it together quite easily. How? By including all disciplines – including a measurement and control expert – in the design process from day one. Not just design from W or E, but build a bridge and discuss with each other directly from the design the consequences of certain choices for the ultimate behavior of the installation in all operating situations. In addition, a specialist in building automation or measurement and control technology is naturally good at process thinking and the operation of hydraulic systems. Valuable knowledge that we must make use of. In this way we give an end customer the installation he deserves. An installation that does not use an unnecessary amount of energy and that is not dependent on software that is difficult to manage. An installation that simply does what it has to do.
With all this attention to modern technology, you would almost fear that the knowledge of hydraulic and air systems will disappear along with our retired professionals. Fortunately, I see a hopeful light in this. At the TU Eindhoven, where I was allowed to give a guest lecture, an entire block has been reserved for the basic principles of hydraulic systems and control strategies for the course Intelligent Buildings. So that future knowledge is good. But we must not forget to continue to use it in practice. No matter how far new technology takes us, what is fundamentally not good will never be optimized again.
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