PhD candidate Arie Taal develops mechanism to track hidden energy waste

‘With this method we can maintain a healthy indoor climate’ The discussion about renewable or sustainable energy is more heated than ever. Should we all pack our roofs with solar panels? Or do we cover entire fields with these? Or do we build huge wind turbines? But who wants to see one of these massive structures, some as tall as 100 metres or more, tower over their neighbourhood?! The closer the topic hits to our own home environment, the more heated the debate. We often forget one key aspect: we can gain a lot of energy simply by reducing waste. On Tuesday 23 November, lecturer–researcher Arie Taal obtained his PhD with a method that helps track and address hidden energy waste.

A lot is being written about renewable and sustainable energy production. But in many buildings 5% to 30% of energy is needlessly wasted. Because an installation doesn’t work properly. Or because it’s used incorrectly. This could even increase in the future, as sustainable installations are becoming more complex. What if we could reduce this waste to 0%? This could result in a 10% energy gain. That is a higher energy yield than the production of all solar panels and wind turbines combined. Arie Taal is taking an important step in that direction with his doctoral research.
‘This method also enables us to maintain a healthy and thermally pleasant indoor climate.’ That has become an even more pressing topic during corona. And a good indoor climate in office buildings also promotes labour productivity.’

Error detection and diagnosis

Arie Taal has been lecturing Mechanical Engineering students at The Hague University of Applied Sciences for more than 30 years. He is also an active researcher in the Energy in Transition research group, participates in the Mission Zero Centre of Expertise and coordinates the minor Sustainable Energy Technology. In the past he also designed new installations. He used this expertise to focus on heating, cooling and air treatment installations for his doctoral research.
‘How do you find errors in a climate installation in buildings? What is the cause?
And how can you resolve these errors?’

‘How do you find errors in an installation or in its use? How do you determine the cause? And how do you resolve these errors?'

Simply put, these are the main three questions in my research. We are talking about error detection and diagnostic methods. People use a technology to discover errors based on the symptoms. We then also require something to diagnose these errors. But the existing methods different greatly from the installation technology that is used. In my research I investigated one integrated method, which you can use to detect the symptoms and isolate and diagnose the errors, the way an installation expert would do it.’

Symptoms and errors

Arie Taal developed the 4S3F method for this. ‘4S represents four categories of symptoms. 3F stands for three categories of errors. I analysed what symptoms I encountered during my research on climate installations in our building in Delft, and the errors behind these symptoms. A symptom could be that the heating uses more gas than expected. What causes this? Or the system indicates an excessively high C02 value in a space. Why is this? The symptoms are associated with possible causes (errors). Because of the complexity of these installations, you can’t really do this without any knowledge of installation technology.’

‘This allows you to greatly reduce the number of wrong diagnoses and consequently reduce energy waste and complaints related to health and comfort’

Using statistics, Arie Taal’s method indicates the most probable error that could cause the identified symptoms. ‘If you don’t find that error after inspection, then you look at the second most likely error. My method is more sophisticated than existing methods. This way you greatly reduce the number of wrong diagnoses and consequently reduce energy waste and complaints related to health and comfort.’


Arie Taal made a lot of people happy with his method. ‘The facility manager in a building, because he no longer receives a list of symptoms, but a list of possible causes. The installation manager, because with my method he knows exactly where to look for a (hidden) error. And also the users of a building. They have their problems resolved quicker. And a good work environment increases labour productivity.’
His method will now be applied to the multi-year project Brains4Buildings, coordinated by TU Delft, in which The Hague University of Applied Sciences is one of the 39 partners. In Brains4Buildings the participants are further developing the 4S3F method to reduce the energy use in buildings. We are using big data of smart meters, building management systems and Internet of things devices.’

Define your research area

Now that he has completed his PhD, Arie Taal looks back with great pride. ‘I’ve delivered a very impressive result!’ He has some tips for anyone who is planning a PhD. ‘Make sure your research has a clear focus. This means carefully defining your research area. And make sure you have good support for the content and supervision during the process.’

Now that he has added a PhD title to his name, he is looking forward to continuing to work until his retirement on applied research and share his knowledge with his Mechanical Engineering students.