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BPS tasks within the design and operation process

Operation

With a reasonable amount of additional work and costs, the BPS model from the planning stage can be calibrated during commissioning and the first year of operation by comparing simulated and measured time series data in such a way that deviations between the building performance actually achieved on one side, and that predicted on the other side, can be explained and adjusted in the BPS model. Which part of the deviation can be attributed to incorrect assumptions in the model, poorer quality of execution, deviating control, extreme external conditions, extreme use or incorrect operation?

In the case of a renovation project, this phase is at the very beginning, when all basic information is collected. A BPS model can be set up and calibrated for the existing building as described in the previous section. A BPS model that was calibrated in that way can be used to improve the performance of the building achieved in real operation. Of course, it will not be possible for a new building that has just been put into operation to make physical improvements such as increasing insulation levels, replacing or resizing windows, or installing more efficient HVAC equipment. Before thinking about the replacement of some physical components, the option of installing a more sophisticated control system should be investigated. The cost and effort of replacing control systems are usually significantly lower than other physical improvement measures. All these and other measures can be added to the calibrated model of existing buildings to be renovated. Finally, the measures are prioritized according to their cost-benefit ratio and examined cumulatively in a series of cascades. This is because combining one measure with another can significantly reduce its benefit. With the outcome of such what-if-studies, a renovation project will directly go on with the design phase.

When all construction measures have been completed – whether in a new building or a renovation project – the operation can be further optimized with the help of the calibrated BPS model. First of all, one should make sure that the building actually works as well as it could, i.e., that there are no serious faults in already existing components and that they operate correctly. If this is done, control parameters such as setpoints can be optimized in the same way as it was done for other planning options during the design.

Calibrating a BPS model can be automated to reduce the costs significantly. But there are more automated methods needed to find faults and further improve controls. This is where Digital twins come in.

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