When your model is drawn and you can perform a successful simulation, it’s very important to critically observe the results of the reference model and thoroughly check whether the entire model does what it is supposed to do.

In this step, we will be showing a couple of important steps to take to verify the model, often done during a simulation of a day, 4 days, a week, or 2 weeks.

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The correct working of end units.

Radiators/Convectors → Zone model

These can be checked by going to either the zone or the modulating room controller and looking at the room temperature compared to the set point. As you can see here, the room goes to the temperature needed and hence, works correctly.

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AHU’s → Capacity controller

These end units are required to deliver a certain capacity at a certain temperature, hence the delivered contribution is to be compared against the setpoint at that temperature. This is done using the PI-controller, with both setpoint and process value. If the process value nicely follows the setpoint, the AHU works as intended.

Domestic Hot Water

Finally, let’s take a look at the Domestic Hot Water, here the most important part is that, besides for some short moments, the buffer vessel stays at a high temperature.

Volume flow and temperatures in the pipes

Even though a spot check on AHUs and other end units could prove to be a good working system, there could still be other issues so it’s very valuable to go through specific points in the building, preferably compared to the information you have. Let’s take a look at the circuit below for example. Here a part of the building is separated through a heat exchanger, with a required supply of 65°C. There is a mistake in the energy center which gives a supply temperature of 55 °C at night, so the required temperature isn’t achievable at night and on the weekends, which as a consequence lets the temperature in the zone drop to low.

Often there is information on the flow rates and return temperatures at the collector/boilers. This information can be easily compared. For example, the main collector here flows around 150 m³/hr at around 80°C supply temperature and a relatively high return temperature, which can be compared to the real situation.

Whenever everything is okay, you can expect that this model runs correctly and the next step, which is load matching can commence.