Measuring versus simulation

 by Dr. Nicolas Morel

In general, both tools need to be used concurrently for the complete checking of a controller. For all the projects carried out at LESO-PB, both approaches were used. The respective advantages of the two approaches can be summarized in the following way.

  • reproductible runs for several different variants (controller, climate, building characteristics, user’s behaviour);
  • immediate feedback on the effect of a change on the controller’s design, when elaborating a smart control algorithm.

Measurements on a real building:

  • reliable results taking into account a real building and not a model;
  • interaction of real user’s behaviour with the controller, including various different users and satisfaction evaluation;
  • the real controller can be shown directly to people interested to see how it operates in the reality.

1. Computer Simulation Tools 

The simulation allows to check both the correct operation of a newly designed controller (by careful analysis of its operations) and the comfort level and energy saving provided on a long duration.
The simulation must include:

  • a detailed model of the room and/or building to be simulated (for the aspect to be simulated, for instance thermal, air quality or lighting);
  • a model of user’s behaviour (in case we need to study its effect on the controller);
  • the implemented controller.

At LESO-PB, we use generally Matlab for all these software components.

2. Measurements on Buildings

The test on a real inhabited building allows to check the operation of a controller in a real situation, with real users interacting with the controlled equipment. The LESO building has been used for all the research projects carried out at LESO-PB.
In order to connect the computer to the sensors and actuators, several possibilities can be considered:

  • fit the computer with conventional measurement data acquisition and output equipment, connected directly to the sensors and actuators;
  • use a proprietary bus system (for instance, Luxmate with the Zumtobel luminaires or blind controllers);
  • use a standardized bus system, like LonWorks or European Installation Bus (EIB); both these two buses have been used at LESO-PB

The LESO building is equipped with an EIB bus. For each office room (there are altogether around 20), the bus is connected to the sensors (presence, air temperature, illuminance, window opening), to the actuators (heating, artificial lighting, blinds) and to the switchboards (heating thermostat, artificial lighting, blinds).