300,000 data points for operation, safety, well-being and energy efficiency

Building automation manages critical building services such as heating, ventilation and lighting to ensure the energy-efficient and safe operation of infrastructure and equipment, while optimising the indoor climate. Because many commands are automatic or programmed into control loops, we refer to this as building automation.

The Building Automation section has a staff of eleven and is responsible firstly for the ETH building management system ¨C one of the largest of its kind in Switzerland with around 30 servers, over 4000 automation stations and more than 300,000 data points ¨C and secondly for the development and implementation of intelligent building solutions.

Field level: controllable devices and sensors

In building automation, we differentiate three levels. The field level includes the control of a wide range of devices such as fans, vents, heating controls, air conditioning, lighting and blinds. There are also sensors that measure temperature, light or air quality and provide the corresponding data.

All these devices and sensors are connected to each other through a communication system. At ETH Zurich, several hundred thousand data points are monitored, and the number is growing rapidly. This is because as buildings become more complex, the number of data points increases in relation to the floor area. One data point corresponds to one piece of information ¨C for example: Temperature in room X ¨C or to a command, e.g: Close blinds on the south side.

Automation level: decentralised control stations

The second level encompasses the automation stations. At ETH Zurich, there are over 4000 of them spread across all buildings. This is where the signals converge, are processed and, if necessary, new commands are looped back into the system.

For example, in a fully occupied lecture theatre, the air quality sensor will report an increase in CO₂ concentration. In the automation station, this signal is fed into the fresh air control loop, automatically increasing the ventilation rate. The increased ventilation will then bring the CO₂ level back to the setpoint and below after the lecture. A new control command is then given to reduce the ventilation to save energy.

Management level: building management system

The building management system is a software to monitor and control the automation stations. ETH has been using ControlMaestro for over 20 years. The building management system forms the third level and thus the centrepiece of building automation. 12,500 process screens display all elements of building automation at various levels of granularity, from the campus with their building areas down to the buildings and individual systems or maintenance groups. The software is also used for data retrieval and control adjustments.

The main purpose of the building management system is to monitor the building systems and to detect faults during operation before users are affected or damage occurs. In addition to these requirements for availability and safety, building automation also seeks to satisfy other, sometimes conflicting, interests. These include user comfort - keeping room temperature and humidity as constant as possible, regardless of the time of year or weather - and optimising and reducing energy and utility consumption.

From alarm system to operational optimisation

Building automation originated from fault analysis. The first systems in the 1980s used room-sized computers to provide detailed fault messages for the first time. Alarms are still part of building automation today. They range from non-critical maintenance messages and non-urgent fault notifications to urgent infrastructure protection alarms and even fire or personal alarms. Events at these two highest levels are handled directly by ETH¡¯s Emergency Desk, but all alarms are also reported by pager to the Facility Services specialists. Not only are they closer to the action in the event of a fault or for maintenance work, they also have the best knowledge of the systems in their building area.

But the importance of the building management system in optimising operations is growing. With 2,340 metering points for electricity and water consumption, cooling and heating output, the system shows the energy flows in buildings and machinery, making it the first port of call when it comes to tapping into potential financial or net-zero savings. The building automation will also be a crucial element in the planned digital twin of the campus.