KNX presence detectors increase energy efficiency in the Police and Justice Centre Zurich

Hardly any other major project in Zurich has attracted as much attention in recent years as the Police and Justice Centre (PJZ). The efficient use of energy is ensured by KNX in combination with over 2,800 presence detectors from Theben HTS.

Task

• Make lighting control in the building more efficient
• Integration of presence detectors into aesthetic room design

Solution

• KNX system with presence detectors and LED luminaires
• Presence detectors in RAL special colours for harmonious interior design

"It takes a good quarter of an hour to walk around the building. And in order not to get lost in the basements, you need a sense of direction like a London taxi driver." This is how PJZ project delegate Hans-Rudolf Blöchlinger describes this unique building in Zurich in his editorial for PJZnews No. 8.

6,800 KNX components were installed and parameterised in the building in the middle of Zurich and close to the Zurich Hard Bridge railway station. It consists of the administration and prison sections, provides over 2,030 workstations and is an exciting project as it combines the complexity of many buildings. It officially began operations at the end of January 2022. The prison for temporarily detained persons as well as for pre-trial and security detainees has been available for use since April.

Not an everyday job for the planners

Marco Andrist of Hefti Hess Martignoni AG, one of the planners, explained the complexity during a tour at the beginning of January 2022, shortly before the completion of the PJZ, as follows: "We have a gymnasium, delivery, large underground garages, kitchens, training, meeting and cloakroom rooms, offices and much more. There is even a shooting cellar. The variety was exciting for us electrical planners, but at the same time a great challenge. Planning something like this is not an everyday occurrence. A great project." Of course, in view of these dimensions, it's easy to get carried away. And indeed, the construction quality is impressive. In future, anyone who wants to go into the building to get an impression will not have it so easy. Either one works for the police or the judiciary, is summoned or subpoenaed, or is escorted in the unpleasant way to one's temporary accommodation in Zurich West Prison.

Why KNX?

For the general contractor HRS Real Estate AG, it was important that good quality components were used. Tom Jakob, project manager at HRS, makes a simple calculation: "We will also be responsible for maintenance in the future. And if we use inexpensive or even cheap material here, it will fall back on us in the years to come. KNX is a very established technology at HRS, and we have had very good experiences with it in the past and also in the PJZ. Especially the manufacturer independence, the quality and the large selection of products are very much appreciated by us." These are, after all, very positive characteristics that the general contractor sees in KNX technology. Of course, for Tom Jakob, the energy-optimised operation of the building is also an important criterion, to which KNX with its many detectors can make an important contribution.

Presence detectors increase energy efficiency

In no other area can electricity be saved as much and as easily as in lighting. Thanks to efficient LED light sources, effective sensors and optimal daylighting, electricity consumption for lighting can be reduced by at least 50 percent - often with a gain in quality and comfort. Practical examples show that even greater savings are easily possible. Anyone who wants to know more about this can find out from the Swiss Lighting Society SLG.

Around 2,800 KNX presence detectors from Theben HTS are installed in the PJZ. They can be seen everywhere, or not. Because for the architect, the aesthetics of the detectors played an important role. He wanted all the elements on the ceilings to be round, including the motion and presence detectors. They also had to match in colour. Theben HTS therefore produced many of the detectors especially for this project in the corresponding RAL colour.

The technical properties are important

For Robert Wolfrum, system integrator at Burkhalter Technics AG, the detectors from Theben HTS offer very good constant light control that is easy to configure. Because the selected devices have a square detection area despite their round shape, relatively few of them were needed, which also had an effect on the price quoted in the tender. In an approximately 60-metre-long connecting corridor in the basement, we counted only three detectors on our tour, which is very modest for this area.

Price plays a role, but not only

The price was also a criterion for Wolfrum when deciding on the detectors, but not only: "Reasons for the choice for Burkhalter Technics AG were the price, the technical requirements with regard to the detection areas and the application. But of course the readiness to deliver as well as the experience with the products in already realised objects also played a role for us. In the 20 or so years that I have now been working as a KNX integrator, a very good cooperation has developed between Burkhalter Technics AG and Theben HTS AG, which is also based on mutual trust."

Beautiful showcase project

The Canton of Zurich has invested a lot of money in this sustainable project. In addition to the efficient building technology with KNX, a lot was done to be able to use regenerative energies. For example, a photovoltaic system on the roof provides around 350 kW peak power, and the use of waste heat from the computer centre and IT rooms as well as heat recovery from the ventilation systems also contribute to the efficient operation of the Minergie Eco-certified building.