A used air handling unit. Now what?

During the renovation of Kantoor Vol Afval, the Central Government Real Estate Agency opted for existing materials as much as possible. Even an air handling unit, chiller, climate ceilings, and lighting fixtures were given a new lease on life. For building automation, this raises an interesting question: when is a used installation suitable for a subsequent building?

An air handling unit does not have to be written off after just one building. At Kantoor Vol Afval (KaVA) at the former Valkenburg Airfield, the Central Government Real Estate Agency (RVB) investigated how far one can go with reuse during the renovation of an office building. Materials from the building itself were given a new application, supplemented with components from other donor buildings.

It didn't stop at doors, walls, or floors. Installation technology was also reused. Vink Bouw lists, among other things, an air handling unit, a chiller, climate ceilings, and lighting fixtures.[1]

That makes KaVA interesting for building professionals. After all, reusing an existing installation component is different from selecting a new product from a catalogue.

Designing with what already exists

At KaVA, maximum reuse was central. New material was the last option within the five so-called KaVA principles. When the building itself did not offer sufficient material, the project team searched for materials in other buildings. According to the RVB, the air handling unit and lighting fixtures are among the products that came from such donor buildings.

This working method has consequences for the design. The RVB therefore refers to an adaptive design process. The design of the building and that of the reused products developed alongside each other and continuously exchanged information.

That partially reverses the usual approach. A solution is not always designed first and the corresponding new product ordered afterwards. The available product can also influence the final design.

For building automation, this raises practical questions. Which characteristics of an existing installation must be known before it can be deployed again? And what does reuse mean for controls, sensors, interfaces, and the connection to a building management system?

KaVA does not provide a ready-made answer to those specific GA questions. However, the project does show why they are becoming important.

Demonstrate performance

One of the lessons learned from KaVA is that the same information is not always available on reused materials as on new products. Quality can vary, and performance or certifications are not always easy to demonstrate. The RVB therefore advises taking this into account when formulating requirements.

This became very concrete with reused interior walls. Because the acoustic properties were not fully known, the project worked with bandwidths. During execution, the walls were optimized and subsequently tested using sound measurements.

For technical installations, a similar technical question arises. What information is needed to determine whether a used component still fulfills the required function? For general commerce companies, this concerns not only the physical condition of an installation, but possibly also the question of which control technology can be retained and how a component can be integrated into a new technical environment.

From material to information

This gives circular construction for building automation an extra dimension. An air handling unit is not just steel, fans, and filters. In a functioning building, it forms part of a coherent technical system.

If installations are given a second life more frequently, knowledge about such an installation therefore becomes important. Not only what is a component, but also what it can do, which performances are demonstrable, and how it relates to other systems.

The Central Government Real Estate Agency explicitly used KaVA as a learning project. According to the RVB, the renovation resulted in 39 percent less CO₂ emissions than a similar renovation using new materials and yielded nearly twenty lessons on reuse.[2]

Perhaps, then, one of the most interesting lessons for building automation is a question that only begins after the renovation.

A used air handling unit can be moved to another building. But what technical information needs to be moved along to ensure it can be used reliably there again?

[1] KaVA Office Full of Waste | Vink Bouw

[2] The lessons learned from an office full of waste | Central Government Real Estate Agency