When we talk about automated façade controls there is no simple answer to the question: ‘is it worth my investment?’ It all comes down to the building, its intended use and its environment.
As we face heightened pressure for zero carbon buildings, we’re increasingly seeing façade controls becoming integrated with the BMS to help us drive efficiency, as well as for safety and security purposes.
But the design and installation of these types of controls require a great deal of planning and coordination at the earliest design stage. And there isn’t a ‘one size fits all’ solution.
Controls & Sensors
Façade and ventilation devices, such as windows, vents and shading devices, which are additional to the wall framing system, may be required only in certain conditions or alternatively may not be suitable in certain conditions such as high winds.
This is where automated controls can really come into their own. Sensors can be used to detect wind speed, rainfall, CO2 levels and temperatures to deploy or detract devices in a proactive way before the conditions become an issue.
These algorithms must be written in to the system at the design stage so that the locations of the sensors (e.g. not under a sheltered part of the building) can be factored in to the design decision.
Another consideration is if the system is to operate on split control i.e. local to the façade and centrally to the building. If this is the case, you must put practices in place to ensure that the controls are not fighting against each other and become counter-intuitive.
Automated or Manual?
Whilst automated façade controls can improve a building’s performance, in other cases its not always the best solution. BREEAM and the Green Building Guide for example, promote the benefits of a naturally vented building as it uses less energy compared to mechanical systems.
Manual controls such as this are usually deployed in responses to conditions such as too much glare, overheating and air quality. But, as you imagine the tolerances vary considerably from person to person and this is often the bane of a building services engineer’s life, trying to satisfy all these different needs.
The other issue is that manual controls are usually left to the occupants to operate and are then used in a responsive way and not in the interest of the building’s performance.
Whether you choose automated façade controls or manual ones, there are drawbacks to both.
- Design Complexity and complicated procurement process
- Higher initial costs
- Vulnerable to malfunctions and requires ongoing maintenance
- Led by human stimuli and not building performance
- Usually deployed too late
- Lack of coordinated system strategies that can be counter-intuitive