Are complex control systems always the best option for achieving the maximum performance and efficiency? Steven Henry of Chalmor suggests that making things too complicated can often defeat the purpose of installing controls in the first place.
IT IS NOW an accepted fact that getting the best performance out of HVAC and other building services systems requires an element of control. However, there is sometimes a tendency to get carried away with the technology and lose sight of the objective.

Like other electronic systems, building services controls have undergone a transformation in recent years and now offer very high levels of sophistication as well as incorporating the latest
technologies.

The important thing, though, is to be very clear about why the controls are there and who is going to be using them. Getting that wrong can lead to the control functionality being under-used, so that energy may be wasted rather than conserved.

Another consideration is the cost of installation. As the cost of the controllers themselves comes down, the installation now forms a more significant proportion of the overall cost. As a rule of thumb, simpler controls cost less to purchase and to install, particularly when retrofitting to existing systems.

Drivers

Clearly, there are now many factors driving the better use of controls, from the Building Regulations and Energy Performance of Buildings Directive (EPBD) to Corporate Social Responsibility (CSR) obligations to reduce carbon emissions.
Unfortunately, it is often assumed that better control requires highly complex, expensive control systems.

In fact, very significant savings can often be achieved with simpler systems.
However, any controls are only as good as the people who are using them day to day.

A complex building management system (BMS) certainly has the potential to provide high levels of control, but only if it is installed, commissioned and used properly.

Here, there is a clear responsibility on the part of the specifier and installer to ensure that the building operator can use the controls effectively.

Flexible practices

This has become particularly important as more businesses use flexible working practices such as hot desking and collaborative workgroups. Workplaces now change configuration regularly and the controls have to be adjusted to accommodate these changes.

However, if the BMS is so complex it requires an expensive specialist to come in every time it needs adjusting there will be a tendency to leave things as they are. The result is often a less comfortable workplace as well as a waste of energy.

One big advantage of the major advances we've seen in technology in recent years is that much higher levels of functionality can now be built into smaller, simpler, more affordable packages.
As a result, specifying and installing user-friendly controls does not have to compromise on performance.

A very simple example is the in-built and somewhat rudimentary control of warm air heaters used in large open spaces.

Just replacing these basic controls with an electronic time and temperature controller, with programmable optimum start, can make a big difference to running costs and payback.
And these savings will be even greater if the optimiser that is used is included in the government's Energy Technology List.

Underlying the points I'm trying to make here is the need to approach each project with an open mind and think beyond just the mechanical aspects of control to the needs of the people who run the building.

Complex solution

Clearly there will be many situations where a complex BMS offers the most suitable solution - especially if the building owner employs qualified engineers.

In other cases, an approach that exploits all of the advanced technology that can be packed into a simple, affordable package will give better, longer-lasting benefits.

Further information: web: www.chalmor.co.uk