SENSIBLE HEAT

HVAC CONTROLS – ARE THEY GETTING EASIER TO INTEGRATE?

Dave Robinson, Managing Director of Sensible Heat Ltd, looks at recent developments in HVAC controls.

In some respects, integrating HVAC controls with AV systems has become simpler. If we take a simple house - let’s say with underfloor heating, and the requirement is to make the simple ‘smart thermostats’ supplied with the heating system appear on the AV touchscreen system, it may well be something that the Custom Installer would be able to handle in-house. If the thermostats have a compatible ‘driver’ for the AV system, then in theory it should be simple enough. However this assumes that the thermostats have been supplied and installed correctly by others; that they are working, acting on the correct zones in the floor, and that the communication side of things works as it should – if it doesn’t, who is going to resolve these issues, the plumber? Seems unlikely. In these circumstances, it is easy to get dragged into a dispute about the heating performance, or in ironing out problems with communications, wiring etc, when you haven’t even earned a margin on the controls products which have been installed by others. So, maybe the Custom Installer should specify, supply and install the thermostats himself? Fine, if he is confident that he understands the way that the HVAC system works well enough. But in the same way that most Custom Installers use external specialists for a range of tasks (for instance, motorised gates, security systems, cameras, sometimes the programming of the AV system itself), why not employ a specialist to deliver a complete, working HVAC control system? It is often the quickest, most cost effective and above all, lowest-risk way of delivering an effective HVAC controls package.

There are other issues too; often, being able to communicate with a few basic ‘smart thermostats’ just isn’t enough. The HVAC systems in each room may be more complex – there may be radiators or trench heaters, perhaps they have to work in sequence with a heated floor? There may be an AC system, perhaps it has to work for heating as well as cooling? And what about the main plantroom – are we going to let the client experience his first heating plant failure, and a cold house, when his expensive AV system is not telling him that anything is wrong? Shouldn’t we be integrating the main plant controls too? It’s no use deciding that this is the domain of the plumber – when we install an AV touchscreen system, it becomes the client’s portal for all things technological – that is how they experience the building’s services.

Having the backing of an experience HVAC specialist is often very useful – especially when things go wrong! If the heating or cooling system isn’t working as expected, or the performance is in question, then inevitably the Custom Installer will find themselves involved in the discussions. Rightly or wrongly, the thing that the client looks at and interacts with to ‘drive’ the heating and cooling, i.e. the AV touchscreen system, is always the first system under suspicion. The task here is to quickly identify, and if possible prove, where the fault might actually lie, probably nothing to do with the controls at all, and that will almost certainly rely on a deep understanding of how the HVAC system itself works.

In fact, perhaps you may be able to use the AV system as a tool, to help analyse and diagnose problems with the HVAC system, or to prove that it is working as it should. We recently helped a developer client with a complex dispute, where the end user was complaining of a lack of performance with the heating and cooling systems – not the HVAC controls, but the mechanical heating and cooling systems themselves. We were able to use the Control4 system which was already installed, together with an App created by Janus Technology called BMS Monitor, to record exactly what was going on in the property, including how the user had set the system (which modes, setpoints etc), and plot all of this against outside temperature (obtained from a web service). The clear graps could be used by the various consulting engineers involved to diagnose a few genuine faults, and then to identify the ‘finger trouble’ issues (i.e. mis-setting of the controls) by the end user, which were the bulk of the issues. A happy resolution, and it is difficult to see how else this might have been achieved.

Such specialist knowledge, and the application of analysis tools like this, helps to add value to our overall package. Energy and CO2 reduction are bound to be more prominent in all our lives going forwards, as we decarbonise the building stock. New technologies are appearing all the time, including heat pumps of course, and they often have attendant issues and complexities which we need to keep abreast of. Properly applied HVAC controls not only improve comfort, but also improve energy efficiency, and the slick visualisation of energy consumption is another thing we can offer. Partnership with a clued-up HVAC specialist to help with all of this would seem to be a no-brainer!