A/C tips

Heat. Cool. Swing. Auto. Fan. Take note on how to efficiently use you buildings air conditioning system.

I visit many clients throughout the UK who ask me how our product can help them save energy. One of the common issues I encounter which could help them in their quest is the lack of understanding on how to set air conditioning set points.

If I visit a site in winter the air conditioning set point will be set to 30°C,and a site in summer will find the air conditioning set point set to 16°C.

For the engineers amongst us, we know that these systems will never reach these set points and even if they could the resulting temperature would be far too uncomfortable to work in!

Personally, I only like 30°C if I’m sitting on a beach with a beer!

Worse still these huge fluctuations in set point control waste a large amount of energy and they also reduce the overall lifetime of the compressor in the outdoor unit.

In my view there are a couple of simple ways to solve this problem:

1. Educate the users how to operate the air conditioning system properly.

This is fine if the user understands the engineering principles behind the system and can grasp the concept, however many people may not understand, or more often than not they are simply not interested. Also it might not be possible to educate every single user, for example an a/c controller in a meeting room could be used by any number of people including visitors to the organisation. Educating every visitor as they enter the building is clearly not feasible.

2. Put a sign on the a/c controller telling people how to use it.

This option is a very simple and cheap way to educate people. The problem is people don’t like to read instructions and even then they may not like the temperature you’ve told them it should be, and ignore it.

3. Lock out the a/c controls altogether.

A little known fact is that most manufacturers of a/c units have special codes that can be typed into the wall controller that lock the user changing the set point altogether. The user can still turn the a/c on or off but can’t change the set point.

This is a handy little feature that stops a huge wastage of energy but what it doesn’t stop is users complaining! Users like to be in control, and as soon as it’s been locked to 21°C they’re too cold and really want it at 22°C.

4. Allow for set point limiting.

This is my favourite technique but is usually the hardest to implement as it requires an intelligent controller (like a t-mac BMS) to interface with the air conditioning unit.

This technique gives the user a certain amount of control and usually stops them from complaining. The principle is simple, it only allows set point control between two points such as 20°C and 22°C. If the user is too hot or too cold they still can change the set point but can’t put it on a silly temperature like 16°C!!

Whilst telling people or leaving notes on how to use the a/c seems like simple and straightforward options to reduce energy wastage, ultimately people are only human... and humans often forget and ignore! But as degrees centigrade amount to pounds sterling, ensuring you have the most effective system in place to control your a/c device pays dividends in the long run!