Air Conditioning Efficiency

To maintain your plant in tip top condition can cost you very little to save a lot.

These tips refer to small split/ multi split / VRF systems with individual room or zone controllers. Large centralised systems are usually centrally controlled and therefore a maintenance regime is already in place, carried out by trained personnel and the building user/occupant has no control over the temperature settings.

One of the main issues of inefficiency of A/C plant is poor maintenance and user operation. By carrying out a few extremely low cost exercises considerable improvements can be achieved in both performance of the equipment and achieved savings on running costs, therefore reducing your Carbon Footprint. Many of the "big boys" have specialist Maintenance companies to carry out these tasks for them, but if you are a small organisation it maybe the case that nobody has touched your A/C since it was installed. Two main areas that can reduce temperature transfer dramatically are blocked or restricted air flow through external condensing units and blocked filters in the indoor units. This will make the plant work much harder to achieve the same results - like getting a car to pull a 10 ton wagon. The less work your system has to do, the less it will cost you to run it and in theory, the longer the kit will last.

It is advisable to employ qualified personnel to carry out these duties, although it is possible to do the very basics yourself - similar to checking the water level on your car radiator, or your windscreen washer reservoir. These tasks are normally described in the user manuals of your equipment and are tasks that can be achieved with minimum knowledge of the kit itself. If access is easy to the plant then ensuring that there are no blockages or restrictions to the outdoor unit (leaves, paper and plastic bags etc, but can also be things like wheelie bins too close) and indoor unit filters (mainly accumulated dust) should be an easy task. Many indoor filter units are washable. Ensure that whoever carries out the task is competent to gain access to the equipment and carry out the work safely (as per manufacturers instructions). Ensure that the units are turned off before carrying out the tasks. A "handyman" type person could probably do this work. If you have visual signs of blockages on the outdoor unit or you are aware that the system hasn't been worked on for many moons then it may be time to organise maintenance, on a regular basis ( refer to manufacturers instructions - they recommend time intervals for filter cleaning - their recommendations do vary so check your user manual for frequency. If the room condition is a very dusty environment, then frequency should be increased to suit). Production of a "Log Book" is a good method of recording any maintenance to the equipment, including attendance by qualified A/C Engineers. This will give you a historical record that can be referred back to - a bit like a car log book for servicing with the A/C Inspection likened to an MOT.

If you have any doubt about doing the work call a specialist. The work should still be very cost effective. Any good specialist company will advise you of the best way to proceed depending on your individual circumstances, and can also advise if your system falls within the realms of the Fgas testing Regulations.(monitoring of greenhouse refrigerant gases and leak testing). Your A/C system may need leak testing on a regular basis, by law.

As far as Air Conditioning Inspections are concerned (Energy Performance in Buildings Directive), if your A/C plant is >250kw cooling then it should have already been inspected, by law. If your A/C plant is between >12kw (when added together for smaller individual systems) and <250kw then it will need inspecting before January 4th, 2011, by law. If your equipment (when added together for small individual systems) is <12kw then you don't need an inspection, but it will still be cost effective and "green" to maintain your equipment regularly, even if you have just 1 small single split system. If in doubt about which category your system is in, make a quick enquiry with a relevant organisation.

If your system has a problem with temperature transfer due to debris, then the Air Conditioning Inspector will pick this up as an issue and advise you as above.

If you haven't got access to User Instruction Manuals, so long as you know the manufacturer and model, they are extremely helpful to find you a copy. Many times you can find the information on the web in the form of downloadable PDF files on Air Conditioning websites. Try putting in the Manufacturers name and model in the search engine box first.

One last item about temperature settings. First form of cooling is opening a window(without the A/C turned on). If you are still too warm, 2nd form of cooling is closing the window and turning on the A/C. Air Conditioning is not designed to form frost on the inside of your office window! Raise the Cooling Set Point on your controller to the maximum that you feel comfortable at(somewhere between 24degC and 27degC). There are recommendations to best settings but the warmer you can tolerate the office temperature the less carbon you are creating. It is pretty pointless quoting best practice temperatures when you are in charge of the controller! Individuals have to decide on their own level of commitment to reducing global warming, and attempt to offer their own contribution. Raising the setpoint on cooling can contribute significantly to reducing emissions (based on the collective effort of many people). The same can be said for heating by lowering the set point. Unless there are circumstances that require specific settings ( like a hospital or nursery for instance), healthy people are able to tolerate that bit more - but at the end of the day, if the controller is in your hands, the choice is yours.
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Added By: Synergy Building Services (Nottm) Ltd