In the harsh Southern African conditions air-conditioning has become more of a necessity than a luxury item. Residential air-conditioning is still a very small segment of the market,but this may be due to a lack of understanding of air-conditioning. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) defines air-conditioning as: “The process of treating air so as to control simultaneously its temperature,humidity, cleanliness and distribution to meet the requirements of the conditioned space.” The aim of the above is to create a comfortable and productive living and working environment.
What aircon should I choose?
When selecting an air conditioning unit a number of important factors should be considered:
- reputable, long standing brand in the market;
- reliable spares back-up;
- correct capacity;
- power consumption;
- correct type of unit for application;
- maintenance costs.
In a market where cost is of high importance, one should look at the life cycle cost of the installation, rather than the initial capital outlay. The running cost of an air conditioner is the part that you will be reminded of every month when you look at your electricity account, long after you have forgotten the initial money spent.
All air-conditioners have an indoor section, situated in the area that has to be conditioned, and an outdoor section, situated in ambient conditions. There are two ways of achieving this. The first is for the outdoor section to protrude through the wall, if it is a self-contained unit, and the second is for the indoor and outdoor section to be two separate units interconnected with two copper refrigerant lines and the necessary electrical connections. When selecting an air-conditioner you have to decide whether you would require a cooling only machine, suitable for areas with moderate winter conditions, where heating is not required, or for areas with a constant heat load, such as computer rooms. The other type is a cooling and heating air-conditioner that uses reverse cycle or heat pump heating. Reverse cycle heating is for more economical than normal electrical resistance heating as it uses approximately a third of the power to achieve the same heating capacity. The cooling capacity of an air conditioner is rated in BTU kilowatt or tons of refrigeration and is an indication of the amount of cooling the machine will produce.
The cooling capacity required of a certain area is determined by a number of factors such as:
- Floor area;
- Type of roof;
- Type of ceiling insulation, if any;
- Size of windows;
- Orientation of windows (N,S,E or West);
- Unconditioned areas adjacent to conditioned area;
- No of people in area and level of activity;
- Heat generating equipment.
From the above it is clear that it is not a matter of a thumb suck to determine the correct capacity unit required, but a number of calculations are required to determine the heat load of the area. It is very important to use the correct capacity air conditioner as a too small capacity machine will run continuously and never bring the temperature down to acceptable levels. A too big capacity machine will tend to switch on and off continuously (commonly known as short cycling) as it brings down the temperature very rapidly.
We have a range of airconditioning contractors, large and small, with the skills and experience to handle any size project.