1 How does an air conditioner work?
An air conditioner’s job is to transfer heat from one place to another. In most cases, this means moving heat from indoors (and thereby cooling a room) to the outdoors, but the principle can also be reversed in order to heat an indoor environment.
This transfer is achieved by piping a special liquid called a refrigerant, which turns from liquid to gas at a very low temperature. This refrigerant is first sent through a series of coils, called ‘evaporator coils’. A fan will blow air over these coils, thereby cooling the room and warming the refrigerant within the pipes. This refrigerant then turns into a gas, which flows into another set of coils on the outside of the building called the condenser coils. Another set of fans then blows air over this set of coils, thereby dispersing the heat to the outside. Finally, a compressor squeezes the gaseous refrigerant so that it reverts to a liquid state. It is then piped through the evaporator coils and thusly the cycle continues.
2 How is cooling capacity measured?
The cooling capacity of an air-conditioning unit can be measured in tons. This measurement can trace its origins back to before air-conditioning was invented, when large blocks of ice were used to cool indoors. The amount of ice consumed by a refrigeration system in a single day would be up to a tons worth! Of course, we no longer use blocks of ice in our refrigeration, but the measurement remains. A ton is roughly equivalent to 12,000 British Thermal Units of cooling per hour.
3 What are the common causes of problems?
Since air conditioners are such complicated mechanical devices, there are a number of ailments which can affect them. Air conditioners are rated for a certain ‘load’ (the volume of air they are expected to cool) and are designed to carry a certain ‘charge’ (the quantity of refrigerant they contain). Straying outside these boundaries will place a strain on the system. Leaks in the refrigerant pipes, for example, will decrease the available charge and thereby reduce the air conditioner’s load capacity.
4 What are filters for?
Filters are an important component of every AC system. They are placed just beside the evaporator coil, and their role is to remove tiny particulates from the air, ensuring that it is clean and thereby protecting the coil. Over time these filters can become clogged with dust and grime and the airflow will be restricted. For this reason it is important that filters are changed a regular intervals – particularly at times of the year where the system is being run regularly.
5 How can I maintain my AC system?
While simple maintenance like cleaning and filter-changing can be performed by a complete layman, air conditioners also contain a number of complicated mechanisms which might require the attention of a professional engineer.
6 How can I make the system more energy efficient?
The best way to ensure that an AC system run efficiently is to improve the energy-efficiency of the building it is placed within. This means installing double or triple glazing, sealing windows and leaky walls and insulating the roof. Anything which prevents heat from entering and escaping the building will reduce the workload of the AC unit, thereby increasing its longevity and reducing energy costs.
7 Why are ducts so important?
Larger air conditioning systems span many rooms and use a series of ducts to transport cold air outward from a centralized evaporator coil. This arrangement is vastly more efficient than a series of isolated units might be. However it is also dependent on the integrity of the ducts.
Leaking ducts will reduce the efficiency of the system. Also if the duct should happen to pass outside of the building – or through attics and garages – then the temperature of the air within it will be influenced. In order to preserve the temperature of the air flowing through the ducts, it is important that they are kept insulated and free from leaks.
8 How can I reduce the load on the AC system?
Repairing ducts and replacing filters are the two best ways of keeping the AC as robust as possible. But there are a few others steps which one might consider. Perhaps the most easily overlooked of these is to ensure that the airflow over the condenser coils is unrestricted. If there is a blockage, then the air around the coil can become stagnant. This prevents the coil from being warmed, which can in turn cause the refrigerant to freeze. This is a problem which will require costly maintenance!
So far we have looked at the air conditioner’s role in cooling an indoor environment. But that is not the only role they play: they can also act as heaters, as dehumidifiers and as ventilation systems. This role is an important one, since if the air within a home is not properly circulated, then it can lead to health problems – particularly in newer homes where walls are tighter.
The modern air conditioners was first used to help to dry out the air in a Brooklyn printing plant. During hot summers in New York, the humidity was having a large effect on the results of the presses – by controlling the humidity, these variations were brought to a minimum. Unfortunately, modern air conditioners cannot independently control both temperature and humidity and so for more thorough control over conditions it is necessary to employ both an air conditioner and a separate dehumidifier.