Air conditioning – what it does

Most people think of air conditioning as simply cooling the air and reducing the temperature during the summer, but it is more complex and beneficial than that.  Air conditioning relates to a distribution of air that has been heated or cooled and has a high element of control over humidity and cleanliness.   The indoor or outdoor air (depending on type of unit) is taken into the air-conditioning unit and passed over pipes containing a refrigerant, thus cooling or heating the air and returning it into the room.

Air conditioning allows a room’s temperature to be controlled, either heating or cooling precisely which in turn improves the working conditions for people and equipment, irrespective of what kind of weather is being experienced outdoors.

How does it do it?

An air conditioning system consists of three main parts. The condenser, which can normally be seen on the outside wall of an air conditioned building, the compressor, which is housed within the condenser and the indoor evaporator.

Operating fluid or refrigerant starts the process by entering the compressor as a cool, low pressure gas. Under the process of compression, this is transformed into a hot high pressure gas which passes through a series of fine air cooled fins, much like the radiator of a car, that help to efficiently dissipate the heat. This drop in temperature changes the gas into a sub cooled high pressure liquid.

By now passing this through a very tiny hole, better known as an expansion valve, the pressure in the liquid drops, causing it to evaporate into a cold low pressure gas. By passing this gas through another series of fins in the indoor evaporator the heat is extracted from the air as it is drawn across and then returned to the room.

The resultant low pressure gas flows to the compressor for the process to continue all over again.

In the case of a heat pump system, the operation is reversed!

Only when the internal thermostat senses the correct temperature does the cycle stop. 

Removing air pollutants

Many of our LG air conditioners are equipped with plasma filters which strip out many pollutants such as dust, smoke and pollen.  These are air airborne and normally come in from outside through windows, doors and vents.  Many of these pollutants cling to the skin, clothing and hair so they are also brought in by people entering the building.    Harmful gasses can also be present in a building due to use of varnishes, paints and cleaning materials.  While many have no serious and immediate effect, prolonged exposure can lead to health problems several years later.

Health Benefits

Air conditioners dehumidify the air and can limit the propagation of dust mites and molds which also have a negative impact on general health.  While air-conditioning is not a cure-all, numerous highly credible research projects have shown it to have a massive and beneficial impact on health.

Air conditioning creates optimum comfort and when people feel cool and fresh, their concentration and work levels are greatly improved.  People feel more active and fit and their performance rates are high. In exceptionally hot weather and without an air conditioned environment, research shows that performance drops and tempers fray.

Impact on computers and machinery

Having the right internal temperature and environment also has an impact on computers and machinery.  Some technological installations are purposely housed in well ventilated, air conditioned rooms with humidity controls to protect the sensitive equipment and ensure optimum efficiency.  With machines that use oils and lubricants, high temperatures can create low performance, breakdowns and more downtime.  This costs a business in two ways: reducing the lifetime of computers and equipment and losing vital business revenue with repairs and in-operation.

Ideal units and placement

Arcotherm can help you choose the ideal air conditioning unit for your premises.  What we recommend depends on the size and scale of the room, whether you want cooling only, cooling and heating, and the addition of ventilation.  Will you need units in one or several rooms, where it may be possible to connect several systems to one outdoor unit?  What kind of room is it – for instance a shop, office or restaurant where there are different types of equipment being used which generate heat, or need cooling protection, pedestrian traffic, and natural ventilation through doors and windows?  How much do you want to control the temperature?  Do you require air purification?  There are many factors but, once again, Arcotherm’s expert team will be on hand to guide you to the best solution.

Air conditioning is the key to healthy people and processes.

Now for the ‘science bit’ about plasma filters

Air filtration is essentially the insurance of a higher quality of air within indoor spaces. It is the procedure in which the harmful aspects of the atmosphere, such as bacteria, are withheld and the non harmful aspects are released.

Bacteria and viruses are not easy to remove from the air though, and this is due to their miniscule size and the fact that they reproduce at such a large speed.

The usual size of bacteria is smaller than that of a pin head so filtration is difficult through normal methods. The speed at which they reproduce creates danger and because we spend so much of our lives indoors, it is obvious that the air has to be filtered. 

There are various methods of filtration; these vary depending on size, efficiency, and cost. These can be divided into various categories. Usually the filter is an inactive type consisting of paper or cloth that is pleated but disposable, or a plastic type mesh that is washable. Then there are active types. These are smaller than inactive types but have better efficiency.

The way that these air filters usually work is that they use electric fields to attract and then kill the bacterium. The plasma filter is based on the technology of the electric attraction.

Air filtration is important within indoor atmospheres because the work place is becoming increasingly dangerous due to either smoking or illnesses. As many illnesses are passed through air, it is sensible to filter air to sustain a healthy workforce and by doing so this reduces allergies and the threat of asthma attacks to sufferers.

There have been many cases in where legal action has been taken against businesses due to illness or damage caused through the lack of air filtration.  It is the company’s responsibility to look after the working atmosphere, ensuring cleaner fresher air and a healthy environment.

Air conditioning is also important within an indoor atmosphere as the right temperature creates a comfortable working atmosphere. There are systems that incorporate the two different features.

Currently the plasma filter is arguably the most effective way of filtration. It was first designed for hospital use to provide a high level of filtration for health reasons. However it can be used in other buildings such as schools. This is because it lowers the risk of sickness, and that the plasma filter has a high level of efficiency and effectiveness.

Air filtration prevents illness and allergies. Air filters purify the air creating a healthy and comfortable atmosphere.

The filtration of bacteria and viruses from indoor air is hindered by two characteristics of the organisms; they are extremely small and they have the ability to propagate at great speed and acceleration.

The typical size of the bacteria is in the order of a few micrometers - that’s less than the size of a pinhead - but viruses can be 1/100 of this size.  It is acknowledged that effective filtration of particles less than one micrometer is difficult.  It is also known that the organisms that are captured by a non active filter can propagate on the filter surface, necessitating frequent filter changes.

The use of active filters using electric fields and electric discharges has been known for years to address both of these challenges.  The improvement of filter capture efficiency through the application of electrostatic fields is well established. 

Polarization effects brought about by an electric field produces an attractive force between particles and filter fibres resulting in significantly enhanced filter efficiency, especially for small particles. 

Simplicity is a good answer to a complex question - a porous, low-pressure drop (LPD) filter to be used to obtain high efficiency service.  The plasma produced by the periodic energisation of the electrode will kill the captured organisms.  It has been shown in tests that a LPD filter can obtain High Efficiency Particle Arrest (HEPA).

Two micro-organisms (S. aureus and Bacteriophage FX 174) challenged the capture and sterilisation capabilities of a field-enhanced, plasma-sterilised, one square foot area filter. 

Parameters that were varied were field strength and plasma exposure time.  It was found that the micro-organism capture efficiency if a low-pressure drop filter could be increased from 93% to 99.99% with the imposition of an electric field.  It was shown that the viable concentration of micro-organisms captured by the filter could be reduced by four orders of magnitude through exposure to the plasma. 

Finally, it was found that the polypropylene fabric used for the efficiency tests was strengthened by plasma exposure.

The advantage of the plasma filter being factory fitted is its cleanability.  When the filter cartridge is removed from the unit, the filter can be washed in clean water, dried and replaced.  As long as this sequence of maintenance is maintained, the filter will last many years, and the performance will not decrease.

So there you have it – the instant guide to high the level science of bacteria and filtration!