What is an inverter AC ?

We are not sure if you have noticed that an increasing number of airconditioners in the market are now labelled as “Inverter Air Conditioners”. We decided to write something on this to demystify the title.

In a conventional airconditioner, a reverse-cycle is used where a heat pump (compressor) is working either at full speed or switched off. So when it is switched off, you can notice that your AC doesnt make much sound (probably only noticed in window AC and not in a split AC , as the compressor for the later is mounted outside the home).

This limitation is imposed because the compressor’s speed cannot be varied. So how do these ACs regulate temperature? They use ambiant temperature sensors like thermistors to detect the room temperature and when it is near the setting, the compressor is switched off while the fan still is operational.

In an inverter AC, the incoming AC signal is first rectified into DC and then switched back to AC with varibale frequency control. (Remember regular AC power is 50 Hertz only). The resultant AC which has variable frequency is used to control a special motor such as a brushless AC motor or an induction motor whose speed is directly proportional to the frequency of the powering signal.

So now it is possible to run the compressor at variable speeds and achieve optimum cooling of the room. A microcontroller is used to sample the ambiant temperature and control the speed of the compressor.

By minimizing the start stop cycles like it is done in conventional AC units, the inverter AC maximized efficiency of operation, increases the life of components used on board and eliminate sharp fluctuations in the load the air-conditioner places on the power supply.

The last example is very apparent when you realize your lights dim momentarily when the AC is switching on its compressor!

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Posted by on Mar 22 2008 Filed under Air Conditioner. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry
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