Inverter Air Conditioning
The inverter air conditioning is the latest technology in the HVAC field that is becoming more popular due to its environmental friendly and energy savings approach. Providing comfort to the users is another big advantage of this kind of system.
Traditionally, the compressor that is used in an air conditioning system is an ON or OFF type in that it either works at the maximum capacity or none at all. It ON when the room thermostat calls for cooling and OFF when the desired temperature has been achieved. This cycle is repeated with the change of load in the room.
Electronic Controls for control of Inverter Air Conditioning DC Inverter Compressor.
Daikin Ceiling Cassette Unit
The advancement in power electronics has enabled the inverter technology to thrive by the use of microcontroller and IGBT modules to drive the compressor DC or AC motor. The speed of the compressor motor can be varied by using the variable frequency drive.
This is done by converting the incoming AC supply to DC voltage and then modulate it by changing the voltage, current and frequency of the power to the compressor. Changing the frequency changes the speed of the compressor by using a more complicated electronics control circuitry.
Advantages of Using Inverter Air Conditioning
Keeping abreast with the latest technology has more advantages than remaining status quo. Here are some of the reasons why you should consider buying an inverter air conditioning system.
- Energy Savings is one of the most important factors to consider when buying an equipment. In the long run, the benefit outweighs the initial cost. The inverter technology uses less energy compared to the traditional system.
ON/OFF type of compressor has large starting current, sometimes 6 times more than the running current. This causes flicker to lights and the energy consumed is greater. Typically, there is a 20% to 30% savings in power consumption.
A study by Daikin(FTK-1115-B Brochure) on the energy saving obtained over a period of 1 year between a 1.5 HP inverter vs a 1.5 HP non-inverter showed that there is a big significant of savings achieved on the inverter unit. The units were tested in a room size of 16.5 square meter, set temperature = 25°C, Fan Speed = High and outdoor temperature = 33°C.
Daily operational hours = 8 hours.
Daily power consumption = 9.51 kWh
Total power consumption in a year = 365 days X 9.51 kWh = 3471 kWh
Daily power consumption = 4.83 kWh
Total power consumption in a year = 365 days X 4.83 kWh = 1763 kWh
Total savings/year = 3471-1763 = 1708 kWh
% of savings = (1708/3471)X100% = 49%.
- Comfort to the users is another advantage of this system. During start-up, the compressor can run full speed to provide quick cooling to the room. After the desired room temperature has been achieved, the speed of the compressor is regulated using the variable frequency drive based on the required cooling load of the room.
The fluctuation of temperature is minimum compared to the ON/OFF type of compressor. This provides a comfortable environment for the occupants at all times.
Better temperature control means better comfort.
- Ozone Friendly refrigerant such as R410a is used in most inverter system. This refrigerant contains only HFC compared to R22 which contains HCFC, an additional chlorine component that destroys the ozone layer of the earth.
Always enquire the kind of refrigerant which is in used as some installers prefer to continue using R22 as it is cheaper compared to R410a and hence lower their cost.
- Quiet Operation is another feature that inverter technology offers. The outdoor unit which contains the inverter compressor is much more quieter compared to the non-inverter compressor. Hence, you do not have to worry about noise when you sleep.
Disadvantages of Using Inverter Technology
Typically, the disadvantages of using inverter air conditioning driven system is due to cost. Here are a few reasons why the cost is higher compared to the non-inverter system.
- Electronics Control circuitry is more complicated compared to the non-inverter type. Electronic components such as electrolytic capacitors, diodes, opto-couplers and IGBT power modules are rated at a higher ratings due to the design requirements of the system. Hence, the cost is higher.
- Electromagnetic noise is generated as a result of chopping the voltage. This noise can create electrical disturbances to other home appliances in the house hence there are regulations that state the amount of noise that it is allowed to generate.
Filtering components such as capacitors and inductors are used to filter out the high frequency electrical noise. This add the cost to the overall system.
- R410a or other more ozone friendly refrigerants usually cost higher compared to R22. The compressor used is also different but as the demand for them increase, there will be more economy of scaled and the price will come down in the near future.
As of this point of time, installers usually charge twice the amount for topping up R410a compared to R22.
- R32 refrigerant is the preferred refrigerant for newer-developed equipment as it not only has zero Ozone Depletion Potential but its property include having 1/3 of Global Warming Potential compared to R410a. Many leading manufacturers such as Daikin, Mitsubishi and Panasonic are promoting this refrigerant for their premium models.
York Multi-split inverter - indoor units.
See also the block diagram of a DC Inverter controller.
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