Inverter Compressor Benefits in a Mini Split Air Conditioner
January 12, 2009 by Shawn Mack
Filed under Technical Guide
Shopping for a mini split air conditioner got a little more difficult in the past couple of years. With the new federal regulations on minimum SEER ratings in the United States, manufacturers have started using inverter compressors to obtain 13 SEER or higher. This has created exceptional efficiency in wall mounted air conditioners, but also has increased the consumer cost.
The compressor is the heart and soul of every mini split air conditioner. It is the most essential component in an air conditioner and the most expensive. When purchasing a mini split air conditioner make sure to find a system with a solid warranty approximately 5 years in length. Also, make sure to purchase your mini split from a company that has parts available in the United States. Some companies can take up to three weeks to ship parts if they have to order them overseas.
I have read many articles talking about inverter compressors versus standard rotary compressors, but I think this sums it up best. A standard rotary or scroll compressor operates like a light switch: either on or off and nothing in between. An inverter compressor operates like a water faucet: it only uses enough power to reach the desired setting.
An inverter compressor is programmed to run at optimum speed, which is regulated by the input frequency as it varies between heat load requirements. Example: Your mini split is set at 72° F. The room becomes hot and the compressor needs to cool it by a couple of degrees. A standard compressor will turn “On” with full power, while an inverter compressor only uses enough resources (RPM) to reduce the room’s temperature to the desired setting.
Over a full day of operation, a standard compressor will have to turn on and off a substantial number of times. An inverter compressor will turn on and reach the desired setting and then idle at that setting until needed further.
By using different rotation speed, the inverter compressor is saving energy and operating more quietly than the standard compressor. Not having to constantly turn on and off at maximum RPM increases the lifespan of the inverter compressor.
When a large temperature change is needed, the inverter compressor can operate at a much higher RPM speed than the standard compressor, reducing the amount of run time and reducing your energy costs. Some researchers show a reduced power consumption as much as 60% versus a fixed speed standard compressor.
Inverter compressors offer a more precise temperature control for your mini split air conditioner. I hope this helps you understand how an inverter compressor operates and will help you make a decision with your ductless air conditioner purchase.
Join the forum discussion on this post - (1) Posts
April 16th, 2009 at 8:24 am
Wow, this is an astonishing review.
I also have same think as yours that by using this inverter, we can get a lot of benefit.
Thank you
June 8th, 2010 at 7:31 am
I know there are industrial ac inverters and softstarters in the market, how can I install one of these on a mini split to get these results?
October 8th, 2010 at 6:18 am
To Gilberto:
So If you want to get good result from your split air cond. You have to install low ambient kit model is SB004A. Result of work this device here
1)for R410
http://priborspb.ru/rezultati_ispitaniy_sb004a_freon_r410.html
July 23rd, 2011 at 3:21 pm
I understand the part of the post describing using an AC inverter motor speed control to allow the system to reduce the compressor volume to match the load.
The part near the end that discusses the inverter driven compressor at maximum output is opaque and tends to be mislead. While noting that the inverter driven motor within the compresor isn’t tied to the power line frequency and can run over a range of RPMs that may be both faster and slower than a synchronous motor is interesting… its also meaningless and misleading.
It meaningless because the internal motor RPM doesn’t n and of itself do anything for the consumer, its just a design parameter for the engineer to match the scroll/rotary/piston compressor mechanics to. There’s also nothing better about 60Hz fixed speed compressors than 50Hz fixed speed compressors even though they run at 20% higher RPM.
Its misleading because compressors are rated for their maximum output and they don’t exceed it. The compressor is rated for its maximum cooling output and that’s all you can get. A 9000 BTU/Hour inverter drive compressor won’t cool a room from 95° to 75° any faster than than any other 9000 BTU/Hour compressor.
It is simply false to imply that an inverter driven compressor will operate more efficiently at maximum output than one with a synchronous motor. In fact, the inverter drive electronics themselves consume energy and impose a small efficiency penalty at maximum output. Further, the higher frequency drive also imposing larger hysteresis losses in the motor core reducing its effiency by some amount. The inverter driven motor compressor is in fact less efficient at maximum output than its synchronous motor counterpart.
Further - the entire article tends to ignore system power consumption rather than just the refrigerant loop. Its important to understand that a significant part of the efficiency gains come from slowing the air movers both indoors and outdoors.