Most of the refrigerators used by us in India have a heart (compressor) that isn’t smart! The compressor is arguably the core component of the refrigerator—circulating refrigerant inside the appliance. So what heart is to human, is what compressor is to a refrigerator!
Addition of inverter to compressors has added ‘brain’ to this ‘heart’. In fact, inverter technology has revolutionized two big home appliances: ACs and refrigerators. Inverters has significantly reduced energy consumption and have led to quieter appliances.
But when you go into the market these inverters are marketed differently. So are these distinctions legitimate or just a slight variation is marketed as “revolutionary” feature. We will inspect different inverter technologies so that you know what they really are and if they are really different from those offered by competitors. But before that, we need to understand the role of compressors a.k.a heart of refrigerators.
Role of Compressors in Refrigeration
Now, the main role of the compressor is to compress refrigerant inside the refrigerator. As the refrigerant is compressed, it converts from a gas into a hot liquid. It then passes through a cooling condenser where refrigerant is cooled into a liquid which is then propagated inside the refrigerator. As it circulates, it expands into a gas by taking in the heat from the refrigerator and finally reaching back to the compressor which squeezes it back into a hot liquid.
So basically, the compressor is like a pump designed for vapor instead of water which compresses warm refrigerant gas into a hot liquid, and then pushes it to the coils to release heat to the environment.
Refrigerators historically used to come, and in fact, even today majority of them come with a standard compressor. This standard compressor activates when the temperature in the refrigerator exceeds a certain threshold limit. But when the temperature falls below this threshold, it turns off awaiting the next refrigeration cycle.
So basically, the standard compressor is a single-speed compressor that is either “on” or “off”. When “on”, it operates with the maximum power. It has no functionality to operate its speed in accordance with the rise in the temperature. Also, as there is constant “on” and “off”, it increases the wear and tear of the appliance and creates noise while switching state, which is quite discernible if you are close to the refrigerator.
Remember I said most refrigerator comes with a heart that isn’t smart at the beginning? And it’s the addition of an inverter to the compressor which endows smartness to otherwise appliance like a refrigerator! Now, from a hardware and design standpoint, this is achieved by using brushless direct current (BLDC) motors. Advantage of having BLDC motor is that it allows the compressor to run with different level of intensity (speed) based on the temperature and other environmental condition. Inverter compressors are variable-speed compressors using BLDC motors for using variable speed in operation.
Now let’s looks at the different types of “Inverter Compressors” marketed by different brands:
When a variable-speed compressor (inverter compressor) is being controlled by a microprocessor using algorithms (software) then it is often marketed as digital inverter.
Like for example, Samsung refrigerator comes with the digital inverter. In conventional non-inverter models, the compressor is either “on” or “off”. And when “on”, it runs at full power. But digital inverter compressor remains “on” most of the time but operates at different speeds depending upon the situation and requirement. Digital inverter technology used in Samsung allows 7 adjustable speed which means cooling precision would be high in Samsung refrigerators.
Godrej markets its digital inverter as nutrifresh inverter. Besides being controlled by microprocessor it has special sensors that provide personalized cooling based upon the type of food inside the refrigerator so that they can stay fresh for longer.
Most of the Whirlpool inverter refrigerator comes with intellisense inverter technology. These inverter models take the help of 3 sensors for optimum control. For instance, one sensor fetches information about internal temperature, other one estimates the amount of food load inside the refrigerator and the third one senses the user pattern for near-perfect speed control of the compressor.
Improving its intellisense inverter technology further, some premium Whirlpool refrigerators released 2019 onwards come with plasma inverter which besides smart sensor-based controls has an additional layer of plasma coating on its compressor rod which improves longevity. Plasma intellisense inverter is designed to last for 25 years as opposed to an ordinary digital inverter which lasts for about 20 years.
Inverter used in single door LG refrigerators is marketed as a smart inverter by LG. Smart inverter is just a rechristened form of the digital inverter where there is the use of microprocessor for optimum cooling control.
Inverter Linear Compressor
Modifying the concept of inverter compressor drastically, premium LG refrigerator comes with what is known as inverter linear compressor. In principle, it also involves compression of the refrigerant, but the linear compressor achieves this using a linear arrangement of an electromagnet that attracts the plate to which the piston is fixed. Digital inverter compressor involves 4 friction point whereas by using electromagnet setup, linear inverter compressor reduces friction point to just 1. This reduces the wastage of energy and translates into high energy efficiency.
Besides improved energy saving, another major advantage of the linear inverter compressor is that they keep the food fresh for longer in a wide range of environmental condition.
So, to conclude it is definitely advised to for a refrigerator with inverter compressor instead of just ordinary compressor. Now the question arises which inverter compressor to choose. Well, the choice would depend on several factors with the budget being the most important one. If budget is not your constraint, then we will advise you to go for models coming with inverter linear compressor or plasma inverter. Because inverter linear compressor is fundamentally unique design while the rest of the inverter technology is just slight tinkered version of digital inverter technology. Plasma is also a type of digital inverter but due to plasma coating, the shelf life of compressor improves by a few years. Moreover, plasma inverters are capable to handle wider voltage fluctuations.
To know more about the difference in different air conditioner’s inverter compressor click here.
About the Author:
Hussain Kanchwala is an Electronics Engineer from University of Mumbai. As an Analyst at BijliBachao he keeps a tab on latest technologies in gadgets and appliances, tracks businesses of white goods companies and monitors the consumer behavior. With a background in engineering, penchant for detail, and flair for writing he regularly write reviews about brands and their products. More from this author.