Planning to buy new refrigerator and stumbled upon inverter refrigerator and wondering about what is inverter refrigerator. In this article we will see what are inverter refrigerator, how they work and the benefits of inverter refrigerators over conventional refrigerators.
Before we talk about inverter refrigerator it is imperative that we understand how a refrigerator cools food.
How refrigerator cools food:
Every refrigerator has two main components viz., compressor and evaporator that does the cooling and the rest of auxiliary components help them in doing that.
The inside wall of your refrigerator has evaporator and on the back side at bottom there is compressor. The refrigerant (refrigerant is the liquid that flows inside the pipes of evaporator and compressor) flows through the evaporator and absorbs the heat from inside of the refrigerator and cools down the space, the absorbed heat makes the refrigerant to evaporate and become vapour.
This vapour is then compressed in the compressor where its pressure is increased and when it comes in contact surrounding air (air near your fridge) it losses its heat to the surrounding and transfers back to liquid which again goes to the evaporator and the process continues.
Now that we know about refrigeration lets see the difference between conventional and inverter refrigerator.
How conventional refrigerator works:
In conventional refrigerator the compressor is a single speed compressor and runs at the same speed at all time irrespective of the atmosphere condition and load on the refrigerator.
The moment your refrigerator temperature goes above the set temperature by couple of degrees the compressor starts (which can be heard as a clear audible noise) and begins the cooling process and once the set temperature is achieved the compressor stops (which can be heard too as refrigerator goes silent).
The frequent on, off and same high speed operation requires high current hence more electricity is needed.
Most conventional refrigerator compressor are designed to run at maximum load hence they operate at high speed at all time which is a problem here’s why.
During summer when the outside temperature is high it is understood that the compressor has to work harder to reach the set temperature hence more electricity is needed but during winter when the outside temperature is low the compressor can operate at slow speed which means less power is needed to reach the same temperature.
But since compressor is single speed it runs at the same high speed during winter, summer, rainy, day, night, zero load, half load, and at full load resulting in high power consumption at all times.
The solution for this single speed compressor operation is inverter refrigerator.
How inverter refrigerator works:
Inverter refrigerator has a variable speed compressor which adjusts it speed depending on the outside temperature and load on the refrigerator.
In an inverter refrigerator the compressor does not starts and stop, but runs at slow speed just enough to maintain the required temperature in the fridge at all times. So the compressor in an inverter fridge does not waste electricity in starting up at regular intervals and runs very efficiently at the slowest speed.
If its day time and hot outside then the inverter compressor will operate at high speed to achieve the set temperature and during night when the temperature is low the compressor will operate at slow speed to reach the same temperature.
Hence inverter refrigerator saves power by adjusting its compressor speed as per the load on the refrigerator.
This helps inverter refrigerator to save 30 % power for cooling the same volume of air in comparison to a conventional refrigerator.
Check out this simple video from Samsung outlining how inverter refrigerator works and its benefits over conventional refrigerartors.
Latest tech in inverter refrigerator:
Most compressor be it in a conventional or inverter refrigerator are of rotary type.
A regular rotary compressor has to convert the rotary motion of an electric motor to linear motion with the use of a crank shaft and piston rods to compress the refrigerant. This leads to 4 major points of friction which means more loss of power. To save power in this area as well, linear (reciprocating) type compressors are introduced in the market.
Linear compressors move in a straight line with an oscillating piston. The linear moving piston hits a spring at the end of its motion on one side and bounces back. Magnets are used to maintain the linear motion.
LG has introduced new line of refrigerator having reciprocating compressor here’s a video explaining how linear compressor technology works from LG.
With a linear motion there is no wastage of energy due to radial centrifugal forces which occurs in a rotary motion. Because of the simple mechanism of the linear compressor, with no crank and piston rods, the linear compressor is able to achieve 20 to 30% better efficiency than any crank driven rotary compressor. Linear Compressors use lesser energy and make lesser noise and lasts much longer than conventional rotary refrigerator compressors.
Advantages of Inverter Refrigerator:
- Better temperature control : Inverter refrigerators are designed for precise cooling.
- Lower Noise & Vibration Levels : Conventional refrigerators make loud noise and also vibrate when the compressor starts, but an inverter technology refrigerator uses low speeds when it starts and gradually works up its way to maximum speed hence the noise and vibration level are low.
- Longer Life Span : As there is no sudden shock loads from the stop-start- run at full speed of the compressor, there is less wear and tear hence longer life span.
- Consumes Less Power : As we saw above the power consumption of an inverter refrigerator is about 30% less than a conventional refrigerator of same size all because of variable speed of the compressor.
Disadvantages of Inverter Refrigerator:
Inverter refrigerator does not have many disadvantages the biggest one I could find was the slow cooling speed. Unlike a conventional refrigerator which is quite fast in cooling, an inverter refrigerator is a bit slow presumably, due to slow start-ups of compressor.
The difference in the cooling time isn’t drastic but a small one which can be overlooked keeping in mind the amazing advantages it offer.
Less known facts about inverter refrigerator:
There are many misconceptions about inverter refrigerator, I hope the following points help you to get it cleared.
- Every compressor has an electric motor, regular motors need 3-4 times more current (more than running current) at startup. So the size of the inverter/generator needed to run any AC or Refrigerator increases significantly. But Inverter Technology refrigerators have variable speed motors that start up gradually needing much lesser current at startup. Thus the size of inverter/generator required to power them is small. Thus if a conventional refrigerator needs 5 kW inverter to power it, and inverter refrigerator of the same volume can be powered just by a 2 kW or 3 kW inverter.
- If you are planning to use Solar PV for your house, then it is the best to use inverter technology air conditioner or refrigerator as it not only reduces the size of PV panels needed to power them because it consumes lesser electricity, but it also reduces the size of inverter to be put along with the PV panel.
Refrigerator Energy Saving Tips :
Whether you have a conventional refrigerator or inverter refrigerator follow these tips to save power consumption of your refrigerator.
- Keep the refrigerator full – This sounds bizarre but keeping your refrigerator full helps to cut down the power consumption. By full refrigerator I don’t mean to over stuff the refrigerator always keep place for proper air circulation.
- Optimize temperature settings – Most of the refrigerator are running at temperature way below its needed. On an average a temperature of 2 C to 5 C is ideal for fridge compartment and for freezer anything between -10 C to -15 C is good. Don’t overdo the temperature. If you don’t have a thermometer to measure the temperature then just switch your refrigerator setting to normal in normal days and below normal in cold days (use the regulator inside your refrigerator).
- Keep refrigerator door closed – Frequent opening and closing of refrigerator door puts unnecessary load on the compressor to cool the warm fresh air that enters the space every time you open the door. If you cut down your door opening frequency you will see a cut in your electricity bill.
- Place refrigerator strategically – Two questions you should ask yourself before finalizing your refrigerator place. First, is the place getting direct sunlight? If yes then look for some other place or restrict the sunlight coming to that place by some means. Second, after placing the refrigerator is there any space between the refrigerator walls and your house wall? Ideally you should keep 6 inches of space on all the three side for proper ventilation. You can check out this awesome article from Samsung on how to place your refrigerator how much free space should I allow around my refrigerator?
- Lifestyle changes – Do not keep hot food directly in the refrigerator. First let the food cool down and then put it in the refrigerator. Periodically clean the evaporator and condenser coils. Keep your food organised so that there is enough space for free movement of air.
If you are planning to buy a new inverter refrigerator in 2020 then following list will help you. It is a list of 5 best inverter refrigerator available in India with lowest power consumption.
Best inverter refrigerators to buy in 2020:
- LG 260 L 3 Star Frost Free Double Door Refrigerator – Annual Power Consumption – 194 kWh – Amazon Link
- LG 235 L 4 Star Inverter Direct Cool Single Door Refrigerator – Annual Power Consumption – 143 kWh – Amazon Link
- Whirlpool 292 L 4 Star Inverter Frost-Free Double Door Refrigerator – Annual Power Consumption – 194 kWh – Amazon Link
- Whirlpool 340 L 4 Star Inverter Frost-Free Double-Door Refrigerator – Annual Power Consumption – 207 kWh – Amazon Link
- Samsung 345 L 3 Star Inverter Frost-Free Double Door Refrigerator – Annual Power Consumption – 213 kWh – Amazon Link
Conclusion on what is inverter refrigerator:
An inverter refrigerator has a variable speed compressor which adjust its speed according to the load on the refrigerator unlike a conventional refrigerator compressor which runs at same speed at all times irrespective of the load.
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