How do Freezers Work and to Keep Them Operational ?

The humble freezer has revolutionized the way people live. It has changed the way we eat, what we eat and how we eat it. It has also changed the way we shop by helping bring many food product prices down.

We can now eat foods that are out of season or from faraway places. Imagine life without ice cream. It has also made life a lot more convenient by being a huge helping hand in the kitchen, as many women work, coming home to hungry families.

The freezer is one of those common household appliances that most people take for granted. Unless it breaks or stops working, we seldom give it a second thought. If you suddenly found yourself without a freezer, you would immediately realize how much you depend on it.

What’s interesting about freezers is that they predate your TV dinners and leftovers. They even predate  modern civilization itself. Many years ago the ancient Mesopotamians discovered that food that was cold tended to rot a lot slower than foods left outside in the heat. This got them thinking.

They came up with an ingenious idea: they dug pits in the ground. They insulated them with straw or sand, then topped them off with snow and ice from nearby mountains. These ice pits were used to preserve their food for weeks.

Moreover, they kept the entrance to these ice pits small and narrow in order to prevent air seepage. Because they knew that warm outside air may possibly prevent the snow from cooling the food down.

It was only centuries later, in the 1600s, when the French and English created their very own versions of the ‘icehouse’. The majority of these ‘ice houses’ were partially in the ground, but some were also designed as thatched roof pits in which they would keep food cold and provide chipped ice for beverages and desserts.

They also used ice, provided on a large scale, from the lakes – lasting them up to a year. It was a similar process to the ice cave – as it also had an insulator; yet, theirs was either made from sawdust or small branches, then topped with snow and sawdust.

It wasn’t long until the icebox was created: a small cabinet with a compartment to hold a large ice block. It then had a separate compartment designated for storing food. Yet, it took until the 1920s before the electric fridge and freezer combination made its debut in the market.

Further, it was at this time that the science behind mechanical refrigeration had been firmly established. It was a chemical gas set in circulation that kept the items contained in the compartment cold. Today we have vapor-driven freezers, which are more efficient, yet, also more complicated than the ice caves of yesteryear.

There are several discoveries that led to the creation of the freezers that we know today.

Development of the Modern Freezer

Food decay is usually caused by bacteria. However, when food is stored in freezing temperatures, below 32 degrees, bacteria cannot grow as fast, or as large. Food spoils a lot slower if you lower the liquid inside to freezing temperatures.

Scientists in the early 1800s made significant discoveries regarding the nature of temperature, as well as the laws of thermodynamics. It was soon after when artificial temperature regulation became a little more real. Jacob Perkins, an American inventor, built onto the ideas of vapor absorption that was set forth by another inventor, Oliver Evans. He went on to create a cooling unit that relied on vapor compression.

Perkins eventually figured out that a substance, which is now used as a refrigerant, will absorb and give off heat as it goes through pressure. It changes from liquid to vapor and back. Basically, he discovered that certain chemicals can lower air temperatures by absorbing heat.

He later obtained the first patent for a refrigeration unit. Unfortunately, his invention never saw major commercial success.

It was later in the late 1940s when a Florida doctor patented something that was able to create ice by pressurizing and then depressurizing refrigerants. It did, however, have an issue of leaking, and did not always work. In 1860, Ferdinand Carre, a French inventor, worked on improving vapor compression technology. His idea was to use a more effective and stable refrigerant. He used ammonia – which was toxic – instead of ether that Perkins used.

By the time the 1920s rolled around, technology had been refined enough that freezers became available commercially in the U.S. and Europe; it also helped that electricity was now available on a wider scale.

They were still far from perfect at that stage.  Most freezers were wildly inefficient, as air seeped through into the freezer compartment. Thus, often times, freezers were positioned in ice houses for better temperature control.

Things have vastly improved since then, and the capabilities of fridges and freezers now are much greater. They’ve managed to improve the machinery, use better chemicals and have a more efficient way of trapping cold air inside.

Types of Freezers

Nowadays, the vast majority of homes around the world have a freezer. These can be a stand-alone unit like a chest freezer, a side by side freezer, or a refrigerator/freezer combination unit. It doesn’t matter what type of fridge/freezer model you have, however, as they’re all pretty similar. All single unit freezers use the same machinery that is in pursuit of vapor compression.

Energy efficiency is the only real difference. The model that uses the least amount of power is the bottom mount. This is because the compressor is on the bottom – meaning vapor does not need to be pushed far.

Top-freezer, or side-by-side freezers, place more pressure on the compressor, however, as it forces the refrigerant through a tube that reaches the freezer compartment. There is also the standalone freezer, which is also called the ‘deep freeze’ or ‘sub-zero’. They also operate on the general principals of vapor compression.

Pictured below we have one of the standard refrigerator and freezer combination units that you commonly see.

Side by side refrigerator freezer

And then as we see below is another model, where the freezer is placed at the bottom, which is very common as well. This is the most power efficient design of the refrigerator and freezer combination units, as the vapor does not need to be pushed up far.

Kenmore bottom freezer refrigerator stainless steel

Restaurants however are known to have very large walk-in freezers. They also use vapor-compression. The major benefit of this type of unit is that many of them can hold up to 600 pounds of weight per square foot of their aluminum floors.

Obviously, this isn’t necessary for a small family home, yet, for a high-volume restaurant, it’s nearly impossible not to own one. Therefore, it doesn’t matter what type of freezer you acquire, as long as it maintains a consistently low temperature. In the event that temperatures are inconsistent, you’ll find frost build-up – better known as a freezer’s worst nightmare!

An alternative to a walk-in freezer is the standalone freezer for a home, which is convenient if you store a lot of meat or other frozen produce that you can’t fit inside of your standard refrigerator and freezer combination unit. You can place this freezer inside of your garage if you have the space, and then enjoy the extra freezer space and power efficiency of this standalone freezer unit.

Standalone freezer packed with food

How does a freezer work?

Most modern household freezers work on a technology known as the vapor compression cycle.

The mechanics of a freezer are actually fairly straightforward. First, you need a solid, airtight box with no cracks, dents or warped edges. The freezer needs to be thermally insulated and good seals are essential to the correct functioning of the freezer. Any cold air escaping or warm air entering the freezer will interfere with the correct functioning of the unit.

All domestic freezers work in the same way: whether they are chest freezers, side by side or fridge/freezer combinations.

The mechanism is filled with a refrigerant, which is a type of gas; the exact gas used has changed over the years and there are still a number of different types in use. Most modern fridges use a gas known as R600a refrigerant, which is safe and efficient. This gas has the ability to transform from gas to liquid and then back to gas again under certain conditions.

It starts off in the freezer as a hot gas and as the compressor, which is essentially a powerful fan, forces the gas through the freezer coils, the gas condenses and becomes liquid.

From there it is forced through capillaries to remove any moisture and contaminants before moving onto the freezer, evaporating coils. In the coils, the liquid expands and reverts to gas. This process draws the heat out of the system, thereby cooling the freezer.

The cycle continues to repeat until the desired temperature is achieved. Once the temperature is achieved, the process pauses until the temperature drops below the required temperature and the cycle starts again. While a thermostat constantly measures the temperature in order to decide when to switch on and off.

We can better see the operation of a freezer in the schematic below, showing how the heat is taken in and then released to keep your favorite foods fresh and tasty.

Freezer operation schematic diagram

There are other types of freezers that use different technology, for example: camping freezers that use an absorption process, or freezers that are used in scientific or industrial applications that rely on other mechanisms to cool the units. Yet, most household freezers rely on the vapor compression cycle.

New technologies

Other new technologies that are being developed, include: magnetic refrigerators that use a metal alloy to create a magnetic field that cools the freezer, and acoustic refrigerators that rely on sound waves to cool compressed helium gas. This forces out warm air, while replacing it with cold air, cooling the freezer.

Although little has changed in the past few decades, the freezers of the near future are sure to be more reliable, quieter and more energy efficient.

Freezer tips

Freezer wall filled with frost

There are a number of things that you can do to keep your freezer working at its peak – extending the life of your appliance:

  • Clean the coils regularly. Gently clean the coils in order to remove any dust or dirt that may accumulate on the coils, keeping them working more efficiently. Do this with care as you do not want to damage the coils.
  • Defrost when necessary. As soon as you see excess ice build-up, defrost the freezer. Never use a sharp object to chip or scrape ice away. Dry the inside of the freezer before switching it back on.
  • A freezer works better when it is about two thirds full. The frozen items in the freezer retain the temperature and reduce the workload.
  • Never put warm or hot food into the freezer. Always let it cool first because a dramatic temperature drop can cause the food to spoil and make your freezer work a lot harder in order to get back to the desired temperature.
  • Replace door seals when they are worn. Over time the seals become loose, brittle and worn. This will make the freezer very inefficient and will also lead to excess frost or ice build-up.
  • New freezers in good condition close easily, yet, as they get a bit older, some require a bit of pressure in order to close the door properly. Thus, ensure that household members close the door tightly in order to prevent cool air from escaping.
  • If you are going away for a few days, you can lower the temperature slightly. The fact that no one will be around to frequently open and close the door will mean that it loses less cold air and the fridge will be much colder than under normal use.
  • If you experience a power outage, try to open the fridge as little as possible in order to retain the cool air as long as possible.
  • When transporting a freezer, always try to do so in an upright position. It will survive if you have to lay it horizontally, but if you do, let it stand for about 24 hours before switching it back on.

Re-gassing a freezer

When a freezer is not working efficiently, you often hear people say that it needs to be re-gassed. This is simply not true. While the gas inside the coils is essential in keeping your freezer cool, it does not run out or disappear over time. If your freezer is not working properly, there is a bigger problem. It may need more gas, yet, it is clearly escaping due to a larger problem and simply adding more gas is not going to solve this problem.

Be very wary of repair companies that offer to re-gas your freezer – as this will be a very short-term solution and will not solve the underlying problem.

Fridges Vs Freezers

It should not really come as a surprise to learn that the only difference between a freezer and a fridge is temperature. As we know, the refrigerant moves through a tube to the freezer in order to maintain the core temperature of 0 degrees Fahrenheit (-18 degrees Celsius).

This is at a faster pace than the fridge, where the vapor travels much slower. A fridge is only in need of 32 degrees Fahrenheit (0 degrees Celsius) consistency.

Freezer Frost: the Frost Menace

Freezer needs defrosting

Frost buildup is one of the worst things that can happen to a freezer. It is also likely to damage much of the food stored in the freezer. Frost is a thick, cold (obviously) dusting of fine ice. It covers the entire inside of the freezer – including the items inside. It encases them in a big solid icy mess.

So what causes frost? Well, it’s a few things really and you’d be surprised to find out you may be the reason for it. Opening and closing the freezer can be an issue as you’re allowing warm air to interact with the cool air inside of the freezer. This shuts down the freezer elements, which are built to process only the cold air.

When you bring your new fridge home, where do you place it? Be careful not to place it too close to the wall or you may find some problems. The closer to the wall, the more difficult it is for the condenser coils to do what’s necessary. Another way of allowing room temperature air in is when your fridge has a loose rubber seal around the door.

In such situations, what is common is that warm air mixes with sub-freezing air. The end result is frost. Thus, newer models have become better equipped with automatic frost prevention features. They regulate temperatures and keep the inside temperature at what it needs to be consistently.

Don’t have that feature? Don’t worry! There are ways to prevent it from happening to you.

The ideal temperature for your freezer is 0 degrees Fahrenheit. It shouldn’t be colder or warmer than that. Now attempt to open and close the freezer only when necessary, and don’t leave it open for too long. With every use, you’re wearing down the rubber seals around the door.

Make sure that your freezer is at least three inches away from the wall, especially if it has coils on the back.

If you do all of this, and still find frost accumulating fast, there is a possibility that the rubber seal is shot, a coil has fried, or an internal part has become overworked and given up. The general consensus here is that you will need to find the broken part and get it repaired or replaced.

Buying a New Freezer

At a certain point, repairs will no longer be possible or may cost more than the value of the freezer. At this stage, you will realize that you need a new freezer. It can be quite a daunting task to choose a new appliance for your home. A new unit can cost anywhere between $500 and $4000, sometimes even more.

Therefore, you will need to do some research and look at the brands available. Decide on what size you will need in your household. It would then be wise to find one with a good warranty, and also advisable to find one that is considered easy to repair or is long lasting.

The freezers of today come packed with bells and whistles that would be foreign to people from the early 20th century; yet, for us, they’re rather common.

Another feature to look out for is a digital external temperature regulator. This a fancy keypad where you can type in the desired temperature of your freezer – as it is then displayed on the front.

This cuts out the step of needing to open the freezer and reach the back wall for the knob in order to adjust the temperature. It is convenient because the internal ones are often hard to reach and difficult to turn and you need to open and close the doors. The external regulator eliminates unnecessary opening and closing.

Many modern fridges have a nifty feature called a cold water filter. Convenience at its finest! It will supply freshwater, already chilled and dispensed right from the freezer door. Say goodbye to millions of water bottles and jugs and just rely on the fridge to provide all of your cold water needs.

Ever had a dinner party and you’ve neglected to provide enough ice? Well look for a fridge with an automatic ice maker and this will easily become a problem of the past. This is a great convenience, yet, will add to the cost of the freezer.

Refrigerator ice maker

They’ve been around for a long time, but have improved dramatically over time. Once again, this lowers the number of times you open and close your fridge because you won’t need to get ice from the inside.

Some fridge/freezer combos have a little secret. It’s in the form of a hidden tube that routes super cold freezer air to a little compartment in the fridge known as the ‘cooling zone’. It’s designed for items that tend to perish just a tad faster than others. Milk and other dairy products are good examples.

As mentioned before, frost is a freezers worst nightmare and modern fridges fight it off with ease by having an automatic defrost. This will prolong the life of your freezer and will mean that you won’t need to go freezer shopping for many years following your purchase.

We hope that this has helped form a better understanding of the world of fridges and freezers. From their humble beginnings, they’ve come far and have won their way into the homes of billions. Who knows what the future holds for these much-needed devices.

Life without a freezer would be a lot more challenging; thus, appreciate it, look after it and it will give you many years of convenience.

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