When we moved to our current house, our oldest son was 3 and son #2 was just about to be born. We moved because we needed a larger house, which included space for a chest freezer. As soon as we got the keys, we ordered a small chest freezer and put it in the garage. It was like a huge luxury.
But guess what? We should have ordered a bigger on. Keep that in mind – if you’re getting a standalone freezer, get a big one. You won’t regret it.
A freezer is an appliance that stores and preserves food at very low temperatures. Sometimes, it is a separate compartment that is attached to a refrigerator and at times, it is a separate appliance altogether.
The freezer is one of the most commonly used appliances, both domestically and commercially. A freezer is essential for keeping foods preserved for a long time. It keeps the food at extremely low temperatures which ensures that the food is protected from any microbial contamination and damage. The mechanism by which a freezer works is quite simple. A little knowledge about its components and working can help you fix the problems that may arise from time to time. Also, understanding the appliance’s functions can also help you maintain it better.
Table of Contents
- Components of a Freezer
- How Do Freezers Work?
- Types of Freezers
- Difference between Freezing and Deep Freezing
- Unusual Uses of Freezers
Related: 32 Types of Appliances
The refrigerant is a compound which is usually found in the gaseous state. It absorbs heat produced during the refrigeration process readily and provides cooling necessary for freezing. Without refrigerant, there would be no freezing. After the refrigerant absorbs heat, it converts into a high-pressure liquid from a low-pressure gas.
The most common refrigerants used are:
- CFCs (Chlorofluorocarbons), including R12: They contributed greatly to the greenhouse effect. New stocks of CFCs have not been produced since 1994.
- HCFCs (Hydrochlorofluorocarbons), including R22: HCFCs are less damaging to the ozone as compared to CFCs. HCFCs will be completely phased out by 2020 as a result of the Clean Air Act.
- Hydrofluorocarbons (HFCs), including R410A and R134: They do not contain any chlorine. Hence, they are safer for the environment. HFCs are now used in place of R22.
Components of a Freezer
A freezer is composed of different components that form a freezing system. This system is responsible for the freezing effect. The major parts of a freezer are as following:
The compressor is a reciprocating pump that is hermetically sealed. A compressor is the heart of the entire refrigeration system. It is responsible for pumping the refrigerant gas to all the parts of the freezer to keep the refrigeration cycle running repeatedly. The sizes of compressor vary according to the load-bearing capacity of the freezer. The sizes range from 1/12 to 1 horsepower.
A compressor is enclosed in a steel casing. Inside the steel casing, there is an electric motor, piston, cylinder, crankshaft, intake, exhaust valves, connecting rod, and a ceramic terminal block. A small quantity of Capilla oil is also present within.
Condensers are the heat exchangers of freezers. The condenser is made of coiled serpentine copper with aluminum fins. It is located at the rear end of a freezer. The purpose of a condenser in a freezer is to remove all the heat that is supplied to the refrigerant in the evaporator and the heat produced in the compressor during compression. It also condenses the vapors of the refrigerant into a liquid.
Condensing units are of various types.
- Evaporating Type: In an evaporative type of condenser, the coil assembly is housed within a steel casing. Air is forced through the coils and discharged on top of the unit.
- Air-Cooled Type: In an air-cooled type of condenser, the coils are housed within a steel casing that is open at the top and bottom. The cooling of coils is done by natural air.
- Water-Cooled Type: In this type of condenser, the water enters into the cylinder in which coils are enclosed. The water circulates inside the coils and discharged through the outlet pipe.
A further classification of condensers is as below:
- Finned-Static Type: In this type of condenser, the coils are held together with the help of very thin fins which provide more area for the transmission of heat into the atmosphere.
- Plate-Static Type: In plate-static type condensers, the oils are sandwiched inside a rectangular steel box.
- Wire-Static Type: For this type of condenser, the coils are held in place by straight steel wires that form a rectangular shape.
- Convection Type: the coils are enclosed in a steel box in this type of condenser. The air is forced through the coils with the help of an attached fan.
- Finned-Forced Convection Type: It is a convection type of condenser with a fan that cools coils.
This component of a freezer is responsible to filter any iron particles, moisture, and dirt from the refrigerant and keep them from entering the refrigeration system. If left unfiltered, the flow of refrigerant into the expansion valve will be restricted. Some filters/dryers fried contain a moisture absorbent material like silica gel that absorbs any moisture that may be present in the refrigerant. The filter/dryer is responsible for protecting the compressor by filtering or restricting any impurities or moisture content that may have contaminated the refrigerant.
Filters are of two types:
- Flare Tube Connection: They may become lose over time due to the constant vibrations in the refrigeration system and cause a refrigerant leakage problem.
- Brazing Connection: Refrigerant leakage in this type of filter is less likely to occur as the joints are brazed.
- Expansion Valve
Expansion valve or capillary tube made of copper is another common component of a refrigeration system. It controls the flow of refrigerant through the system. High-pressure liquid refrigerant enters the expansion valve and leaves as low pressure, low-temperature liquid refrigerant.
It is necessary that the refrigerant is converted into low-pressure refrigerant before entering the evaporator. When it absorbs heat, it is converted into gas. A compressor allows only gas refrigerant to enter since gases can be compressed and liquids cannot be compressed.
The outer diameter of an expansion valve is 2.5mm and the length is usually between 8 feet to 12 feet.
There are five different types of expansion valves:
- Capillary Tube Type: This type is made up of small copper tubing. Having a hole with diameter from 1mm to 3mm. it serves as a consistent limiting valve for the flow of refrigerant from the condenser to the evaporator.
- Automatic Expansion Type: This type of expansion valve controls the flow of refrigerant by a simple mechanism of opening and closing of a control valve for low pressure. The refrigerant is sprayed into the evaporator.
- Thermostatic Expansion Type: This type of expansion valve controls the refrigerant flow by sending signals to a sensing bulb which is attached to an outlet of the evaporator. This sensing bulb sends instructions to the valve for opening and closing.
- Low-Side Float Expansion Type: The valve is controlled by a finned cooling coil. A constant level of refrigerant is maintained in the evaporator.
- High-Side Float Expansion Type: It is the same as the low-side float expansion type. The only difference is that it keeps the evaporated completely flooded with liquid refrigerant.
The evaporator is a serpentine aluminum tube component with aluminum fins. It is responsible for absorbing heat in the freezing compartments and transferring it all to the condenser. After the low-pressure liquid refrigerant absorbs this heat, it becomes gas. This refrigerant vapor makes its journey to the compressor, through the accumulator.
An accumulator accumulates refrigerant. It behaves as a refrigerant tank ensuring that the evaporator does not run out of it. If there is no accumulator, symptoms of refrigerant starvation will become visible.
- Fan Motor
The main purpose of a freezer fan motor is to keep the compressor cool. It is situated in the compressor room, just beside the compressor. It is composed of a steel bracket and a stand and is found bolted into a cross member. The fan runs with the compressor. If the aluminum blade of a fan is bent during maintenance, it can vibrate quite furiously which is detrimental to the shaft bearings. This can cause an early breakdown of the freezer.
If any component of a freezer is not working properly, they would not provide the cooling and would cause defrosting.
How Do Freezers Work?
The mechanism by which a freezer works revolves around drawing heat out from the freezing compartment. At the start of the process, the gaseous refrigerant goes into the compressor where the refrigerant is compressed. The temperature of the gas at this point is very high. As the hot gaseous refrigerant moves through various coils in the freezing system, it loses its heat and starts to cool off.
As the gaseous refrigerant is cooled to a very low temperature, it is liquefied. It is then forced into the expansion valve which converts the liquid refrigerant into a cold mist by forcing it through its extremely small opening.
The cold mist moves through the system through more and more coils. It starts evaporating and comes back in a gaseous state as it absorbs heat along the way. At this point, the temperature of the mist is -27 degrees. It takes the heat of the freezing compartment with it, hence turning back into the gas form.
When the refrigerant becomes gas again, it gets moved to the compressor again where it is compressed and the process is repeated. The process continues until the refrigerant has taken away all the heat from the freezing compartment, leaving behind none. This is what causes the food in a freezer to freeze.
Types of Freezers
There are five types of freezers available. You can choose the type that suits your requirements.
1. Chest Freezers
Chest freezers are also called reach-in freezers. They are the most common types of freezers that are used commercially. They are economical and spacious. The interior and exterior are shaped like a large box that gives it amazing storage capacity. Chest freezers have hinged lids that open upwards and are easy to use.
A drawback of chest freezers is that their large size requires a lot of space. Also, these freezers do not have a fan which results in an inconsistent temperature. The bottom area of the freezer is cooler as cold air is heavier. Therefore, meats are usually stored in lower parts. An additional feature of baskets in the freezer helps with better organization and easy access to stored items.
The capacity of chest freezers ranges from 2.1 cubic feet to 40 cubic feet. Because of its exceptionally large storage capacity, they are used commercially in hotels, restaurants, and other large-scale businesses for storing bulk foods.
2. Upright Freezers
Upright freezers are of three main types:
- Stacked fridge freezer – with freezer above or below the refrigerator
- American-style side-by-side freezer
a. Standalone upright freezer
An upright freezer costs twice as much as the chest freezer. However, an upright freezer is worth the money. Unlike chest freezers, the upright freezers have more height and they cover less floor space. This makes them suitable for domestic use. Because of their vertical design, they allow easy access to stored items. Most of the items are at an eye level. The compartments in an upright freeze are stacked which is another reason why the stored items are easier to access and retrieve.
b. Refrigerator with freezer below
c. Refrigerator with freezer on top
d. Side-by-side refrigerator/freezer
3. Drawer Freezers
Drawer freezers are beneficial for both catering and home use. They keep the items highly organized. You can access the food items easily. A major drawback of drawer freezers is their price. They are very expensive and cannot substitute for a full-size freezer.
The best thing about drawer freezers at home is that children and disabled people who use a wheelchair can access them easily.
4. Portable Freezers
Portable freezes have a limited storage capacity. They are made to store only a limited number of items while you are traveling or if you wish to transfer any food items that should stay frozen. They are perfect for small offices and can be placed in any corner of your room, as they do not occupy a lot of space.
5. Display Freezers
Display freezers are a type of upright freezers that have glass displays. They are mostly used in shops and supermarkets where people need to have a clear look at all the items. They are available in numerous sizes. Different businesses prefer different sizes.
You can get an upright display freezer such as the following:
Or a chest-style ice cream display freezer:
Difference between Freezing and Deep Freezing
Freezing and deep freezing are two entirely different things. Although they both involve the freezing of food, there is a major difference between the two.
Freezing involves a slow decrease in temperature. It may take up to 24 hours to freeze a food item completely. The water that is contained in the food is converted into large ice crystals. Many individuals use this technique to keep their food frozen.
A major disadvantage of freezing is that the food items being frozen may get dry and damaged. Since the crystals are large, they may end up perforating the cell walls of the food items. Aroma and parts of water may escape the food.
Deep freezing involves a rapid decrease in temperature. It is an industrial technique that freezes the foods at extremely low temperatures. It takes only a few minutes to one hour to completely freeze the food items. In this technique, food is exposed to extremely low temperatures, usually -30 to -50oC. It causes the core temperature of the product to reach as low as -18oC. As a result, the water that is present in the food is finely crystallized. The proliferation of microorganism and killing of cells is limited. The products that are frozen by this technique retain their freshness and flavor because the cells become dormant.
Unusual Uses of Freezers
Apart from storing foods and beverages, freezers can be used for various purposes which you might have not thought about before. Below are some unusual yet interesting uses of a freezer:
- If you have bought a shoe that is a bit snug for you, a freezer can help you make it your size. Fill a sealable plastic bag with water and place it your shoe. Put the shoe with the plastic bag in the freezer overnight. Your shoe will be stretched enough to make them fit you nicely. If you want to stretch it more, repeat the same procedure.
- If you have bubblegum stuck to the sole of your shoe, you can get it off with the help of your freezer. Just place a piece of paper on the bubble gum and freeze the shoe for 1-2 hours. The bubblegum will come off easily.
- You can keep the lipsticks in a freezer to keep them fresh. Cold temperatures are ideal for keeping lipsticks and a freezer is the absolute best option for this.
- Before sharpening your eyeliner, place it in a freezer for 15 to 20 minutes. Sharpening the eyeliner after doing this will give you a perfectly pointed tip.
- Keeping your candles in a freezer can increase their life. Their burning time can be increased up to two times.
Freezers are a must-have in today’s era. Every household has a freezer. Imagining life without one is just not possible now. Understanding how they work, the types of freezers that are available and the proper usage can help you keep your freezers maintained for a very long time.