Many users, when purchasing a thermal bag for picnics or transporting medicine, are faced with a non-obvious problem: what are the correct names for the inserts that create cold inside this bag? In everyday life they are called differently, which leads to confusion when searching in stores. Some are looking for “cold accumulators”, others are looking for “gel briquettes”, and still others are simply asking for “refrigerator inserts”. Understanding the correct terminology directly affects the cooling efficiency of your products.
In fact, these elements have a clear technical name - cold cells or cold accumulators (AX). This is how they are designated in the technical documentation for most thermal bags, be they budget models or professional isothermal containers. The duration of temperature retention and the scope of application depend on the type of substance used inside.
In this article we will look in detail at what containers for a cooler bag are called, how they differ from each other and how to choose the best option for your needs. You will learn about the physical principles of their operation, learn to distinguish high-quality refrigerant from a cheap analogue and understand why the shape and size of the container matters.
Terminology: what are the correct names of cooling elements
The first thing you need to decide on is vocabulary. If you go to a store and ask for a “plastic ice box,” the salesperson may not understand you or may offer the wrong product. The official name is cold accumulator. This is a sealed container filled with a heat-intensive substance, which at low temperatures accumulates cold and then slowly releases it, maintaining the microclimate inside the thermal bag.
The second common name is cold element. This term is more often used in professional logistics and when transporting medicines. The third name that can be found in catalogs of tourist goods is refrigeration element. All three of these terms are synonymous and refer to the same device, differing only in shape and filling.
It is important not to confuse these elements with regular ice or dry ice. Although the principle of operation is similar, the design of the cold accumulator allows it to be used repeatedly. Inside there is not just water, but a special gel or saline solution that freezes at lower temperatures and melts more slowly than ordinary water. This ensures stable temperature conditions for a long time.
Types of fillers: gel, salt or water?
Externally, all containers may look the same - a plastic case with a colored liquid inside. However, it is chemical composition the filler that determines its effectiveness. There are three main types of substances used in modern cold storage batteries. Each of them has its own advantages and limitations on freezing temperature.
The first and most common type is gel batteries. Inside there is an aqueous solution of thickened gel. Their main advantage is versatility. They freeze at around -20°C and can stay cold for 5 to 12 hours depending on the size of the bag. The gel does not leak even if the case is damaged (if it is of high quality), since it has a viscous structure.
The second type is salt refrigerants. They contain an aqueous solution of salt with the addition of thickeners. Such elements are capable of cooling to lower temperatures, often down to -18°C and below. Salt batteries are ideal for deep freezing food, but they are heavier than their gel counterparts. Their cold retention time is also long, but they require a more powerful freezer to fully charge.
- 💧 Gel - universal, safe, suitable for food and drinks.
- 🧂 Salt - provide lower temperatures, are heavier, ideal for frosts.
- 💧 Water - the simplest and cheapest option, they melt quickly, suitable for short trips.
The third type - silicone containers. They are flexible bags filled with silicone gel. Their advantage is plasticity: they easily fit products of any shape. However, their heat capacity is usually lower than that of hard plastic blocks, so they have a shorter battery life.
Design and shapes: from bags to briquettes
The shape of a container for a cooler bag is not just a matter of aesthetics, but an important functional characteristic. The geometry determines how tightly the elements will fill the internal space of the thermal bag and how effectively they will transfer cold to the products. Manufacturers produce refrigerants in several standard formats.
The most popular format is rectangular briquettes (or cassettes). They have a flat shape and are often equipped with stiffeners. Such containers are convenient to stack (place on top of each other) or place along the walls of the bag. The flat shape maximizes the contact area with the food, which speeds up the cooling process. Standard sizes are often multiples of the internal dimensions of popular bag models.
Why does shape matter?
Shape affects the heat transfer area. Flat and wide containers release cold faster and more evenly than narrow and tall ones. In addition, rectangular briquettes take up less useful volume of the bag, leaving more space for products.
There are also round containers elements in the form balls. They are more often used in thermos bags for bottles or in children's lunch boxes. They are more difficult to pack compactly into a large bag, leaving empty spaces, so they are less effective for long trips. However, for cooling one or two bottles of wine or baby food, this is an ideal option.
It is worth mentioning separately flexible bags. They can be filled with gel or silicone. Their main advantage is the ability to freeze them when empty (they become flat) and then, once in the bag, they take the shape of the available space. This is convenient if you are carrying few products and do not want to take up space with rigid blocks.
Comparison table of refrigerant characteristics
To make it easier for you to navigate the variety of offers, we have prepared a comparison table. It will help you choose the right type of container depending on your needs. Pay attention to the freezing temperature and operating time.
| Type of filler | Freezing temperature | Working time (average) | Weight | Best application |
|---|---|---|---|---|
| Gel | up to -20°C | 5-10 hours | Average | Picnics, food, drinks |
| Saline | up to -24°C and below | 10-15 hours | Heavy | Frozen meat, fish, long trips |
| Silicone | up to -18°C | 3-6 hours | Lightweight | Lunch boxes, cosmetics, short trips |
| Water | 0°C | 2-4 hours | Medium | Cooling drinks, short-term storage |
Rules of use and preparation
The efficiency of the cold accumulator directly depends on the correctness of its preparation. Many users make the mistake of simply throwing the warm element into their bag. For the system to work, the container must undergo a process of crystallization (freezing) to the state of solid ice or thick gel.
Place containers in the freezer in advance. To completely freeze a gel battery of a standard volume (400-500 ml) it takes 8 to 12 hours at a temperature of -18°C. If you take it out earlier, a liquid fraction will remain inside, which will heat up quickly and will not be able to keep the cold for long. Salt elements may take even longer due to the lower freezing point of the solution.
☑️ Preparing for the trip
When laying in the bag, the principle “cold from above and below.” Warm air rises, so there must be a layer of refrigerants on the lid of the bag. It is also recommended to line the bottom and side walls with them, creating a kind of “thermococoon”. Products must be already chilled: putting warm food in a bag with refrigerant means forcing the cold to work to cool the product, and not to maintain the temperature.
⚠️ Attention: Never freeze glass bottles with liquid together with cold accumulators in the same chamber without protection. If it cools suddenly, the glass may break. Use an intermediate layer of fabric or cardboard.
Safety and service life
Modern cold cells safe for household use. In case of case depressurization, most gel fillers are non-toxic. The gel usually consists of water, a thickener (such as carboxymethylcellulose) and a coloring agent. However, it is strictly forbidden to eat it. If the gel gets on the skin, just wash it off with water. If on clothes, wash the item, as the dye may leave traces.
The service life of high-quality cold batteries is practically unlimited. The plastic from which the body is made (often high-density polyethylene) can withstand thousands of freezing and defrosting cycles. Degradation occurs slowly: over time, the plastic may become more fragile, and the gel may lose some of its properties, but this takes 5-7 years of active use. HDPE - high-density polyethylene), withstands thousands of freezing and defrosting cycles. Degradation occurs slowly: over time, the plastic may become more fragile, and the gel may lose some of its properties, but this takes 5-7 years of active use.
However, there are risks of mechanical damage. If you drop a container from a great height or step on it, carefully inspect the case. Microcracks can expand when freezing, since water (the gel base) expands when freezing. This will cause a leak inside your cooler bag.
Frequently asked questions and misconceptions
There are many myths surrounding containers for cooler bags. Often, users do not understand the difference between “dry ice” and a regular gel briquette, or try to use automotive elements in home freezers. Let's look at the most popular questions that arise when operating these devices.
One of the main misconceptions concerns temperature. Many people think that the cold accumulator freezes on its own. This is wrong. It only accumulates the cold transferred to it by the freezer. If you put a warm element in your bag, it will simply become an extra burden. It is also important to understand that a cooler bag does not produce cold, it only slows down heat transfer.
⚠️ Attention: Do not use car compressor elements (those powered by a cigarette lighter) as refrigerants for regular bags. They are not cold storage batteries in the classical sense and require constant power.
Another important aspect is compatibility. Not all containers fit all bags. Standard rectangular briquettes measuring 280x190 mm (the so-called VR format) are suitable for 90% of medium-sized bags. For large containers of 30-40 liters, larger sized elements or a larger number of standard ones may be required.
Is it possible to use ice instead of a cold accumulator?
It is possible, but ineffective. Ice melts at 0°C, turning into water, which takes up the same volume and can wet food. The cold accumulator keeps the temperature below zero longer and does not leak when used correctly.
How long does the accumulator keep cold in the bag?
The time depends on the quality of the bag, the ambient temperature and the amount of refrigerants. A good bag with 4-6 batteries (400-500 ml each) will keep food cold for 12 to 24 hours. If the bag is cheap or often opens, the time is reduced to 4-6 hours.
Is it possible to heat containers for a cooler bag?
Yes, some models are heat accumulators. They can be heated in a microwave oven (if there is a corresponding marking on the body) or in hot water. They are used to keep hot food warm. It is not recommended to heat ordinary gel briquettes unless indicated in the instructions, since the pressure inside can rupture the case.
What to do if the container has lost its seal?
If you notice a crack or the gel begins to leak, such an element must be disposed of. Covering it with tape is a temporary and unreliable solution that will ruin the food and clothing in your bag. The gel filler is non-toxic, but ingestion (swallowing) is undesirable.
Are these containers suitable for transporting vaccines?
To transport medicines and vaccines, certified thermal containers and special refrigerants with precisely controlled phase transition temperatures are required. Conventional household cold batteries can overcool the drug (freeze it), which will ruin the medicine. Use only specialized equipment.
How to properly dispose of old refrigerant?
The plastic housing is classified as recyclable waste (usually labeled PET or HDPE). Gel litter can be poured down the drain (it is safe and soluble) or thrown into the general trash if it is in a solid state. Saline solutions are also safe for sewage in small quantities.