How Does an Electric Cool Box Work: A Friendly Guide

How Does an Electric Cool Box Work A Friendly Guide

Last Updated on July 25, 2023

Electric cool boxes, also known as thermoelectric coolers, are popular portable devices that make it easy to keep food and drinks chilled during outdoor activities, picnics, and road trips. They work by exploiting the Peltier effect, a phenomenon in which an electric current passing through the junction of two different metals causes heat to be transferred from one side to the other. This creates a temperature difference that cools the contents of the box.

There are various types of electric cool boxes available, each with different cooling capacities and features to suit specific needs. Some models can be powered by a car’s 12V socket, while others can use an AC adapter for home or office use. Maintenance and cost are other factors to consider when choosing the right electric cool box for your needs.

Key Takeaways

  • Electric cool boxes use the Peltier effect to transfer heat and keep contents chilled.
  • Different types of cool boxes cater to diverse needs, with varying power options and features.
  • Consider cooling performance, ease of transport, and maintenance when selecting an electric cool box.

How an Electric Cool Box Works

An electric cool box, also known as a thermoelectric cooler, is a portable and practical solution for keeping drinks and food cool without the need for ice packs. They function using the Peltier effect, which involves thermoelectric cooling and heat conduction to maintain the desired temperature inside the box.

Peltier Effect

The Peltier effect is a thermoelectric phenomenon discovered in the 19th century by French physicist Jean Charles Athanase Peltier. It occurs when electric current passes through a junction of two different conductive materials, causing one side to heat up and the other to cool down. In the case of an electric cool box, this effect is harnessed to generate the desired temperature inside the device.

Thermoelectric Cooling

A thermoelectric cooler is the key component of an electric cool box, responsible for generating the cooling effect. It consists of a thermoelectric heat pump, commonly made from semiconductor materials arranged in a series of Peltier elements. When an electric current passes through these elements, the Peltier effect causes one side of the heat pump to become cooler, while the other side heats up. The cool side is in contact with the interior of the cool box, thus lowering its temperature.

It is worth noting that thermoelectric coolers are energy efficient, as they do not contain any moving parts or refrigerants. In addition, they are quiet, highly reliable, and have a long service life.


Conduction is the process by which heat is transferred from one area to another through direct contact between materials. In the context of an electric cool box, it plays a crucial role in ensuring efficient and effective cooling.

The interior of the box is often made of materials that are good conductors of heat, such as aluminium or copper, which help to efficiently transfer the heat generated by the Peltier cooler to the surrounding environment. This prevents the box from overheating, while also maintaining the desired cool temperature inside.

On the outside, insulation materials are used to minimise any heat transfer from the exterior. This helps to maintain the efficiency of the cooling process and ensures the contents of the cool box stay chilled.

In between the two layers, a fan is often used to dissipate the heat from the hot side of the Peltier cooler, further enhancing the efficiency of the system and ensuring optimum performance.

By combining the principles of the Peltier effect, thermoelectric cooling, and heat conduction, electric cool boxes provide a convenient and energy-efficient solution for keeping food and drinks cool on the go.

Types of Electric Cool Boxes

There are various types of electric cool boxes available in the market, offering a range of cooling capabilities and designs. In this section, we will explore three main categories of electric cool boxes: Passive Cool Boxes, Compressor Cool Boxes, and Absorption Coolers.

Passive Cool Boxes

Passive cool boxes, also known as cooler boxes or cool bags, are non-electric coolers that rely on insulation to keep their contents cold. They are often small to medium in size, making them perfect for picnics, camping trips, and other outdoor activities. To enhance cooling, users often add ice packs or frozen gel packs.

  • Insulation: Passive cool boxes are typically made with insulating materials like foam, polystyrene, or polyurethane, which help to maintain a low temperature inside the box.
  • Size & Design: Passive cool boxes come in a variety of sizes and designs, ranging from small cool bags to larger cooler boxes.

Compressor Cool Boxes

Compressor cool boxes are essentially portable refrigerators, using a compressor to actively cool down their contents. They are excellent for longer trips and situations where extended cooling is needed.

  • Cooling Capability: Compressor cool boxes can cool down to a lower temperature than other types and even maintain freezing temperatures. This feature makes them ideal for food items that require strict temperature control.
  • Size & Design: Compressor cool boxes are usually larger and heavier than passive cool boxes, making them more suitable for car camping or trips where weight is not a major concern.

Absorption Coolers

Absorption coolers, also known as thermoelectric cool boxes, use a unique cooling mechanism that doesn’t require a compressor. Instead, they use a thermoelectric cooling module to transfer heat from one side to another, keeping the inside cold.

  • Cooling Capability: Absorption coolers can cool their contents to roughly 15-20°C below the ambient temperature, making them suitable for general cooling purposes, but not as cold as compressor cool boxes.
  • Size & Design: These cool boxes tend to be similar in size to passive cool boxes, but with added electrical components. They offer a great balance between cooling performance and portability.

In conclusion, the best type of electric cool box for you depends on your specific needs, including the size, cooling capability, and portability that you require for your outdoor activities or trips.

Important Features and Considerations

When selecting an electric cool box to keep your food and drinks fresh, there are several key features and considerations to keep in mind. This section will explore some of the most important aspects, including capacity, weight, portability, energy efficiency, and noise.


When considering the capacity of an electric cool box, it is essential to think about how much food and drinks you will typically want to store in it. The capacity of a cool box is usually measured in litres, and there are various sizes available to suit your needs, whether it is for just a few snacks or for a family picnic.


As well as the capacity, the weight of an electric cool box can be an important factor to consider, especially if you plan to carry it for extended periods or use it during activities such as camping. Lightweight cool boxes may use materials like polyurethane foam, which is not only light but also provides good insulation.


Portability is another crucial consideration when selecting an electric cool box. Look for features such as ergonomic handles, compact dimensions, and wheels if you plan to transport it frequently. It is also essential to consider the power source of your cool box, as some may require a mains power supply, while others could utilise a 12V connection, making them ideal for use in vehicles.

Energy Efficiency

Energy-efficient electric cool boxes will not only save you money on electricity but also help reduce your impact on the environment. To determine the efficiency of a cool box, consider its power consumption, materials used for insulation, and any additional features like adjustable temperature settings.


Some electric cool boxes can generate noise while in operation due to the cooling mechanisms and fan systems. When choosing a cool box, it’s worth considering a model with a low noise level, especially if you plan to use it in a peaceful environment like a campsite or during overnight stays.

By keeping these key features and considerations in mind, you can find a suitable electric cool box to enjoy fresh food and cold drinks during your outdoor adventures.

Cooling Performance

Ambient Temperature

A key factor that affects the cooling performance of an electric cool box is the ambient temperature. The cooler will not be able to reach extremely low temperatures if the surrounding environment is hot. For example, during a hot summer day, the temperature inside a parked van may become significantly warmer than the outdoors, leading to a decrease in the cooling capacity of the cool box. Using ice packs can be a helpful addition to your electric cool box, as they can help maintain a lower internal temperature and reduce the cooling load on the thermoelectric system.

Heat Dissipation

Another critical factor in an electric cool box’s performance is the ability to dissipate heat from the hot side. Typically, an electric cool box utilises a thermoelectric module made of ceramic materials, which generates a cooling effect on one side and a heating effect on the other when voltage is applied. A fan is often installed to assist in the heat dissipation on the hot side of the thermoelectric module, ensuring that the device’s overall cooling performance remains efficient.

Proper heat dissipation also helps to maintain the long-term performance and durability of the cool box system; increased heat levels can lead to a reduction in cooling efficiency or more power consumption from the car battery. It is important to consider factors such as the space between the box and surrounding objects and the position of the heat-producing components, like the fan, to maximise its cooling capability.

In summary, the cooling performance of an electric cool box can be significantly impacted by the ambient temperature and the ability to dissipate heat effectively. By considering these factors when designing, operating, and maintaining electric cool boxes, a more efficient and long-lasting cooling solution can be achieved.

Storing and Transporting Food and Drinks

When it comes to outdoor activities, such as family trips, picnics, and camping, storing and transporting food and drinks can be a challenge. An electric cool box is an excellent solution for maintaining the freshness of perishable items during transport and storage. In this section, we will discuss the features of cool bags, carrying handles, and additional equipment.

Cool Bags

These portable coolers come in various sizes and styles, making them perfect for any occasion, from a weekend getaway with the family to a day out by the RV. Cool bags offer several advantages for storing and transporting food and drinks:

  • Insulation: With a combination of materials like foam and reflective linings, cool bags provide excellent insulation, ensuring that items stay cold for up to 4 hours.
  • Compactness: Cool bags can be folded or rolled up when not in use, making them easy to store without taking up valuable space.
  • Ease of cleaning: Cool bags typically feature a removable liner that can be easily wiped down or washed to maintain hygiene.

Carrying Handle

One essential feature of portable coolers, such as electric cool boxes, is a sturdy carrying handle. This practical design element allows for easy transportation of the cooler to and from your preferred location. In addition, some electric cool boxes may include an adjustable or detachable shoulder strap to provide extra convenience when carrying the cooler, particularly during outdoor activities.


Electric cool boxes often include additional equipment to enhance their functionality and improve the user experience. Some examples include:

  • An in-built thermometer: This provides a quick and easy way to monitor the internal temperature of the cooler.
  • A drain plug: This allows for easy removal of melted ice or condensation.
  • Dry ice compatibility: Some electric cool boxes are designed to work with dry ice, which offers an extended cooling time compared to traditional ice packs.

To summarise, electric cool boxes, featuring cool bags, carrying handles, and additional equipment, provide a practical and friendly solution for storing and transporting food and drinks during outdoor activities.

Maintenance and Cost

Low Maintenance

Electric cool boxes, also known as camping fridges, are generally low maintenance alternatives to traditional compressor fridges. They require minimal upkeep, making them ideal for outdoor activities such as camping. One significant advantage of electric cool boxes is that they produce little to no noise, resulting in a more peaceful camping experience.

These cool boxes utilise thermoelectric technology, using electric current to transfer heat from the inside to the outside, effectively keeping the contents cool. Since there are no moving parts in the cooling system, the maintenance required for these boxes is significantly lower than compressor fridges, which may have issues with mould build-up and ongoing maintenance.

Most thermoelectric cool boxes are designed to be easy to clean. As such, the chances of RNA or DNA contamination, which might be a concern in specific applications such as polymerase chain reaction (PCR) or other industrial use cases, are considerably reduced.


Electric cool boxes are generally more budget-friendly than compressor fridges, making them an attractive option for those conscious of cost. They tend to have a lower initial purchase price, and the ongoing expenses associated with operating them are typically minimal, as they consume less electric current compared to compressor fridges.

However, it’s important to remember that the cooling capabilities of electric cool boxes may not be as efficient as compressor fridges when it comes to maintaining extremely low temperatures. That being said, for casual camping trips and short-term food storage, the performance is usually more than adequate.

In conclusion, electric cool boxes offer a low maintenance and budget-friendly solution for those seeking to keep their food and beverages cool during outdoor activities. The ease of cleaning and low noise output make them particularly suitable for a variety of users, including campers and those in industrial settings.

Frequently Asked Questions

What is the difference between 12V and 240V electric cool boxes?

12V electric cool boxes are designed to be used with a car’s 12V power socket, making them perfect for road trips and camping. They typically consume less power than 240V models, but may not cool as effectively. On the other hand, 240V electric cool boxes require a mains power supply and can cool items more effectively. Some electric cool boxes also offer dual voltage options, allowing you to switch between 12V and 240V according to your needs.

Are electric cool boxes effective for preserving food?

Yes, electric cool boxes can effectively preserve food by maintaining a cool temperature inside the box. They are ideal for picnics, camping trips, and other outdoor activities where refrigeration is not available. However, their cooling capacity may vary depending on the model and the ambient temperature. It is advisable to use ice packs in addition to the electric cooling feature to keep the contents fresh and safe for a longer duration.

How do compressor cool boxes compare to electric ones?

Compressor cool boxes work similarly to household refrigerators by using a compressor system to cool the contents inside. They usually offer better cooling performance and can reach lower temperatures than electric cool boxes. However, they can be more noisy, expensive, and consume more power. Electric cool boxes, like thermoelectric coolers, are less powerful and may struggle in high temperatures but are more affordable and portable.

What are the safety guidelines for food storage in a cool box?

To ensure the safety of your food stored in a cool box, follow these guidelines:

  1. Always pre-cool the box before adding food
  2. Use ice packs or frozen gel packs, especially when the electric cooling feature may not be sufficient
  3. Keep the cool box in a shaded area to minimise the effect of external heat sources
  4. Separate raw and cooked food items to prevent cross-contamination
  5. Pack perishable food items near the bottom of the cool box, close to the cold source
  6. Keep the cool box closed as often as possible to maintain the internal temperature.

How long can electric cool boxes maintain their cold temperature?

The duration for which an electric cool box can maintain a cold temperature depends on factors like the model, external temperature, and whether ice packs are used. In general, electric cool boxes can keep the contents cool for several hours, but they might require additional cooling sources like ice packs to maintain the desired temperature for an extended period, especially in warm environments.

Is it necessary to use ice packs in an electric cool box?

While electric cool boxes can cool items on their own, using ice packs can help maintain a lower temperature for a longer time and improve the box’s overall cooling performance. In situations where the electric cooling system might not be sufficient, or when you are not able to use the box’s built-in cooling feature, ice packs can be a valuable addition to ensure food safety and freshness.

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