In the modern logistics business, delivery speed is often second in importance to only one factor - cargo safety. When it comes to transporting food, medicine or chemicals, temperature control becomes a critical issue. This is where it comes into play isothermal body, which is the standard for transporting thermolabile cargo over medium and short distances.
Many novice entrepreneurs confuse this type of equipment with full-fledged refrigerators, but there are fundamental differences between them in design and operating costs. Understanding that what is an isothermal body, will help to avoid unnecessary costs for the purchase of excess equipment or, conversely, loss of goods due to unsuitable transportation conditions.
In this article, we will analyze in detail the design of sandwich panels, consider popular cladding materials and find out in which cases the use of an autonomous refrigeration unit is really necessary, and when high-quality thermal insulation is sufficient.
Main purpose and principle of operation
The main task of an isothermal van is to keep the temperature of the cargo loaded inside unchanged for as long as possible. The operating principle is based on the thermos effect: the multilayer structure of the walls, floor and ceiling creates a barrier to heat exchange between the external environment and the internal volume. This allows products to be delivered from the warehouse to the retail outlet without sudden temperature changes.
Unlike a refrigerator, here no active source of cold. The body only slows down the heating or cooling process. The efficiency of operation directly depends on the quality of assembly, the absence of cracks and the initial temperature of the cargo. If you load a warm product, it will arrive warm, just cooling down more slowly than in the open air.
The use of such vehicles is regulated by sanitary standards, especially for the food industry. Violation of the temperature regime can lead not only to product damage, but also to serious fines from regulatory authorities.
⚠️ Attention: An insulated van is not capable of cooling the cargo. It only maintains the current temperature. Loading hot products into a cold body is unacceptable, as this will disrupt the temperature regime of the goods already inside.
The scope of application of such vehicles is extremely wide. Most often they can be found in the urban distribution of goods. Here are the main categories of cargo:
- 🥦 Fresh vegetables, fruits and herbs that require protection from direct sunlight and wind.
- 🥩 Meat, fish and semi-finished products transported chilled or frozen over short distances.
- 💊 Pharmaceutical products that lose their properties when overheated or frozen.
- 🌸 Flowers and plants sensitive to temperature changes when delivered to stores.
Construction and materials of sandwich panels
The heart of any isothermal body is sandwich panel. This is a multi-layer design that provides the necessary thermal insulation. A standard panel consists of two outer sheets of sheathing and an inner layer of insulation, bonded together with a special high-pressure adhesive.
The thickness of the walls varies depending on the purpose. For the transportation of refrigerated products ("ref"), panels with a thickness of 50 mm are usually used. For frozen cargo (“frost”), the thickness can reach 80–100 mm or more. The thicker the insulation layer, the longer the load will retain its properties during stops or in hot weather.
Polyurethane foam (PPU) is most often used as an internal filler. This material has excellent thermal insulation properties, does not absorb moisture and is not susceptible to rotting. An important parameter is the density of polyurethane foam: for trucks it must be high in order to withstand mechanical loads during loading.
External and internal cladding also plays an important role. The durability of the body and its resistance to damage depend on its material. Let's look at the main options:
- 🛡️ Clad steel: steel with polymer coating. Durable, but susceptible to corrosion if the coating is damaged.
- ✨ Stainless steel: ideal for food production. Easy to clean, does not rust, but costs more.
- 🚛 Aluminum sheet: lightweight and corrosion resistant, but less impact resistant than steel.
- 🪵 Plywood (laminated): a budget option for interior cladding, often used in combination with other materials.
When choosing a van for aggressive environments (for example, transporting fish or chemicals), give preference to stainless steel interior lining and plastic floor trims to avoid corrosion.
Differences between an isotherm and a refrigerator
A common question that arises when purchasing commercial vehicles is: what is the difference between an isotherm and a refrigerator? Visually they may be identical, but their technical content is different. Refrigerator is an isothermal body equipped with an autonomous or driven refrigeration unit (HOU).
The presence of a cold storage device makes it possible not only to maintain, but also to actively change the temperature inside the body, maintaining it at a given level regardless of external conditions and travel time. The isotherm works passively. The difference in price between these two types of equipment can be twofold or more, not counting the cost of servicing the refrigerator.
The choice between them depends on the supply chain. If you transport goods from a warehouse to a store within the city in 2-3 hours, there is no point in overpaying for a refrigerator. If you are planning long-distance transportation for 10–12 hours, especially in summer, it will be difficult to do without an active refrigeration unit.
Is it possible to install an isothermal refrigeration unit later?
Theoretically it is possible, but it will require serious modifications. It will be necessary to strengthen the front wall of the body to mount the evaporator, conduct electrical wiring, install additional batteries or a power take-off system from the engine. It’s easier and cheaper to initially buy a ready-made refrigerator.
Cost efficiency also plays a role. The refrigerator requires regular maintenance, refilling with refrigerant and consuming fuel (or engine energy). Isotherm in this regard requires virtually no costs, except for maintaining the cleanliness and integrity of the seals.
Comparison of characteristics of isotherms and refs
To organize the information and help you make an informed decision, we have prepared a comparison table. It clearly demonstrates the differences in operational parameters.
| Parameter | Isothermal van | Refrigerator |
|---|---|---|
| Source of cold | Missing | Autonomous or driven HOU |
| Operating principle | Passive temperature maintenance | Active cooling/heating |
| Cost of equipment | Low / Medium | High |
| Fuel consumption | Standard for car | Enlarged (HOU work) |
| Transportation distance | City, region (up to 6-8 hours) | Intercity, no time restrictions |
As can be seen from the table, isotherms are a more rational choice for local transportation. However, if your business plans to scale to interregional deliveries, investing in a refrigerated truck will become a necessity.
Nuances of operation and maintenance
Even the highest quality isothermal body requires proper care. The main threat to it is a violation of the tightness. Any gap, worn door seal or crack in the floor will negate all thermal insulation properties. Therefore, regular inspection of the condition of the rubber seals around the perimeter of the doors is mandatory.
It is important to keep the internal volume clean. Residues of food and spilled liquids can become a source of bacteria and unpleasant odors that are absorbed into finishing materials. For washing (it is recommended) to use special disinfectants that are safe for food production.
⚠️ Attention: When washing the body, it is strictly forbidden to use high-pressure water jets (Kärcher) near the joints of panels and doors. Water can penetrate inside the sandwich panel, causing delamination and loss of thermal insulation, as well as corrosion of the frame.
It is also worth paying attention to the condition of the floor. Isotherms often use an aluminum or steel floor with an anti-slip coating. Damage to it can lead to corrosion of the load-bearing elements of the body frame. All minor defects should be corrected immediately upon discovery.
☑️ Daily body inspection
How to choose the right van for your business
Choosing a commercial vehicle is an investment that should pay off. When purchasing an isotherm, first of all, decide on the type of cargo. Lightweight vans with thin walls are suitable for bread and pastry products. Meat and fish require “heavy” insulation and, possibly, a metal floor with high sides (caissons) to drain water during washing.
Pay attention to the dimensions of the internal volume. Manufacturers often indicate external dimensions, but for logistics it is the internal dimensions that are important. Also take into account the loading height: to work with EUR standard pallets (you may need) a tail lift, which also has its own weight and affects the load capacity.
Build quality is another critical point. Cheap Chinese analogues can be assembled on a wooden frame, which dries out over time, forming cold bridges. European or high-quality domestic bodies often have a metal or composite frame, which guarantees a long service life.
The optimal choice for starting in urban transportation is a new or used isotherm with a wall thickness of 50 mm and internal lining made of food-grade plastic or stainless steel.
Don't forget to check the documentation. The body must have a passport, and if it is certified for transportation of perishable goods, then relevant documents confirming the isothermal class (for example, FRC, FNA according to the APR classification, if you are planning international flights, although for domestic Russian transportation the requirements are softer).
Do I need a refrigerator if I only carry frozen goods?
If the delivery time from the loading point to the unloading point does not exceed 4-6 hours, and you pre-cool the body well, then a high-quality isotherm with thick walls (80-100 mm) can cope. However, to guarantee quality and comply with all standards during long periods of downtime, it is better to use a refrigerator.
Is it possible to transport building materials in an isotherm?
Yes, you can. The isothermal van perfectly protects the cargo from precipitation, dust and wind. However, it is irrational to use expensive food isotherms for construction due to the risk of damaging the interior finish. For construction, regular all-metal vans or awnings are better suited.
How often does an isothermal body need to be verified?
For domestic transportation within the Russian Federation, mandatory periodic verification of isothermal properties is not legally regulated as strictly as for refrigerators. However, sanitary services may require proof of the body's condition. For international transport (APR), verification is required once every 6 years (with an intermediate check after 3 years).
What is "isothermal class"?
This is an indicator that determines how well the body maintains temperature. Identified by letters (A, B, C...) and numbers. For example, the FRC class means that the body is capable of maintaining an internal temperature of no higher than -20°C with an external temperature of +30°C for a certain time (12 hours) without running the refrigerator.
Does body color affect temperature control?
Yes, it does. Light colors (white, silver) reflect the sun's rays and heat up less from the outside, which reduces the thermal load on the insulation. Dark vans get hotter in the sun, causing the insulation to work harder. For hot climates, light colors are preferable.