Advantages of dry ice used as cold source in cold chain transportation (insulation box)

Advantages of dry ice used as cold source in cold chain transportation (insulation box)

(1) Large cooling capacity and fast cooling speed

Dry ice has a large cooling capacity. The temperature of dry ice under normal pressure is -78.9℃, and the heat of evaporation is 573 kJ/kg. When 1 kg of dry ice changes to 25°C, CO2 gas can absorb 653kJ of heat, while when 1kg of liquid nitrogen (-196°C) is converted into 25°C of nitrogen, the heat absorbed is 411 kJ, which is only 60% of dry ice. It can be seen that using dry ice as The dry ice required for the cold source is only 60% of the liquid nitrogen.

In addition, dry ice refrigeration is achieved through its sublimation process, and the refrigeration process is rapid and efficient. By adding the amount of dry ice and adjusting the vaporization amount of dry ice, the internal temperature of the incubator can reach the required standard in a short time. In contrast, a mechanically refrigerated insulated box takes a long time from the start of the refrigeration system to reaching the maximum cooling capacity, and its maximum cooling capacity is limited by the refrigeration unit, so the cooling rate is slow.

(2) Simple structure, reliable operation and low cost

An insulated box using dry ice as a cold source uses the large amount of vaporization heat and extremely low evaporation temperature generated during the sublimation of dry ice to achieve the refrigeration effect. The incubator has no moving parts other than dry ice storage and temperature control, reducing the likelihood of malfunctions, improving operational reliability and reducing maintenance costs.

In contrast, the insulated box system of mechanical refrigeration has a complex structure, many parts, and high working pressure. It is prone to equipment failure and system leakage, and the maintenance workload is large and expensive. Statistics show that the depreciation and maintenance costs of mechanical refrigeration systems are much higher than those of non-mechanical refrigeration systems. In addition, dry ice refrigeration insulation boxes do not have a refrigeration unit, so the manufacturing cost is relatively low.

Compared with liquid nitrogen refrigeration insulation boxes, dry ice insulation boxes also have two major advantages in terms of cost: first, the price of dry ice is lower than that of liquid nitrogen; second, the structure of dry ice insulation boxes is simpler, and an external pressure reducing device is used to reduce the temperature before use. High-pressure liquid CO2 is converted into normal-pressure snowflake-like dry ice, which is filled into the cold source storage room of the insulated box without the need for additional spray devices, further improving operational reliability.

(3) Fast filling speed and easy to use

The snowflake-like dry ice in the insulating box is converted from high-pressure liquid CO2 through a decompression device, and its filling speed is fast, up to 60~100 kg/min. Taking a certain brand's 1300L insulated box as an example, the dry ice consumption required for a day's filling only takes a few seconds, which is much shorter than the cold storage time of other refrigeration methods. The filling process is simple and fast, and does not require professionals to operate.

(4) Broad application fields

The vaporization temperature of dry ice is extremely low. By adjusting the temperature control device in the insulating box, the temperature inside the box can be controlled within the range of -78.9~25°C to meet the temperature requirements of different refrigerated goods. In contrast, mechanical refrigeration insulation boxes are limited by the refrigerant and refrigeration system. The evaporation temperature is generally not lower than -30°C, and the lower the evaporation temperature, the efficiency of the refrigeration system will drop sharply. Additionally, mechanical refrigeration requires a large power supply, which may be limiting in some modes of transportation. The dry ice refrigeration insulation box only needs to control the amount of dry ice and does not require an external power supply, so it has a wider range of applications.

(5) Advantages of using dry ice for transportation of fruits and vegetables in cold chain insulated boxes

Dry ice cools quickly and causes less damage to food tissue cells. Low-temperature CO2 gas is introduced into the insulated box, combined with appropriate circulation, to quickly make the temperature inside the box uniform and effectively prevent food from deteriorating. In addition, CO2, as an inert gas, has stable chemical properties and can inhibit the oxidative respiration process of fruits and vegetables, making it an ideal choice for controlled atmosphere preservation. Therefore, the dry ice refrigeration insulation box can increase the concentration of CO2 in the box by introducing gasified CO2 to achieve the effect of controlled atmosphere preservation. At the same time, because the respiration of fruits and vegetables is inhibited, the respiratory heat is reduced, which reduces the heat load in the incubator, thereby reducing the consumption of dry ice. Of course, in order to ensure that the air composition in the box is appropriate, the amount of CO2 can be adjusted to avoid excessive concentration that may cause fruit rot.

ICECON specializes in a series of rotational molded boxes such as constant temperature (cold and hot) boxes, dry ice insulated boxes. During refrigerated transportation, our company has a variety of insulation methods such as cold storage panels, dry ice and CO2 for you to choose from. They are safe, environmentally friendly, efficient and easy to operate, meeting your diverse application scenarios of the same vehicle at different temperatures.