The emergence of refrigerated trucks in Chongqing has greatly improved people's living standards and quality. With refrigerated trucks, we can eat around the world without leaving home. So, how do refrigerated trucks refrigerate and what are the refrigeration methods? The refrigerated truck manufacturer will briefly explain to everyone.

The cooling of water ice and salt ice occurs at atmospheric pressure, and the melting point of ice is 0 ° C. The heat absorption value when ice melts is 334.8 kJ/kg. Adding salt to water ice can lower its melting point. In some ranges, the higher the salt content in water ice, the lower its melting point.

Experiments have shown that when the amount of salt added is 29% of the mass of water ice, the melting point of the mixture can reach a lower value of -21.2 ° C. If the salt content increases, the melting point will no longer decrease. Usually, different salt ice compositions are selected based on the appropriate temperature of the refrigerated goods being transported.

For example, using salt ice with a salt content of 22%, the container temperature can be maintained at -18 to -13 ° C. Water ice refrigeration equipment requires less investment and has lower operating costs, but ordinary water ice has a smaller heat absorption per unit mass and limited cooling capacity in the cabin.

In addition, the melting of salt ice can also pollute the environment, food, corrosive containers, and valuable commodities. Therefore, water ice refrigeration is mainly used for refrigerated truck transportation of fish and other aquatic products.

Dry ice refrigeration has a low sublimation temperature and high sublimation heat absorption at atmospheric pressure. Therefore, as a cooling source for the cabin, it can not only achieve lower temperatures but also greater cooling capacity.

Therefore, the refrigeration method is suitable for the transportation of frozen food. Dry ice refrigeration equipment is simple, with low investment and operating costs, easy to use, and the goods will not get wet. The CO gas produced by dry ice sublimation can inhibit microbial growth, slow down fat oxidation, and weaken the respiration of fruits and vegetables.

However, the sublimation of dry ice can easily cause frosting. Excessive carbon dioxide gas will cause refrigerated fruits and vegetables to be difficult to breathe and die; The temperature inside the container is difficult to regulate.

Dry ice is expensive and consumes a large amount, so its practicality is poor. The principle of a refrigeration board is to use the cooling capacity stored in the refrigerant for cooling. Before transportation, fill the cold plates in the cold storage with cold air to cool and freeze them.

Then, during transportation, the cold medium in the cold plate is used to melt and absorb heat, so that the temperature reaches the appropriate temperature range for the transported goods in the compartment. Inside. Therefore, this cold plate is also known as a "cold storage plate".