The principle of refrigeration equipment are the following:
1, water ice and salt ice refrigeration
In the atmospheric pressure, the melting point of ice is 0 ℃. Ice melting heat absorption of 334.8kJ/kg in water ice bai add salts can reduce its melting point. Within a certain range, the more salt content in water ice, the lower the melting point. Experiments
prove that when the mass of salt added is 29% of the mass of water ice, the melting point of the mixture can reach a minimum value of -21.2℃. If the salt is added, the melting point no longer decreases. Usually according to the refrigerated cargo transportation temperature to
select different components of salt ice. For example, using salt ice with 22% salt content, the temperature inside the compartment can be maintained at -18 to -13℃.
Water ice refrigeration device investment is small, low operating costs, but ordinary water (salt) ice heat absorption per unit mass is small, limited cooling in the carriage. In addition, salt ice melting will contaminate the environment, food, corrosion of carriages and value of cargo moisture. Therefore, water (salt) ice refrigeration is mainly used in the month of fish and other aquatic products refrigerated transportation.
2, dry ice refrigeration
In an atmospheric pressure, dry ice (solid CO2) sublimation temperature is low (-78.9 ℃), sublimation of heat absorption is large (573.5kJ/kg), so it will be used as a cold source of carriages, not only to obtain a lower temperature (generally lower than -20 ℃), but also to obtain a larger refrigeration capacity. Therefore, the refrigeration method is suitable for the transportation of frozen food.
Dry ice refrigeration device is simple, low investment and operating costs, easy to use, the goods will not be damp. The COZ gas produced by sublimation of dry ice can inhibit microbial reproduction, slow down fat oxidation and weaken the respiration of fruits and vegetables. However,
dry ice sublimation easy to cause frost; CO2 gas is too much will lead to fruits, vegetables and other cold storage material breathing difficulties and necrosis; compartment temperature is difficult to adjust; dry ice cost is higher, and consumption is larger, so the practical application is less.
3, cold plate refrigeration
Cold plate refrigeration principle is the use of cold storage agent (refrigerant) frozen after the storage of cold for refrigeration. Before transportation, the refrigerant in the cold plate in the compartment will be "charged with cold", so that it is cooled and frozen, and then during transportation, the refrigerant in the cold plate is used to melt and absorb heat, so that the temperature inside the compartment is maintained in the temperature range of the transported goods. Therefore, the cold plate is also called "cold storage plate".
The structure of the cold plate refrigeration device is divided into integral and split type. Integral power unit, refrigeration unit and cold storage plate, etc., are placed in the car; split in the car only equipped with refrigeration unit and cold storage plate. Parking, the use of solid ground dynamic
power device drive refrigeration unit on the cold storage board "cold". Practical application of the latter. Commonly used cold storage agent are low melting point **** crystal solution, its melting point is usually lower than the compartment temperature about 10 ℃. When the appropriate temperature of the transported goods change
When the selected *** crystal solution composition should also be changed.
A few common refrigerated truck models are as follows:
Foton Xiangling V1 National 6 2.8m refrigerated truck
Chassis configuration
Xiangling V-1600 body, DAM15KR engine, 115 hp, DAT18R-5-speed gearbox, 102 rear axle, 175R14 tires, ABS, electric power steering, front stabilizer bar , single wheel, oil brake. Gross mass: 2.185 tons, car weight: 1.56 tons, hauling weight: 0.495 tons (the actual hauling weight of 1.5 tons or so), cab can be loaded: 2 people,
Exterior dimensions: 4960 × 1720 × 2385mm
Cabin dimensions: 2795 × 1545 × 1535mm
Cabin volume: 6.6 cubic meters.
National Six Fukang 156hp Foton Omaco 4.2m refrigerated truck
Chassis configuration
Truck size: 5.95×2.24/2.34/2.55×3.22/3.42m
Cabin size: 4.085×2.1/2.2/2.35×2.2/2.3m
Cabin Volume: 18.2/19.2/22 cubic meters
High-end light truck, reversible 2020 wide center body
Silver metallic paint cab, Foton Cummins National 6 156hp F3.8NS6B156 engine, ZF 6-speed transmission, 6-ton rear axle, power steering, air conditioning, multi-function steering wheel, cruise control, directional assistance, air brakes (with air-break brakes). EP fuel-saving switch, ABS, central locking + electric glass + remote key, brake self-adjusting arm, adjustable headlights, 7.50R16 steel wire tires, wheelbase 3360mm.