1 salt water ice and ice refrigeration
At atmospheric pressure, the melting point of ice is 0 ℃. Ice melts when heat is 334.8kJ / kg, add salt in the water ice can reduce the melting point. Within a certain range, the salt content of water ice in the more, the lower the melting point. Experiments show that when the mass of salt added to the water ice mass of 29%, the melting point of the mixture can be as low as -21.2 ℃. Increase if more salt, the melting point is no longer declining. Optimum temperature is normally based on the transport of refrigerated truck cargo to select different components of salt ice. E.g., the use of 22% salt content of the salt of the ice, the inside temperature can be kept at -18 ~ -13 ℃.
Water ice refrigeration means less investment, low operating costs, but ordinary water (salt) of ice per unit mass of absorbing less heat, the cooling inside is limited. Also will pollute the environment, food, value cargo compartments and moisture corrosion after salt ice melt. Therefore, water (salt) ice cooling mainly in fish and other aquatic months of refrigerated transport,
2 ice refrigeration
At an atmospheric pressure, dry ice (solid CO2) low sublimation temperature (-78.9 ℃), sublimation endothermic amount (573.5kJ / kg), it will be as cold source car, not only can get a lower temperature (typically low at -20 ℃), and results in greater cooling capacity. So that the cooling mode is suitable for the transport of refrigerated foods.
Dry ice cooling device is simple, low investment and operating costs, ease of use, the goods will not damp. Dry ice sublimation COZ gas produced can inhibit microbial growth,
reduce fat oxidation and impair respiration of fruits and vegetables. However, dry ice sublimation can lead to frost; fruits, vegetables and other frozen CO2 gas was breathing
too much will cause necrosis; difficult to adjust the temperature inside the car; the higher cost of dry ice, and the consumption is large, it is less practical use.
3 cold plate refrigeration
The cold accumulator will be refrigerated cold plate refrigeration principle is to use coolant freezing. Before shipping within the first compartment in cold storage agent "full cold", allowed to cool to freeze, then use cold in transit in the coolant absorbs heat to melt, the inner compartment temperature is kept at the temperature range transport of goods Inside. It will be cold, also known as "storage plate."
Structure type cold plate refrigeration unit is divided into the overall style and split. Integral power plant, refrigeration units and storage board, are set to dry the car; the car is equipped with only a split refrigeration units and storage plate. When parking, use of secured power unit driven refrigeration unit for storage board "charge cold."
Practice in the use of the latter. Common coolant are low melting point eutectic solution, the melting point is usually lower than the optimum temperature inside the car about 10 ℃. When the optimum temperature change transport of goods, the chosen solution eutectic composition have to change,
Cold plate unit itself heavier, larger, occupy a certain volume of the car, but only once the cold cold charge lasts 8 ~ 15H. So cold plate refrigeration adapted in the short- distance transport of light refrigerated trucks in recent years, as energy and environmental pollution have become increasingly prominent question, the cold plate refrigeration applications developed rapidly, has become second only to mechanical refrigeration cooling the way.
4. Liquid nitrogen cooling
Liquid nitrogen cooling is the use of heat of vaporization of liquid nitrogen for cooling. At atmospheric pressure, liquid nitrogen boils at -196 ℃, latent heat of vaporization is 200kJ / kg. The specific heat of nitrogen 1.05kJ / (Kg. ℃), per kg of liquid nitrogen thus vaporized and warmed to -20 ℃, the absorbed heat is about 385kJ, low boiling point of liquid nitrogen, and oxygen is a byproduct, thereby obtaining a wider range of applications.
Liquid nitrogen refrigeration device structure is simple, reliable, no noise and pollution; liquid nitrogen cooling capacity, cooling rapidly, suitable for quick-frozen.
Vaporization of liquid nitrogen does not cause moisture inside the car, and nitrogen food preservation, to prevent moisture loss are good. In addition, liquid nitrogen refrigeration temperature control accuracy (± 2 ℃). But the high cost of liquid nitrogen, often filling the need, therefore promotion subject to certain restrictions.
Similarly, other low-temperature vaporized liquid gas, may be used as a refrigerant, such as liquid two carbon nitride (CN2).
5. Mechanical refrigeration
Mechanical refrigeration methods are: vapor compression, absorption, steam injection and the like. Currently the most widely used vapor compression. Here refrigeration works.
Under a certain pressure, the liquid reaches a certain temperature (boiling point) will boil. When the liquid boils, absorbing latent heat of vaporization to produce a phase change into a saturated vapor. At the same pressure, the boiling point and latent heat of vaporization of different liquids is not the same as at an atmospheric pressure boiling
point of water is 100 ℃, latent heat of vaporization 2256.7kJ / kg, while the boiling point of Freon 12 (R12) is -29.8 ℃, latent heat of vaporization is 165kJ / kg. Where the boiling liquid for cooling the refrigerant called or known as refrigerants. In refrigeration technology, the refrigerant boiling is called "evaporation", its boiling point is called "the evaporation temperature", the boiling refrigerant is called "evaporative cooling."
A vapor compression refrigeration belong to evaporative cooling. Placed in a closed system the refrigerant, the liquid refrigerant is vaporized in the evaporator refrigerant
heat absorption, heat in the condenser and condensed into a liquid again, the driving of the compressor, the refrigerant cycle work continuously.
Mainly due to a mechanical refrigeration devices are widely used in refrigeration unit that not only cooling but also heating, expanding the scope of use; inside compartment temperature can be adjusted to achieve self-control, thermostat accurate, reliable, wide range of temperature control, can adapt to a variety of refrigerated cargo transport.
Although mechanical refrigeration device structure is more complex, higher acquisition and operating costs, and other operating noise larger question, but so far, mechanical
refrigeration is still a reliable and effective cooling methods.
Hubei Changjie Special Purpose Vehicle Co. Ltd
E-mail: cj802@urspv.com
Tel: 0086-0722-3229933
At atmospheric pressure, the melting point of ice is 0 ℃. Ice melts when heat is 334.8kJ / kg, add salt in the water ice can reduce the melting point. Within a certain range, the salt content of water ice in the more, the lower the melting point. Experiments show that when the mass of salt added to the water ice mass of 29%, the melting point of the mixture can be as low as -21.2 ℃. Increase if more salt, the melting point is no longer declining. Optimum temperature is normally based on the transport of refrigerated truck cargo to select different components of salt ice. E.g., the use of 22% salt content of the salt of the ice, the inside temperature can be kept at -18 ~ -13 ℃.
Water ice refrigeration means less investment, low operating costs, but ordinary water (salt) of ice per unit mass of absorbing less heat, the cooling inside is limited. Also will pollute the environment, food, value cargo compartments and moisture corrosion after salt ice melt. Therefore, water (salt) ice cooling mainly in fish and other aquatic months of refrigerated transport,
2 ice refrigeration
At an atmospheric pressure, dry ice (solid CO2) low sublimation temperature (-78.9 ℃), sublimation endothermic amount (573.5kJ / kg), it will be as cold source car, not only can get a lower temperature (typically low at -20 ℃), and results in greater cooling capacity. So that the cooling mode is suitable for the transport of refrigerated foods.
Dry ice cooling device is simple, low investment and operating costs, ease of use, the goods will not damp. Dry ice sublimation COZ gas produced can inhibit microbial growth,
reduce fat oxidation and impair respiration of fruits and vegetables. However, dry ice sublimation can lead to frost; fruits, vegetables and other frozen CO2 gas was breathing
too much will cause necrosis; difficult to adjust the temperature inside the car; the higher cost of dry ice, and the consumption is large, it is less practical use.
3 cold plate refrigeration
The cold accumulator will be refrigerated cold plate refrigeration principle is to use coolant freezing. Before shipping within the first compartment in cold storage agent "full cold", allowed to cool to freeze, then use cold in transit in the coolant absorbs heat to melt, the inner compartment temperature is kept at the temperature range transport of goods Inside. It will be cold, also known as "storage plate."
Structure type cold plate refrigeration unit is divided into the overall style and split. Integral power plant, refrigeration units and storage board, are set to dry the car; the car is equipped with only a split refrigeration units and storage plate. When parking, use of secured power unit driven refrigeration unit for storage board "charge cold."
Practice in the use of the latter. Common coolant are low melting point eutectic solution, the melting point is usually lower than the optimum temperature inside the car about 10 ℃. When the optimum temperature change transport of goods, the chosen solution eutectic composition have to change,
Cold plate unit itself heavier, larger, occupy a certain volume of the car, but only once the cold cold charge lasts 8 ~ 15H. So cold plate refrigeration adapted in the short- distance transport of light refrigerated trucks in recent years, as energy and environmental pollution have become increasingly prominent question, the cold plate refrigeration applications developed rapidly, has become second only to mechanical refrigeration cooling the way.
4. Liquid nitrogen cooling
Liquid nitrogen cooling is the use of heat of vaporization of liquid nitrogen for cooling. At atmospheric pressure, liquid nitrogen boils at -196 ℃, latent heat of vaporization is 200kJ / kg. The specific heat of nitrogen 1.05kJ / (Kg. ℃), per kg of liquid nitrogen thus vaporized and warmed to -20 ℃, the absorbed heat is about 385kJ, low boiling point of liquid nitrogen, and oxygen is a byproduct, thereby obtaining a wider range of applications.
Liquid nitrogen refrigeration device structure is simple, reliable, no noise and pollution; liquid nitrogen cooling capacity, cooling rapidly, suitable for quick-frozen.
Vaporization of liquid nitrogen does not cause moisture inside the car, and nitrogen food preservation, to prevent moisture loss are good. In addition, liquid nitrogen refrigeration temperature control accuracy (± 2 ℃). But the high cost of liquid nitrogen, often filling the need, therefore promotion subject to certain restrictions.
Similarly, other low-temperature vaporized liquid gas, may be used as a refrigerant, such as liquid two carbon nitride (CN2).
5. Mechanical refrigeration
Mechanical refrigeration methods are: vapor compression, absorption, steam injection and the like. Currently the most widely used vapor compression. Here refrigeration works.
Under a certain pressure, the liquid reaches a certain temperature (boiling point) will boil. When the liquid boils, absorbing latent heat of vaporization to produce a phase change into a saturated vapor. At the same pressure, the boiling point and latent heat of vaporization of different liquids is not the same as at an atmospheric pressure boiling
point of water is 100 ℃, latent heat of vaporization 2256.7kJ / kg, while the boiling point of Freon 12 (R12) is -29.8 ℃, latent heat of vaporization is 165kJ / kg. Where the boiling liquid for cooling the refrigerant called or known as refrigerants. In refrigeration technology, the refrigerant boiling is called "evaporation", its boiling point is called "the evaporation temperature", the boiling refrigerant is called "evaporative cooling."
A vapor compression refrigeration belong to evaporative cooling. Placed in a closed system the refrigerant, the liquid refrigerant is vaporized in the evaporator refrigerant
heat absorption, heat in the condenser and condensed into a liquid again, the driving of the compressor, the refrigerant cycle work continuously.
Mainly due to a mechanical refrigeration devices are widely used in refrigeration unit that not only cooling but also heating, expanding the scope of use; inside compartment temperature can be adjusted to achieve self-control, thermostat accurate, reliable, wide range of temperature control, can adapt to a variety of refrigerated cargo transport.
Although mechanical refrigeration device structure is more complex, higher acquisition and operating costs, and other operating noise larger question, but so far, mechanical
refrigeration is still a reliable and effective cooling methods.
Hubei Changjie Special Purpose Vehicle Co. Ltd
E-mail: cj802@urspv.com
Tel: 0086-0722-3229933
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