The difference between ammonia refrigeration and fluorine refrigeration system

The difference between ammonia refrigeration and fluorine refrigeration system

The vapor compressor refrigeration system can adopt a variety of methods for refrigeration, such as fluorine refrigeration and ammonia refrigeration. What are the differences and differences between the two methods? Today okmarts.com will give you a detailed analysis of ammonia refrigeration system and fluorine refrigeration system. The similarities and differences, so that the friends can make reasonable choices and decisions on the refrigeration system.

　　 Because of the different working fluids used in the refrigeration system, the characteristics, structure and application range of the refrigeration system are also different.

　　 1. One-time investment

　　 Under normal circumstances, large and medium-sized ammonia refrigeration systems have less investment than fluorine refrigeration systems of the same scale. This is mainly because the refrigeration unit, equipment, pipelines and valves of the fluorine refrigeration system are expensive, and the fluorine refrigeration system has a high degree of automation and relatively high investment.

　　2, operating cost

　　The working fluid of the ammonia refrigeration system is cheap, and the unit refrigeration capacity of the refrigerating medium is large, the power consumption is less, and the operating cost is low. Fluorine refrigeration systems have relatively high working fluid prices, low unit refrigeration capacity, relatively high power consumption, and high operating costs.

　　3, environmental protection characteristics

　　 The refrigerant ammonia of the ammonia refrigeration system is a natural working fluid, the ozone depletion coefficient ODP=0, the global warming coefficient GWP=0, and it has no pollution to the environment. The CFCs working fluid of fluorine refrigeration system has been eliminated because of its ozone-depleting characteristics. The working fluid of HCFCs has a small ozone depletion coefficient ODP and a small global warming coefficient GWP, which has a certain destructive effect on the environment. According to relevant international agreements, developing countries are allowed to use it before 2040.

　　4, safety

　　 When ammonia reaches 16%~25% in the air, it can explode when exposed to an open flame. Ammonia is toxic and can cause suffocation and frostbite. Security is poor. In densely populated places, large-capacity ammonia refrigeration systems should not be used. F-22 is non-toxic, does not explode when mixed with air, and has good safety. In crowded places (developing countries), it is safer to use F-22 system and F-134a system. Of course, if conditions permit, the application of CO2 refrigeration systems is more environmentally friendly and safer.

　　 5. Liquid supply and return gas pipeline

　　Ammonia system generally uses bottom-in and top-out to connect to the evaporator; fluorine system generally uses top-in and bottom-out to connect to the evaporator to facilitate oil return. The horizontal suction pipeline of the ammonia system should slope to the circulation barrel or the gas-liquid separator; the horizontal suction pipeline of the fluorine system should slope to the compressor.

　　 6. Liquid supply method

　　Ammonia system and fluorine system can use direct liquid supply, liquid pump liquid supply and gravity liquid supply to supply liquid to the evaporator.

　　7, application range

　　Ammonia system and fluorine system are both medium-temperature refrigeration working fluids, both of which have moderate pressure and temperature. They can be used in refrigeration, air conditioning, industrial refrigeration, beer industry and pharmaceutical industry. Fluorine system is safer when used in direct evaporative air conditioning system. The ammonia system can adopt indirect cooling (via refrigerant) for air conditioning.

　　 8. Degree of automation control

　　 The fluorine refrigeration system is highly automated and generally does not require manual operation, which can save labor costs. The ammonia refrigeration system is mostly manual operation, with low automation, but it has good operational stability.

　　 9. Solubility of oil

　　The solubility of ammonia and oil is small, and an oil film is easily formed on the surface of the ammonia system heat exchanger, which affects heat transfer. Therefore, the evaporator, condenser, liquid reservoir, intercooler, and oil-ammonia separator should be drained regularly. In the fluorine system, fluorine and oil dissolve each other, and no oil film will be formed on the surface of the heat exchanger, which will not affect heat transfer, but too much oil in the evaporator will increase the evaporation temperature. The fluorine system is generally equipped with an automatic oil return device, the fluorine system pipeline design and installation should consider the setting of an oil return bend, and the parallel unit should consider the oil balance problem.

　　10, performance

After years of design, installation, and operation management practices, the ammonia refrigeration system has mature technology and stable operation; the fluorine refrigeration system is not standardized due to the design, installation, and operation management, coupled with the quality of automatic control components, although the degree of automation is high, but the operation is stable It still needs improvement, and it is prone to burn-in accidents.

　　11、Applicable

　　Ammonia refrigeration system is generally suitable for large and medium-sized refrigeration, industrial refrigeration, ice making, artificial ice rinks and indirect central air conditioning. Fluorine refrigeration systems are generally suitable for refrigerators, freezers, display cabinets, household air conditioners, commercial air conditioners, small and medium-sized cold storage and freezing, factory low temperature air conditioners, mine air conditioners, ice cream, cold drinks, edible ice, artificial ice rinks and small industrial refrigeration.

　　12. Refrigeration system equipment, pipelines and valves

　　Ammonia system pipelines all use seamless steel pipes, steel containers and equipment, aluminum alloy pistons, seamless steel pipe evaporators or aluminum alloy pipe evaporators; valves and pipe fittings use ammonia special products. Compressors are mostly piston type and screw type. The fluorine system pipeline adopts copper pipes and seamless steel pipes, steel equipment, copper pipe evaporator or aluminum alloy pipe evaporator, valves and pipe fittings adopt fluorine special products. Compressors include digital scroll type, screw type, piston type, etc.

　　13, there is moisture in the system

　　 When moisture exists in the ammonia system, ammonia will corrode equipment and pipelines. When the fluorine system contains water, the fluorine will also corrode equipment and pipelines and easily form ice plugs. Therefore, the fluorine system should be equipped with a filter dryer.