In general, large and medium ammonia refrigeration systems have slightly more investment than fluorine refrigeration systems of the same scale. The fluorine refrigeration system has a high degree of automation and less investment. Ammonia machine system is large, auxiliary machine is many, high pressure vessel is many, pipeline is complex, valve is many, each component is bigger and bulky. The fluorine machine system adopts intensive design, the whole unit leaves the factory, the unit occupies small area, the structure is simple, the use is convenient.
The refrigerant of ammonia refrigeration system is cheap, the refrigerant unit refrigerating capacity is large, the electricity consumption is less, and the operation cost is low. Fluorine refrigeration system has higher working fluid price, smaller unit refrigerating capacity, higher electricity consumption and higher operating cost.
1. Environmental characteristics.
Ammonia, the refrigerant of ammonia refrigeration system, is a natural working medium with ozone depletion coefficient and no pollution to the environment. Because of the characteristics of destroying ozone layer, the ozone depletion coefficient (ODP) and the global warming coefficient (GWP) of CFCS are smaller, which can destroy the environment to a certain extent.
4. Energy saving characteristics
The ammonia refrigeration system has a larger COP coefficient and a better energy saving effect. The COP coefficient of the fluoro refrigeration system is small and the energy saving effect is poor.
When the volume concentration of ammonia in the air reaches 5 ~ 0.6%, the person can be poisoned by staying in it for half an hour, and the concentration can be ignited when the concentration reaches 11 ~ 14. When the concentration reaches 16 ~ 25%, it will cause an explosion. No flammable explosive toxic refrigerant can be used. Freon is colorless, odorless, non-combustible, non-explosive, stable in chemical properties, and suitable for high, medium and low temperature refrigerators. The lowest evaporation temperature is -80 ℃.
6.Liquid supply and gas return pipeline
Ammonia system is connected with evaporator by down-inputting and outputting mode, and fluorine system is connected with evaporator by up-in and down-exit mode to facilitate oil recovery. The horizontal suction pipe of ammonia system should be sloping towards the circulating drum or the gas-liquid separator, and the horizontal suction pipe of the fluorine system should be sloping towards the compressor.
7. Liquid supply mode
Ammonia system and fluorine system can supply liquid directly, liquid pump and gravity liquid, and supply liquid to evaporator.
Ammonia system and fluorine system are medium temperature refrigerants with moderate pressure and temperature. They can be used in refrigeration, air conditioning, industrial refrigeration, beer industry and pharmaceutical industry. Fluorine system is safer for direct evaporative air conditioning system. Ammonia systems can be used in air conditioning by indirect cooling
9.Automation control degree
The fluorine system automation degree is high, generally does not need the manual operation, may save the labor cost. Most ammonia systems are operated manually, and the degree of automation is low, but the operation stability is good.
10.Noise, vibration comparison
Ammonia machine volume is relatively large, noise and vibration are very large, a greater impact on the environment. Low noise and vibration of fluorine machine system.
11. Applied range
Ammonia systems are generally suitable for large and medium refrigerating, industrial refrigeration, ice making, artificial ice rink and indirect central air conditioning. Fluorine systems are generally suitable for refrigerators, display cabinets, domestic air conditioners, commercial air conditioners, small and medium cold storage and refrigeration, factory low temperature air conditioning, edible ice, and small industrial refrigeration.
12. Equipment, pipes and valves for refrigeration systems
Ammonia system pipes are made of seamless steel tubes, steel containers and fittings, aluminum alloy pistons, seamless steel pipe evaporators or aluminum alloy evaporators; valves and fittings are specially designed for ammonia. Compressors are mostly piston type and screw type. The fluorine system pipe adopts copper pipe and seamless steel pipe, steel equipment, copper tube evaporator or aluminum alloy pipe evaporator, valves and fittings adopt fluorine special products. Compressor has digital scroll type, screw type, piston type, etc.
13. Ammonia corrodes equipment and pipes when the ammonia system contains moisture. When fluorine system contains water, fluorine will also corrode equipment and pipeline, and form ice plug easily. Therefore, fluorine system should be equipped with dry filter.
14. Find the leak
Ammonia has irritating odor, ammonia system leak can be detected by using phenolphthalein test paper to turn ammonia red and litmus paper to ammonia to turn blue to find out that fluorine is colorless and tasteless, fluorine system leak can be detected by soapy water smear method and electronic leak detector method.
15.The selection decision of ammonia refrigeration system and fluorine refrigeration system. It should be determined according to the specific application environment and temperature conditions, investment and operation expenses, environmental protection requirements, energy saving requirements, safety requirements, operation stability, automation control requirements and so on.