Understand the working pressure and performance of R290 refrigerant

1. Basic information of R290

Chinese name: propane

Molecular formula: C3H8

Molecular weight: 44.10

Appearance and properties: colorless gas, pure and odorless

Solubility: Slightly soluble in water, soluble in ether and ethanol

2. R290 characteristics

Flash point (℃): -104

Explosion upper limit % (V/V): 9.5

Lower explosion limit% (V/V): 2.1

Relative density (air=1): 1.56

Heat of combustion (kJ/mol): 2217.8

Ignition temperature (℃): 450~470

The disadvantage of R290 as a refrigerant is the flammability of R290 (compressors, condensers, evaporators, pipelines and other components of the refrigeration system may cause leakage of working fluid, and electronic components such as thermostats, compressor relays, lights, defrost buttons, etc. may be sources of ignition.)

The maximum filling amount of R290 in the refrigerator should be controlled at about 150g; in order to ensure safe operation, the refrigeration system and control components should be set up in different spaces; protectors and flame-retardant relays should be installed on the compressor; forced ventilation should be used to avoid local concentration accumulation, and gas sensors should often be used to detect places prone to leaks; the R290 refrigeration system should be closed, and strict leak detection should be carried out before filling the refrigerant

4. Pressure of R290 refrigerant

At -25°C, R290 is similar to R22, higher than R134a, and lower than R404A. Standard boiling point and critical temperature: similar to R22; compared with R22, the suction temperature of R290 can be higher and the evaporation temperature can be lower.

At a condensation temperature of 45°C, a suction temperature of 32°C, and no subcooling, the volumetric cooling capacity of R290 is similar to that of R22, and is 1.5 times that of R134a. It is 2.5 to 3 times that of R600a, which means that for a household refrigerator with the same cooling capacity, the structure size of the R290 refrigerator refrigeration system is smaller and the overall space occupied by the refrigerator is reduced.

Completely environmentally friendly

R290 refrigerant is derived from the natural component propane and is derived from nature. Its GWP is 3 and ODP is 0. It neither damages the ozone layer nor has a greenhouse effect. It is an environmentally friendly refrigerant that is completely friendly to the environment.

Affordable

Calculated based on the charge weight, the usage of R290 refrigerant is only 40% to 55% of that of R22 and R410a, which is less and more economical.

High efficiency and energy saving

The freezing point is low and the latent heat of evaporation is greater, resulting in a faster cooling rate per unit time; the isentropic compression ratio is small, making the compressor work easier and extending the service life of the compressor; the molecular weight is small, the fluidity is good, and the delivery pressure is lower, which reduces the load of the compressor. Using R290 refrigerant, the energy saving rate can reach 15~35%.

Good refrigeration

Shorten the cooling time of air conditioning compressor, and the cooling effect is the same as R22. R290 refrigerant has a large cooling capacity per unit volume and unit mass, and the heat exchange performance of the condenser and evaporator is high. It shortens the cooling time of the air conditioning compressor and can save 30% of electric energy while maintaining the same cooling effect.

Shanghai KUB Refrigeration Equipment Co., Ltd.

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