Basic Information of R290 Propane Gas

R290 is a new type of environmentally friendly refrigerant, mainly used in central air conditioners, heat pump air conditioners, household air conditioners and other small refrigeration equipment. R290 (propane), also known as propane, has excellent thermal performance, low price, and R290 is compatible with ordinary lubricating oil and mechanical structural materials, ODP=0, GWP is small, does not need to be synthesized, and does not change the content of natural hydrocarbons , Has no direct impact on the greenhouse effect. Propane has a large refrigeration capacity per unit volume, which is very suitable for small rotary compressors. The main physical properties of propane are very similar to R22. The R22 system can be used. The original machine and production line are not modified, and propane can be filled directly, which is a direct substitute. Considering the cost of CFC replacement, propane is particularly suitable for developing countries.

 

　　 Currently, R290 has been used in domestic heat pump water heaters and air conditioning systems in Germany. Wolf Laborato-ries Limited has produced R290 household refrigerators. DANFOSS is also developing R290 household refrigerators.

 

 Physical properties of R290
 

　　 At -25℃, the pressure of R 290 is similar to that of R22, which is higher than R1 34a and lower than R404A. The standard boiling point of R290 is similar to R22, and the critical temperature is also close to R22, but the exhaust temperature of R290 is lower than that of R22. Therefore, the pressure of R290 is lower than R22. In other words, the suction temperature of R290 can be higher and the evaporation temperature can be lower. some. At 45°C condensing temperature, 32°C suction temperature and no subcooling, the volumetric cooling capacity of R290 is similar to that of R22, which is 1.5 times that of R134a. It is 2.5 to 3 times that of R600a, which means that for household refrigerators with the same cooling capacity, the R290 refrigerator refrigeration system has a smaller structural size, and the overall space occupied by the refrigerator is reduced.

Physical Properties
Molecular Formula	CH3CH2CH3
Molecular Weight	44.1
Boiling Point  ℃	-42.1
Freezing Point	N/M
Critical Temperature (℃)	96.6
Critical Pressure (MPa)	4.248
ODP	0
GWP	3.3

 

The safety performance of R290
 

The disadvantage of using R290 as a refrigerant is the flammability of R290. The compressor, condenser, evaporator, pipeline and other components of the refrigeration system may cause the leakage of working fluid, and the temperature controller, compressor relay, lighting, etc. Electronic components such as defrost buttons can be sources of ignition. Therefore, the maximum charge 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 arranged in different spaces. Install a protector and flame-retardant relay on the compressor. Control ventilation to avoid local concentration accumulation, and often use gas sensors to detect leaks. The R290 refrigeration system should be closed, and leak detection should be strictly carried out before charging the refrigerant.

 

R290 refrigeration system performance
 

The theoretical COP values ​​of R290, R600a and R134a are higher than those of R22 at the evaporating temperature of -25°C and the condensing temperature of 45°C, without subcooling and high superheat; the theoretical COP values ​​of JR290, R600a and R134a at low superheat Lower than R22. The COP values ​​of R290 and R134a are similar. Just like R134a, R404A and R600a, the superheat of the suction is very important to the performance of the R290 refrigeration system, which can improve the COP of the refrigeration system, while R22 has little effect. For the R290 refrigerator refrigeration system, because R290 has a high specific heat of hot steam, it can have a superheat temperature of 20°C to 32°C, which can increase the COP of the 290 refrigerator.

Quality Index
Purity	≥ 99.90%
Sulfur content ppm by weight	less than 1.0
Water content ppm by weight	less than 10
Acidity ppm by weight	less than 1.0
Evaporation residue	≤ 0.01%
Appearance	Colorless and clear
Odor	Odorless

 

 Conclusion  

　　 R290 (propane) has excellent thermal performance, low price, large refrigeration capacity per unit volume, small size, physical properties very similar to R22, and it is a direct substitute. Taking corresponding safety protection measures has a good application prospect for environmental protection and energy saving.

 

Temperature Unit: centigrade

Remark: 1KPa≈0.01kg/cm2=0.001MPa，1kg/cm2 ≈98.0665KPa≈0.1MPa

R32 and R410A Comparison

 

1. R32 charge is less, only 0.71 times that of R410A. The working pressure of R32 system is higher than R410A, but the maximum increase does not exceed 2.6%, which is equivalent to the pressure requirement of R410A system. At the same time, the exhaust temperature of R32 system is higher than that of R410A. The maximum rise is as high as 35.3°C.

 

2. The ODP value (ozone depleting potential value) is 0, but the GWP value (global warming potential value) of R32 refrigerant is moderate. Compared with R22, the CO2 emission reduction ratio can reach 77.6%, while R410A is only 2.5%. It is significantly better than R410A refrigerant in terms of CO2 emission reduction.

3. Both R32 and R410A refrigerants are non-toxic, while R32 is flammable, but among several alternatives to R22, R32, R290, R161, and R1234YF, R32 has the highest lower limit of combustion (LFL), which is relatively incombustible. However, it is still a flammable and explosive refrigerant, and there have been many accidents in recent years, and the performance of R410A is more stable.

 

4. In terms of theoretical cycle performance, the cooling capacity of the R32 system is 12.6% higher than that of the R410A, the power consumption increases by 8.1%, and the overall energy saving is 4.3%. The experimental results also show that the refrigeration system using R32 has a slightly higher energy efficiency ratio than R410A. Considering that R32 has a greater potential to replace R410A.

 

R32 and R290 comparison

 

1. R290 and R32 have a relatively small charge, the ODP value is 0, the GWP value is also much smaller than R22, the safety level of R32 is A2 and the safety level of R290 is A3.

2.R290 is more suitable for medium and high temperature air conditioning systems than R32. R32's pressure resistance design is higher than R290, and R32's flammability is much lower than R290, and the cost of safety design is low.

3.The dynamic viscosity of R290 is less than R32, and the pressure drop of the system heat exchanger is less than R32, which helps to improve the efficiency of the system.

　　
4.R32 unit volume refrigeration capacity is about 87% higher than R290, R290 system should use a larger displacement compressor under the same refrigeration capacity.

5.R32 has a higher exhaust temperature, and the pressure ratio of the R32 system is about 7% higher than that of the R290 system, and the overall energy efficiency ratio of the system is about 3.7% lower.

6. ​The pressure drop of the R290 system heat exchanger is less than R32, which helps to improve system performance. But its flammability is far greater than R32, and higher investment in safety design.