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.

1. Is R290 being phased out, or is it a good long-term investment?

R290 is not being phased out; it is a future-proof refrigerant actively promoted as a sustainable alternative. With a Global Warming Potential (GWP) of just 3 and zero Ozone Depletion Potential (ODP), it aligns perfectly with global environmental regulations like the Kigali Amendment and the EU F-Gas Regulation. Its use is expected to grow significantly, making it a sound strategic investment for wholesalers.

 

2. What is the key difference between refrigerant-grade R290 and fuel-grade propane?

They are not the same product. The critical difference is purity and additives. Refrigerant-grade R290 must meet AHRI Standard 700 specifications, which require a minimum purity of 99.5% and no odorants.

 

Fuel-grade propane contains odorants like ethyl mercaptan, which can contaminate a system's lubricating oil, leading to compressor failure and costly repairs. Always verify your supply is explicitly labeled as refrigerant-grade and non-odorized.

 

3. What are the main disadvantages and safety concerns with R290?

The primary drawback is its high flammability, as it is classified as ASHRAE Safety Group A3. This classification imposes strict rules on:

 

Charge Sizes: Limits are often capped (e.g., 150 grams per indoor unit under ASHRAE 34) to mitigate risk.

 

Handling and Installation: Requires trained technicians, specialized equipment (leak detectors, explosion-proof tools), and strict no-smoking policies.

 

Logistics: Classified as a hazardous good for transport (UN 1978), which increases shipping costs and requires specific documentation.

 

4. How should R290 cylinders be stored safely in my warehouse?

Safe storage is critical due to its flammability. Key requirements include:

 

Environment: Store in a cool (<52°C/125°F), dry, well-ventilated area, preferably outdoors or in a detached, non-combustible building.

 

Handling: Keep cylinders upright, secured, with valve caps in place. Protect from physical damage (do not roll or drop) and separate full from empty cylinders.

 

Ignition Sources: Absolutely no smoking. Keep away from heat, sparks, and open flames. Separate from oxidizers by a minimum of 20 feet or a fire-rated barrier.

 

Regulations: Always consult and comply with local building, electrical, and fire codes, which will dictate the specific construction and capacity of storage areas. Consider a risk assessment for explosion protection if storing large quantities.

 

5. What are the specific transport regulations for R290?

R290 is classified as a dangerous good (UN 3537 / UN 1978). While there may be some exceptions for hermetically sealed equipment, new regulations now require:

 

Special Labeling: Packages must display specific hazard labels (e.g., hazard label 2.1).

 

Documentation: Delivery notes must include the UN number, sender/recipient details, and total quantity of R290.

 

Personnel Training: All persons involved in the transport chain must be instructed in accordance with dangerous goods regulations (e.g., ADR).

 

6. Which lubricating oils are compatible with R290?

This is a nuanced topic. Historically, mineral oils (MO) have been used as they are miscible with R290. However, R290's high solubility in MO can dilute the oil, reducing viscosity and potentially harming the compressor.

 

As a result, polyalkylene glycol (PAG) synthetic oils are gaining favor because they have lower solubility with R290, helping to maintain proper lubrication and even reducing the required refrigerant charge. It's essential to use a lubricant specifically formulated for hydrocarbon refrigerants and to contact the compressor manufacturer for their specific recommendation.

 

7. How can I verify the authenticity and quality of an R290 supplier?

Due to the risks of counterfeit or substandard product, due diligence is crucial. You should:

 

Request Documentation: Always ask for the Safety Data Sheet (SDS) and proof of AHRI 700 certification ensuring ≥99.5% purity and <10 ppm water content.

 

Check Certifications: Verify supplier has valid ISO 9001, CE, or UL certificates.

 

Review Lab Reports: Ask for third-party lab reports from accredited institutions like SGS or TÜV.

 

Conduct Audits: Order samples for independent testing or consider a virtual audit of their production facilities.

 

8. What are the different cylinder types and valve connections for R290?

R290 cylinders come in various sizes (e.g., 5 kg/cylinder, 10000KG/ISO Tank). A critical point is that cylinders typically have a left-handed DIN 477-1 valve, which means an adaptor may be required to connect to standard equipment. FRIOFLOR notes their cylinders are fitted with a Residual Pressure Device (RPD) to prevent refilling with foreign substances.

 

9. Are there specific procedures for charging and recovering R290?

Yes, due to its flammability, R290 requires different charging and recovery procedures compared to non-flammable refrigerants. While R290 can be charged from either the liquid or vapor phase, a key advantage is that it requires a smaller charge volume—about 43% of R22 for the same system volume. However, all handling must be done by trained persons using specialized, non-sparking equipment and following strict safety protocols to prevent leaks and ignition.

 

10. Can I mix R290 with other refrigerants or use it as a "drop-in" replacement?

Mixing R290 with other refrigerants is highly inadvisable and generally violates regulations. While some research has explored blends like R134a/R290 to match the properties of R22, these are for specific, engineered systems and not standard practice. Using R290 as a "drop-in" replacement requires a complete system evaluation and modification, as it operates at different pressures and has different oil compatibility requirements. For new equipment, consult the OEM's guidelines.