Introduction of R290 Propane (Properties, Benefits, Problems)

Application of R290 Propane:

High-purity R290 is used as a temperature-sensing working fluid; premium and first-grade R290 can be used as a refrigerant to replace R22, R502, compatible with the original system and lubricating oil, and used for central air conditioning, heat pump air conditioning, household air conditioning and other small refrigeration equipment , Can also be used for metal oxygen cutting gas.

Physical Properties of R290 refrigerant

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

Benefits of R290: A potential refrigerant substitute

With the application and development of the world's refrigeration and air conditioning technology, the demand for refrigerants is also showing an upward trend year by year, reaching hundreds of thousands of tons of consumption each year. Therefore, from the perspective of long-term impact, reusing the natural working fluids that exist in nature is an ideal choice to realize the sustainable development of environment and resources.

    The refrigerant R290, or propane, is a natural hydrocarbon refrigerant that can be obtained directly from liquefied petroleum gas. Compared with Freon, a synthetic refrigerant, the natural working fluid R290 does not contain chlorine atoms in its molecules, so the ODP value is zero, which does not have a destructive effect on the ozone layer. In addition, compared with HFC substances that also have no destructive effect on the ozone layer, the GWP value of R290 is close to 0, which has no effect on the greenhouse effect. Currently in Germany R290 has been used in domestic water heaters and air conditioning systems.

At present, the most used refrigerant in my country's air-conditioning industry is HCFC substance R22. The standard boiling point, freezing point, critical point and other basic physical properties of R290 and R22 are very close, and they have the basic conditions to replace R22. In the saturated liquid state, the density of R290 is lower than that of R22, so the perfusion volume of R290 under the same volume is smaller. Experiments show that the perfusion volume of R290 under the same system volume is about 43% of R22. In addition, because the latent heat of vaporization of R290 is about twice that of R22, the refrigerant circulation in the refrigeration system using R290 is smaller. R290 has good material compatibility and can be well compatible with copper, steel, cast iron, lubricants, etc.

Problem of R290 Refrigerant Application

Although R290 has the above advantages, its "flammable and explosive" disadvantage is currently the biggest obstacle to its large-scale promotion. R290 can form an explosive mixture when mixed with air, and may burn and explode when exposed to heat sources and open flames. The means to improve the safety of R290 include reducing the filling volume, isolating the ignition source, preventing refrigerant leakage and improving the safety prevention and control capabilities after leakage.

Solutions How to avoid risky problems in using R290 Refrigerant

In order to reduce potential safety hazards, the IEC standard restricts the maximum safe perfusion volume of R290 refrigerant: when the installation height is 2.2m in a 10 square meter room, the perfusion volume must be less than 290g. After reducing the amount of filling, the leakage of refrigerant can be reduced to a certain extent, thereby improving the safety of R290. Will the decrease in the amount of refrigerant filling lead to a decrease in refrigeration capacity? In this regard, industry insiders say that the latent heat of vaporization of R290 is approximately twice that of R22, which means that the refrigeration capacity per unit mass of R290 is higher. And the current test has confirmed that the refrigeration effect of R22 can be achieved or exceeded by the structural transformation of the refrigeration system under the condition of reducing the amount of R290 refrigerant.

Reducing leakage and improving leakage detection and response capabilities are important measures to improve the safety of R290. It is understood that the current air-conditioning sealing test standards of most manufacturers are very demanding, and the annual leakage of normal air-conditioning can be controlled below 5g without any danger. Nowadays, refrigerant leaks are mostly concentrated in the air-conditioning installation, use, and maintenance processes. In these processes, there are many uncontrollable factors such as environment and usage methods. Therefore, the safety control measures in these processes still need to be further studied and improved.