R290s

R290s is not a formal refrigerant designation but is sometimes used informally to describe equipment or systems that use R-290, the hydrocarbon refrigerant propane. R-290 itself is a pure refrigerant with the chemical formula C3H8. It is classified as A3 for flammability and is regarded as a natural refrigerant with very low environmental impact compared with many HFCs.

R-290's properties yield high energy efficiency and good cooling capacity in small-capacity equipment. Its low boiling point and favorable thermodynamics make it attractive for domestic refrigerators, small commercial refrigeration, and some air-conditioning and heat-pump applications. Safety and handling considerations include its flammability and the need for charge limits and leak-prevention measures in occupied spaces. System design typically uses closed piping, robust joints, and leak detectors, and service must be performed by qualified technicians.

Although effective, R-290-based equipment must comply with local regulations regarding flammable refrigerants. In practice, many jurisdictions set maximum charge limits for appliances installed in occupied spaces and require labeling and containment features.

Environmentally, R-290 has ODP 0 and a GWP around 3, making it a low-GWP alternative to many HFC refrigerants. It is supported by policies aiming to reduce HFC emissions, though safety requirements can limit its use in larger systems.

Note: The term R290s is not a standardized refrigerant class; if encountered, verify the specific refrigerant and equipment with the manufacturer.