This thesis investigates gas-water separators for R290 (propane) heat pumps, focusing on enhancing safety in heating and domestic hot water systems. The flammability of R290 poses a risk in case of heat exchanger failure, and gas-water separators can mitigate this by preventing refrigerant from reaching critical parts of the building. Among available designs, cyclone and filter separators were studied, with cyclone types showing higher efficiency and simpler manufacturability. Separator performance depends on factors such as bubble size, two-phase flow patterns, pipe geometry, and Reynolds number characterisation, highlighting the need for case-specific evaluation. Computational fluid dynamics (CFD) simulations examined both a proof-of-concept device and newly designed cyclone separators.