In order to achieve the climate neutrality goals and the forthcoming F-gas regulation, it is important to promote the transition toward low-GWP refrigerants. Almost all low GWP refrigerants are flammable and the safety issues of these refrigerants (hydrocarbons and HFOs) prevent them from being used in larger systems. The purpose of this project is to develop and improve the knowledge required for the safe use of flammable refrigerants in refrigeration and heat pump systems. This project will evaluate and quantify the refrigerant concentration around a plant in connection with unintentional emissions. We will use CFD tools, with experimental verification, to model and identify the ignition risks and quantify the concentrations of the leaked refrigerants in case of accidental emissions in different scenarios such as domestic heat pumps, restaurant kitchens and other commercial stores that use different types of refrigeration units. An air dispersion model will be used to determine if leaking refrigerant would reach the concentrations required for ignition in several refrigeration systems. The investigation of gas dispersion during unintentional emissions in different application scenarios requires careful modeling and the use of simulation tools makes it possible to model different emission scenarios. A limited amount of studies have been performed, but the effects of the type of refrigerant, differences in density, effects of temperature of the released fluid, effects of boundary conditions in terms of air movements, room size, possible effects of fans, effects of release of inert gases to mitigate the buildup of flammable concentrations etc. have not been investigated in full. we are going to fill this gap and provide CFD-modelling solutions to improve the safety regarding the use of flammable refrigerants in heat pump and refrigeration systems.