Sistema de refrigeración y método de funcionamiento de un sistema de refrigeración

A refrigeration system comprises a main refrigeration circuit for holding refrigerant fluid, the main refrigeration circuit including: a compression device 12, a heat rejecting heat exchanger 14, an expansion device 18 and a heat absorbing heat exchanger 16. In addition, the refrigeration system includes a buffer tank 20 attached to the main refrigeration circuit, with valves 22, 24 for controlling flow of refrigerant fluid between the main refrigeration circuit and the buffer tank 20. The refrigeration system is arranged such that the valves 22, 24 are controlled to transfer refrigerant fluid between the main refrigeration circuit and the buffer tank 20 based on a measure of sub-cooling in the main refrigeration circuit. Via the use of a buffer tank 20 and controllable valves 22, 24 it becomes possible to vary the refrigerant charge level of the main refrigeration circuit in order to allow for increased efficiency during changes in operating conditions, as well as increased refrigerant capacity, the potential to enlarge the operating envelope of the refrigerant system, and other enhancements including greater robustness over time as refrigerant charge is depleted.