Refrigeration system

A refrigeration system comprising a circuit around which a refrigerant circulates, the circuit comprising:

• a first heat exchanger;
• a second heat exchanger, wherein the second heat exchanger exchanges heat between the refrigerant and a thermal store;
• a compressor;
• a metering device, wherein the refrigeration system is operable in a first mode in which a pressure of the refrigerant is reduced by the metering device, and a second mode in which the pressure of the refrigerant is not reduced by the metering device;
• a controller for switching between the first mode and the second mode in response to an input;
• and
• a temperature sensor for measuring a temperature of the thermal store, wherein the controller switches between the first mode and the second mode in response to changes in the temperature of the thermal store as measured by the temperature sensor.

A method for operating a circuit around which a refrigerant circulates, the circuit comprising:

• a compressor;
• a metering device;
• a first heat exchanger for exchanging heat between the refrigerant and a medium;
• and
• a second heat exchanger for exchanging heat between the refrigerant and a thermal store;
• the method comprising:
• operating the circuit in a first mode in which the metering device has a first restriction such that the medium is cooled at the first heat exchanger and the thermal store is heated at the second heat exchanger;
• and
• operating the circuit in a second mode in which the metering device has a second, less restrictive restriction or is bypassed such that the medium is heated at the first heat exchanger and the thermal store is cooled at the second heat exchanger,
• wherein the refrigerant circulates around the circuit in the same direction in both the first mode and the second mode, and wherein the refrigerant undergoes a phase transition in the first mode only.