Refrigeration system and the control method thereof

A refrigeration system comprising a compressor and a condenser, and further comprising:

• a first throttling device for throttling liquid refrigerant from the condenser to produce gas-liquid two-phase refrigerant;
• an ejector having a high-pressure fluid inlet, a fluid suction inlet and a fluid outlet, wherein the high-pressure fluid inlet of the ejector is connected to the first throttling device to receive the gas-liquid two-phase refrigerant, the fluid outlet of the ejector is connected to a flash tank, a gas-phase outlet of the flash tank is connected to a compressor inlet, a liquid-phase outlet of the flash tank is connected to an evaporator via a second throttling device, and the evaporator is connected to the fluid suction inlet of the ejector;
• and
• a controller configured to control an opening of the first throttling device based on a sensed pressure difference between the fluid outlet and the fluid suction inlet of the ejector and a dryness of the gas-liquid two-phase refrigerant;
• wherein pressure sensors are respectively provided at the fluid suction inlet or upstream the fluid suction inlet of the ejector and at the fluid outlet or downstream the fluid outlet of the ejector to sense the pressure difference,
• wherein, (i) the refrigeration system comprises a dryness sensor that directly senses the dryness of the gas-liquid two-phase refrigerant, or (ii) the refrigeration system comprises (a) a first pressure sensor and a first temperature sensor upstream of the first throttling device and (b) a second pressure sensor or a second temperature sensor downstream of the first throttling device, and the controller calculates the dryness of the gas-liquid two-phase refrigerant downstream of the first throttling device based on a temperature and a pressure of the refrigerant upstream of the first throttling device and a temperature and a pressure of the refrigerant downstream of the first throttling device.