Air conditioning system and method for controlling same

A method for controlling an air conditioning system, wherein the air conditioning system comprises:

• an enhanced vapor injection compressor comprising a housing, a liquid accumulator and a compression mechanism disposed in the housing, wherein the housing is provided with an air discharge port, an air supplement port, a first air suction port and a second air suction port;
• wherein the liquid accumulator is provided with an air return port, the air return port is in communication with the first air suction port;
• and wherein the first air suction port and the second air suction port are in communication with air suction channels of two air cylinders of the compression mechanism, respectively, and a pressure in a sliding vane chamber of one air cylinder, corresponding to the second air suction port, of the compression mechanism is equal to a discharge pressure at the air discharge port;
• a first direction switching assembly comprising a first pipe port, a second pipe port and a third pipe port, wherein the first pipe port is connected to the second air suction port, the second pipe port is connected to the air discharge port, the third pipe port is connected to the liquid accumulator, and the first pipe port is in communication with one of the second pipe port and the third pipe port;
• a second direction switching assembly having a first valve port, a second valve port, a third valve port and a fourth valve port, wherein the first valve port is in communication with one of the second valve port and the third valve port, the fourth valve port is in communication with the other one of the second valve port and the third valve port, and the first valve port and the fourth valve port are connected to the air discharge port and the air return port, respectively;
• a first heat exchanger having a first end connected with the second valve port and a second end;
• a second heat exchanger having a first end connected with the third valve port and a second end;
• and
• a flash evaporator having an air outlet, a first port and a second port, wherein the air outlet is connected to the air supplement port, the first port is connected with the second end of the first heat exchanger, the second port is connected with the second end of the second heat exchanger, a first throttling element is connected in series between the first port and the first heat exchanger, and a second throttling element is connected in series between the second port and the second heat exchanger,
• wherein the method for controlling the air conditioning system comprises:
• detecting an operation mode of the air conditioning system, an indoor temperature T1, an outdoor temperature T4 and a user-set temperature TS;
• detecting whether the outdoor temperature T4 is larger than a first set temperature T2, when the air conditioning system operates in a refrigerating mode, controlling the first direction switching assembly to communicate the first pipe port with the third pipe port, if the outdoor temperature T4 is larger than the first set temperature T2;
• controlling the first direction switching assembly to communicate the first pipe port with the third pipe port, if the outdoor temperature T4 is less than or equal to the first set temperature T2 and it is detected that a first difference value T1−TS between the indoor temperature T1 and the user-set temperature TS is larger than or equal to a second set temperature T3;
• and controlling the first direction switching assembly to communicate the first pipe port with the second pipe port, if the outdoor temperature T4 is less than or equal to the first set temperature T2 and it is detected that the first difference value T1−TS is less than the second set temperature T3;
• and
• detecting whether the outdoor temperature T4 is larger than a third set temperature T5, when the air conditioning system operates in a heating mode, controlling the first direction switching assembly to communicate the first pipe port with the third pipe port, if the outdoor temperature T4 is less than or equal to the third set temperature T5;
• controlling the first direction switching assembly to communicate the first pipe port with the third pipe port, if the outdoor temperature T4 is larger than the third set temperature T5 and it is detected that a second difference value TS−T1 between the user-set temperature TS and the indoor temperature T1 is larger than or equal to a fourth set temperature T6;
• and controlling the first direction switching assembly to communicate the first pipe port with the second pipe port, if the outdoor temperature T4 is larger than the third set temperature T5 and it is detected that the second difference value TS−T1 is less than the fourth set temperature T6.