Defrosting control method of multifunctional multi-split system with double four-way valves

A defrosting control method of a multi-functional multi-split system with double four-way valves, the multi-split system comprising:

• an outdoor unit (100),
• at least one set of hydraulic modules (200),
• at least one set of indoor modules (300),
• a liquid pipe (7),
• a high-low pressure gas pipe (8), and
• a high-pressure gas pipe (9),
• wherein the outdoor unit (100) comprises a compressor (1), a first four-way valve (2), a second four-way valve (3), and an outdoor heat exchanger (4),
• wherein an output end of the compressor (1) is respectively connected to port D of the first four-way valve (2) and port D of the second four-way valve (3), an input end of the compressor (1) is respectively connected to port S of the first four-way valve (2) and port S of the second four-way valve (3), port E of the first four-way valve (2) is connected to port S of the second four-way valve (3) via a throttling unit, port C of the second four-way valve (3) is connected to port S of the first four-way valve (2) via a throttling unit, and port C of the first four-way valve (2) is connected to the outdoor heat exchanger (4);
• wherein one end of the liquid pipe (7) is connected to the outdoor heat exchanger (4), and the other end of the liquid pipe (7) is respectively connected to the other end of a hydraulic heat exchanger (10) of each set of hydraulic modules (200) and the other end of an indoor heat exchanger (11) of each set of indoor modules (300);
• wherein one end of the high-pressure gas pipe (9) is connected between the four-way valves and the output end of the compressor (1) by bypassing, and the other end of the high-pressure gas pipe (9) is connected to one end of the hydraulic heat exchanger (10) of each set of hydraulic modules (200);
• wherein one end of the high-low pressure gas pipe (8) is connected to port E of the second four-way valve (3), and the other end of the high-low pressure gas pipe (8) is respectively connected to one end of the hydraulic heat exchanger (10) of each set of hydraulic modules (200) and one end of the indoor heat exchanger (11) of each set of indoor modules (300);
• wherein a first electronic expansion valve (12) is arranged between the liquid pipe (7) and each hydraulic heat exchanger (10) and each indoor heat exchanger (11);
• wherein a first electromagnetic valve (13) is arranged between the high-pressure gas pipe (9) and any one of the hydraulic heat exchangers (10);
• wherein a second electromagnetic valve (14) is arranged between the high-low pressure gas pipe (8) and any one of the hydraulic heat exchangers (10);
• the method comprising, when the multi-split system is switched from a normal operation mode to a defrosting mode, the first four-way valve (2) and the second four-way valve (3) are powered down, and operation modes of each set of indoor modules (300) and each set of hydraulic modules (200), the on/off state of fans of the indoor heat exchangers (11) and the hydraulic heat exchangers (10), opening degrees of the first electronic expansion valves (12) of the indoor heat exchangers (11) and the first electronic expansion valves (12) of the hydraulic heat exchangers (10), and the on/off state of the first electromagnetic valves (13) and the second electromagnetic valves (14) are correspondingly adjusted based on the previous operation modes of each set of indoor modules (300) and each set of hydraulic modules (200);
• wherein when the first four-way valve (2) is powered down, the first port (D) thereof is in communication with the fourth port (C), and the third port (E) is in communication with the second port (S) and, when the second four way valve (3) is power down, the first port (D) thereof is in communication with the third port (C), and the fourth port (E) is in communication with the second port (S);
• and
• wherein the adjusting comprises:
• adjusting the first expansion valve (12) of each set of indoor modules (300) previously in an operating mode to a maximum opening degree;
• each indoor module previously in an off state remaining off;
• turning off the first electromagnetic valve (13), the second electromagnetic valve (14), and the first electronic expansion vale (12) of each set of hydraulic modules (200) previously in an off state;
• and
• switching each set of hydraulic modules (200) previously in a water heating mode to a water refrigeration mode, and turning on the first electromagnetic vale 913) thereof, turning off the second electromagnetic valve (14) thereof, and adjusting the first electronic expansion vale (12) thereof to a maximum degree opening.