Heat Recovery Multi-Split Air Conditioning System and Control Method

Abstract

A heat recovery multi-split air conditioning system including: an indoor module, an outdoor module, and a hydraulic module. The outdoor module comprises a compressor, two four-way valves, three electronic expansion valves, an outdoor heat exchanger, an outdoor fan, and a subcooler. The hydraulic module includes a heat exchange water tank and a refrigerant flow path. An inlet of the refrigerant flow path is communicated with an outlet of the compressor. Four joints of the subcooler are respectively communicated with the outlet of the refrigerant flow path, an outdoor heat exchanger, an air return port of the compressor, and the indoor module. The system further includes a temperature acquiring module, a water tank temperature correction coefficient acquiring module, and a control module. In a hot water production mode, an opening degree of the third electronic expansion valve is adjusted.

1 . A heat recovery multi-split air conditioning system, comprising: an indoor module, an outdoor module, and a hydraulic module, wherein the outdoor module comprises a compressor, a first four-way valve, a second four-way valve, multiple electronic expansion valves, an outdoor heat exchanger, and an outdoor fan; the hydraulic module comprises a heat exchange water tank and a refrigerant flow path;
 further comprising a subcooler, wherein four joints of the subcooler are respectively communicated with an outlet of the refrigerant flow path, the outdoor heat exchanger, an air return port of the compressor, and the indoor module; an inlet of the refrigerant flow path is communicated with an outlet of the compressor;   the multiple electronic expansion valves comprise: a first electronic expansion valve disposed between the outdoor heat exchanger and the indoor module, a second electronic expansion valve disposed between an outlet of the refrigerant flow path and the first electronic expansion valve, and a third electronic expansion valve disposed between an outlet of the refrigerant flow path and a joint of the subcooler;   further comprising: a temperature acquiring module configured to acquire a water tank temperature and a refrigerant liquid pipe temperature of the hydraulic module; a water tank temperature correction coefficient acquiring module, which obtains a water tank temperature correction coefficient; and a control module, wherein when in a hot water production mode, the control module adjusts an opening degree of the third electronic expansion valve according to a comparison result between a different value among the water tank temperature, the water tank temperature correction coefficient, and the refrigerant liquid pipe temperature of the hydraulic module and a first preset value.   
     
     
         2 . The heat recovery multi-split air conditioning system according to  claim 1 , wherein the temperature acquiring module is further configured to acquire a pre-subcooling temperature of the refrigerant before entering a subcooling pipe of the indoor module and a post-subcooling temperature of the refrigerant after entering the subcooling pipe of the indoor module;
 the control module is configured to: when the difference value of the water tank temperature, the water tank temperature correction coefficient, and the refrigerant liquid pipe temperature of the hydraulic module is within a prescribed temperature range, adjust the opening degree of the third electronic expansion valve according to a comparison result between a difference value of the pre-subcooling temperature and the post-subcooling temperature and a second preset value.   
     
     
         3 . The heat recovery multi-split air conditioning system according to  claim 1 , wherein the temperature acquiring module is configured to acquire an outdoor ambient temperature and a temperature of an outlet in a lowest path of a condenser; in a refrigeration mode, after the outdoor fan runs a specified time length according to a maximum fan speed corresponding to the outdoor ambient temperature, the control module adjusts an operating fan speed of the outdoor fan according to the temperature of the outlet in a lowest path of the condenser. 
     
     
         4 . The heat recovery multi-split air conditioning system according to  claim 1 , wherein in a refrigeration mode, an operating energy demand of the compressor is NC 1 =NC+€1+€2, NC is an original energy demand of the compressor; €1 is a corrected value for a refrigeration internal unit, and €2 is a corrected value for a temperature difference of hot water. 
     
     
         5 . The heat recovery multi-split air conditioning system according to  claim 4 , wherein the temperature acquiring module is configured to acquire a temperature of an outlet of an evaporator; in a refrigeration mode, the control module adjusts a corrected value of the refrigeration internal unit according to a comparison result between the temperature of the outlet of the evaporator and a third preset value. 
     
     
         6 . The heat recovery multi-split air conditioning system according to  claim 4 , wherein the temperature acquiring module is configured to acquire a water tank temperature; during refrigeration, the control module adjusts the temperature difference of hot water according to a comparison result between a set temperature of the water tank and the water tank temperature and a fourth preset value. 
     
     
         7 . The heat recovery multi-split air conditioning system according to  claim 3 , wherein in a hot water production mode, a refrigerant returns to the compressor after sequentially passing through the compressor, a refrigerant flow path of the hydraulic module, the second electronic expansion valve, the first electronic expansion valve, the outdoor heat exchanger, and the first four-way valve; and/or a refrigerant returns to the compressor after sequentially passing through the compressor, a refrigerant flow path of the hydraulic module, the third electronic expansion valve, and the subcooler. 
     
     
         8 . The heat recovery multi-split air conditioning system according to  claim 4 , wherein in a refrigeration mode, a refrigerant returns to the compressor after sequentially passing through the compressor, the second four-way valve, the outdoor heat exchanger, the first electronic expansion valve, the subcooler, the indoor module, and the first four-way valve. 
     
     
         9 . A method for controlling a heat recovery multi-split air conditioning system according to  claim 1 , comprising the following steps:
 acquiring a water tank temperature and a refrigerant liquid pipe temperature of the hydraulic module; acquiring a water tank temperature correction coefficient;   acquiring a water tank temperature correction coefficient;   when mainly employed in producing hot water, the control module adjusts an opening degree of the third electronic expansion valve according to a comparison result between a difference value of the water tank temperature, the water tank temperature correction coefficient, and the refrigerant liquid pipe of the hydraulic module temperature, and a first preset value.   
     
     
         10 . The method for controlling a heat recovery multi-split air conditioning system according to  claim 9 , further comprising: in a refrigeration mode, acquiring an outdoor ambient temperature and a temperature of an outlet in a lowest path of a condenser; after the outdoor fan runs a specified time length according to a maximum fan speed corresponding to the outdoor ambient temperature, the control module adjusts an operating fan speed of the outdoor fan according to the temperature of the outlet in a lowest path of the condenser; and/or
 acquiring a temperature of an outlet of an evaporator, wherein the control module adjusts an operating energy demand of the compressor according to a comparison result between a temperature of an outlet of the evaporator and a third preset value; and adjusts an operating energy demand of the compressor according to a comparison result between a difference value of a set temperature of the water tank and the water tank temperature and a fourth preset value.