Heat recovery variable-frequency multi-split heat pump system and control method thereof
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Solution Overview
Problem
The existing heat recovery variable-frequency multi-connected heat pump systems are complex and costly to control due to the need for multiple four-way valves to allocate refrigerant and recover discharged heat, which degrades thermal comfort, especially in rainy or low-temperature environments.
Innovation Solution
A heat recovery variable-frequency multi-connected heat pump system utilizing a four-way valve with three pipes, oil separator, check valve, vapor-liquid separator, and multiple electromagnetic valves to manage refrigerant flow across various operating conditions, including refrigerating, heating, and dehumidifying, allowing for flexible operation of indoor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple four-way valves are arranged to allocate refrigerant and recover discharged heat, then heat recovery function is improved, but device complexity and control cost increase
Solution Approach 1:
The patent merges multiple four-way valves into a single four-way valve with multiple ports (A, B, C, D ends) that can control refrigerant flow to multiple indoor units. This consolidation reduces the number of valves from multiple to one, simplifying the device structure and control mechanism while maintaining the heat recovery function across multiple units.
Solution Approach 2:
The single four-way valve is designed with multi-functionality to perform the roles of multiple traditional four-way valves. It can allocate refrigerant to different indoor units (heating or cooling modes) and manage heat recovery from multiple sources simultaneously through its multiple ports and configurable connection paths.
2Productivity
If temperature is lowered for dehumidification in rainy or low-temperature environments, then dehumidification effect is improved, but thermal comfort deteriorates
Solution Approach 1:
The patent segments the dehumidification process into two independent functional paths: one path (through the evaporator) handles moisture removal by condensing water vapor, while another path (through the heater) handles temperature maintenance. This segmentation allows dehumidification to occur without necessarily lowering the outlet air temperature, preserving thermal comfort.
Solution Approach 2:
The patent introduces a heater as an intermediary component between the evaporator and the outdoor environment. The heater warms the air after dehumidification, acting as a mediator that decouples the dehumidification effect from temperature reduction, thereby maintaining thermal comfort while achieving effective moisture removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves thermal comfort and efficiency by enabling six operating conditions, effectively managing heat recovery and dehumidification without lowering temperatures, thus enhancing the system's refrigerating and heating capacity.
Implementation Method 1
at least one compressor; an exhaust end of the compressor is connected with an end of the four-way valve
Implementation Method 2
the four-way valve, an outdoor heat exchanger, an outdoor electronic expansion valve... an end of the four-way valve is connected with a suction end of the compressor; an end of the four-way valve is connected with a low-pressure gas return pipe
Implementation Method 3
another end of the four-way valve is connected with the outdoor heat exchanger, and an other end of the outdoor heat exchanger is connected with the high-pressure liquid pipe through the outdoor electronic expansion valve
Implementation Method 4
an other end of the outdoor heat exchanger is connected with the high-pressure liquid pipe through the outdoor electronic expansion valve
Implementation Method 5
a second electromagnetic valve, a third electromagnetic valve... an end of the four-way valve is connected with the low-pressure gas return pipe
Implementation Method 6
heat in the system is recovered... enable the operating indoor units to refrigerate and heat concurrently
Data Source
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AI summary
A heat recovery variable-frequency multi-split heat pump system and a control method thereof. The system comprises an outdoor unit and at least two indoor units. The system is a three-pipe heating recovery multi-split heat pump system designed on the basis of a four-way reversing valve, and one indoor unit thereof is provided with two electronic expansion valves and two heat exchangers so that any indoor unit in the system can operate independently under three working conditions of refrigeration, heating or heat recovery dehumidification. Under multi-split condition, the system can operate under six working conditions, namely, the full-refrigeration working condition, the full-heating working condition, the common-heat-recovery working condition, the common-heat-recovery-dehumidification working condition, the heat recovery dehumidification-refrigeration-combination working condition and the heat recovery dehumidification-heating-combination working condition. Under the heat recovery dehumidification condition, a lower outlet air temperature, during low-temperature dehumidification, is raised by means of heat removal of a condenser so as to achieve the purpose of dehumidification without temperature fall or temperature rise, so that the thermal comfort and efficiency of the system are improved, and the refrigerating capacity and heating capacity of the system are effectively improved.