Heat Pump Suction Mixing Control for Compressor Protection
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Solution Overview
Problem
Heat pump cycle devices face challenges in reliably protecting compressors when refrigerants with different enthalpies are mixed and sucked into the compressor, as the flow rate regulation range of the heating-unit side decompression unit differs from the bypass-side flow-rate regulating valve, potentially leading to inappropriate suction refrigerant states and reduced compressor protection.
Innovation Solution
A heat pump cycle device is configured with a compressor, branch portion, heating unit, heating-unit side decompression unit, bypass passage, bypass-side flow-rate regulating unit, mixing portion, target temperature determination unit, and regulating performance determination unit, where the operations of these units are controlled to ensure the suction refrigerant approaches a predetermined quality and degree of superheating, and the throttle openings are regulated to maintain an appropriate state, even when refrigerants with different enthalpies are mixed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If refrigerants with different enthalpies are mixed and sucked into the compressor, then heating performance is improved, but compressor protection reliability deteriorates
Solution Approach 1:
The control unit receives signals from a suction refrigerant temperature sensor and suction refrigerant pressure sensor to detect the state of the suction refrigerant. Based on this feedback information, the control unit adjusts the opening degrees of the electronic expansion valve and bypass valve to maintain appropriate suction refrigerant quality and prevent compressor damage
Solution Approach 2:
The system dynamically adjusts the opening degrees of the electronic expansion valve and bypass valve based on real-time detection of suction refrigerant temperature and pressure. This dynamic control allows the system to adapt to changing operating conditions while maintaining safe suction refrigerant states during hot-gas air-heating mode
2Adaptability or versatility
If the flow rate regulation range of the heating-unit side decompression unit differs from the bypass-side flow-rate regulating valve, then system adaptability is improved, but suction refrigerant state control deteriorates
Solution Approach 1:
The control unit coordinates both the electronic expansion valve in the heating unit side and the bypass valve in the bypass passage, making them work together to achieve proper suction refrigerant quality control. This multi-functional coordination compensates for the different flow rate regulation ranges of the two valves
3Reliability
If the operation of decompression units is controlled to maintain suction refrigerant quality, then compressor protection is improved, but device complexity increases
Solution Approach 1:
The control unit integrates the control functions of both the electronic expansion valve and bypass valve into a single coordinated control system. By merging the control logic, the system achieves comprehensive suction refrigerant quality management while avoiding the need for separate independent control systems that would increase complexity
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
This configuration ensures the compressor is reliably protected by maintaining the suction refrigerant in an appropriate state, preventing gas-liquid two-phase refrigerants with inadequate quality and gas-phase refrigerants with excessive superheating, thereby ensuring efficient and safe operation.
Implementation Method 1
The heating unit is configured to heat an object using one refrigerant branched at the branch portion
Implementation Method 2
The heating-unit side decompression unit is configured to decompress the refrigerant flowing out of the heating unit
Data Source
AI summary
A heat pump cycle device includes a compressor, a branch portion, a heating unit, a heating-unit side decompression unit, a bypass passage, a bypass-side flow-rate regulating unit, a mixing portion, and a target temperature determination unit. When a regulating performance determination unit determines that a flow rate regulating performance of one of the heating-unit side decompression unit or the bypass-side flow-rate regulating unit is equal to or less than the reference regulating performance, a throttle opening of the other of the heating-unit side decompression unit or the bypass-side flow-rate regulating unit is set to be equal to or less than an upper limit opening.