Heat Pump Bypass Injection for Simultaneous Heating and Defrost
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Solution Overview
Problem
In heat pumps that perform simultaneous heating and defrosting operations, the mixing of refrigerants in a two-phase gas-liquid state and gas refrigerants compromises compressor efficiency, leading to decreased performance and energy efficiency due to the need to raise refrigerant pressure for both heating and defrosting processes.
Innovation Solution
The heat pump design includes a configuration where the refrigerant for defrosting is injected at an intermediate pressure into the compressor, allowing only the heating refrigerant to be raised from low pressure to high pressure, reducing the compressor's load and improving efficiency by heating the two-phase gas-liquid refrigerant to a gas state within the compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If refrigerant for defrosting is mixed with heating refrigerant in the compressor, then simultaneous heating and defrosting operations are enabled, but compressor efficiency decreases due to the need to raise pressure for both refrigerants
Solution Approach 1:
The refrigerant flow path is segmented into separate channels: a main circuit for heating refrigerant and a bypass circuit for defrosting refrigerant. The bypass circuit branches off from the main circuit, allowing defrosting refrigerant to be supplied to the outdoor heat exchanger separately from the heating refrigerant, thus preventing mixing in the compressor while enabling simultaneous operations
Solution Approach 2:
A bypass circuit acts as an intermediary pathway that diverts a portion of the refrigerant from the main circuit to the outdoor heat exchanger for defrosting. This intermediary path allows the defrosting function to operate independently without affecting the main heating circuit or requiring mixing in the compressor
2Reliability
If defrosting refrigerant pressure is lowered to suction temperature, then defrosting operation is effective, but compressor workload increases
Solution Approach 1:
The pressure parameter of the defrosting refrigerant is changed by diverting it through a bypass circuit that supplies it at intermediate pressure rather than low suction pressure. This parameter change allows defrosting to occur at higher pressure, reducing the compression workload while maintaining defrosting effectiveness through the bypass path
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 enhances the energy efficiency of the heat pump by reducing the compressor's workload and improving reliability, allowing continuous heating operations without compromising indoor comfort and reducing the need to lower defrosting refrigerant pressure to suction temperature.
Implementation Method 1
the refrigerant in the two-phase gas-liquid state flowing from the injection port is heated by the intermediate-pressure gas refrigerant that is undergoing compression, and changes into a gas state in the compressor
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A first bypass pipe (6 )whose one end of the first bypass pipe (6) is connected to a main pipe (5) extending from a compressor (1) to an indoor heat exchanger (2), and whose the other end is branched off into parts that are each connected to the main pipe (5) on the inlet side of outdoor heat exchanger (4A, 4B) and a second bypass pipe (40) whose one end of the second bypass pipe (40) is connected to an injection port (43) communicating with the compression chamber of the compressor (1) in which compression is taking place and whose the other end is branched off into parts that are each connected to the main pipe (5) on the outlet side of the outdoor heat exchangers (4A, 4B) are provided. During a defrosting operation that removes frost on the outdoor heat exchangers (4A, 4B), a part of the refrigerant discharged from the compressor (1) is supplied from the first bypass pipe (6) to the outdoor heat exchanger to be defrosted, and is then passed through the second bypass pipe (40) and injected from the injection port (43) of the compressor (1).