Gas-Liquid Separator Injection for CO2 Defrost Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of carbon dioxide as a refrigerant in air conditioners increases the compression ratio, leading to a severe burden on compressors and reduces the driving efficiency, especially during defrosting operations where the high pressure side compressor struggles with wet vapor suction, resulting in insufficient defrosting capacity and prolonged defrosting times.
Innovation Solution
A refrigerating apparatus with a two-stage compression/two-stage expansion refrigeration cycle, including a low pressure side compressor, a high pressure side compressor, and an intermediate-pressure refrigerant gas-liquid separator, where the refrigerant circuit is switched between heating and defrosting cycles, with the high pressure side compressor driven to increase defrosting capacity by injecting refrigerant from the gas-liquid separator and using heating means to prevent liquid refrigerant from entering the compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon dioxide is used as refrigerant with high compression ratio, then refrigeration effect is improved, but compressor burden increases and driving efficiency decreases
Solution Approach 1:
The compression process is divided into two stages: a low-pressure compressor compresses refrigerant to intermediate pressure, then a high-pressure compressor further compresses it to high pressure. This segmentation reduces the burden on individual compressors and improves overall driving efficiency while maintaining the refrigeration effect of carbon dioxide.
Solution Approach 2:
An intermediate-pressure refrigerant gas-liquid separator is introduced as an intermediary component between the low-pressure and high-pressure compressors. This separator divides intermediate-pressure refrigerant into gas and liquid phases, with the gas phase being injected into the high-pressure compressor suction side, enabling efficient two-stage compression.
2Productivity
If high pressure side compressor is driven during defrosting operation, then defrosting capacity is improved, but risk of liquid refrigerant entering compressor increases
Solution Approach 1:
The state of refrigerant in the gas-liquid separator is changed by heating, which increases the proportion of gas phase refrigerant. This parameter change ensures that when the high-pressure compressor operates during defrosting, it receives predominantly gas-phase refrigerant, preventing liquid suction while maintaining high defrosting capacity.
3Power
If gas-liquid separator is used to separate intermediate-pressure refrigerant, then compressor performance is improved, but device complexity increases
Solution Approach 1:
The gas-liquid separator performs multiple functions: it separates intermediate-pressure refrigerant into gas and liquid phases, serves as a reservoir for gas-phase refrigerant injection into the high-pressure compressor, and prevents liquid refrigerant from entering the high-pressure compressor. This multi-functionality improves compressor performance while minimizing the increase in device 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 allows both compressors to be driven during defrosting, enhancing defrosting capacity and reducing the time required for defrosting, thereby improving comfort and efficiency in heating operations.
Implementation Method 1
intermediate-pressure refrigerant gas-liquid separator for separating intermediate-pressure refrigerant into gas and liquid
Implementation Method 2
using heating means to prevent liquid refrigerant from entering the compressor
Implementation Method 3
liquid refrigerant from the gas-liquid separator flows into the outdoor heat exchanger to be evaporated
Data Source
AI summary
An optional unit (30) including a high pressure side compressor (31) and a gas-liquid separator (33) is provided between an outdoor unit (20) including a low pressure side compressor (21) and an indoor unit (40). During a defrosting operation, refrigerant discharged from the low pressure side compressor (21) defrosts an outdoor heat exchanger (21) while refrigerant in the gas-liquid separator (33) is sucked into the high pressure side compressor (31) and is then discharged to the suction side of the low pressure side compressor (21). The optional unit (30) includes an injection pipe (36) for returning part of the refrigerant discharged from the high pressure side compressor (31) to the suction side of the high pressure side compressor (31) in the defrosting operation. Hence, the refrigerant flowing into the high pressure side compressor (31) from the gas-liquid separator (33) is gasified by the high-temperature discharged refrigerant.