Air conditioning system
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Solution Overview
Problem
Existing carbon dioxide air conditioning systems with injectors face challenges in improving system performance and energy efficiency, particularly in large-scale commercial applications.
Innovation Solution
Incorporating a first subcooling circuit with a subcooler and optional additional components such as a second subcooler, throttling elements, and a liquid pump to further cool the refrigerant downstream of the injector, increasing the proportion of liquid-phase refrigerant for enhanced heat exchange and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a subcooling circuit is added to cool refrigerant downstream of the injector, then the proportion of liquid-phase refrigerant increases and system performance improves, but the device complexity increases
Solution Approach 1:
The subcooling circuit is integrated into the existing refrigerant circulation system by utilizing the liquid outlet of the gas-liquid separator and connecting it back to the injector through a subcooling heat exchanger. This merging approach allows the subcooling function to be added without creating a completely separate system, thereby improving liquid-phase refrigerant proportion while limiting the increase in device complexity.
Solution Approach 2:
A subcooling heat exchanger is introduced as an intermediary component between the gas-liquid separator and the injector. This intermediary device enables heat exchange that converts gas-phase refrigerant to liquid-phase refrigerant, thereby increasing the proportion of liquid-phase refrigerant entering the evaporator without requiring direct modification of the injector or separator structures.
2Loss of energy
If multiple subcooling components are added to increase liquid-phase refrigerant proportion, then energy efficiency improves, but the volume of the system increases
Solution Approach 1:
The subcooling heat exchanger serves multiple functions: it acts as both a subcooling device for converting gas-phase refrigerant to liquid-phase refrigerant and as part of the overall heat exchange system. This multi-functionality allows energy efficiency to be improved without proportionally increasing system volume, as the same component structure performs multiple thermal management tasks.
Solution Approach 2:
The system utilizes phase change parameters of the refrigerant, specifically transforming refrigerant from gas-phase to liquid-phase through controlled heat exchange in the subcooling circuit. By changing the phase parameter of the refrigerant rather than simply cooling it, the system achieves improved energy efficiency with relatively compact equipment volume.
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 solution effectively improves system performance and energy efficiency by increasing the proportion of liquid-phase refrigerant participating in heat exchange, thereby enhancing cooling capacity and reliability.
Implementation Method 1
a two-phase flow of refrigerant flowing out of the outlet of the injector of the main circuit is further cooled by the first subcooling circuit disposed downstream of the injector, so that part of the gas-phase refrigerant is further condensed into a liquid-phase refrigerant
Implementation Method 2
an injector for initially compressing a refrigerant fluid before the refrigerant fluid enters the main compressor, thereby increasing a suction pressure of the fluid entering the main compressor
Data Source
Figure 1~2
Figure 3
AI summary
An air conditioning system (100) and a control method thereof are provided by the present disclosure. The air conditioning system includes a main circuit (110) and a first subcooling circuit (120), wherein the main circuit has: a main compressor (111) and an injector (112); a gas cooler (113) and a gas-liquid separator (114) connected between the main compressor and the injector; and a main throttling element (115) and an evaporator (116) connected between the gas-liquid separator and the injector; and wherein the first subcooling circuit has: a first subcooling compressor (121), a first condenser (122), a first subcooling throttling element (123) and a first subcooler (124) connected in sequence; wherein the first subcooler is further disposed in a flow path between the outlet of the injector and the gas-liquid separator. According to the air conditioning system of the present disclosure and the control method thereof, a two-phase flow of refrigerant flowing out of the outlet of the injector of the main circuit is further cooled by the first subcooling circuit disposed downstream of the injector, so that part of the gas-phase refrigerant is further condensed into a liquid-phase refrigerant; as a result, the proportion of the liquid-phase refrigerant that subsequently enters the evaporator to participate in heat exchange is increased, thereby effectively improving the system performance and energy efficiency thereof.