Cascade air conditioner system
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Solution Overview
Problem
Traditional self-cascade air conditioner systems face difficulties in controlling the degree of dryness of the refrigerant outlet, leading to poor stability and performance due to the two-phase state of the refrigerant exiting the condenser.
Innovation Solution
A cascade air conditioner system design where the gas-phase refrigerant from the compressor is introduced to a flash tank, allowing for convenient control of the degree of dryness through heat and mass exchange, eliminating the need to control the dryness at the condenser outlet, thereby simplifying system regulation and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional self-cascade system uses a two-phase refrigerant outlet from the condenser, then the system can operate under large temperature difference conditions, but the degree of dryness control becomes extremely difficult and system stability deteriorates
Solution Approach 1:
The system divides the refrigerant flow into separate liquid-phase and gas-phase paths. The condenser outlet is segmented to deliver liquid-phase refrigerant to the flash tank, while gas-phase refrigerant is separately managed. This segmentation eliminates the need to control the degree of dryness of a two-phase mixture, as the phases are separated at the source.
Solution Approach 2:
The flash tank serves as an intermediary device between the condenser and evaporator. It receives liquid-phase refrigerant and performs flash evaporation to generate the required two-phase mixture for the evaporator, while separately handling gas-phase refrigerant from the compressor. This intermediary structure simplifies control by decoupling the condenser outlet state from the evaporator inlet state.
2Device complexity
If the refrigerant is allowed to be in two-phase state at the condenser outlet, then the system can maintain simple structure, but the system performance and stability become poor due to difficult regulation
Solution Approach 1:
The system dynamically adjusts the flash evaporation ratio in the flash tank to optimize performance under different operating conditions. By controlling the amount of liquid-phase refrigerant entering the flash tank and the flash evaporation process, the system can adapt to varying temperature and pressure conditions while maintaining stable two-phase refrigerant supply to the evaporator, thereby improving reliability without significantly increasing structural complexity.
3Ease of operation
If gas-phase refrigerant is introduced directly to the flash tank, then the degree of dryness can be controlled conveniently, but additional components and connections are required
Solution Approach 1:
The flash tank is designed to perform multiple functions: it serves as a separator for liquid-phase refrigerant from the condenser, a flash evaporation chamber for generating two-phase refrigerant, and a mixing chamber for combining with gas-phase refrigerant from the compressor. This multi-functionality reduces the need for additional dedicated components, as the flash tank handles both liquid-phase and gas-phase refrigerant management in a single device.
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 design ensures the refrigerant remains in a liquid phase, reducing control complexity and improving system stability and performance by maintaining consistent pressures and optimizing heat exchange efficiency.
Implementation Method 1
a refrigerant of the system coming out of a condenser is in two-phase state, and a degree of dryness of an outlet has a great influence on the performances
Implementation Method 2
A first heat exchanger is connected in series between the first gas outlet and the first flash evaporation port
Data Source
AI summary
Disclosed is a cascade air conditioner system. The cascade air conditioner system includes a compressor (1) having a first gas outlet (11), a second gas outlet (12) and a gas inlet (13); a flash tank (2) having a first flash evaporation port (21), a second flash evaporation port (22), a third flash evaporation port (23), and a fourth flash evaporation port (24); and a condenser evaporator (3) having a first port (31), a second port (32), a third port (33), and a fourth port (34), wherein a first heat exchanger (41) is connected in series between the first gas outlet (11) and the first flash evaporation port (21), the second flash evaporation port (22) is connected via a pipe with the first port (31), the second gas outlet (12) is connected via a pipe with the fourth flash evaporation port (24), the third flash evaporation port (23) is connected via a pipe with an inlet of a first throttle element (51), an outlet of the first throttle element (51) is connected via a pipe with a second heat exchanger (42) and is connected via a pipe with the third port (33), the second heat exchanger (42) is also connected via a pipe with the second port (32) through a second throttle element (52), and the fourth port (34) is connected via a pipe with the gas inlet (13). In the cascade air conditioner system, a gas-phase refrigerant in the compressor (1) is introduced to the flash tank (2), such that the degree of dryness in the flash tank (2) can be controlled conveniently, thereby enhancing performances of the system.