Refrigerant Cooling Control Near the Saturation Line
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Solution Overview
Problem
In refrigeration devices, when the refrigerant is expanded by the first expansion valve to a state near the saturation line, it can reach a critical point, leading to cavitation risks and difficulties in controlling the fluid level in the liquid receiver, making it challenging to maintain an appropriate refrigerant amount in the circuit.
Innovation Solution
A refrigeration device with a compression mechanism, radiator, first expansion mechanism, refrigerant cooling unit, liquid receiver, second expansion mechanism, and control unit, where the refrigerant cooling unit cools the refrigerant to prevent it from reaching a state near the critical point, using an internal heat exchanger to control the refrigerant's state near the saturation line without requiring an external cooling device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refrigerant is expanded by the first expansion valve to a state near the saturation line, then the refrigeration efficiency is improved, but the refrigerant may reach a critical point causing cavitation and control difficulties
Solution Approach 1:
The patent applies preliminary action by introducing a refrigerant cooling unit that cools the refrigerant before it reaches the first expansion valve. This pre-cooling prevents the refrigerant from reaching the critical point during expansion, thereby avoiding cavitation and control difficulties while maintaining efficient refrigeration. The control unit monitors refrigerant conditions and activates cooling in advance when necessary.
2Reliability
If a refrigerant cooling unit is added to prevent critical point, then the refrigerant state control is improved, but the device complexity increases
Solution Approach 1:
The refrigerant cooling unit is designed with multi-functionality, serving both as a heat exchanger for cooling refrigerant and as an integrated component within the existing refrigeration system. The control unit that manages the cooling operation also monitors overall system conditions, allowing one component to perform multiple functions and thereby reducing overall system complexity despite adding cooling capability.
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
Prevents the refrigerant from reaching a critical state during expansion, maintaining stable refrigerant levels and reducing manufacturing costs by eliminating the need for external cooling devices.
Implementation Method 1
a refrigerant cooling unit, disposed between an exit side of the radiator and a refrigerant inflow side of the first expansion mechanism
Data Source
AI summary
A refrigeration device includes a control unit, and a refrigerant circuit in which a compression mechanism, a radiator, a refrigerant cooling unit, a first expansion mechanism, a liquid receiver, a second expansion mechanism, and an evaporator are connected in sequence. The control unit performs refrigerant cooling control whereby the refrigerant is cooled by the refrigerant cooling unit so that the state of the refrigerant that has flowed out from the first expansion mechanism is near the saturation line and not near the critical point.