Refrigerant Subcooling Circuit for Stable Single-Phase Cooling
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Solution Overview
Problem
Conventional refrigeration systems fail to supply refrigerant in a liquid single-phase state to the utilization side circuit during cooling operations, leading to reduced cooling capacity due to the refrigerant changing to a gas-liquid two-phase state, which decreases wetness fraction and increases pressure loss.
Innovation Solution
The system incorporates a gas-liquid separator and cooling means, including a gas refrigerant pressure reducing mechanism and a cooling heat exchanger, to maintain the refrigerant in a subcooled state, ensuring it remains in a liquid single-phase state despite pressure losses, and utilizes a liquid refrigerant pressure reducing mechanism to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If refrigerant is supplied as saturated liquid from gas-liquid separator, then refrigerant circulation is simple, but refrigerant changes to gas-liquid two-phase state due to pressure loss, reducing cooling capacity
Solution Approach 1:
The patent applies preliminary action by subcooling the liquid refrigerant before it leaves the gas-liquid separator. The subcooling heat exchanger pre-cools the refrigerant below its saturation temperature, creating a temperature margin that prevents premature phase change during subsequent pressure loss in the piping system. This advance preparation ensures the refrigerant remains in liquid state when reaching the expansion device.
Solution Approach 2:
The subcooling heat exchanger acts as an intermediary component between the gas-liquid separator and the expansion device. It provides a thermal interaction pathway where refrigerant can exchange heat with the subcooling medium, transforming the refrigerant's thermal state without requiring direct modification of the main refrigeration cycle components.
2Ease of operation
If refrigerant undergoes pressure loss in piping, then refrigerant flow is natural, but wetness fraction decreases and pressure loss increases, reducing cooling efficiency
Solution Approach 1:
The system performs preliminary subcooling of the refrigerant before it enters the piping system. By reducing the refrigerant temperature below its saturation point in advance, the system creates a buffer against the inevitable pressure losses during flow, preventing the pressure drop from causing premature flash evaporation and associated energy losses.
3Stress or pressure
If refrigerant wetness fraction decreases in utilization side circuit, then pressure loss increases, but cooling capacity drops
Solution Approach 1:
The subcooling heat exchanger performs advance cooling of the liquid refrigerant, creating a temperature margin that maintains liquid phase stability throughout the piping system. This preliminary thermal preparation ensures that even when pressure loss occurs, the refrigerant wetness fraction remains stable and high, preserving both low pressure loss characteristics and high cooling capacity in the utilization side circuit.
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 maintains the refrigerant in a subcooled state, reducing pressure losses and enhancing cooling capacity by maintaining a liquid single-phase state, thereby improving the overall efficiency and reliability of the refrigeration system.
Implementation Method 1
a gas-liquid separator for separating refrigerant flowing in from the expander into liquid refrigerant and gas refrigerant
Implementation Method 2
a cooling heat exchanger for cooling the liquid refrigerant heading from the gas-liquid separator to the utilization side circuit in the cooling operation by exchange of heat with the refrigerant reduced in pressure
Implementation Method 3
a gas refrigerant pressure reducing mechanism, disposed in a gas supply pipe for feeding gas refrigerant within the gas-liquid separator to a suction side of the compressor, for reducing pressure of refrigerant in the gas supply pipe
Data Source
Figure 1
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AI summary
A heat source side circuit (14) includes a gas-liquid separator (35) for the separation of refrigerant flowing therein from an expander (31) into liquid refrigerant and gas refrigerant and a cooling means (36, 45, 53, 55) for the cooling of liquid refrigerant heading from the gas-liquid separator (35) to a utilization side circuit (11). Since the refrigerant exiting the gas-liquid separator (35) is in a saturated liquid form, it always changes state to a subcooled state whenever cooled by the cooling means (36, 45, 53, 55).