Intercooler Bypass Layout for Two-Stage Refrigerant Compression
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Solution Overview
Problem
Conventional refrigeration apparatuses with multistage compression cycles face inefficiencies due to high heat radiation loss in outdoor heat exchangers and reliability issues from liquid refrigerant accumulation in intercoolers, leading to reduced compressor reliability and performance.
Innovation Solution
Incorporating an intercooler bypass tube and an intake return tube to bypass the intercooler during startup and operation, reducing refrigerant pressure and preventing liquid accumulation, thus minimizing heat radiation loss and enhancing compressor reliability by ensuring refrigerant is not drawn into the second-stage compression element as a liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the refrigerant is cooled in the intercooler before entering the second-stage compression element, then the temperature of the refrigerant discharged from the second-stage compression element is reduced and heat radiation loss in the outdoor heat exchanger is decreased, but liquid refrigerant may accumulate in the intercooler and be drawn into the second-stage compression element causing liquid compression
Solution Approach 1:
The patent implements dynamic valve control to switch the refrigerant flow path between two modes: during normal operation, the intercooler cooling path is active to reduce heat radiation loss; during startup or abnormal conditions, the bypass path is activated to prevent liquid compression. This dynamic switching resolves the contradiction by adapting the system configuration to operational conditions.
Solution Approach 2:
The patent changes the flow resistance parameters dynamically by controlling valve openings. The first valve controls the opening degree of the bypass passage, while the second valve controls the opening degree of the intercooler passage. By adjusting these parameters based on operational state, the system optimizes between cooling efficiency and liquid prevention.
2Reliability
If the refrigerant flow path is switched to bypass the intercooler during startup, then liquid refrigerant accumulation is prevented and compressor reliability is improved, but the temperature reduction benefit from intercooler cooling is not achieved
Solution Approach 1:
The system dynamically switches between bypass mode during startup (prioritizing reliability) and cooling mode during normal operation (prioritizing energy efficiency). The control unit monitors operational state and automatically transitions between configurations, ensuring both reliability during vulnerable periods and energy efficiency during stable operation.
Solution Approach 2:
The bypass path is prepared and activated before startup occurs to prevent liquid accumulation from the outset. By taking preliminary action to establish a safe flow path during startup, the system prevents the harmful condition before it can occur, then transitions to the more efficient cooling path once operation is stable.
3Productivity
If the intercooler is used continuously to cool the refrigerant, then operating efficiency is improved through reduced heat radiation loss, but the complexity of the refrigerant flow control system increases
Solution Approach 1:
The patent designs the refrigerant flow control system with multi-functional valves that serve dual purposes: they control both the bypass flow and the intercooler flow using the same valve mechanisms. This universal approach reduces the need for separate dedicated control components for each function, thereby limiting the increase in system complexity while maintaining the ability to switch between operational modes.
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 reduces heat radiation loss and prevents liquid compression in the second-stage compression element, improving the operating efficiency and reliability of the refrigeration apparatus by ensuring the refrigerant is not compressed as a liquid, thereby enhancing overall performance and reducing the risk of compressor failure.
Implementation Method 1
the intercooler which functions as a cooler of the refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element
Implementation Method 2
the refrigerant discharged from a first-stage compression element, which is one of the plurality of compression elements, is sequentially compressed by a second-stage compression element
Data Source
AI summary
A refrigeration apparatus includes a compression mechanism, a heat source-side heat exchanger, a usage-side heat exchanger, an intercooler, an intercooler bypass tube and an intake return tube. The compression mechanism has a plurality of compression elements configured so that refrigerant discharged from a first-stage compression element is sequentially compressed by a second-stage compression element. The intercooler is connected to an intermediate refrigerant tube configured to draw refrigerant discharged from the first-stage compression element into the second-stage compression element to cool the refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element. The intercooler bypass tube is connected to the intermediate refrigerant tube so as to bypass the intercooler. The intake return tube is configured to connect the intercooler and an intake side of the compression mechanism when the refrigerant discharged from the first-stage compression element is drawn into the second-stage compression element through the intercooler bypass tube.