Heat source unit and refrigeration apparatus
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Solution Overview
Problem
The refrigeration apparatus faces challenges in maintaining optimal pressure within the refrigerant circuit, particularly during high outdoor temperatures, leading to excessive high pressure and potential operational failures due to inadequate venting actions.
Innovation Solution
The system employs a control mechanism that adjusts the number of revolutions of compressors and expansion valves to manage intermediate pressure, allowing for effective venting and maintaining subcritical refrigerant states, thereby preventing excessive pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigeration apparatus operates during high outdoor temperatures, then the cooling capacity is maintained, but the high pressure in the refrigerant circuit exceeds critical levels leading to operational failures
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the expansion valve opening degree based on the detected high pressure level. When high pressure exceeds a predetermined threshold, the control unit increases the expansion valve opening degree to increase refrigerant flow through the heat source heat exchanger, thereby reducing the high pressure back to safe levels and preventing operational failures.
Solution Approach 2:
The patent implements a feedback control mechanism where the control unit continuously detects the high pressure in the refrigerant circuit and automatically adjusts the expansion valve opening degree in response. This closed-loop feedback system ensures that pressure remains within safe operating limits by comparing actual pressure readings against predetermined thresholds and making real-time adjustments to the expansion valve position.
2Stress or pressure
If the expansion valve opening degree is increased to reduce high pressure, then pressure control is improved, but the refrigerant flow distribution between air-conditioning and refrigeration-facility units becomes unbalanced
Solution Approach 1:
The patent applies local quality by making the expansion valve opening degree specific to the operational conditions and pressure requirements. Instead of using a fixed opening degree, the control unit dynamically adjusts the opening degree based on detected high pressure levels, allowing the system to optimize pressure control while maintaining appropriate refrigerant flow distribution to different units based on current operational demands.
Solution Approach 2:
The patent implements dynamics by transitioning from a static expansion valve opening degree to a dynamically adjustable one. The control unit continuously monitors high pressure and automatically modifies the expansion valve opening degree in real-time, enabling the system to adapt to changing pressure conditions while maintaining balanced refrigerant flow distribution among connected units.
3Device complexity
If a predetermined expansion valve opening degree is used, then the system structure is simple, but the system cannot adapt to varying pressure conditions leading to excessive high pressure
Solution Approach 1:
The patent implements feedback control by equipping the system with a pressure detection mechanism and a control unit that automatically adjusts the expansion valve opening degree based on detected high pressure levels. This feedback loop enables the system to adapt to varying pressure conditions, maintaining reliable pressure management without requiring complex manual intervention or overly complicated control mechanisms.
Solution Approach 2:
The patent applies self-service by enabling the system to automatically monitor and adjust its own pressure levels through the control unit and expansion valve mechanism. The system detects high pressure conditions and autonomously adjusts the expansion valve opening degree to correct pressure imbalances, eliminating the need for external intervention or complex manual control systems while maintaining reliable pressure management.
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 control strategy ensures reliable operation by maintaining a sufficient pressure difference for refrigerant release, preventing high pressure from exceeding critical levels and ensuring continuous operation.
Implementation Method 1
a heat source heat exchanger of the heat source circuit functions as a radiator, and a utilization heat exchanger of the air-conditioning unit and a utilization heat exchanger of the refrigeration-facility unit function as evaporators
Implementation Method 2
a heat source heat exchanger of the heat source circuit functions as a radiator
Data Source
AI summary
If a first condition that an intermediate pressure corresponding to a pressure of an intermediate flow path is greater than a predetermined value is satisfied in an operation in which first, second, and third compressors are operated, the control unit executes a first action of increasing the number of revolutions of the third compressor.