Refrigeration device
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Solution Overview
Problem
In refrigeration apparatuses using refrigerants that reach or exceed critical pressure, the pressure increase during temperature rises can damage refrigerant storage reservoirs and heat source-side heat exchangers when refrigerant is returned to the heat source-side unit, leading to abnormal pressure conditions.
Innovation Solution
A control unit is implemented to recover refrigerant from the utilization-side unit and return it to the heat source-side unit only when certain conditions are met, such as a stop condition being satisfied and the pressure at the heat source-side unit being below critical pressure, and to prohibit this action when the pressure exceeds critical levels, using adjustable expansion mechanisms to manage pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If refrigerant is returned to the heat source-side unit when the utilization-side unit stops operating, then the refrigerant circuit maintains proper refrigerant distribution, but abnormal pressure increases occur in the refrigerant storage reservoir and heat source-side heat exchanger when outdoor temperature rises
Solution Approach 1:
The control unit checks the outdoor temperature before allowing refrigerant return to the heat source-side unit. When the temperature exceeds the predetermined threshold, the control unit prohibits refrigerant return in advance, preventing the pressure increase from occurring. This preliminary check and preventive action resolve the contradiction by maintaining proper refrigerant distribution only under safe temperature conditions.
2Reliability
If refrigerant return is prohibited when pressure reaches critical levels, then component damage is prevented, but refrigerant distribution in the circuit becomes unbalanced
Solution Approach 1:
The control unit monitors outdoor temperature as a parameter and uses it to control the refrigerant return process. By changing the operational state based on temperature parameter thresholds, the system ensures component safety while maintaining proper refrigerant distribution. The temperature parameter serves as a control variable that balances reliability and distribution stability.
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 prevents abnormal pressure rises in the refrigerant storage reservoir and heat source-side heat exchanger, thereby protecting these components from damage and ensuring safe operation by controlling the refrigerant flow and pressure within safe limits.
Implementation Method 1
the refrigeration apparatus is configured to perform a refrigeration cycle in which a high pressure reaches or exceeds a critical pressure of the refrigerant
Data Source
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AI summary
A refrigeration apparatus (1) includes a heat source-side unit (10) and a utilization-side unit (50) that are connected to each other, and performs a refrigeration cycle in which a high pressure of a refrigerant reaches or exceeds a critical pressure. The refrigeration apparatus (1) also includes a control unit (100) configured to perform a first action of returning the refrigerant to the heat source-side unit (10) when a stop condition of the utilization-side unit (50) is satisfied, and a second action of prohibiting the first action when a pressure at the heat source-side unit (10) is equal to or more than the critical pressure of the refrigerant. This configuration suppresses damage to a refrigerant storage reservoir (15) and the like in returning the refrigerant to the heat source-side unit (10).