Refrigeration apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigeration apparatuses face issues with abnormal pressure rises in the gas-liquid separator and outdoor heat exchanger when performing a pump-down action during stop conditions, potentially damaging components due to high pressures exceeding critical refrigerant pressures.
Innovation Solution
A control unit in the refrigeration apparatus performs a pump-down action to recover refrigerant from the indoor unit and returns it to the outdoor unit, but prohibits this action when the pressure at the gas-liquid separator exceeds critical pressure, thereby preventing further pressure increases by adjusting the outdoor expansion valve and maintaining the indoor expansion valve open during prohibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump-down action is performed to recover refrigerant from the indoor unit and return it to the outdoor unit, then refrigerant recovery is achieved, but abnormal pressure rises occur in the gas-liquid separator and outdoor heat exchanger that can damage components
Solution Approach 1:
The control unit continuously monitors the pressure in the gas-liquid separator and uses this feedback to determine whether to execute the pump-down action. When the pressure exceeds the critical pressure threshold, the control unit prohibits the pump-down action, thereby preventing abnormal pressure rises that could damage components.
Solution Approach 2:
The system changes the operational parameter (pump-down action execution) based on the pressure condition. By monitoring the pressure parameter and comparing it against the critical pressure threshold, the system dynamically adjusts whether to perform refrigerant recovery or maintain current operation to avoid component damage.
2Stress or pressure
If the pump-down action is prohibited when pressure exceeds critical pressure, then component damage is prevented, but refrigerant recovery from the indoor unit cannot be performed
Solution Approach 1:
The pump-down action is partially executed or modified based on pressure conditions. When pressure exceeds critical levels, the system prohibits only the refrigerant recovery portion that would cause damage, while potentially maintaining other necessary operations, thus achieving partial action that balances safety with functionality.
Data Source
AI summary
A refrigeration apparatus includes a heat source-side unit and a utilization-side unit 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 also includes a control unit configured to perform a first action of returning the refrigerant to the heat source-side unit when a stop condition of the utilization-side unit is satisfied, and a second action of prohibiting the first action when a pressure at the heat source-side unit is equal to or more than the critical pressure of the refrigerant. This configuration suppresses damage to a refrigerant storage reservoir and the like in returning the refrigerant to the heat source-side unit.