Refrigeration Circuit Isolation Using Lockable Non-Return Valves
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Solution Overview
Problem
Existing refrigeration circuits face challenges in safely disconnecting components like evaporators and compressors, leading to increased pressure risks and refrigerant loss when shut-off valves are closed prematurely or simultaneously, especially with high-pressure refrigerants like CO2, resulting in material strain and potential hazardous venting of refrigerant.
Innovation Solution
Incorporating non-return valves upstream and downstream of functionally disconnectable components, which allow refrigerant to flow back into the circuit if pressure exceeds adjacent pressures, replacing traditional three-way and pressure relief valves to prevent refrigerant loss and material strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If traditional three-way valves and pressure relief valves are used to disconnect components, then components can be functionally disconnected for maintenance, but refrigerant is lost through atmospheric venting and material strain occurs due to pressure buildup
Solution Approach 1:
A receiver vessel is introduced as an intermediary component between the refrigeration circuit and the atmosphere. When components need to be disconnected, the refrigerant is transferred to the receiver vessel instead of being vented to the atmosphere, thus preventing refrigerant loss while still enabling component maintenance and replacement
Solution Approach 2:
Instead of discarding (venting to atmosphere) the refrigerant when disconnecting components, the system recovers the refrigerant by transferring it to a receiver vessel. This allows the refrigerant to be retained and reused, eliminating the substance loss that occurs with traditional pressure relief valve venting
2Ease of repair
If shut-off valves are closed simultaneously or prematurely during component disconnection, then component disconnection is achieved, but pressure builds up causing material strain and safety hazards
Solution Approach 1:
The system performs preliminary actions by providing multiple disconnect paths and a receiver vessel before component disconnection occurs. The receiver vessel is prepared in advance to receive refrigerant, and the multiple valve configurations allow for staged disconnection that prevents pressure buildup, thereby protecting material strength
Solution Approach 2:
The receiver vessel acts as a cushioning element that absorbs pressure fluctuations and prevents dangerous pressure buildup. By having this cushioning capacity available beforehand, the system can handle disconnection operations without creating the material strain and safety hazards that result from premature or simultaneous valve closure
3Productivity
If high-pressure refrigerants like CO2 are used to improve cooling efficiency, then refrigeration performance increases, but pressure risks and safety concerns increase requiring expensive high-strength materials
Solution Approach 1:
The receiver vessel serves as an intermediary that manages high-pressure refrigerant safely. It provides a controlled environment for storing and transferring high-pressure CO2, reducing the pressure risks associated with using high-pressure refrigerants while maintaining their refrigeration efficiency benefits
Solution Approach 2:
The receiver vessel provides beforehand cushioning capacity to handle pressure fluctuations inherent in high-pressure refrigerant systems. This cushioning effect mitigates pressure risks and allows the system to use efficient high-pressure refrigerants like CO2 without requiring expensive high-strength materials throughout the entire 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 solution ensures safe operation by preventing refrigerant venting into the atmosphere, maintaining system pressure within safety limits, and allowing for the same material usage across components, reducing investment costs and ensuring continuous refrigerant flow without blockages.
Implementation Method 1
If pressure within the functionally disconnected component increases above the pressure of the portion of the refrigerated circuit adjacent to the functionally disconnected component, the non-return valve allows refrigerant to flow back into the refrigeration circuit
Data Source
AI summary
Refrigeration circuit (1, 1′) for circulating a refrigerant in a predetermined flow direction through at least one functionally disconnectable component, the refrigeration circuit having in flow direction an expansion device (b, b′, 26, 26′, 33), an evaporator, a compressor (2, 2′, 29, 36) and a heat-rejecting heat exchanger (6, 20), wherein an upstream-side shut-off valve is provided upstream of the component and a downstream-side shut-off valve is provided downstream of the component, wherein at least one of these shut-off valves is a non-return valve (a, c, 25, 27, 32, 34). Preferably, the component has in flow direction the expansion device (b, b′, 26, 26′, 33) and the evaporator (12, 12′, E1, E1′, E2) or the compressor (2, 2′). Preferably the non-return valve (a, c, 25, 27, 32, 34) is lockable in it's open position.