Hydrocarbon Refrigeration Loops Under the 150 g Charge Limit
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Solution Overview
Problem
Existing refrigeration systems using hydrocarbon refrigerants face challenges in minimizing refrigerant charge to prevent ignition risks, requiring multiple parallel loops with each loop limited to 150 grams of hydrocarbon refrigerant to ensure safety.
Innovation Solution
A modular refrigeration system with multiple circuits, including a primary coolant circuit and hydrocarbon refrigerant circuits, where each hydrocarbon refrigerant circuit is designed to operate within a micro-chiller loop with a refrigerant charge not exceeding 150 grams, allowing for efficient heat exchange and temperature control in a merchandiser product support area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple parallel hydrocarbon refrigerant loops are used to meet the 150 gram charge limit, then safety is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple hydrocarbon refrigerant loops into a single integrated loop while maintaining the 150 gram charge limit through strategic placement of safety devices and heat exchangers. This merging approach maintains safety requirements while reducing the complexity associated with managing multiple separate parallel loops.
2Object-affected harmful factors
If hydrocarbon refrigerant charge is minimized to 150 grams per loop, then ignition risk is reduced, but cooling capacity is limited
Solution Approach 1:
The patent segments the cooling function across multiple heat exchangers and evaporators within a single refrigerant loop, allowing the system to achieve adequate cooling capacity while maintaining the refrigerant charge below 150 grams. The segmentation of thermal management functions enables distributed heat exchange that compensates for the limited refrigerant quantity.
Solution Approach 2:
The patent transitions from a single-phase refrigerant system to a two-phase system utilizing phase change in the evaporator, and from direct refrigerant-to-air cooling to a refrigerant-to-coolant-to-air indirect cooling approach. These dimensional changes in the cooling mechanism enable enhanced cooling capacity within the constrained refrigerant charge.
3Device complexity
If a single hydrocarbon refrigerant loop is used, then device complexity is reduced, but the 150 gram charge limit cannot be met for safety
Solution Approach 1:
The patent introduces an intermediate coolant loop that acts as a mediator between the hydrocarbon refrigerant and the air to be cooled. This intermediary approach allows the system to use a single refrigerant loop with minimal charge while still achieving effective cooling, thereby maintaining both safety and simplicity.
4Reliability
If multiple parallel refrigerant loops are implemented, then safety requirements are satisfied, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple refrigerant loops into a single loop configuration, simplifying manufacturing processes while maintaining safety through optimized heat exchanger design and strategic placement of safety devices within the unified system.
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
The system effectively maintains a predetermined temperature threshold while minimizing the risk of refrigerant ignition by distributing the hydrocarbon refrigerant charge across multiple loops, enhancing efficiency and safety by maximizing the use of hydrocarbon refrigerant while adhering to safety regulations.
Implementation Method 1
a second circuit that circulates a hydrocarbon refrigerant in heat exchange relationship with the coolant in the first circuit within the second heat exchanger to cool the refrigerant
Implementation Method 2
An evaporator is fluidly connected in series with the compressor and the second heat exchanger and positioned to condition the entire product support area within a predetermined temperature threshold
Implementation Method 3
The chiller unit is positioned in communication with the second circuit such that heat from the fluid is transferred to the hydrocarbon refrigerant in the chiller unit
Data Source
AI summary
A refrigeration system including a plurality of circuits that have one or more heat exchangers providing heat exchange relationship relative to one or more of the other circuits. At least one of the circuits circulates a hydrocarbon refrigerant and includes a chiller unit or a merchandiser that has an evaporator.