Modular Hydrocarbon Refrigeration Loops for Ultra-Low Charge Cooling
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Solution Overview
Problem
Existing refrigeration systems using hydrocarbon refrigerants face challenges in minimizing refrigerant charge while maintaining efficient cooling, as they need to adhere to strict safety regulations regarding flammability, requiring multiple parallel loops which can complicate system design and efficiency.
Innovation Solution
A modular, ultra-low charge refrigeration system is designed with multiple discrete hydrocarbon refrigerant loops and micro-chiller circuits, each with a refrigerant charge not exceeding 150 grams, allowing for efficient heat exchange and temperature control through a network of heat exchangers and pumps, optimizing the use of hydrocarbon refrigerants like propane across various circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple parallel hydrocarbon refrigerant loops are used to meet EPA safety requirements, then refrigerant charge safety is improved, but system complexity increases
Solution Approach 1:
The refrigeration system is divided into multiple discrete refrigerant loops, each containing a separate compressor and heat exchanger assembly. This segmentation allows each loop to operate independently with limited refrigerant charge (150 grams or less), meeting EPA safety requirements while maintaining system functionality through modular architecture
Solution Approach 2:
Each modular loop is designed to perform multiple functions: cooling during refrigeration mode and heating during heat pump mode. The shared heat exchanger infrastructure and control systems allow all loops to cooperatively condition the same space, reducing overall system complexity despite multiple compressors
2Reliability
If multiple parallel hydrocarbon refrigerant loops are used to meet EPA safety requirements, then refrigerant charge safety is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses identical modular loop assemblies that can be manufactured separately and then installed in parallel configurations. This standardization of modules simplifies manufacturing processes, as each loop can be produced using the same tooling and assembly procedures, then scaled to meet different refrigeration loads
Solution Approach 2:
The modular loop design allows smaller refrigerant loops to be nested within or alongside larger system architectures. Each loop is a self-contained unit that can be manufactured independently and then integrated into the overall system, facilitating modular manufacturing and assembly
3Productivity
If hydrocarbon refrigerant is used to achieve efficient cooling, then cooling efficiency is improved, but flammability risk increases
Solution Approach 1:
By dividing the total refrigerant charge into multiple separate loops with 150 grams or less per loop, the system maintains the high cooling efficiency of hydrocarbon refrigerants while limiting the amount of refrigerant available in any single location, thereby reducing flammability risk
Solution Approach 2:
The system uses shared heat exchanger infrastructure as an intermediary between multiple independent refrigerant loops and the conditioned space. This allows efficient heat transfer using hydrocarbon refrigerant while the physical separation of loops limits the potential hazard from refrigerant leakage
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 approach minimizes refrigerant charge while maximizing efficiency, ensuring safe operation by distributing hydrocarbon refrigerant across multiple loops, enhancing cooling performance and reducing the risk of flammability, while allowing for flexible system configurations to meet varying temperature requirements.
Implementation Method 1
efficient heat exchange and temperature control through a network of heat exchangers and pumps
Implementation Method 2
optimizing the use of hydrocarbon refrigerants like propane across various circuits
Data Source
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AI summary
A refrigeration system including a first circuit with a first heat exchanger, a second heat exchanger, and a pump fluidly connected in series with the first heat exchanger and the second heat exchanger to circulate a coolant within the first circuit. The refrigeration system also includes 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. The second circuit includes a compressor, the second heat exchanger, and a refrigerated merchandiser, which defines a product support area. 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.