Low charge packaged refrigeration systems
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Solution Overview
Problem
Existing industrial refrigeration systems, particularly ammonia-based ones, are highly compartmentalized and require large refrigerant charges, leading to regulatory challenges and safety concerns due to ammonia toxicity and potential leaks.
Innovation Solution
A packaged, pumped liquid, recirculating refrigeration system with a pre-packaged modular machine room housing the compressor and condenser, utilizing internal enhancements in evaporator and condenser coils, and replacing large receiver vessels with liquid-vapor separation structures, such as cyclonic separators, to reduce refrigerant charge to less than 10 lbs per ton of refrigeration capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional compartmentalized refrigeration systems are used with large receiver vessels, then refrigerant storage capacity is sufficient, but refrigerant charge quantity becomes excessively large leading to safety and regulatory issues
Solution Approach 1:
The system divides refrigerant storage into multiple small distributed evaporators rather than one large centralized receiver. Each evaporator contains only the refrigerant needed for its local cooling load, segmenting the total refrigerant charge across multiple small units throughout the refrigerated space.
Solution Approach 2:
The evaporators are nested within the refrigerated space itself rather than requiring separate mechanical rooms and penthouses. The refrigerant charge is nested within compact evaporator units that are integrated into the building structure, eliminating the need for large external storage vessels.
2Ease of operation
If traditional compartmentalized systems with separate mechanical rooms and penthouses are used, then system functionality is complete, but device complexity and installation difficulty increase
Solution Approach 1:
The system merges the functions of separate mechanical rooms, penthouses, and distributed cooling units into a single integrated package. The evaporators are pre-assembled with compressors and controls in compact modular units that can be installed directly in the refrigerated space, combining multiple system functions into one simplified structure.
Solution Approach 2:
The modular evaporator units serve multiple functions simultaneously: they act as refrigerant storage vessels, heat exchangers, and cooling distribution units. Each unit is designed to perform multiple system functions, reducing the need for separate specialized components and simplifying overall system installation.
3Productivity
If ammonia-based refrigeration systems are used for industrial refrigeration, then refrigeration effectiveness is high, but harmful factors increase due to ammonia toxicity and regulatory requirements
Solution Approach 1:
The system extracts the harmful concentrated ammonia charge from the traditional mechanical room and penthouse configuration and redistributes it into multiple small dispersed evaporators. By taking out the large centralized refrigerant storage and replacing it with small distributed units, the total amount of ammonia present in any one location is minimized while maintaining overall refrigeration capacity.
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 achieves a significant reduction in refrigerant charge, requiring less than six pounds of ammonia per ton, minimizing safety risks and regulatory burdens, as the entire refrigerant charge can be discharged without causing significant harm, and operates efficiently with reduced ammonia usage.
Implementation Method 1
the liquid-vapor separation structure/device may be a single or dual phase cyclonic separator
Implementation Method 2
the evaporator coil tubes are preferably formed with internal enhancements that improve the flow of the refrigerant liquid through the tubes, enhance heat exchange
Implementation Method 3
the condenser may be constructed of coil tubes preferably formed with internal enhancements that improve the flow of the refrigerant vapor through the tubes, enhance heat exchange
Data Source
AI summary
A packaged, pumped liquid, recirculating refrigeration system with charges of 10 lbs or less of refrigerant per ton of refrigeration capacity. The compressor and related components are situated in a pre-packaged modular machine room, and in which the condenser is mounted on the machine room and the evaporator is close coupled to the pre-packaged modular machine room. Prior art large receiver vessels may be replaced with a single or dual phase cyclonic separator also housed in the pre-packaged modular machine room.