Refrigeration system for chilled storage container
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Solution Overview
Problem
Current refrigeration systems for chilled storage containers aboard boats are inadequate due to accelerated warming from inadequate insulation, saltwater intrusion, and radiant heating, leading to ice melting, and they lack cooling capacity, are prone to leaks, and create unsanitary conditions.
Innovation Solution
A two-phase refrigeration system using Non-Ozone Depleting Hydrofluorocarbon (NODHFC) refrigerant with a circulation pump and coils installed in the CSC, which circulates cooling liquid through coils for efficient heat extraction and maintains ice, utilizing thermodynamic properties to enhance cooling and using environmentally friendly refrigerants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-phase cooling system with rigid copper tubing and expansion valves is used, then the system can deliver high pressure refrigerant directly to freezer plates, but the rigid lines are susceptible to failure under vibration and impact, leading to leaks and system failure
Solution Approach 1:
The patent replaces rigid copper tubing with flexible hoses that can withstand vibration and impact without failing. The flexible hose system maintains refrigerant delivery while being resistant to the mechanical stresses of boat environments, eliminating the leakage problems associated with rigid tubing.
Solution Approach 2:
The system uses a circulation pump to drive refrigerant through flexible hoses, replacing the rigid high-pressure delivery system. This hydraulic approach with pumped circulation provides both flexibility and reliability in the refrigerant distribution system.
2Reliability
If expansion valves and other components are enclosed in a walled-off compartment, then the equipment is protected from water and debris intrusion, but the available chilled storage container volume is reduced and unsanitary conditions can develop in the walled-off area
Solution Approach 1:
The patent removes the expansion valve and other components from the chilled storage container entirely, placing them outside the container. This eliminates the need for walled-off compartments within the container, maximizing available storage volume while preventing unsanitary conditions in component housing areas.
Solution Approach 2:
The flexible hose system allows components to be positioned externally while still serving the internal cooling function. The same hoses that deliver refrigerant also facilitate easy access for maintenance without requiring internal component housing.
3Volume of stationary object
If freezer plates are mounted lower in the box to maximize storage space, then more volume is available, but ice accumulates rapidly on the plate and the cooling effect is not evenly distributed across the box
Solution Approach 1:
The patent transitions from localized cooling at the bottom (single-point cooling) to distributed cooling throughout the container. By placing flexible hoses at multiple locations including upper areas, the system achieves three-dimensional temperature distribution, preventing the uneven cooling and rapid ice accumulation associated with bottom-mounted plates.
Solution Approach 2:
The system provides different cooling characteristics at different locations within the container. Flexible hoses can be positioned to deliver cooling where needed, creating locally optimized temperature zones rather than uniform cooling from a single location, thereby achieving even temperature distribution throughout the entire volume.
4Speed
If a single-phase system with low mass of cooling inertia is used, then the system responds quickly to cooling demands, but the system lacks cooling capacity during recovery phases when heat is added from opening/closing or warm products
Solution Approach 1:
The circulation pump system enables continuous refrigerant circulation throughout the container via distributed flexible hoses. This continuous action maintains cooling capacity during recovery phases by constantly removing heat from all areas, preventing the cooling capacity deficiency that occurs in low-mass systems when heat loads are introduced.
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 low temperatures, reduces ice melting, is easy to clean, and provides greater cooling capacity with durable components, ensuring reliable operation and eco-friendliness.
Implementation Method 1
A conduit is disposed in a plurality of coils that are configured to be attached to an interior sidewall of the CSC. The plurality of coils are disposed about an upper margin of the interior sidewall. The conduit is in communication with the input coolant tube and the output coolant tube.
Implementation Method 2
The plurality of coils are disposed about an upper margin of the interior sidewall... for efficient heat extraction
Implementation Method 3
A circulation pump is provided for circulating the cooling liquid through the input coolant tube, the plurality of coils, and the output coolant tube.
Implementation Method 4
A two-phase refrigeration system using Non-Ozone Depleting Hydrofluorocarbon (NODHFC) refrigerant... utilizing thermodynamic properties to enhance cooling
Data Source
AI summary
A dual-phase refrigeration system for chilled storage containers (CSC) aboard boats maintains cold temperatures in the CSC by chilling the airspace in the upper portion of the CSC. A cooling liquid is circulated through coils installed on an interior sidewall about an upper margin of the CSC. The cooling liquid chills the air in the upper portion of the CSC which creates a thermodynamic airflow within the CSC which aids in cooling. The temperature of the cooling liquid is maintained by a heat exchange with a Non-Ozone Depleting Hydrofluorocarbon (NODHFC) refrigerant which, in turn, is cooled by a heat exchange with circulating water sourced from the body of water supporting the boat. If ice is added to the CSC, the cooling liquid in the coils reduces the air temperature differential across air/ice interface and maintains the quality of the ice.