Ice Making Surface Cooling With CO2 Two-Phase Flow Control
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Solution Overview
Problem
Existing ice making machines face issues with uneven ice production, energy inefficiency, and contamination due to refrigerant properties, particularly in chlorofluorocarbon direct expansion types, and brine systems which suffer from high viscoelasticity leading to pressure losses and channeling.
Innovation Solution
An ice making machine utilizing carbon dioxide as the cryogen, controlled to maintain a gas-liquid mixed state at the outlet of the cryogen flow channel, ensuring uniform cooling and eliminating the need for refrigerant oil, which reduces heat transfer inefficiencies and allows for high-quality ice production with reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If chlorofluorocarbons are used as refrigerant in direct expansion type, then refrigerant circulation is simplified, but liquid back risk increases and heat transfer efficiency decreases due to oil adhesion
Solution Approach 1:
The patent changes the refrigerant parameter from chlorofluorocarbon to carbon dioxide, which has different thermodynamic properties. This parameter change allows the system to operate without refrigerant oil, eliminating the oil adhesion problem and liquid back risk while maintaining simplified system complexity
Solution Approach 2:
The patent treats refrigerant oil as a harmful substance to be eliminated rather than maintained. By using carbon dioxide which does not require oil lubrication, the system removes the need for ongoing oil management, effectively treating the oil-related maintenance burden as something to be discarded
2Reliability
If refrigerant is completely vaporized near outlet of flow channel to prevent liquid back, then liquid back is prevented, but temperature difference increases causing uneven ice making
Solution Approach 1:
The patent changes the refrigerant from chlorofluorocarbon to carbon dioxide, which has superior heat transfer properties and lower viscosity. This allows the refrigerant to maintain more uniform temperature distribution throughout the flow channel while still preventing liquid back, thereby achieving both reliability and manufacturing precision
3Object-affected harmful factors
If brine is used for cooling, then toxic refrigerant is avoided, but pressure loss increases due to high viscoelasticity causing channeling
Solution Approach 1:
The patent changes the cooling medium parameter from brine to carbon dioxide. Carbon dioxide has much lower viscosity than brine, which dramatically reduces pressure loss and eliminates channeling issues while maintaining non-toxic operation. This parameter change simultaneously improves both safety and energy efficiency
4Manufacturing precision
If pump flow rate is increased to suppress channeling in brine system, then channeling is reduced, but transport power increases
Solution Approach 1:
The patent changes the fluid parameter from brine to carbon dioxide, which has lower viscosity and better flow characteristics. This allows the system to achieve uniform distribution (suppress channeling) at lower flow rates, thereby reducing the transport power required while maintaining manufacturing precision
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 machine achieves uniform ice thickness and quality, increased production efficiency, and energy savings by utilizing the latent heat of liquid carbon dioxide for cooling, minimizing refrigerant oil adhesion and pressure losses, and maintaining consistent ice growth conditions.
Implementation Method 1
a cryogen flow channel through which a cryogen for cooling the ice making surface flows
Implementation Method 2
the cryogen is in a gas-liquid mixed state at the outlet of the cryogen flow channel
Implementation Method 3
a pump that pressurizes and discharges the cryogen cooled by the heat exchanger
Implementation Method 4
a heat exchanger for cooling the cryogen flowing out from an outlet of the cryogen flow channel
Data Source
AI summary
This ice making machine includes an ice making unit that includes an ice making surface and a cryogen flow channel through which a cryogen for cooling the ice making surface flows; a pump that pressurizes and discharges the cryogen cooled by a heat exchanger; and a control unit that controls a discharge amount of the pump. The cryogen is carbon dioxide, and the control unit controls the pump such that the cryogen is in a gas-liquid mixed state at an outlet of the cryogen flow channel.