Ice making system and control method of evaporation temperature used therein

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Solution Overview

Problem

The existing evaporation pressure control device for icemaking systems fails to adjust refrigerant evaporation temperature effectively with changing solution concentration, leading to ice lock and inadequate icemaking capacity.

Innovation Solution

An icemaking system with a control unit that adjusts refrigerant evaporation temperature based on solute concentration, using correlations specific to the type of ice generator and inner pipe surface roughness, and prioritizes either freezing prevention or icemaking capacity based on solute concentration levels, with adjustable compressor frequency, expansion valve opening, fan speed, and solution flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If refrigerant evaporation temperature is lowered immoderately during icemaking operation, then icemaking capacity is improved, but ice lock occurs and damages devices

Engineering Contradiction:
Improveicemaking capacityVSAvoiddevice safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the refrigerant evaporation temperature based on the solution concentration. As the solution concentration increases during icemaking operation, the control unit automatically lowers the evaporation temperature in a controlled manner. This resolves the contradiction by allowing the system to achieve high icemaking capacity when needed (high concentration) while preventing ice lock and device damage when concentration is low, thus maintaining both productivity and reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a constant temperature difference ΔT is used regardless of solution concentration, then control simplicity is maintained, but ice lock occurs at low concentration and icemaking capacity is not improved at high concentration

Engineering Contradiction:
Improvecontrol simplicityVSAvoidicemaking capacity
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from a static, constant temperature difference control to a dynamic control system that adapts the temperature difference based on solution concentration. The control unit continuously monitors solution concentration and adjusts the evaporation temperature accordingly, making the control parameter variable rather than fixed. This resolves the contradiction by maintaining control simplicity through automated feedback while achieving variable icemaking capacity that responds to changing solution conditions.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If evaporation temperature is not adjusted according to solution concentration, then system complexity is reduced, but ice lock occurs and icemaking operation becomes inappropriate

Engineering Contradiction:
Improvecontrol system complexityVSAvoidicemaking operation stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies feedback control by implementing a closed-loop system where the control unit continuously monitors solution concentration and adjusts the refrigerant evaporation temperature in response. This feedback mechanism ensures that the evaporation temperature is always appropriate for the current solution concentration, preventing ice lock and ensuring stable icemaking operation. The feedback approach resolves the contradiction by automating the adjustment process, which maintains reliability without requiring complex manual intervention.

Inventive Principle:
Principle #23Feedback

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

Inhibits ice lock and secures desired icemaking capacity by accurately adjusting evaporation temperature according to solute concentration changes, improving icemaking performance and notifying users of low solute levels to prevent capacity deterioration.

Implementation Method 1

a refrigerant circuit configured to execute a vapor compression refrigeration cycle

Methodology Applied
Scientific EffectVapor compression refrigeration cycle:

Implementation Method 2

an evaporator of the ice generator... adjusts to lower evaporation temperature at the evaporator

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a compressor...

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

a condenser...

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

an expansion valve...

Methodology Applied
Scientific EffectExpansion:

Implementation Method 6

a pump configured to pressure feed the solution to the solution flow path

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3742085B1Ice making system and control method of evaporation temperature used therein
Publication Date: 2022.10.19 DAIKIN INDUSTRIES LTD
  • EP3742085B1 patent drawingFigure 1
  • EP3742085B1 patent drawingFigure 2
  • EP3742085B1 patent drawingFigure 3

AI summary

The disclosure relates to an icemaking system (50) including a refrigerant circuit (60) configured to execute a vapor compression refrigeration cycle, a circulation circuit (70) for solution as a cooling target of the refrigerant circuit (60), and a control device (80) configured to control refrigerant evaporation temperature at the refrigerant circuit (60). The circulation circuit (70) includes a solution flow path (12A) of an ice generator (1), a solution tank (8) used to store the solution, and a pump (9) configured to pressure feed the solution to the solution flow path (12A). The refrigerant circuit (60) includes an evaporator (20) of the ice generator (1), a compressor (2), a condenser (3), and an expansion valve (5). The control device (80) includes a control unit (81) configured to adjust to lower evaporation temperature at the evaporator (20) as the solution has higher solute concentration.