Refrigerated Display Cabinet Defrost Control by Door Open Time

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Solution Overview

Problem

Refrigerated display cabinets face inefficiencies in defrosting systems due to standardized defrost cycles that do not account for varying usage patterns and environmental conditions, leading to suboptimal evaporator performance.

Innovation Solution

A smart defrost system that calculates the maximum door open time based on ambient temperature and humidity levels using a polynomial function, allowing for adaptive defrost cycle timing to maintain optimal evaporator operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If periodical defrost cycles are carried out based on test standards, then the evaporator is defrosted regularly, but energy is wasted when door openings do not occur (e.g., when stores are closed)

Engineering Contradiction:
Improvedefrost effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The defrost cycle timing is made dynamic by using a polynomial function that calculates the maximum door open time based on ambient temperature. This replaces static periodical defrost cycles with adaptive timing that responds to actual environmental conditions and usage patterns, preventing unnecessary defrost operations when stores are closed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of defrost cycle timing from fixed periodical intervals to variable intervals calculated by a polynomial function of ambient temperature. This allows the defrost timing to adapt to different environmental conditions and actual door usage patterns, eliminating energy waste while maintaining defrost effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If standardized defrost cycles are used, then defrosting is performed according to test conditions, but actual evaporator performance is suboptimal due to varying usage patterns and environmental conditions

Engineering Contradiction:
Improveimplementation simplicityVSAvoidevaporator performance
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The polynomial function changes the defrost timing parameter from standardized fixed intervals to adaptive intervals based on ambient temperature and door open time. This maintains implementation simplicity while significantly improving evaporator performance by aligning defrost cycles with actual operating conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback from ambient temperature sensors and door open detection to dynamically adjust defrost cycle timing. This feedback mechanism allows the system to optimize evaporator performance based on actual conditions while maintaining ease of implementation through a straightforward polynomial calculation.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the polynomial function calculates maximum door open time based on ambient temperature, then defrost timing adapts to actual conditions, but the system complexity increases

Engineering Contradiction:
Improvedefrost timing adaptabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system achieves adaptability by changing the defrost timing parameter based on ambient temperature through a polynomial function. Despite the increased adaptability, the complexity is kept manageable by using a mathematical function rather than complex control logic, requiring only temperature sensing and basic calculation capabilities.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical or electronic control systems with a mathematical polynomial function that can be implemented in software or microcontroller. This substitution reduces physical device complexity while maintaining high adaptability to different environmental conditions and usage patterns.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 ensures efficient and reliable defrosting, optimizing evaporator performance by aligning defrost cycles with actual usage and environmental conditions, thereby maintaining consistent refrigeration.

Implementation Method 1

When the moist air touches the evaporator, it undergoes a solidification process, changing from the vapor state to the solid state of ice

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

the frost must be removed from the evaporator by means of a defrost cycle. There are different types of defrost systems, but all of them work by giving up heat to the evaporator to melt the frost and the ice formed on the evaporator

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4246067B1Refrigerated display cabinet with a smart defrost system
Publication Date: 2024.09.11 INDUSTRIE SCAFFALATURE ARREDAMENTI ISA SPA
  • EP4246067B1 patent drawingFigure 1
  • EP4246067B1 patent drawingFigure 2
  • EP4246067B1 patent drawingFigure 3

AI summary

Refrigeration display cabinet (100) comprising a compartment (101), at least one door (102) for providing access to the compartment (101), a refrigeration system (103) comprising an evaporator (130), a defrost system (104) of the evaporator (130), a control unit (2) configured to operate the defrost system (104), temperature detection means (3) to detect an ambient temperature (Ta), door open detection means (4) and a timer (5) to detect a door open time (tdo), and an algorithm (6) configured to receive the ambient temperature (Ta) and the door open time (tdo) to calculate a maximum door open time (tdef), after which the defrost system (104) is to be operated.