Heat exchange unit for absorption-type refrigerator, absorption-type refrigerator, and corresponding heat exchange method

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Solution Overview

Problem

Absorption refrigerators face challenges in achieving high wettability of heat transfer tubes for solutions with higher viscosity than refrigerant liquids, as existing drip feed configurations are not effective in spreading and adhering high-viscosity solutions uniformly on these tubes.

Innovation Solution

A heat exchange unit with a second drip feed configuration that has a smaller interval between dripping portions compared to the first drip feed, allowing for improved wettability of heat transfer tubes by forming uniform liquid films on the second heat transfer tubes, specifically designed for the absorber in absorption refrigerators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional drip feed configuration with larger intervals between dripping portions is used, then the device complexity is reduced and ease of manufacture is improved, but the wettability of heat transfer tubes for high-viscosity solutions deteriorates

Engineering Contradiction:
Improveease of manufactureVSAvoidwettability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the drip feed configurations for the evaporator and absorber. The absorber's second drip feed has a smaller interval between dripping portions specifically tailored for high-viscosity solutions, while the evaporator's first drip feed maintains a larger interval suitable for low-viscosity refrigerant liquids. This localized adaptation optimizes wettability for each component's specific fluid characteristics without requiring complete redesign of the entire system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the interval parameter of the drip feed portions between the evaporator and absorber. The second drip feed in the absorber has a smaller interval between its dripping portions compared to the first drip feed in the evaporator. This parameter change addresses the higher viscosity of absorption solutions, enabling better liquid distribution and wettability on the heat transfer tubes while maintaining manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the interval between dripping portions is reduced to improve wettability, then the heat exchange efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the heat exchange system into two distinct units with different drip feed configurations: the evaporator with first drip feeds having larger intervals, and the absorber with second drip feeds having smaller intervals. This segmentation allows each unit to be optimized for its specific fluid type and viscosity characteristics, improving overall heat exchange efficiency without requiring complex adjustable mechanisms throughout the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal heat exchange unit design that can handle different fluid viscosities by incorporating two types of drip feeds with different interval configurations. This multi-functional approach allows the same basic unit structure to serve both evaporator and absorber functions, accommodating both low-viscosity refrigerant liquids and high-viscosity absorption solutions without requiring entirely separate designs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enhances the wettability of heat transfer tubes for solutions with higher viscosity, improving the heat exchange efficiency and reducing the area that remains unwetted, thereby increasing the coefficient of performance (COP) of the absorption refrigerator.

Implementation Method 1

uniform liquid films are easily formed on the second heat transfer tubes owing to the small interval between droplets of the solution to be dripped from the plurality of second portions. Therefore, the heat exchange unit for an absorption refrigerator according to the present disclosure is advantageous in increasing the wettability of heat transfer tubes

Methodology Applied
Scientific EffectWetting: Wetting

Implementation Method 2

a first heat transfer tube group including a plurality of first heat transfer tubes arranged in rows and columns inside the first container; a second heat transfer tube group including a plurality of second heat transfer tubes arranged in rows and columns inside the second container

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP4151927B1Heat exchange unit for absorption-type refrigerator, absorption-type refrigerator, and corresponding heat exchange method
Publication Date: 2025.01.08 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4151927B1 patent drawingFigure 1
  • EP4151927B1 patent drawingFigure 2A
  • EP4151927B1 patent drawingFigure 2B

AI summary

A heat exchange unit 1 for an absorption refrigerator of the present disclosure includes a first container 5a, a first heat transfer tube group 6f, a first drip feed 7a, a second container 5b, a second heat transfer tube group 6s, and a second drip feed 7b. The first drip feed 7a has a plurality of first portions 74a for dripping arranged along the longitudinal direction of the first heat transfer tubes 6a. A refrigerant liquid is dripped from the first portions 74a toward the first heat transfer tube group 6f. The second drip feed 7b has a plurality of second portions 74b for dripping arranged along the longitudinal direction of the second heat transfer tubes 6b. A solution is dripped from the second portions 74b toward the second heat transfer tube group 6s. An interval P2 between the second portions 74b adjacent to each other in the longitudinal direction of the second heat transfer tubes 6b is smaller than an interval P1 between the first portions 74a adjacent to each other in the longitudinal direction of the first heat transfer tubes 6a.