Humidity controller

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Solution Overview

Problem

The existing humidity controllers with refrigerant circuits face issues due to large pressure differences in the refrigeration cycle, which can cause switching mechanism troubles and reduce reliability, as they require alternating cooling and heating of adsorbent heat exchangers.

Innovation Solution

Incorporating a differential pressure detection system and a control mechanism that adjusts the compressor capacity or stops it when pressure differences exceed certain thresholds to prevent adverse effects on the switching mechanism, ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the switching mechanism reverses refrigerant circulation flow to alternate cooling and heating of adsorbent heat exchangers, then humidity control function is achieved, but large pressure difference causes switching mechanism troubles

Engineering Contradiction:
Improvehumidity control functionVSAvoidswitching mechanism reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control unit detects the pressure difference between high and low pressure sides before switching occurs, and when the pressure difference exceeds a predetermined threshold, it prevents the switching mechanism from operating. This preliminary detection and prevention approach avoids the harmful effect of large pressure differences on the switching mechanism, thereby resolving the contradiction between maintaining humidity control functionality and ensuring switching mechanism reliability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If compressor capacity is reduced to limit pressure difference, then switching mechanism reliability is improved, but refrigeration cycle efficiency decreases

Engineering Contradiction:
Improveswitching mechanism reliabilityVSAvoidrefrigeration cycle efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control unit applies partial action by selectively limiting compressor capacity only when the pressure difference exceeds the predetermined threshold. When the pressure difference is within acceptable limits, the compressor operates at full capacity to maintain refrigeration efficiency. This partial limitation approach ensures switching mechanism reliability while minimizing the impact on overall refrigeration cycle productivity.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If the switching mechanism operates frequently to alternate adsorption and desorption, then humidity control precision is improved, but switching mechanism wear increases

Engineering Contradiction:
Improvehumidity control precisionVSAvoidswitching mechanism durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The control unit continuously monitors the pressure difference between high and low pressure sides and uses this feedback information to determine whether switching should occur. When the pressure difference exceeds the threshold, the control unit prevents switching, thereby reducing unnecessary switching operations and mechanical wear. This feedback-based control maintains humidity control precision by enabling switching only under safe pressure conditions while extending switching mechanism durability.

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

This solution effectively manages pressure differences within safe limits, preventing damage to the switching mechanism and enhancing the reliability of the humidity controller by controlling compressor capacity and operation based on detected pressure thresholds.

Implementation Method 1

a differential pressure detection means (93, 97) for detecting a difference between high pressure and low pressure in the refrigeration cycle of the refrigerant circuit (50)

Methodology Applied
Scientific EffectPressure detection:

Implementation Method 2

a compressor (53)... for performing a refrigeration cycle by circulating a refrigerant

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

two adsorbent heat exchangers are included... On the adsorbent heat exchanger serving as the evaporator, the adsorbent is cooled by the refrigerant and adsorbs moisture in the air

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

On the adsorbent heat exchanger serving as the condenser, the adsorbent is heated by the refrigerant and desorbs the moisture adsorbed thereon

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 5

a refrigeration cycle for circulating a refrigerant in the refrigerant circuit is performed when the compressor is actuated

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 6

an operation in which one of the adsorbent heat exchangers serves as an evaporator and the other serves as a condenser

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP1887292B1Humidity controller
Publication Date: 2020.06.17 DAIKIN INDUSTRIES LTD
  • EP1887292B1 patent drawingFigure 1A~1B
  • EP1887292B1 patent drawingFigure 2
  • EP1887292B1 patent drawingFigure 3

AI summary

A humidity controller includes a differential pressure detection means (93, 97) for detecting a difference between high voltage and low voltage in a refrigeration cycle of a refrigerant circuit (50) and a control means (30) for controlling the capacity of the compressor (53). The control means (30) reduces the capacity of the compressor (53) when a detected value of the differential pressure detection means (93, 97) exceeds a reduction threshold. Further, the control means (30) stops the compressor (53) when the detected value of the differential pressure detection means (93, 97) exceeds a stop threshold higher than the reduction threshold.