Adsorption Heat Exchanger Switching for Compressor-Off Humidity Control

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Solution Overview

Problem

Conventional humidity control apparatuses with refrigerant circuits struggle to control humidity effectively when the compressor operation is stopped, leading to uncontrolled temperature and humidity conditions in indoor spaces, as they cannot adjust the compressor's operation capacity below a certain threshold, resulting in continuous ventilation without humidity control.

Innovation Solution

The apparatus incorporates a refrigerant circuit with a compressor, adsorption heat exchangers, and a switching mechanism to alternate between dehumidifying and humidifying cycles, even when the compressor is stopped, by switching the air flow path between two adsorption heat exchangers, ensuring controlled temperature and humidity levels in indoor spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the compressor operation capacity is reduced below the lower limit, then the humidity control capability can be increased, but the compressor cannot operate properly and reliability deteriorates

Engineering Contradiction:
Improvehumidity control capabilityVSAvoidcompressor operation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system segments the humidity control function by introducing a second adsorption heat exchanger that can operate independently when the compressor is stopped. This allows the first adsorption heat exchanger to continue providing humidity control during compressor stop periods, effectively segmenting the operational phases and enabling adaptability across different compressor states.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements periodic switching between two operational modes: (1) compressor operation mode with first adsorption heat exchanger, and (2) compressor stop mode with second adsorption heat exchanger. This periodic action allows the system to maintain humidity control capability while respecting the compressor's minimum operation capacity requirements, preventing frequent start-stop cycles.

Inventive Principle:
Principle #19Periodic action

2Loss of energy

If the compressor is stopped to avoid excessive humidity control capability, then energy consumption is reduced, but temperature and humidity control in indoor space deteriorates

Engineering Contradiction:
Improvecompressor energy consumptionVSAvoidindoor space temperature and humidity control
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The second adsorption heat exchanger is pre-configured and maintained in readiness to take over humidity control function when the compressor stops. This preliminary preparation ensures that indoor space environmental control continues without interruption or deterioration, even during compressor stop periods for energy conservation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second adsorption heat exchanger acts as an intermediary device that bridges the gap between compressor stop mode and continuous indoor space environmental control. It mediates the transition by providing alternative humidity control capability, ensuring that energy savings from compressor shutdown do not compromise indoor comfort.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If frequent start-stop cycles are implemented to match humidity control demand, then energy efficiency is improved, but mechanical part reliability deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidmechanical part reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system ensures continuous useful action for humidity control by having two adsorption heat exchangers that can alternately operate. When the compressor stops, the second adsorption heat exchanger continues the humidity control function, maintaining continuous environmental control capability while allowing the compressor to operate less frequently for energy efficiency without compromising overall system reliability.

Inventive Principle:
Principle #20Continuity of useful action

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 allows for controlled humidity and temperature management in indoor spaces even when the compressor is not operating, enhancing comfort and extending the compressor's operational reliability by preventing frequent start-stop cycles and maintaining sufficient refrigerant flow.

Implementation Method 1

an adsorption heat exchanger carrying an adsorbent

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the moisture desorbed from the adsorption heat exchanger serving as a radiator

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 3

a refrigerant circuit which performs a refrigeration cycle is provided with two adsorption heat exchangers

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP2767772B1Humidity control device
Publication Date: 2018.03.28 DAIKIN INDUSTRIES LTD
  • EP2767772B1 patent drawingFigure 1
  • EP2767772B1 patent drawingFigure 2(A)~2(B)
  • EP2767772B1 patent drawingFigure 3

AI summary

A refrigerant circuit (50) of a humidity control apparatus (10) is provided with two adsorption heat exchangers (51, 52). In the refrigerant circuit (50), refrigerant can circulate in reverse directions. A switching mechanism (40) of the humidity control apparatus (10) switches between a transfer path of the outdoor air to be supplied into a room and a transfer path of the indoor air to be exhausted to the outside the room. In a first operation of the humidity control apparatus (10), a direction of refrigerant circulation and a flow path of the air are changed every predetermined period. In a second operation of the humidity control apparatus (10), the refrigerant circuit (50) is stopped, and the flow path of the air is changed every predetermined period. In the second operation, although the refrigerant circuit (50) is stopped, the outdoor air whose temperature and humidity are controlled is supplied into the room to ensure comfort of the room.