Adsorption Humidity Control With Stable Refrigerant Superheat
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Solution Overview
Problem
Conventional humidity control systems lack a means to control the opening of the expansion valve in the refrigerant circuit, leading to unstable refrigerant superheat variations due to frequent switching between batch modes, which is not addressed by control methods used in conventional air conditioners.
Innovation Solution
A humidity control system with an opening control means that adjusts the expansion valve to maintain a predetermined refrigerant superheat value by controlling its opening based on a predetermined time after each batch mode starts, and includes mechanisms to adjust the opening when superheat deviates from target values, preventing wet operation and superheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the humidity control system switches between batch modes frequently to maintain humidity control, then the humidity control responsiveness is improved, but the refrigerant superheat becomes unstable causing unreliable expansion valve operation
Solution Approach 1:
The control system performs preliminary actions by predicting the required expansion valve opening based on the current batch mode state and refrigerant flow characteristics before the mode switching occurs. This allows the expansion valve to be pre-positioned to maintain stable superheat despite the upcoming refrigerant circulation change.
Solution Approach 2:
The system continuously monitors the actual refrigerant superheat and compares it with the target superheat value. Based on this feedback, the control system dynamically adjusts the expansion valve opening to compensate for superheat deviations caused by batch mode switching, ensuring stable and reliable operation.
2Device complexity
If conventional air conditioner control methods are used on the humidity control system, then the device complexity remains simple, but the control effectiveness deteriorates due to unaddressed superheat variation
Solution Approach 1:
The control system transitions from static expansion valve positioning to dynamic control that adapts to changing operating conditions. The expansion valve opening is continuously adjusted based on real-time superheat measurements and batch mode state, enabling precise superheat control despite the simple overall device architecture.
Solution Approach 2:
The system changes the control parameter from fixed valve opening to variable valve opening that responds to superheat variations. By making the expansion valve opening a dynamic parameter rather than a fixed setting, the system achieves precise superheat control without significantly increasing device complexity.
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 stabilizes the expansion valve opening, preventing refrigerant liquid return and superheating, ensuring stable operation by adjusting the valve opening to match changing superheat levels and compressor capacity.
Implementation Method 1
a first heat exchanger (51) carrying an adsorbent thereon, an expansion valve (55) adjustable in opening and a second heat exchanger (52) carrying an adsorbent thereon and supplies humidity-controlled air to a room by operating alternately in a first batch mode in which the second heat exchanger (52) adsorbs moisture in air and the first heat exchanger (51) releases moisture to air
Implementation Method 2
a refrigerant circuit (50) including a compressor (53), a first heat exchanger (51) carrying an adsorbent thereon
Implementation Method 3
a refrigerant circuit (50) including a compressor (53), a first heat exchanger (51) carrying an adsorbent thereon
Data Source
AI summary
A humidity control system (10) includes a refrigerant circuit (50) including a compressor (53), a first adsorption heat exchanger (51) carrying an adsorbent thereon, an expansion valve (55) adjustable in opening and a second adsorption heat exchanger (52) carrying an adsorbent thereon, supplies humidity-controlled air to a room by operating alternately in a first batch mode in which the second adsorption heat exchanger (52) adsorbs moisture in air and the first adsorption heat exchanger (51) releases moisture to air and a second batch mode in which the first adsorption heat exchanger (51) adsorbs moisture in air and the second adsorption heat exchanger (52) releases moisture to air, and controls the opening of the expansion valve (55), when a valve control start time has come a predetermined time after the start of each batch mode, so that the degree of superheat of refrigerant in the refrigerant circuit (50) reaches a predetermined value.