Humidity control unit and method having bypass for process air
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Solution Overview
Problem
Traditional air conditioning systems are poorly designed to handle varying humidity loads independently of temperature loads, leading to uncomfortable conditions and potential mold formation, and existing desiccant cooling systems have air flow capacity limitations and high energy consumption.
Innovation Solution
An air conditioning and dehumidification system using multiple air plenums with a desiccant wheel and a liquid vapor refrigeration circuit, allowing for increased air flow capacity without additional desiccant wheels, and incorporating a third ambient air plenum for selective cooling and bypassing desiccant treatment to efficiently control humidity and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional air conditioning systems are sized to accommodate peak temperature design conditions, then adequate dehumidification capacity is achieved during cooling demands, but the systems are poorly designed for conditions where humidity load exists without temperature load, leading to uncomfortable conditions and potential mold formation
Solution Approach 1:
The air conditioning system is divided into separate temperature control and humidity control subsystems. The temperature control uses traditional refrigeration cycle while the humidity control uses a desiccant wheel that operates independently, allowing each subsystem to be optimized for its specific function and enabling reliable dehumidification regardless of temperature conditions.
Solution Approach 2:
The desiccant wheel rotation speed is dynamically adjusted based on humidity load conditions. The control system varies the wheel speed to match the required dehumidification capacity, enabling the system to adapt to varying humidity loads from low to high conditions while maintaining optimal performance across different operating scenarios.
2Manufacturing precision
If desiccant cooling systems are used to provide close and independent control of humidity and temperature, then very close and independent control is achieved, but the systems are typically more expensive to install than traditional systems
Solution Approach 1:
The system changes the operational parameters of the desiccant wheel, specifically rotating it at varying speeds depending on the humidity load. This allows the single desiccant wheel to provide precise humidity control across different operating conditions, replacing the need for multiple fixed-capacity units and reducing installation complexity and cost.
Solution Approach 2:
The desiccant wheel serves multiple functions: it provides dehumidification during cooling demands, handles humidity loads without temperature loads, and can operate independently of the refrigeration system. This multi-functionality allows a single integrated system to replace what would traditionally require separate dedicated dehumidification equipment, reducing installation cost.
3Productivity
If multiple units are needed to meet capacity requirements in desiccant based systems, then air flow capacity requirements are met, but the need for multiple units increases complexity and cost
Solution Approach 1:
The desiccant wheel rotates at variable speeds controlled by a motor, allowing a single unit to dynamically adjust its air flow capacity to meet varying productivity requirements. This eliminates the need for multiple fixed-capacity units, reducing system complexity while maintaining the ability to meet peak air flow demands.
Solution Approach 2:
By changing the rotational speed parameter of the desiccant wheel, the system can adjust its air flow capacity over a wide range. This parameter adjustment allows one unit to replace multiple units, simplifying the overall system architecture while maintaining the required productivity and air flow capacity.
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
The system provides efficient and cost-effective air conditioning with higher air flow capacity, allowing for variable desiccant treatment and additional cooling, reducing the need for multiple units and energy consumption, while maintaining desired humidity and temperature conditions.
Implementation Method 1
supply the thus cooled and dehumidified first air stream through the process segment of a rotating desiccant wheel to further reduce moisture content in the first ambient air stream
Implementation Method 2
cooling a first ambient supply air stream with the evaporator cooling coil of a DX refrigeration system
Implementation Method 3
cooling a first ambient supply air stream with the evaporator cooling coil of a DX refrigeration system and then passing the thus cooled and dehumidified first air stream
Implementation Method 4
passing the thus heated second ambient air stream through a regeneration segment of the desiccant wheel
Data Source
AI summary
In conditioning air for an enclosure, a first ambient airstream is cooled by the cooling coil of a refrigerant cooling system to reduce its temperature and humidity content. The thus cooled and dehumidified air is then passed through a segment of a rotating desiccant wheel to reduce moisture content and increase temperature and is then supplied to the enclosure. The desiccant wheel is regenerated by the use of a second ambient airstream which is first heated with the condenser coil of the refrigerant system and then passed through the regeneration segment of the desiccant wheel. A bypass plenum is provided in the apparatus that selectively allows a third ambient airstream to be cooled in the plenum independent of the evaporator coil and desiccant wheel in the first plenum. That airstream is then supplied with the air treated in the first plenum to the enclosure.