Dual Desiccant Recirculation Loops for Low-Loss Moisture Control
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Solution Overview
Problem
Existing air conditioning systems using desiccant wheels face significant heat loss and energy inefficiency due to open regeneration loops, where heat is lost to the atmosphere, and closed loop systems require additional energy to reheat air for desiccant regeneration.
Innovation Solution
A method and apparatus utilizing a pair of desiccant contact structures with closed recirculation loops, where the process side of one desiccant structure is connected to the regeneration side of another, allowing for efficient moisture control without the need for additional heat input, using superheated steam for regeneration and minimizing waste heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If open cycle desiccant systems are used, then moisture removal is achieved, but significant heat loss occurs in the regeneration stream discharged to atmosphere
Solution Approach 1:
The patent combines the regeneration stream with the process stream in a closed loop system, merging two previously separate flows into one continuous cycle. This allows the regeneration stream to be reused for cooling without being discharged to atmosphere, eliminating heat loss while maintaining moisture removal capability through the integrated desiccant contactor.
Solution Approach 2:
Instead of discarding the heated regeneration stream to atmosphere, the system recovers its cooling capacity by passing it through the desiccant contactor where it absorbs heat from the process air. The cooled stream is then reused for regeneration, recovering the cooling energy that would otherwise be wasted.
2Loss of energy
If closed loop systems with condensers or heaters are used, then moisture control is achieved, but additional energy is required to cool and reheat the air
Solution Approach 1:
The desiccant contactor performs dual functions: it removes moisture from the process air and simultaneously cools the regeneration stream through evaporative cooling within the desiccant structure. This self-service approach eliminates the need for separate condensers and reheaters, reducing energy consumption while simplifying system operation.
Solution Approach 2:
The desiccant contactor is designed as a multi-functional device that simultaneously dehumidifies the process air and cools the regeneration stream. This universal component replaces multiple specialized devices (condensers, reheaters, coolers), reducing both energy requirements and operational complexity.
3Reliability
If multiple desiccant wheels operate in parallel, then service reliability is improved, but energy efficiency is reduced due to independent operation
Solution Approach 1:
The patent connects multiple desiccant contactors in series within a single closed loop, merging their operation into one integrated system. The regeneration stream passes through each contactor sequentially, allowing heat recovery and cooling to occur across all units. This maintains service reliability through redundancy while improving energy efficiency through systematic heat exchange.
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 reduces energy requirements by up to 50% compared to single-stage systems, retaining regeneration heat and achieving higher moisture removal efficiency with reduced fan power consumption and indoor temperatures.
Implementation Method 1
The desiccant contained on the structure adsorbs moisture from one gaseous flow (process side)
Implementation Method 2
releases moisture contained in the desiccant to a gaseous flow (regeneration side), to regenerate the desiccant
Implementation Method 3
A first closed recirculation loop to provide a fluid connection between the process side of a first desiccant contact structure to the regeneration side of a second desiccant contact structure
Data Source
AI summary
A method and system for controlling moisture content of a gaseous flow. A pair of desiccant contact structures each provided with a process adapted to pass through a process gaseous stream to altering the moisture content of the gaseous stream. Each desiccant contact structure also has a regeneration side adapted to pass through a regeneration gaseous stream for altering the moisture content of a desiccant in the contact structure. The process side of a first desiccant contact structure is fluidly connected to the regeneration side of a second desiccant contact structure via a first closed recirculation loop. In an alternative embodiment a second closed recirculation loop may also be provided on the regeneration side of the first desiccant contact structure. Gaseous flow is then provided to the process side of the second desiccant contact structure to thereby control its moisture.