Double-Effect Liquid Desiccant Dehumidification for Humidity Control
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Solution Overview
Problem
Current HVAC systems face challenges in efficiently handling humidity levels, leading to poor Indoor Air Quality (IAQ) and high energy consumption, particularly in hot and humid climates, due to the limitations of vapor compression systems in managing latent and sensible heat loads separately.
Innovation Solution
The implementation of a double-effect liquid desiccant dehumidification system (LDDS) that uses ionic liquids as the desiccant, incorporating a high desorber and low desorber configuration with heat exchangers to efficiently remove moisture from air and regenerate the desiccant solution, allowing for separate handling of sensible and latent heat loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If vapor compression systems are used for cooling, then cooling capacity is achieved, but energy consumption increases and humidity control deteriorates
Solution Approach 1:
The system divides the thermal load into two independent parts: a liquid desiccant dehumidification system that handles latent heat (moisture removal) and a conventional vapor compression system that handles sensible heat (temperature control). This segmentation allows each subsystem to optimize its function, with the desiccant system removing moisture without cooling and the vapor compression system providing temperature control, thereby improving overall energy efficiency and humidity control independence.
2Ease of operation
If liquid desiccant dehumidification is implemented, then humidity control improves, but system complexity increases
Solution Approach 1:
The patent combines the liquid desiccant dehumidification system with the conventional vapor compression cooling system into a hybrid HVAC system. The desiccant system handles moisture removal while the vapor compression system handles temperature control, and the two systems are integrated through shared components and coordinated operation. This merging approach manages complexity by using established technologies in complementary roles rather than replacing the entire system.
3Power
If high GWP refrigerants are used, then cooling performance is maintained, but environmental impact increases
Solution Approach 1:
The system changes the operating parameters and working substances by introducing liquid desiccant (such as ionic liquids or salt solutions) as the primary dehumidification medium. This parameter change eliminates or reduces the need for high GWP refrigerants in the dehumidification function, using instead environmentally friendly liquid desiccants that can be regenerated thermally. The vapor compression system retains its refrigerant for sensible cooling only, thereby reducing overall refrigerant quantity and environmental impact.
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 significantly enhances energy efficiency, reduces system complexity and cost, and improves IAQ by enabling independent control of humidity and temperature levels, while also reducing the reliance on high global warming potential refrigerants.
Implementation Method 1
a high desorber configured to heat the working solution to evaporate water
Implementation Method 2
configured with the low desorber for condensation of water evaporated from a working solution within the high desorber in a condenser
Implementation Method 3
The working solution from the low desorber is configured with the absorber for condensation of water from ambient air into the working solution within a working solution conduit of the absorber
Implementation Method 4
The double-effect LDDS can have a low heat exchanger thermally coupling portions of the working solution
Data Source
AI summary
A liquid desiccant system including a high desorber, a low desorber, and an absorber that are in fluid communication with a working solution, where the high desorber provides rejected water vapor from the working fluid for condensation in a condenser of the low desorber that provides heat for rejection of additional water from the working solution in the low desorber effectively multiplying the heat provided for desorption. The low desorber provided the concentrated working solution to the absorber where water from ambient air is condensed into the concentrated working solution to provide a dilute working solution within a working solution conduit of the absorber that is thermally coupled to an internal cooler of the absorber. In some embodiments, the working solution can be an aqueous solution of at least one ionic liquid.