Ionic Liquid Salt Dehumidification for Low-Grade Heat Regeneration
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Solution Overview
Problem
Conventional HVAC systems require inefficient cooling and reheating to dehumidify air, using large amounts of heat to regenerate desiccants, which is not energy-efficient.
Innovation Solution
An integrated ionic liquid salt dehumidification system using thermally stable organic liquid salts, such as 1-Ethyl-3-methylimidazolium acetate, that can absorb and desorb water vapor efficiently with low-grade heat, reducing energy consumption by minimizing over-cooling and reheating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vapor compression refrigeration cycles are used to dehumidify air through condensation, then moisture is removed from humid air, but inefficient cooling and reheating is required
Solution Approach 1:
The patent changes the fundamental parameter of moisture removal from condensation-based (temperature-dependent) to absorption-based (chemical potential-dependent). Ionic liquid desiccants operate at higher temperatures than dew point, eliminating the need for over-cooling and subsequent reheating, thus resolving the energy inefficiency while maintaining dehumidification effectiveness
Solution Approach 2:
The patent transitions from relying on phase change (condensation) for moisture removal to using absorption/desorption cycles of ionic liquids. The ionic liquid absorbs moisture in liquid phase at operating conditions and releases it during regeneration, avoiding the energy-intensive cooling-below-dew-point-and-reheating process of conventional VCR systems
2Loss of energy
If conventional desiccant systems are used to absorb moisture, then latent cooling load is reduced, but large amounts of heat is required to regenerate the desiccant
Solution Approach 1:
The patent modifies the regeneration temperature parameter by using ionic liquids that enable low-grade heat sources (60-120°C) to effectively regenerate the desiccant. This is achieved through selecting ionic liquids with appropriate hygroscopic properties and vapor pressure characteristics, reducing regeneration heat consumption compared to conventional desiccants while maintaining latent cooling load reduction
3Reliability
If ordinary hydroscopic salts are used for dehumidification, then moisture absorption is achieved, but high driving temperatures are required for regeneration
Solution Approach 1:
The patent employs ionic liquids as composite desiccant materials that combine the hygroscopic properties of traditional salts with organic cations and anions. This composite structure enables moisture absorption at ambient conditions while allowing regeneration at significantly lower temperatures (60-120°C) compared to ordinary hydroscopic salts, resolving the contradiction between absorption capacity and regeneration temperature
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 effectively dehumidifies air with reduced energy usage by using low-grade heat for regeneration, enhancing the efficiency of cooling systems and reducing the latent cooling load on HVAC systems.
Implementation Method 1
an ionic liquid desiccant that absorbs moisture from an inlet air stream
Implementation Method 2
a heating device that regenerators the organic ionic salt composition by heating it to drive out moisture
Implementation Method 3
whereby moisture is desorbed from the ionic liquid desiccant
Data Source
AI summary
A cooling system utilizes an organic ionic salt composition for dehumidification of an airflow. The organic ionic salt composition absorbs moisture from an inlet airflow to produce an outlet airflow with a reduce moisture from that of the inlet airflow. The organic ionic salt composition may be regenerated, wherein the absorbed moisture is expelled by heating with a heating device. The heating device may be an electrochemical heating device, such as a fuel cell, an electrochemical metal hydride heating device, an electrochemical heat pump or compressor, or a condenser of a refrigerant cycle, which may utilize an electrochemical pump or compressor. The efficiency of the cooling system may be increased by utilization of the waste heat the cooling system. The organic ionic salt composition may circulate back and forth or in a loop between a conditioner, where it absorbs moisture, to a regenerator, where moisture is desorbed by heating.