Membrane Liquid Desiccant HVAC for Closed-Loop Humidity Control
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Solution Overview
Problem
HVAC systems face challenges in effectively regulating humidity levels within conditioned spaces, particularly due to the limitations of traditional moisture-altering devices that rely on open exposure of liquid desiccants, leading to splashing or spraying issues and inefficient moisture exchange.
Innovation Solution
The implementation of a closed-conduit desiccant circuit with vapor-permeable membranes within a processing volume, allowing for moisture exchange between liquid desiccant and conditioned air without open exposure, and incorporating a refrigerant conduit for enhanced heat transfer to improve moisture exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid desiccant is openly exposed for moisture exchange, then moisture exchange can occur, but desiccant splashing or spraying occurs and efficiency is reduced
Solution Approach 1:
The patent employs a hydrophobic membrane as a thin film barrier that allows water vapor to pass through while preventing liquid desiccant from splashing or spraying. The membrane selectively permits vapor transmission based on its hydrophobic properties, resolving the contradiction between enabling moisture exchange and preventing harmful liquid dispersion.
Solution Approach 2:
The hydrophobic membrane functions as a porous material with specific pore structures that allow vapor molecules to pass through while blocking liquid desiccant. The porous structure enables selective permeability based on phase and size, achieving efficient moisture exchange without desiccant splashing.
2Reliability
If traditional moisture-altering devices are used, then humidity regulation is attempted, but the regulation effectiveness is insufficient
Solution Approach 1:
The patent changes the physical and chemical parameters of the membrane material by selecting hydrophobic properties and specific pore size distributions. These parameter changes enable the membrane to selectively transmit vapor while blocking liquid, thereby improving both humidity regulation effectiveness and moisture exchange rate simultaneously.
Solution Approach 2:
The system uses a composite structure combining the hydrophobic membrane with the liquid desiccant reservoir. This composite material approach creates a functional system where the membrane's selective permeability properties enhance the overall performance of the moisture-altering device, achieving reliable humidity regulation with high exchange rates.
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 solution enables continuous and efficient regulation of moisture content in conditioned air, preventing desiccant splashing and improving exchange rates, thus maintaining optimal humidity levels within HVAC systems.
Implementation Method 1
Water vapor diffuses through the vapor-permeable membranes, thereby enabling an exchange of moisture between the liquid desiccant and the conditioned air
Implementation Method 2
The processing volume includes a refrigerant conduit to allow a transfer of heat between refrigerant flowing through the refrigerant conduit and the liquid desiccant in the processing volume. The transfer of heat improves an exchange rate of moisture between the liquid desiccant and the conditioned air
Data Source
AI summary
Systems, devices, and methods are presented for using a liquid desiccant to regulate a moisture content of air conditioned by a heating, ventilating, and air conditioning (HVAC) system. The liquid desiccant is disposed within a processing volume, which is substantially-enclosed and substantially segregates the liquid desiccant from the conditioned air. A pair of vapor-permeable membranes define opposite surfaces of the processing volume. Water vapor diffuses through the vapor-permeable membranes, thereby enabling an exchange of moisture between the liquid desiccant and the conditioned air. The refrigerant circuit itself is used to cool desiccant in the absorber and heat desiccant in the desorber. Other systems, devices, and methods are presented.