Membrane Air Dehumidification With Evaporative Cooling
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Solution Overview
Problem
Traditional HVAC systems require cooling air to 55° F. for dehumidification, which is inefficient and results in a coefficient of performance (COP) of approximately 3-5, as they need to condense water vapor out of the air, leading to energy inefficiencies and higher operational costs.
Innovation Solution
A dehumidification system using a water vapor permeable membrane to separate air channels from water vapor channels, allowing water vapor to pass through while blocking other components, facilitated by an evaporative cooling unit and a pressure increasing device to create a humidity gradient, enabling water vapor removal without initial condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional refrigerant compressors are used to cool air to 55° F. for dehumidification, then water vapor is condensed out of the air, but energy consumption is high and COP is limited to 3-5
Solution Approach 1:
The system divides the air stream into separate channels: a first channel for air flow and a second channel for water vapor transport. A water vapor permeable membrane separates these channels, allowing selective passage of water vapor while blocking other air components. This segmentation enables independent handling of dehumidification and cooling processes, avoiding the energy-intensive practice of cooling entire air volumes to condensation temperatures.
Solution Approach 2:
The system extracts water vapor from the air stream by allowing it to pass through the water vapor permeable membrane into the second channel where it is removed at lower temperatures. This extraction approach removes only the moisture component without requiring the entire air stream to be cooled to 55° F., significantly reducing energy consumption while maintaining dehumidification effectiveness.
2Quantity of substance
If air is cooled to 55° F. to achieve dehumidification, then humidity ratio is reduced to 0.009, but the process requires high energy input resulting in COP of only 3-5
Solution Approach 1:
The system changes the operating parameters by maintaining the air stream at higher temperatures (avoiding cooling to 55° F.) while still achieving dehumidification. The water vapor permeable membrane enables water vapor removal at elevated temperatures by creating a vapor pressure gradient across the membrane, fundamentally changing the temperature parameter from which traditional systems must cool air.
Solution Approach 2:
The system replaces the mechanical refrigeration cycle (compressors, condensers, evaporators) with a membrane-based separation process. Instead of using mechanical compression and phase change to remove moisture, the system uses the selective permeability properties of the membrane to transport water vapor, eliminating the need for energy-intensive mechanical cooling equipment.
3Quantity of substance
If water vapor is condensed out of air at 55° F., then dehumidification is achieved, but the system complexity increases with refrigerant compressors and condensation equipment
Solution Approach 1:
The water vapor permeable membrane acts as an intermediary between the air stream and the water vapor removal system. This membrane mediator enables selective water vapor transport without requiring direct contact between the air stream and complex condensation equipment, simplifying the overall system architecture while maintaining effective dehumidification performance.
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 reduces energy consumption by allowing dehumidification at constant temperature, achieving a higher COP of up to five times that of conventional systems, and efficiently removing water vapor with minimal energy input.
Implementation Method 1
The membrane is configured to facilitate removal of water vapor from an airstream by facilitating passage of H2O from the water vapor to the second channel through permeable volumes of the membrane while substantially blocking all other components of the airstream from passing through the membrane
Implementation Method 2
an evaporative cooling unit configured to cool the airstream
Implementation Method 3
a pressure increasing device configured to create a lower partial pressure of water vapor within the second channel than in the first channel, such that the H2O moves through the membrane to the second channel
Implementation Method 4
The pressure increasing device is also configured to increase the pressure of water vapor at an outlet of the pressure increasing device to a partial pressure of water vapor in a range suitable for subsequent condensing into liquid water
Data Source
AI summary
The present invention relates to systems and methods for dehumidifying air by establishing humidity gradients in one or more dehumidification units. Water vapor from relatively humid atmospheric air entering the dehumidification units is extracted by the dehumidification units without substantial condensation into low pressure water vapor vacuum volumes. The water vapor is extracted through water vapor permeable membranes of the dehumidification units into the low pressure water vapor vacuum volumes. The air exiting the dehumidification units is less humid than the air entering the dehumidification units. The low pressure water vapor extracted from the air is compressed to a slightly higher pressure, condensed, and removed from the system at ambient conditions. In addition, each of the dehumidification units may be associated with one or more evaporative cooling units through which the air will be directed, with the evaporative cooling units being upstream and/or downstream of the dehumidification units.