Microporous Membrane Heat-Moisture Exchanger for Building Enclosures
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Solution Overview
Problem
Conventional heat and moisture exchangers in buildings face challenges such as energy loss, humidity issues, corrosion, and contamination of indoor air quality due to their size, material limitations, and inefficiencies in heat and moisture transfer, particularly when integrated into building structures.
Innovation Solution
The development of a heat and moisture exchanger system that incorporates a water-vapor-permeable barrier within an opaque exterior building element, utilizing a microporous polymeric membrane to separate air streams and enhance energy recovery while preventing air and particle exchange, allowing for integration into various building components like walls, roofs, and floors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If desiccant materials are used to transfer moisture, then moisture exchange can be achieved, but additional mechanical energy and thermal energy input is required
Solution Approach 1:
The patent replaces mechanical relocation of desiccant materials with a stationary hygroscopic membrane that passively transfers moisture through adsorption and diffusion mechanisms. The membrane material (such as silica gel, zeolite, or polymeric hygroscopic materials) inherently absorbs and releases moisture based on humidity gradients without requiring mechanical movement or external energy input.
Solution Approach 2:
The hygroscopic membrane operates autonomously by utilizing the humidity difference between exhaust and makeup air streams. The membrane automatically adjusts its moisture content based on the surrounding humidity environment, enabling self-regulating moisture transfer without external control systems or energy input.
2Quantity of substance
If porous polymeric or ceramic films are used for heat and moisture exchange, then both heat and moisture transfer is enabled, but substantial amounts of air and particles are exchanged between gas streams
Solution Approach 1:
The patent employs a hygroscopic membrane with specifically engineered pore structure that provides selective permeability. The membrane allows water vapor molecules to pass through via adsorption-diffusion mechanisms while blocking larger particle structures and most air molecules. This local quality differentiation at the membrane level enables simultaneous moisture transfer and air contamination prevention.
Solution Approach 2:
The patent utilizes hygroscopic porous materials (such as silica gel, zeolite, or polymeric porous structures) that possess controlled pore sizes and surface properties. These materials create a tortuous path that facilitates water vapor diffusion while physically blocking particles, cigarette smoke, cooking odors, and harmful fumes from passing through the membrane.
3Object-generated harmful factors
If pore volume of porous film is reduced to prevent air exchange, then indoor air quality is protected, but heat exchange efficiency decreases and manufacturing becomes difficult and expensive
Solution Approach 1:
The patent changes the fundamental operating parameters of the membrane material by selecting hygroscopic substances with inherent high surface area-to-volume ratios and controlled pore distributions. These materials naturally achieve the desired low effective pore volume for air blocking while maintaining adequate heat transfer capability through their thermal conductivity and surface properties, eliminating the need for extreme manufacturing precision.
Solution Approach 2:
The patent employs composite hygroscopic membrane structures that combine multiple materials with complementary properties. For example, combining hygroscopic porous materials with hydrophilic coatings or integrating them within a supportive matrix structure creates a composite that achieves both air blocking and acceptable heat transfer while being manufacturable with standard industrial processes.
4Quantity of substance
If total heat exchangers are designed with large surface area for moisture exchange, then moisture transfer is improved, but exchanger size becomes very large requiring additional mechanical room space
Solution Approach 1:
The patent utilizes hygroscopic porous materials that provide extremely high internal surface area within a compact external volume. The porous structure creates millions of microscopic adsorption sites per unit volume, enabling high moisture transfer rates without increasing the external dimensions of the exchanger. This volumetric efficiency allows the exchanger to fit within standard mechanical room configurations.
Solution Approach 2:
The patent implements a compact exchanger design where the hygroscopic membrane is nested within the existing heat exchanger structure. The membrane can be configured as thin-walled partitions, coated surfaces, or inserted panels within the conventional heat exchanger housing, effectively nesting the moisture transfer function within the existing thermal exchange framework without requiring separate large-volume moisture exchanger equipment.
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 effectively recovers energy and moisture, reduces mechanical energy input, prevents indoor air contamination, and provides a compact design that fits within existing building infrastructure without compromising structural integrity or indoor air quality.
Implementation Method 1
a water-vapor-permeable barrier was provided within the apparatus, to divide the interior of the apparatus into sub-channels for receiving makeup and exhaust air streams, respectively
Implementation Method 2
Heat exchangers are commonly used in the exhaust air and makeup airflow paths of these systems to recover some of the energy from the exhaust air
Implementation Method 3
Porous polymeric or ceramic films are capable of transferring both heat and moisture when interposed between air streams of differing energy and moisture states
Data Source
AI summary
An architectural heat and moisture exchanger. The exchanger defines an interior channel which is divided into a plurality of sub-channels by a membrane configured to allow passage of water vapor and to prevent substantial passage of air. In some embodiments, the exchanger includes an opaque housing configured to form a portion of a building enclosure, such as an exterior wall, an interior wall, a roof, a floor, or a foundation.