Membrane HVAC Enthalpy Exchange Without Evaporative Surfaces
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Solution Overview
Problem
Conventional HVAC systems face challenges in maintenance and efficiency, particularly with evaporative cooling towers and condensing heat exchangers, which are costly to maintain and inefficient in smaller applications due to size scaling issues and interference from condensed liquids.
Innovation Solution
The implementation of membrane-based mass exchangers that use selective transport membranes to allow only water vapor to pass through, eliminating the need for evaporative surfaces and condensation surfaces, thereby reducing maintenance and increasing efficiency by allowing water desorption and condensation directly into a flowing stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If evaporative cooling towers are used, then cooling efficiency is improved, but maintenance cost and complexity increase due to cleaning of evaporative surfaces and remediation of toxic salt and metal buildup
Solution Approach 1:
The patent extracts the harmful evaporative surface from the system by using a membrane that allows water vapor transmission without requiring a physical evaporative surface. This eliminates the source of salt and metal buildup while maintaining the cooling function through latent heat transfer.
Solution Approach 2:
The membrane acts as an intermediary between the liquid water and the air stream, allowing selective water vapor transmission while preventing direct contact between the water and the air handling components. This mediator function eliminates the need for cleaning evaporative surfaces while maintaining cooling efficiency.
2Volume of moving object
If evaporative cooling towers are scaled down for smaller applications, then system size is reduced, but cooling efficiency deteriorates due to size scaling issues
Solution Approach 1:
The patent uses thin membrane films that provide high surface area for water vapor transmission in a compact form factor. This allows the system to maintain high cooling efficiency while being scaled down for smaller applications, as the membrane's thin film structure provides efficient mass transfer without requiring large volumes.
3Loss of energy
If condensing heat exchangers are used, then heat removal is improved, but condensation efficiency deteriorates when liquid already condensed on the surface interferes with further condensation
Solution Approach 1:
The patent extracts the condensation process from the heat exchanger surface by using a membrane that allows water vapor to condense directly into the liquid stream without forming liquid on the heat transfer surface. This eliminates the interference of condensed liquid with further condensation while maintaining heat removal efficiency.
Solution Approach 2:
The patent replaces the conventional mechanical condensation process on heat exchanger surfaces with a membrane-based phase change process. Instead of relying on surface condensation that gets blocked by liquid accumulation, the system uses membrane permeation followed by condensation in the liquid stream, eliminating the blocking mechanism.
4Ease of operation
If conventional HVAC components are used, then system functionality is achieved, but device complexity and maintenance burden increase
Solution Approach 1:
The membrane component performs multiple functions simultaneously: it acts as a selective barrier for water vapor transmission, a heat transfer medium, and a separator between liquid and gas streams. This multi-functionality reduces the number of separate components needed while maintaining full HVAC functionality, thereby reducing device complexity and maintenance burden.
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 reduces maintenance burdens, enhances efficiency by allowing for smaller-scale applications, and increases the system's tolerance to high ambient temperatures, achieving a higher energy efficiency ratio compared to traditional systems.
Implementation Method 1
a selective transport membrane that allows only one or more selected liquids and gases to pass therethrough
Implementation Method 2
When used in a gas-to-liquid phase-change mode (an enthalpy absorber), a portion of a gas, such as water vapor, is allowed to pass through the membrane as the gas, such as water vapor, and to condense directly into a liquid
Implementation Method 3
When used in a liquid-to-gas phase-change mode (an enthalpy desorber), a portion of a liquid, such as water from a water stream, is allowed to pass through the membrane of the mass exchanger as a gas without need of a conventional evaporative surface
Implementation Method 4
Existing HVAC systems use heat of condensation and/or heat of vaporization of a liquid, such as water, to adjust temperature and humidity within a structure
Data Source
AI summary
Particular embodiments disclosed herein relate to methods, compositions, and systems relating generally to heating, ventilation, and air conditioning (HVAC) systems, and more specifically, to HVAC systems that transfer sensible and/or latent energy between air streams, humidify and/or dehumidify air streams. In certain embodiments, a polymeric membrane is utilized for fluid exchange, with or without an additional support. Certain embodiments allow for individual regulation of air temperature and humidity.