Cross-Flow Membrane Heat Exchanger Array for Low-ΔT Air Conditioning
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Solution Overview
Problem
Conventional heat exchangers face limitations due to high temperature differences (ΔT) that lead to inefficiencies in heat transfer, increased mass and cost, and fragility, particularly in applications requiring high surface areas and low thicknesses, such as in power plants and cooling systems.
Innovation Solution
The development of membrane heat exchanger systems utilizing thin-film polymer membranes with increased surface areas, which reduce temperature differentials and enhance heat transfer efficiency while maintaining mechanical resilience and low material costs, achieved through advanced manufacturing techniques and computational design optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metallic heat exchangers are used to increase surface area for heat transfer, then heat transfer rate is improved, but mass and cost increase significantly
Solution Approach 1:
The patent employs thin-film polymer membranes (typically 1-10 micrometers thick) as heat transfer elements, replacing conventional thick metallic structures. These flexible thin films provide high surface area-to-mass ratio, enabling efficient heat transfer while minimizing the mass of the heat exchanger system.
Solution Approach 2:
The patent utilizes three-dimensional stacked configurations of thin-film membranes, creating multiple heat transfer surfaces in a compact volume. This dimensional arrangement increases the effective heat transfer area without proportionally increasing mass, as the thin films are stacked in layers rather than requiring large single surfaces.
2Weight of moving object
If metallic heat exchangers are made thinner to reduce mass, then mass is reduced, but fragility and corrosion sensitivity increase
Solution Approach 1:
The patent uses polymer composite materials that combine flexibility, corrosion resistance, and adequate mechanical strength. These composite thin-film structures maintain reliability even at minimal thicknesses where conventional metals would become fragile and corrosion-sensitive.
Solution Approach 2:
The flexible thin-film polymer membranes are designed to be resilient rather than rigid, allowing them to withstand operational stresses without becoming fragile. The flexibility inherent in thin polymer films provides mechanical tolerance that prevents the brittleness issues associated with thin metallic structures.
3Productivity
If temperature difference ΔT is increased to improve heat transfer rate, then heat transfer rate increases, but exergy loss increases
Solution Approach 1:
The patent compensates for the reduced temperature difference by increasing the heat transfer area through three-dimensional stacking of thin-film membranes. This allows the system to maintain adequate heat transfer rates while operating with smaller ΔT, thereby reducing exergy losses.
Solution Approach 2:
The patent changes the key heat transfer parameters by using thin-film materials with high surface area-to-volume ratios and optimizing the stacking configuration. This enables the system to achieve required heat transfer rates through increased area rather than increased temperature difference, reducing thermodynamic losses.
4Productivity
If surface area is increased to improve heat transfer, then heat transfer rate increases, but device complexity increases
Solution Approach 1:
The patent divides the heat transfer function into multiple discrete thin-film membrane elements that can be individually manufactured and then stacked together. This segmentation allows for simplified manufacturing of individual components while achieving high total surface area through the assembled configuration.
Solution Approach 2:
The patent employs nested or stacked configurations where thin-film membranes are arranged in layers, with each layer contributing to the total heat transfer area. This nesting approach packs large surface area into a compact structure without requiring complex external frameworks or support systems.
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
These membrane heat exchangers significantly improve heat transfer rates and system performance by increasing surface area without increasing mass or cost, achieving higher coefficients of performance and reducing fan power consumption, while being more durable and resistant to corrosion.
Implementation Method 1
the heat transfer rate in a heat exchanger can be directly proportional to the surface area in the heat exchanger... k is the thermal conductivity of the material
Implementation Method 2
this heat flux from one fluid, through a wall, into a second fluid is a function of the combined heat transfer due to convection in both fluids and conduction
Data Source
AI summary
An air thermal conditioning system, for at least one of heating air and cooling air, which includes a cross-flow heat exchanger array. The cross-flow heat exchanger array includes a plurality of planar membrane heat exchangers disposed in parallel with a space separating adjacent planar membrane heat exchangers. Each of the planar membrane heat exchangers include a first sheet; a second sheet coupled to the first sheet; and at least one fluid chamber defined by the first and second sheets, with the at least one fluid chamber extending between first and second ends of the planar membrane heat exchangers and opening to a first and second port at the first and second ends respectively.