Vehicle HVAC Membrane Dehumidification for Cold-Weather Recirculation
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Solution Overview
Problem
Conventional HVAC systems in vehicles face inefficiencies in managing moisture and humidity levels, particularly in electric and hybrid vehicles, leading to increased electrical power consumption and reduced range due to the need for high HVAC load during cold weather operations.
Innovation Solution
Incorporation of a semipermeable membrane in the HVAC system to selectively remove moisture from recirculating air, combined with a vacuum source to drain condensed water vapor, reducing the humidity and dew point of recirculated air, and minimizing electrical power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional HVAC systems are used to manage moisture in vehicle air conditioning, then cooling capacity is maintained, but electrical power consumption increases and vehicle range decreases
Solution Approach 1:
The patent employs a semipermeable membrane with specific porosity characteristics to selectively remove water vapor from recirculated air. The membrane's porous structure allows water molecules to pass through while blocking larger air molecules, achieving effective dehumidification without requiring high-energy compression or cooling cycles, thus reducing electrical power consumption while maintaining reliable moisture management.
Solution Approach 2:
The system changes the physical parameters of air by passing it through the semipermeable membrane, which selectively permits water vapor transmission based on molecular size and polarity differences. This parameter-based separation enables energy-efficient moisture removal by exploiting inherent molecular properties rather than requiring energy-intensive thermal or mechanical processes.
2Reliability
If high HVAC power is used during cold weather operations, then humidity control is improved, but vehicle range is reduced
Solution Approach 1:
The system performs preliminary dehumidification by passing recirculated air through the semipermeable membrane before the air enters the evaporator. This preliminary removal of water vapor reduces the moisture load that the evaporator must handle, enabling more effective humidity control with reduced HVAC power consumption during cold weather operations when the engine or heat pump is already running.
Solution Approach 2:
The semipermeable membrane acts as an intermediary device between the recirculated air and the evaporator system. It performs the initial water vapor separation function, reducing the workload on the main HVAC system and enabling efficient humidity control without requiring high power input from the primary cooling system during cold weather operation.
3Use of energy by moving object
If recirculated air is used in cold weather, then energy efficiency improves, but window fogging increases due to high humidity
Solution Approach 1:
The system extracts water vapor from recirculated air by passing it through the semipermeable membrane, which selectively removes moisture while allowing dry air to recirculate. This extraction of the harmful moisture component enables the use of energy-efficient recirculated air mode without the adverse effect of window fogging, as the dehumidified air maintains lower humidity levels suitable for cold weather operation.
Solution Approach 2:
The system converts the potentially harmful effect of recirculated humid air (which causes window fogging) into a benefit by using the semipermeable membrane to selectively remove water vapor. The recirculated air, which would normally be problematic due to high humidity, becomes beneficial after dehumidification, providing both energy efficiency and fog-free windows simultaneously.
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
The system effectively maintains lower humidity levels in the passenger compartment, reducing the need for high HVAC power consumption, thus extending the vehicle's range and preventing window fogging during cold weather.
Implementation Method 1
The housing comprises a semipermeable membrane that is aligned with the first inlet such that air that flows through the first inlet flows through the semipermeable membrane before flowing to the outlet
Implementation Method 2
a first port that is fluidly connected to the housing, such that water vapor that is removed from the air that flows into the semipermeable membrane flows into the first port from the semipermeable membrane
Data Source
AI summary
A heating and ventilation system is provided. The system includes a housing with air inlet that receives air from a fan, which takes an intake from either or both of fresh air from outside of the vehicle and the passenger compartment. The housing includes a semipermeable membrane that is aligned to receive air flowing from the fan. A first port receives water vapor that is removed from the air that flows into the semipermeable membrane. The housing receives an evaporator of a heat pump system.