Regenerative vehicle air conditioning system
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Solution Overview
Problem
Air conditioning systems in vehicles with built-in phase change materials face delays in cooling effect initialization and lack energy storage during deceleration, leading to inefficient fuel usage and inadequate cooling during stops.
Innovation Solution
A regenerative air conditioning system incorporating a storage evaporator with phase change material and a solenoid-controlled expansion valve, allowing for thermal energy storage during deceleration and controlled release during stops to maintain cabin cooling without engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phase change material is built into the main evaporator, then cooling is provided during stops without engine running, but cooling effect initialization is delayed and energy storage during deceleration is not possible
Solution Approach 1:
The evaporator is divided into two separate components: a main evaporator for active cooling and a storage evaporator containing phase change material for thermal energy storage. This segmentation allows each component to perform its specific function optimally without the compromises of a combined design.
Solution Approach 2:
A solenoid-controlled expansion valve is introduced as an intermediary device to control refrigerant flow between the two evaporators. This valve acts as a mediator that directs refrigerant to the storage evaporator during deceleration for charging and to the main evaporator during active cooling, enabling flexible system operation.
2Duration of action of moving object
If phase change material is frozen to store cooling potential, then cooling is available during stops, but the cooling effect is delayed when the air conditioning system is first turned on
Solution Approach 1:
The storage evaporator is charged with cooled phase change material during deceleration events before the vehicle comes to a complete stop. This preliminary action ensures that cooling capacity is pre-loaded and immediately available when the vehicle stops, eliminating the delay that would occur if the system had to start cooling from scratch.
Solution Approach 2:
The system utilizes periodic deceleration events during normal driving to repeatedly charge the storage evaporator. This periodic charging maintains the phase change material in a cooled state, ensuring continuous availability of cooling capacity during subsequent stops without requiring prolonged continuous operation.
3Temperature
If the vehicle engine is restarted to maintain cabin cooling during stops, then cooling is maintained, but fuel consumption increases
Solution Approach 1:
The storage evaporator with phase change material serves the cooling function autonomously during vehicle stops without requiring engine operation. The phase change material releases stored cooling energy as it melts, automatically maintaining cabin temperature without consuming additional fuel.
4Loss of energy
If mechanical energy during deceleration is not captured, then the system is simple, but energy is wasted
Solution Approach 1:
The system converts the previously wasted mechanical energy during deceleration into useful thermal energy storage. By operating the compression system during deceleration, the phase change material in the storage evaporator is charged with cooling capacity, transforming energy that would otherwise be lost into a valuable resource for subsequent cooling periods.
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
Enhances cooling efficiency by storing thermal energy during deceleration and releasing it during stops, reducing fuel consumption and maintaining cabin comfort without engine restarts.
Implementation Method 1
the phase change material absorbs heat from the evaporator and keeps the evaporator cool
Implementation Method 2
the phase change material is cooled to change phase when the vehicle engine was running and the compressor thus running. For example, the phase change material is frozen from a liquid to a solid state
Implementation Method 3
the refrigerant which is circulated through the air conditioning system by the compressor which is also a phase change material, typically changing phases between liquid and gas and back to liquid
Implementation Method 4
refrigerant flows through the storage evaporator to cool the phase change material to cause it to change to a lower enthalpy phase state
Data Source
AI summary
A regenerative air conditioning system for a vehicle includes a condenser, a compressor, an evaporator subsystem, an expansion valve, and a solenoid controlled expansion valve arranged and coupled together in a direct expansion cooling circuit. The evaporator subsystem has a main evaporator and a storage evaporator. The storage evaporator has a phase change material therein surrounding refrigerant passages in the storage evaporator. The storage evaporator in a charge state when the vehicle is decelerating wherein refrigerant flows through the storage evaporator to cool the phase change material to cause it to change phases to store thermal cooling potential. The storage evaporator in a discharge state when the vehicle is stopped and an engine of the vehicle is off to cool cabin cooling air flowing across the storage evaporator by the phase change material absorbing heat from the cabin cooling air flowing across the storage evaporator.