Nested Heat Exchanger With Thermal Storage for Engine-Off Cooling
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Solution Overview
Problem
Conventional heat exchangers in automotive air-conditioning systems fail to provide cooled air when the engine is not running, as they rely on engine-driven fluid circulation, and existing solutions with thermal storage material are complex and expensive to produce.
Innovation Solution
A novel heat exchanger design featuring nested heat-exchange elements with tubular reservoirs and tubes, where thermal storage material surrounds the heat-transfer fluid tubes, enhancing heat exchange efficiency and simplifying manufacturing by allowing separate production of tubes and reservoirs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat exchangers with engine-driven fluid circulation are used, then heat exchange can occur when the engine is running, but no cooled air is provided when the engine is not running
Solution Approach 1:
The thermal storage material is pre-cooled by the refrigerant while the engine is running, storing cold energy in advance. When the engine stops, this stored cold energy is released to continue cooling the cabin air without requiring active refrigerant circulation
Solution Approach 2:
The thermal storage material acts as an intermediary between the refrigerant and the cabin air. It receives heat from the air and transfers it to the refrigerant, enabling continued cooling function even when the refrigerant circulation system is inactive
2Temperature
If special tubes with longitudinal cavities for thermal storage material are used, then heat exchange can occur during engine-off periods, but production becomes complicated and expensive
Solution Approach 1:
The tube is nested inside the reservoir, with the thermal storage material filling the annular space between them. This nested configuration allows simple cylindrical components to be manufactured separately and assembled, avoiding complex special-shaped tubes while achieving the same thermal storage function
Solution Approach 2:
The heat exchanger is divided into separate functional components: simple cylindrical tubes for refrigerant flow, separate reservoirs for thermal storage material, and end pieces for connection. This segmentation allows each component to be manufactured using standard processes and assembled into the final device
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 design ensures effective heat transfer between thermal storage material and heat-transfer fluid, maintaining cabin cooling even when the engine is off, while reducing production costs and complexity.
Implementation Method 1
reservoirs of thermal storage material in contact with the tubes so that the storage material and the heat-transfer fluid exchange heat with one another
Implementation Method 2
The thermal storage material then releases the coldness (more specifically the cold energy) to the air passing through the heat exchanger when the engine is switched off
Data Source
AI summary
Heat exchanger, for example for a motor vehicle air-conditioning circuit, comprising a plurality of tubes (12) for circulating a heat-transfer fluid, the ends of said tubes (12) opening into manifolds and reservoirs (11) of thermal storage material in contact with the tubes (12) so that the storage material and the heat-transfer fluid exchange heat with one another. The exchanger comprises a plurality of heat-exchange elements (4) each housing at least one reservoir (11) and at least one tube (12) which are nested.