Mechanically Expanded Microfin Tubes for Power Electronics Cooling
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Solution Overview
Problem
Current liquid cooled heat exchangers for power electronics have high manufacturing costs and low effectiveness, failing to maintain optimal temperatures under varying load conditions.
Innovation Solution
A heat exchanger design featuring tubular members with internal surface enhancements, such as fins, secured into an interference fit with the heat exchanger body via mechanical or thermal expansion, forming fluid pathways that enhance thermal energy transfer using refrigerant from an HVAC system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid cooled heat exchangers are used for power electronics, then cooling function is provided, but manufacturing costs are high and effectiveness is low
Solution Approach 1:
The heat exchanger is divided into multiple tubular members (at least two) that are inserted into pathway openings in the heat exchanger body. Each tubular member contains internal surface enhancements (fins) that are segmented along the fluid pathway length, creating multiple heat transfer zones that collectively provide effective cooling while using simpler manufacturing processes.
Solution Approach 2:
The tubular members incorporate internal surface enhancements (fins) that create a porous-like structure within the fluid pathways. These fins increase the effective heat transfer surface area within the tubular members, enhancing cooling effectiveness without requiring complex external heat exchanger structures that would increase manufacturing costs.
2Area of stationary object
If conventional heat exchanger designs are used, then cooling is provided, but heat transfer area is insufficient
Solution Approach 1:
The heat transfer surface is extended into the third dimension by inserting fins along the internal surface of tubular members. This radial extension of the heat transfer surface within the fluid pathways significantly increases the heat transfer area without proportionally increasing the external dimensions or overall complexity of the heat exchanger structure.
Solution Approach 2:
The tubular members with internal fins are nested within the pathway openings of the heat exchanger body. This nested configuration allows the heat transfer surfaces to be contained within the existing heat exchanger structure, maximizing heat transfer area utilization without requiring additional external space or complex structural additions.
3Strength
If mechanical expansion is used to secure tubular members, then interference fit is achieved, but manufacturing complexity increases
Solution Approach 1:
The tubular members are designed with an outer diameter that is slightly smaller than the pathway opening diameter in the heat exchanger body. This dimensional parameter difference enables the tubular members to be inserted and then secured through mechanical expansion or thermal expansion processes, achieving a strong interference fit while maintaining relatively simple manufacturing procedures compared to precision machining approaches.
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 design increases heat transfer area and convective evaporation, improving cooling efficiency while reducing manufacturing costs by minimizing machining operations.
Implementation Method 1
The fluid pathways transfer thermal energy from the one or more power electronics devices into a flow of fluid in the one or more fluid pathways
Implementation Method 2
The flow of fluid is a flow of liquid refrigerant diverted from a condenser of a heating, ventilation, and air conditioning (HVAC) system
Implementation Method 3
An interference fit is defined between the tubular members and the heat exchanger body via one or more of mechanical or thermal expansion
Implementation Method 4
An interference fit is defined between the tubular members and the heat exchanger body via one or more of mechanical or thermal expansion
Implementation Method 5
The design increases heat transfer area and convective evaporation, improving cooling efficiency
Implementation Method 6
The design increases heat transfer area and convective evaporation, improving cooling efficiency
Data Source
AI summary
A method of forming a power electronics assembly includes forming a plurality of pathway openings in a heat exchanger body and inserting a tubular member in each pathway opening of the plurality of pathway openings. The tubular member includes a plurality of internal surface enhancements. An interference fit is defined between the tubular members and the heat exchanger body via one or more of mechanical or thermal expansion to define a plurality of fluid pathways in the heat exchanger. One or more power electronics devices are installed to the heat exchanger body.