PTC Heat Exchanger Tube Structure for High-Voltage Insulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motor vehicle air conditioning systems with exclusively electric or hybrid drives face safety concerns due to the need for high-voltage operation to achieve sufficient heating, as existing heat exchangers using PTC elements pose risks of electrical shock to humans.
Innovation Solution
A heat exchanger design featuring a flat tube with broad and narrow side walls, where the tube is deformed to apply a compressive force on electrical insulating elements, eliminating the need for external clamping frames and ensuring safe operation by distributing stress evenly, thus preventing electrical shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage is used to operate PTC elements for sufficient heating capacity, then heating performance is improved, but safety risk increases due to potential electrical shock to humans
Solution Approach 1:
The patent introduces an electrical insulating element as an intermediary between the high-voltage PTC heating element and external environment. This insulating element acts as a mediator that allows the high-voltage system to operate while preventing direct contact between humans and live electrical components, thus resolving the contradiction between heating performance and safety risk
Solution Approach 2:
The heating element is nested within the heat exchanger structure with the insulating element positioned between the PTC element and external components. This nesting arrangement ensures that the high-voltage component is contained within a protective structure, allowing sufficient heating capacity while eliminating direct exposure to electrical shock hazards
2Strength
If a clamping frame is used to apply force to the pipe for attaching the heating element, then connection strength is improved, but device complexity increases
Solution Approach 1:
The patent merges the clamping function into the heat exchanger structure itself rather than using a separate clamping frame. The heat exchanger structure is designed to inherently provide the necessary clamping force through its geometry and material properties, combining the support and clamping functions into a single integrated component, thus reducing overall device complexity while maintaining connection strength
Solution Approach 2:
The heat exchanger structure is designed to automatically provide the necessary clamping force without requiring external actuation or additional components. The structure itself serves the dual purpose of heat exchange and mechanical attachment, eliminating the need for separate clamping mechanisms and reducing system complexity
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 allows for safe and reliable operation of high-voltage heat exchangers without endangering people, providing efficient heating while minimizing the risk of electrical shock and ensuring reliable performance.
Implementation Method 1
PTC elements (PTC: Positive Temperature Coefficient) are electrically conductive materials that exhibit electrical resistance and conduct electricity better at lower temperatures than at higher temperatures. Their electrical resistance thus increases with rising temperature.
Implementation Method 2
heat-conducting elements, in particular fins or corrugated fins, which increase the surface area for heating the air
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a heat exchanger (1), comprising at least one electric resistance heating element (2), in particular at least one PTC element (3), at least two conductors (4), in particular circuit boards (6, 7), which are connected to the at least one electric resistance heating element (2) in an electrically conductive manner in order to conduct electric current through the at least one electric resistance heating element (2) and thereby heat the electric resistance heating element (2), at least one thermally conductive element (11) for transferring heat from the at least one electric resistance heating element (2) to a fluid to be heated, at least one electrically insulating element (22), which electrically insulates the at least two conductors (4), preferably from the at least one thermally conductive element (11), and at least one pipe (18), wherein the at least two conductors (4) and the at least one electric resistance heating element (2) are arranged within a cavity (19) bounded by the pipe (18) and the pipe (18) lies on the at least one electrically insulating element (22) under a compressive force at at least one contact surface (14). The aim of the invention is to operate the heat exchanger with high electric current under high voltage, for example greater than 50 V, without any risk to the surroundings, in particular persons. Said aim is achieved in that the pipe (18) has a greater thickness at the at least one contact surface (14) than outside of the at least one contact surface (14) and a step (17) is formed on the pipe (18) between the contact surface (14) and the region outside of the contact surface (14) as a result of the differing thickness.