PTC Heater Housing Ribs for Better Heat Dissipation
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Solution Overview
Problem
Existing electric heating devices, particularly those using PTC elements, face limitations in heat dissipation efficiency due to suboptimal design, leading to potential overheating and reduced operational efficiency, especially when used in applications like motor vehicles.
Innovation Solution
The electric heating device incorporates longitudinal ribs on its outer surface within the heating chamber, arranged transversely to the main flow direction, which disrupts laminar boundary layers and enhances heat transfer coefficients, combined with a wedge element for preload and insulation layers to prevent mechanical stress, ensuring effective heat extraction and dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the PTC element is operated at higher temperature to increase heat generation, then the heating power is improved, but the thermal conductivity between the PTC element and the medium deteriorates, leading to reduced heat dissipation efficiency
Solution Approach 1:
The invention transitions from point-contact or face-contact heat transfer to edge-contact heat transfer by inverting the PTC element. This dimensional change in contact geometry creates a line contact along the edge, significantly increasing the heat transfer surface area and improving thermal conductivity between the PTC element and the medium.
Solution Approach 2:
The invention applies different functional qualities to different parts of the PTC element: the main heating function is concentrated in the bulk of the PTC element, while the edge surface is optimized for heat transfer to the medium. The edge contact ensures localized high-quality thermal coupling without compromising the overall heating performance.
2Loss of energy
If the PTC element is inverted to improve heat transfer, then the thermal conductivity is improved, but the mechanical stability and protection of internal components deteriorates
Solution Approach 1:
The invention uses a flexible heating chamber wall that can deform to accommodate the inverted PTC element while maintaining sealing. This flexible structure provides mechanical protection to the inverted PTC element and its internal components, ensuring reliability while allowing the inverted configuration for improved heat transfer.
Solution Approach 2:
The heating chamber is designed with sufficient volume and flexible boundaries to cushion and protect the inverted PTC element from mechanical stress. This beforehand cushioning design prevents damage to the fragile ceramic PTC element and its internal conductor tracks during operation.
3Ease of operation
If the conductor tracks are exposed for electrical connection, then the ease of operation is improved, but the risk of direct contact between current-carrying components and the medium increases
Solution Approach 1:
The invention uses an insulating material as an intermediary substance that fills the heating chamber and surrounds the PTC element. This insulating medium allows electrical connections to be made through it without creating direct contact between the conductor tracks and the heated medium, thus maintaining electrical safety while enabling operational access.
Solution Approach 2:
The heating chamber creates an inert electrical environment by filling it with insulating material that prevents electrical conduction pathways between the exposed conductor tracks and the medium. This inert electrical atmosphere allows easy electrical connection while eliminating the harmful effect of direct electrical contact.
4Loss of energy
If the PTC element is inverted with edge contact, then the heat transfer surface area is improved, but the complexity of the heating device structure increases
Solution Approach 1:
The heating chamber serves multiple functions simultaneously: it contains the inverted PTC element, provides mechanical protection, enables heat transfer through its flexible wall, and acts as an electrical insulator. This multi-functionality reduces the need for additional protective structures, thereby limiting the increase in device complexity despite the improved heat transfer surface area.
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 significantly improves heat dissipation on the outer surface of the heater housing, maintaining the PTC element at lower operating temperatures, thereby increasing efficiency and preventing overheating, while also protecting ceramic components from mechanical stress.
Implementation Method 1
Longitudinal ribs on its exposed outer side in the heating chamber, which extend along a direction connecting the lower end of the heater housing to its upper end and thus transversely to the main flow direction through the heating chamber
Implementation Method 2
significantly improves heat dissipation on the outer surface of the heater housing, maintaining the PTC element at lower operating temperatures
Implementation Method 3
at least one PTC element, which is typically a cuboid-shaped ceramic block with a metallized coating on opposite sides to conduct the power current
Implementation Method 4
At least beyond a critical temperature, also known as the Curie temperature, the electrical resistance of the PTC element typically increases exponentially with temperature
Implementation Method 5
The housing has inlet and outlet openings for introducing the medium to be heated into the housing and discharging it from the housing
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The present invention relates to an electric heating device with a housing (2) having inlet and outlet openings (18) for a medium to be heated, the housing having a heating chamber (8) for passing the medium to be heated through the housing (2) and a connection chamber (14) for the electrical connection of at least one PTC heating element (24), wherein the PTC heating element (24) has at least one PTC element (28) and conductive traces (30) electrically connected to the PTC element (28) for supplying current to the PTC element (28) with different polarities, and wherein the PTC heating element (24) is incorporated into a heating element housing (20) which is open at its upper end and towards the connection chamber (14) and closed at its lower end and towards the heating chamber (8) and projects from the partition (12) towards the heating chamber (8).wherein, in order to increase the efficiency of the electric heating device, the heating device housing (20) has longitudinal ribs (48) on its outer side exposed in the heating chamber (8), which extend along a direction connecting the lower end of the heating device housing (20) with its upper end.