Continuous Flow Heater With External PTC Mounting to Reduce Heat Loss
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Solution Overview
Problem
Continuous-flow heaters for motor vehicles have complex structures leading to high manufacturing costs and significant heat loss, limiting their efficiency in heating liquids.
Innovation Solution
The PTC heater is mounted externally on a metal housing base with a spring element for efficient thermal coupling, and the housing base features heat dissipation projections to enhance heat transfer, while a plastic hood and cover improve thermal isolation and manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the PTC heater is arranged inside the housing through which liquid flows, then heat utilization is very good, but the structure becomes complex and manufacturing cost increases
Solution Approach 1:
The PTC heater is extracted from the interior of the housing and mounted on the exterior surface of the housing base. This simplifies the internal flow path structure while maintaining effective heat transfer to the liquid through the housing base material.
Solution Approach 2:
The housing base acts as an intermediary heat transfer medium between the externally mounted PTC heater and the liquid flowing through the housing. The spring element and heat dissipation projections enhance this intermediary heat transfer function.
2Ease of manufacture
If the PTC heater is mounted on the outside of the housing, then manufacturing becomes simpler, but heat loss to the environment increases
Solution Approach 1:
The housing base has different thermal properties at different locations: the front side (with PTC heater) has high thermal conductivity for efficient heat transfer, while the rear side has lower thermal conductivity to minimize heat loss to the environment. The spring element and heat dissipation projections create localized thermal management zones.
Solution Approach 2:
The housing base is functionally segmented into a front heat transfer region (with PTC heater and spring element) and a rear flow path region (with heat dissipation projections), allowing each segment to be optimized for its specific function while maintaining overall manufacturing simplicity.
3Shape
If the spring element has small contact surfaces, then the PTC heater fits better, but heat transfer from the back of the heater to the housing base decreases
Solution Approach 1:
Heat transfer is enhanced by adding vertical dimension through heat dissipation projections that extend into the liquid flow path, compensating for the reduced horizontal contact area between the spring element and PTC heater back surface.
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 configuration achieves efficient heat utilization with reduced manufacturing complexity and heat loss, enabling cost-effective and efficient liquid heating in motor vehicles.
Implementation Method 1
PTC heaters enable very good utilization of the heat generated
Implementation Method 2
Aluminum alloys have a good thermal conductivity, so that heat generated by the PTC heater can then advantageously also be dissipated via the spring element
Implementation Method 3
the housing base has heat dissipation projections, for example pins, which protrude into the housing interior and are bathed there by the liquid to be heated. In this way, the pins ensure an advantageously large contact surface between the bottom of the housing and the liquid
Data Source
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AI summary
The invention describes an instantaneous water heater, particularly for a motor vehicle, comprising a housing with a liquid inlet (3), a liquid outlet (4), an interior space through which the liquid to be heated flows, and a metal housing base (1) which carries heat dissipation projections (8) extending into the interior space. It also includes a PTC heater (10) comprising at least one PTC heating element and a contact element (11), and a metal spring element (5) which generates a spring force that presses the PTC heater (10) against the housing base (1), wherein the spring element (5) is snapped or riveted to the housing base (1). According to the invention, the housing has a cover (2) which sits on the housing base (1) and forms the liquid inlet (3) and the liquid outlet (4).