Water Heater Electronic Switch with Thermal Path for Heat Management
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Solution Overview
Problem
Conventional electric water heaters rely on snap-disc thermostats, which are binary and cannot modulate power to resistive heating elements, limiting control and diagnostic capabilities, and transitioning to solid-state control systems faces challenges such as heat management and increased costs, which are not cost-effective for consumers.
Innovation Solution
A water heater design incorporating an electronic switch and thermal path on a circuit board, where the electronic switch is thermally coupled to the tank, allowing for accurate temperature control and diagnostic algorithms, including power modulation and fault detection, while managing heat generated by solid-state components through thermal interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If snap-disc thermostats are used to control heating elements, then the water heater can be manufactured at lower cost, but the control precision and diagnostic capability are limited
Solution Approach 1:
The patent replaces the mechanical snap-disc thermostat system with an electronic control system comprising solid-state switches, temperature sensors, and a microcontroller. This substitution enables precise temperature measurement and modulation control while providing diagnostic capabilities through electronic monitoring of system parameters.
Solution Approach 2:
The patent implements modulation control that varies the heating power parameter continuously rather than binary on/off control. The microcontroller adjusts the duty cycle of solid-state switches to modulate power delivery to heating elements, achieving precise temperature control through parameter variation.
2Measurement precision
If solid-state switch systems are implemented, then control precision and diagnostic capability improve, but heat management becomes more challenging
Solution Approach 1:
The patent introduces thermally conductive interfaces and heat sinks as intermediary components between solid-state switches and the water heater environment. These intermediaries facilitate efficient heat transfer from the solid-state components to the surrounding structure, managing the heat generated during switching operations.
Solution Approach 2:
The patent extracts the heat management function from the solid-state switch assembly by providing dedicated thermal pathways that conduct heat away from the electronic components. The circuit board and mounting structure serve as heat extraction pathways, routing thermal energy from the switches to the water heater tank or external environment.
3Reliability
If electronic switches with thermal paths are used, then diagnostic algorithms can be implemented, but the device complexity increases
Solution Approach 1:
The patent designs the circuit board to serve multiple functions: electrical switching control, thermal conduction for heat management, and temperature sensing for diagnostic algorithms. The thermal path embedded in the circuit board structure simultaneously cools the solid-state switches and provides temperature data for system monitoring and fault detection.
Solution Approach 2:
The patent merges the thermal management and sensing functions into the circuit board structure itself. The thermal path is integrated into the circuit board design, combining the electrical circuitry with thermal conduction pathways, eliminating the need for separate thermal management components and reducing overall 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
Enables precise control of water temperature, efficient power usage, and reliable diagnostic functions, addressing the limitations of snap-disc thermostats and the challenges of solid-state systems, while maintaining cost-effectiveness.
Implementation Method 1
The circuit board includes a thermal path for conducting heat through the circuit board. The thermal path of the circuit board is thermally coupled to the wall of the tank such that primary heat from the water in the tank is transferred from the wall of the tank to the thermal path.
Implementation Method 2
The electronic switch is also thermally coupled to the thermal path of the circuit board such that secondary heat generated by the electronic switch is transferred from the electronic switch to the thermal path
Implementation Method 3
The temperature sensor is thermally coupled to the thermal path of the circuit board. The temperature sensor is positioned to sense a temperature of the thermal path including the primary heat and the secondary heat.
Data Source
AI summary
A water heater including a tank having a wall with an external surface and an internal surface defining an interior, and a circuit board mounted to the external surface of the tank. The circuit board including a thermal path for conducting heat through the circuit board, where the thermal path of the circuit board is thermally coupled to the external surface of the tank. An electronic switch is mounted to the circuit board and electronically coupled to a heating element, where the electronic switch is thermally coupled to the thermal path of the circuit board so that heat generated by the electronic switch is transferred along the thermal path. A temperature sensor is thermally coupled to the circuit board to sense a temperature of the thermal path relating to a temperature of the electronic switch and relating to a temperature of water stored in the tank.