Ambient Heat Engine Using Complementary Electrochemical Cells
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Solution Overview
Problem
Existing thermal-energy-harvesting devices require a dual-heat source with distinct temperatures, which is not naturally abundant, leading to inefficiencies and parasitic heat conduction losses, especially in small devices with slow temperature changes.
Innovation Solution
An electrochemical conversion system using complementary rechargeable cells with positive and negative voltage temperature coefficients, along with a controller, to generate power from ambient heat without the need for artificial temperature differentials, utilizing thermodynamic principles and thermo-galvanic effects to harness thermal transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a dual-heat source with distinct temperatures is used, then power generation is enabled, but the device requires artificial temperature differentials and thermal mass, increasing complexity and reducing efficiency
Solution Approach 1:
The invention extracts and eliminates the thermal mass component from the system. By using a single heat source at ambient temperature with an electrochemical converter, the patent removes the need for artificial temperature differentials and thermal storage components, directly reducing device complexity while maintaining power generation capability
Solution Approach 2:
The electrochemical converter acts as an intermediary that enables direct conversion of ambient heat to electrical energy without requiring thermal mass or artificial temperature differentials. This intermediary component resolves the contradiction by providing a mechanism to generate power from single-source ambient heat
2Power
If thermal mass is used to create temperature differential, then power generation is enabled, but parasitic heat conduction losses increase, reducing efficiency
Solution Approach 1:
The invention removes thermal mass from the system architecture, eliminating the source of parasitic heat conduction losses. By using ambient heat directly with an electrochemical converter, there is no thermal mass to conduct heat parasitically, thus reducing energy losses while maintaining power generation
Solution Approach 2:
The patent replaces the thermal-mechanical approach (using thermal mass and temperature differentials) with an electrochemical approach. This substitution eliminates parasitic heat conduction losses by using electrochemical reactions to convert ambient heat directly to electrical energy without requiring temperature differentials
3Temperature
If insulation is used to thermally isolate thermal mass, then temperature differential is enhanced, but device complexity and heat transfer efficiency are reduced
Solution Approach 1:
The invention extracts and eliminates both thermal mass and insulation from the system. By using ambient heat directly with an electrochemical converter, the patent removes the need for thermal isolation components, reducing device complexity while operating effectively at ambient temperature without requiring enhanced temperature differentials
4Device complexity
If a single heat source is used, then device simplicity is improved, but power generation capability is limited without artificial temperature differentials
Solution Approach 1:
The invention changes the operating parameters of the electrochemical converter by utilizing ambient temperature variations and the Nernst equation relationship between temperature and voltage. This parameter change enables the simple single heat source design to generate power effectively without artificial temperature differentials
Solution Approach 2:
The electrochemical converter serves as an intermediary that enables power generation from single-source ambient heat. Through electrochemical reactions governed by the Nernst equation, it converts ambient temperature and pressure conditions directly into electrical energy, resolving the limitation of single heat source operation
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 system effectively converts ambient heat into electricity with reduced self-discharge and loss mechanisms, maintaining efficient operation over long periods without manual refueling, by leveraging natural temperature variations in the environment.
Implementation Method 1
The AHE operating principal is based on the thermo-galvanic effect wherein the voltage of an electrochemical cell is a direct function of its temperature and state of charge
Data Source
AI summary
An ambient heat engine that is thermally coupled to its environment is provided. The ambient heat engine includes two complementary electrochemical cells. One cell has a positive voltage temperature coefficient and the other cell has a negative voltage temperature coefficient. The ambient heat engine further includes a controller and an electrical energy storage device. When the ambient temperature increases or decreases, the temperature variation creates a voltage differential between the two cells, and the controller discharges the higher voltage cell and uses a portion of the discharged energy to charge the lower voltage cell. The difference in energy is extracted by the controller and supplied to the electrical energy storage device. The controller includes circuitry for coupling energy from the energy storage device to the cells in order to compensate for self-discharge of the cells which may occur due to electronic leakage and diffusion phenomenon over extended periods of time.