A thermoelectric wearable body heat harvester is a device designed to capture and convert the heat energy produced by a person's body into usable electrical power. This technology is based on the principle of thermoelectric effect, which is the generation of an electric voltage when there is a temperature gradient across a material. In the case of a wearable body heat harvester, the temperature gradient is created between the person's skin and the surrounding environment.
Here's how the working principle of a thermoelectric wearable body heat harvester generally operates:
Thermoelectric Materials: The harvester incorporates thermoelectric materials, often called thermoelectric generators (TEGs), that exhibit the Seebeck effect. The Seebeck effect states that when a temperature difference exists between two sides of a material, it creates a voltage potential across the material. These materials are typically semiconductors, which have properties that allow them to generate electricity when exposed to a thermal gradient.
Heat Absorption: The wearable device is placed against the person's skin or clothing, allowing it to absorb the heat radiating from the body. This heat transfer creates a temperature difference between the side in contact with the body (hot side) and the side exposed to the ambient environment (cold side).
Thermoelectric Modules: The device contains multiple thermoelectric modules or pairs, usually consisting of p-type and n-type semiconductor materials connected in series. These modules are aligned perpendicular to the skin to maximize the temperature difference across them.
Voltage Generation: As heat flows from the body to the ambient environment, the temperature gradient across the thermoelectric modules generates a voltage potential. The Seebeck effect causes electrons to move from the hot side to the cold side within each module, creating an electric current.
Electrical Output: The electric currents generated by the individual thermoelectric modules are then combined and collected through conductive pathways. These pathways lead to electrical contacts that allow the harvested energy to be extracted and utilized.
Power Management and Storage: The harvested electrical energy is typically relatively low in power, so a power management circuit may be included to optimize the voltage and current for specific applications. Additionally, energy storage components, such as batteries or capacitors, can store and regulate the harvested energy to ensure a steady and reliable power supply.
Usable Applications: The harvested electrical power can be used to charge small electronic devices, power sensors, or even contribute to the energy needs of the wearable device itself. Examples of applications include smartwatches, fitness trackers, medical monitoring devices, and other wearable electronics.
It's important to note that the efficiency of thermoelectric conversion is influenced by factors such as the temperature gradient, the choice of thermoelectric materials, and the design of the device. Researchers continue to work on improving the efficiency and practicality of thermoelectric wearables to make them more effective in capturing and utilizing body heat for power generation.