Thermophotovoltaic (TPV) systems generate electricity by converting thermal energy into light energy, and then converting that light energy into electricity using photovoltaic cells. TPV systems are of interest for automotive applications as they have the potential to improve overall vehicle efficiency by harnessing waste heat from the engine and exhaust.
The basic working principle of a thermophotovoltaic system for automotive applications involves the following steps:
Heat Generation: In an automotive application, heat is generated as a byproduct of the engine's combustion process. This heat is typically lost as waste energy through the exhaust and cooling systems. TPV systems aim to capture and utilize this waste heat.
Emitter: The waste heat is directed to an emitter, which is a material specifically designed to emit thermal radiation (infrared light) at wavelengths optimized for the efficiency of the photovoltaic cells. The emitter can be made of various materials, such as ceramics or photonic crystals, that have high emissivity at the desired wavelengths.
Photovoltaic Cells: Photovoltaic cells are semiconductor devices that can convert light energy (photons) into electricity (electrons). These cells are optimized to have high sensitivity to the wavelengths of light emitted by the emitter. When the emitted light strikes the surface of the photovoltaic cells, electron-hole pairs are generated, and this creates an electric current.
Electricity Generation: The electric current produced by the photovoltaic cells is then collected and utilized to power various electrical systems within the vehicle, potentially reducing the load on the alternator and improving overall vehicle efficiency.
It's worth noting that TPV systems face various engineering challenges, such as achieving high emitter efficiency, optimizing photovoltaic cell performance, and managing heat transfer within the system. Nonetheless, the concept of utilizing waste heat through TPV systems shows promise for enhancing automotive energy efficiency and reducing greenhouse gas emissions. Research and development in this field are ongoing, and improvements in materials and technologies may lead to more practical and efficient TPV systems for automotive applications in the future.