The Korean company Lumir have launched a Kickstarter campaign to fund an LED table light powered by the heat of a tea light. The active component inside is a Peltier element which produces energy from the temperature difference between two surfaces. The thermoelectric Peltier element consists of n-type and p-type semiconductors positioned thermally in parallel and electrically in series with a heat conductive surface at each side. When a DC voltage is applied between the free ends of the semiconductors the resulting current flow across the junctions produces a temperature difference between the two surfaces. As in this application, it also works in reverse (Seebeck effect); heat from the tea light causes a temperature difference between the two surfaces which produces a DC output current to light the LEDs. When it comes to energy efficiency, a burning candle only converts a few percent of the energy it consumes to produce visible light. The vast majority of energy is lost as heat...