Decoupling the Electrical and Entropic Contributions to Energy Transfer from Infrared Radiation to a Power Generator

The interaction between infrared radiation and a power generator device in time is studied as a route to harvest infrared, and possibly other electromagnetic radiations. Broadening the spectrum of the usable electromagnetic spectrum would greatly contribute to the renewable and sustainable energy sources available to humankind. In particular, low frequency and low power radiation is important for applications on ships, satellites, cars, personal backpacks, and, more generally, where non-dangerous energy is needed at all hours of the day, independent of weather conditions. In this work, we identify an electric and an entropic contribution to the energy transfer from low power infrared radiation to the power generator device, representing electrical and thermal contributions to the power generation. The electric contribution prevails, and is important because it offers multiple ways to increase the voltage produced. For example, placing black-colored gaffer tape on the illuminated face doubles the voltage produced, while the temperature difference, thus the entropic contribution, is not sensitive to the presence of the tape. We recognize the electric contribution through the fast changes it imparts to the voltage output of the power generator device, which mirror the instabilities in time of the infrared radiation. The device thus acts as sensor of the infrared radiation’s behavior in time. On the other hand, we distinguish the entropic contribution through the slow changes it causes to the voltage output of the power generator device, which reflect the relative delay with which the two faces of the device respond to thermal perturbations.

Polariton Evaporation: The Blackbody Radiation Nature of the Low-Frequency Radiation Emitted by Radiative Polaritons to the Surrounding Space

Upon formation, radiative polaritons in thin oxide films or crystals emit radiation to the surrounding space. This radiation is confined in a small range of the microwave to far-infrared region of the electromagnetic spectrum, independently of the oxide chemistry. This work shows that the low-frequency radiation is blackbody radiation associated with a temperature directly related to the boson character of the radiative polaritons and to their amount. The proximity of this temperature to absolute zero Kelvin explains the confinement of the frequency. This phenomenon is named polariton evaporation.

Effective Thermoelectric Power Generation in an Insulated Compartment

The Seebeck coefficient S is a temperature- and material-dependent property, which linearly and causally relates the temperature difference △T between the “hot” and “cold” junctions of a thermoelectric power generator (TEC-PG) to the voltage difference △V. This phenomenon is the Seebeck effect (SE), and can be used to convert waste heat into usable energy. This work investigates the trends of the effective voltage output △V(t) and effective Seebeck coefficient S'(t) versus several hours of activity of a solid state TEC-PG device. The effective Seebeck coefficient S'(t) here is related to a device, not just to a material’s performance. The observations are pursued in an insulated compartment in various geometrical and environmental configurations. The results indicate that the SE does not substantially depend on the geometrical and environmental configurations. However, the effective Seebeck coefficient S'(t) and the produced effective △V(t) are affected by the environmental configuration, once the temperature is fixed. Heat transfer calculations do not completely explain this finding. Alternative explanations are hypothesized.