Printable thermoelectric film by halide perovskite

Globe box for halide perovskite film fabrication

Printable thermoelectric film by halide perovskite

We investigate the thermoelectric properties of Halide perovskite as a printable semiconductor. High-quality electrical energy (exergy efficiency 100 %) can be directly generated from Low-quality thermal energy (low temperature, low exergy). Thermoelectric devices can be made by printing process at low cost.

Wave-selective radiative properties for thermal management

Experimental setup for spectral reflectance

Wave-selective radiative properties for thermal management

Solar light consists of electromagnetic waves with wavelengths below 2 μm. Materials absorbing these waves in the visible range heat up significantly. Conversely, materials reflecting visible light with high emissivity in the infrared range can undergo cooling, a phenomenon known as radiative cooling. Our research focuses on materials exhibiting wavelength-selective radiative properties that enable passive temperature control.

Microscopic analysis of heat conduction

Snapshot of a molecular dynamics simulation

Microscopic analysis of heat conduction

We carry out Molecular dynamics simulations to investigate the mechanism of heat conduction in solid. Heat conduction can be controlled by nano-structured materials because thermal energy is transferred by lattice vibrations, called phonon. The detailed thermal energy path can be understood by calculation of each atoms motions in solids.

Thermal conductivity measurements by 3ω method

Top: Topview of a sample for 3ω measurements, Bottom: Applied current in ω rad (red) and 3ω signal(blue).

Thermal conductivity measurements by 3ω method

Thermal conductivity can be measured using the 3ω method. We deposited a 30 μm width strip of metal wire on the sample for heating and temperature measurement. We applied an AC current at ω rad for heating and measured the temperature rise through the 3ω rad voltage drop.

Thermophysical Properties of High-Pressure Hydrogen, Hydrogen Filling/Discharge

Thermophysical Properties of High-Pressure Hydrogen | Hydrogen Filling/Discharge

Understanding thermophysical properties of hydrogen is essential in "Hydrogen Society". In Thermofluid Physics Lab, we measure thermophysical properties e.g. PVT characteristics, viscosity, thermal conductivity, etc. of hydrogen at pressures up to 100 MPa, derive equations of state and correlations, and develop a hydrogen property database.We are also developing HRS (Hydrogen Refueling Station) Dynamic Simulation software for calculating the temeprature, pressure, flow rate, etc. of hydrogen running through fuel cell devices from the compressor of a practical hydrogen station to an FCV on-vehicle container, for example. We endeavor to contribute to verifying the safe and efficient hydrogen refueling system at hydrogen stations.

See also Research Center for Hydrogen Industrial Use and Storage (HYDROGENIUS)

Thermodynamic Properties of New Refrigerants

Thermodynamic Properties of New Refrigerants

Conventional hydrofluorocarbon (HFC)-type refrigerants, which are widely used for refrigeration and air-conditioning, have a strong contribution to global warming. Hence, many researchers seek for new refrigerants with almost zero ozone depletion potential (ODP), a small global warming potential (GWP), and low flammability. Although hydrofluoroolefin (HFO)-type refrigerants have recently been proposed as an alternative, most are still flammable.

In Thermofluid Physics Lab, we target R1123, R1234yf and R32, which have a lower boiling point among HFC-type refrigerants, and therefore the suppression of the flammability and dismutation. Specifically we measure the vapor-liquid equilibrium for these binary/ternary refrigerants with an aim to modify the equation of state for refrigerant mixtures.

This work is carried out as part of the national project by the New Energy and Industrial Technology Development Organization (NEDO), in collaboration with Research Center for Next Generation Refrigerant Properties (NEXT-RP).