Network of Collaborations and Organizational Structure (as of May 2017)
NEXT-RP is carrying out the precise measurement of thermodynamic properties for pure refrigerants as well as refrigerant mixtures.
Specifically, the following experimental apparatus is operating.
（1）Measurements of pressure-volume-temperature(PVT) properties, saturation pressures, and critical pressure with an isochoric method
（2）Measurement of PVT properties with a Burnett method
（3）Measurement of critical temperature, critical density, and saturated densities by the direct observation of meniscus disappearance
（4）Measurements of vapor-liquid equilibrium (VLE) with a circulation method
Transport properties of low GWP pure and mixed refrigerants
Boiling/evaporation and condensation heat transfer of plate type heat exchanger
Vapor and liquid two phase flow in plate type heat exchanger
The following experimental apparatuses are in operation.
（1）Tandem capillary tube method to measure viscosity of liquid and vapor
（2）Transient hot wire method to measure thermal conductivity of liquid and vapor
（3）Specially designed test section to measure local heat transfer coefficient of plate heat exchanger
（4）Transparent channel of plate heat exchanger to observe two phase flow
Kyushu Sangyo University
We measure surface tensions, freezing points, and heat transfer coefficients in microfin-tubes for low GWP refrigerants and their mixtures. We started a molecular simulation for physical property prediction at low temperatures, where conducting the measurements are difficult.
（1）Surface tension measurement by a differential capillary method
（2）Assessment of heat transfer coefficient and pressure drop during condensation and evaporation process in microfin tubes.
（3）Triple point and solid-liquid equilibrium measurement (with Università Politecnica delle Marche)
（4）Molecular orbital-dynamic simulation for vapor-liquid equilibrium (with MINES ParisTech)
Toyama Pref. University
We measure the precise thermodynamic properties for pure refrigerants and their mixtures.The following apparatuses are used.
（1）Vapor-liquid equilibrium (VLE) property measurements using a recirculating type apparatus
（2）PVTx and saturation property measurements using a metal-bellows variable volumometer with a thermostatted liquid bath
（3）PVTx property measurements using a metal-bellows variable volumometer with a thermostatted air bath
（4）Critical parameter and saturation property measurements using a variable volumometer and an optical cell
Tokyo University of Marine Science and Technology
Our laboratory is evaluating the heat transfer and pressure drop of pure refrigerant and refrigerant mixtures. Specifically, the following research themes are being conducted.
（1）Boiling / condensation heat transfer and two-phase flow pattern inside multiport tubes
（2）Boiling / condensation heat transfer and two-phase flow pattern inside minichannels
（3）Heat transfer of low GWP refrigerants inside small-diameter tubes using compression heat pump
（4）Boiling / condensation heat transfer and two-phase flow pattern in plate heat exchangers
（5）Condensation / evaporation heat transfer of working fluids for high temperature heat pump and binary cycle
（6）Heat transfer and flow characteristics of falling film evaporation and condensation outside smooth and enhanced tubes
（7）Boiling / condensation heat transfer of refrigerant/lubricating oil mixtures
National Institute of Advanced Industrial Science and Technology (AIST)
We precisely measure thermophysical properties of refrigerants such as speed of sound and relative permittivity．Speed of sound is involved in density and compressibility, leading to evaluation of the ideal gas heat capacity which is an essential information to estimate enthalpy of refrigerants. Relative permittivity also gives an important information on polarizability and dipole moment to comprehend polarity of refrigerants. For the present, the following measurement apparatuses are working.
（1）Speed of sound and relative permittivity measurement apparatus with a cylindrical acoustic-electromagnetic resonator
（2）PVT property measurement apparatus with a magnetic levitation densimeter.
（3）Vapor pressure measurement apparatus for low temperature with a Stirling cooler unit.