| Research Abstract |
P-V-T relationship was measured for propane, butane and dimethylether in the temperature range from 350 to 450 K, and the equation of states were constructed for dimethylether. P-V-T relationship was also measured for a binary mixture composed of carbon dioxide and dimetylether, with the mole fraction of dimetylether 46.36 mol%, at 377.59 K, because dimethylether has a similar physical property to that of conventional refrigerants. Using the P-V-T data, a binary interaction parameter, in the mixing rule of equation of state, was optimized. For the four pure substances, carbon dioxide, propane, butane and dimetylether, Mollier diagram, which is mutual relations among pressure, temperature, enthalpy and entropy, was drawn by applying thermodynamic relations. For the mixture, bubble point pressure, solubility, and vapor-liquid equilibrium, were also measured. Conventional mixing rule and Cosmo-Rs method are available in the systems, and they provided good reproducibility. To determine a suitable lubricant, the solubility of carbon dioxide was measured in some olygomers, and commercially purchased lubricating oils. As a results, tetraethylene glycol has a suitable properties for the new refrigerants. Finally, for a gas mixture, carbon dioxide + dimethl ether with demethyether of 8.00 mol %, a necessary thrust power was evaluated under the assumption of the hypothetic refrigerating system repeating isentropic / isothermal compression and expansion between 322.04 K, 4 MPa and 377.59 K, 20MPa. The calculation shows the effectiveness of adding dimetyletheer, and the power is slightly smaller than that of pure carbon dioxide.
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