A Study of Thermodynamic Properties of Next Generation Mixture Refrigerants Including Hydrocarbons

烃类制冷剂异丁烯（R-600a）是下一代低环境影响混合制冷剂的重要组成部分，由于没有可靠的热力学性质信息，利用改进的Burnett装置，对异丁烯（R-600a）的蒸汽压和气相PVT特性进行了一系列精确测量。在300 ~ 370 K温度下获得了16个蒸汽压数据，在300 ~ 380 K温度下获得了48个气相PVT数据。此外，最近获得了9个温度低至260 K的蒸汽压数据，而该装置的电池常数的温度依赖性的测量正在进行中。本文设计并构建了一套以振动管密度计为辅助的密度测量系统，并验证了该测量系统能达到预期的快速、精确的测量效果。测量纯水，甲醇和3种不同的MFC替代制冷剂，如R-134a， R-125和R-143a已经完成了整个目前的研究项目。此外，HFE-245mc和HFE-143m的压缩液相也进行了类似的精确密度测量，这两种制冷剂最近被开发为下一代制冷剂，也适用于丙烷（R-290）和R-600a等天然碳氢制冷剂。另一方面，在分析研究方面，建立了一系列适用于R-290、R-600a和正丁烷（R-600）等典型天然制冷剂全流体相的具有通用泛函形式的亥姆霍兹-能量型状态方程热力学模型。这些开发的模型已发表在一个主要的国际期刊上。在发展混合规则方面也取得了重大的成功，该规则对建立碳氢化合物（HC）混合物的热力学性质模型起着重要的作用，从而导致HC + HFC制冷剂混合物的热力学性质模型。值得注意的是，本研究为上述3种碳氢化合物开发的热力学性质模型已获得国际认可，即将被纳入下一版本的REFPROP， REFPROP是由美国国家标准与技术研究所（NIST）开发的热力学性质包，在国际上得到广泛应用。少

A series of precise measurements of vapor pressures and gas-phase PVT properties of isobutene (R-600a), a hydrocarbon refrigerant, being an important component of the next generation mixture refrigerants with low environmental impact have been conducted by means of the improved Burnett apparatus, since reliable thermodynamic property information about this substance were not available. Sixteen vapor pressure data at temperatures 300-370 K have been obtained, while 48 gas-phase PVT data at 300-380 K. In addition, 9 vapor-pressure data at temperatures down to 260 K were recently obtained, whereas the measurement of temperature dependence of the cell constant of this apparatus is in progress.A density-measuring system with an aid of the vibrating-tube densimeter was newly designed and constructed, and it was then confirmed that the measurement system could provide us a satisfactory performance with rapid and precise measurements as expected. Measurements for pure water, methanol and 3 dif … More ferent MFC alternative refrigerants such as R-134a, R-125 and R-143a have been completed throughout the present research project. Additionally, similar precise density measurements have been carried out for compressed-liquid phases of HFE-245mc and HFE-143m, promising alternative candidates recently developed as next generation refrigerants, as well as for those or natural hydrocarbon refrigerants including propane (R-290) and R-600a.Concerning the analytical studies, on the other hand, a series of thermodynamic properly model with the Helmholtz-energy type equation of state which is effective for the entire fluid phase of typical natural refrigerants including R-290, R-600a and n-butane (R-600), have been developed with a universal functional form. These models developed have been published in one of the leading international journals. A significant success has also been confirmed in developing the mixing rule which does play an important role to formulate the thermodynamic property models for hydrocarbon (HC) mixtures so as to lead to those for the HC + HFC refrigerant mixtures.It should be noted that the thermodynamic property models developed by the present study for 3 HCs mentioned above have been accepted with international qualification for their forthcoming inclusion to the next version of the REFPROP, a thermodynamic property package developed by the U.S. National Institute of Standards and Technology (NIST) and being widely used on the international basis. Less