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The table above gives properties of the vapor–liquid equilibrium of anhydrous ammonia at various temperatures. The second column is vapor pressure in kPa. The third column is the density of the liquid phase. The fourth column is the density of the vapor.
Sometimes [ambiguous] the critical point does not manifest in most thermodynamic or mechanical properties, but is "hidden" and reveals itself in the onset of inhomogeneities in elastic moduli, marked changes in the appearance and local properties of non-affine droplets, and a sudden enhancement in defect pair concentration. [9]
Ammonia occurs in nature and has been detected in the interstellar medium. In many countries, it is classified as an extremely hazardous substance. [15] Ammonia is produced biologically in a process called nitrogen fixation, but even more is generated industrially by the Haber process. The process helped revolutionize agriculture by providing ...
By changing the pressure and temperature of the fluid, the properties can be "tuned" to be more liquid-like or more gas-like. One of the most important properties is the solubility of material in the fluid. Solubility in a supercritical fluid tends to increase with density of the fluid (at constant temperature).
Thermodynamic databases contain information about thermodynamic properties for substances, the most important being enthalpy, entropy, and Gibbs free energy. Numerical values of these thermodynamic properties are collected as tables or are calculated from thermodynamic datafiles.
Ammonia has been used frequently in industrial refrigeration since it was first used in the compression process in 1872. It is used for its favorable thermodynamic properties, efficiency, and profitability. [16] Ammonia is produced in massive quantities due to the fertilizer industry, making it relatively inexpensive. [1]
Work and heat are not thermodynamic properties, but rather process quantities: flows of energy across a system boundary. Systems do not contain work, but can perform work, and likewise, in formal thermodynamics, systems do not contain heat, but can transfer heat.
The physical and chemical properties of the working fluid are extremely important when designing thermodynamic systems. For instance, in a refrigeration unit, the working fluid is called the refrigerant. Ammonia is a typical refrigerant and may be used as the primary working fluid. Compared with water (which can also be used as a refrigerant ...