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According to ASHRAE standard 34, the R-number of a chemical refrigerant is assigned systematically according to its molecular structure and has between two and four digits. If there are carbon -carbon multiple bonds , there are four digits in all: the number of these bonds is the first digit and the number of carbon atoms minus one (C-1) is next.
An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar , and temperatures up to 800 degrees Celsius . [ 3 ]
A representative pressure–volume diagram for a refrigeration cycle. Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), [1] in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles.
The main feature of thermodynamic diagrams is the equivalence between the area in the diagram and energy. When air changes pressure and temperature during a process and prescribes a closed curve within the diagram the area enclosed by this curve is proportional to the energy which has been gained or released by the air.
Molar enthalpy of zinc above 298.15 K and at 1 atm pressure, showing discontinuities at the melting and boiling points. The Δ H °m of zinc is 7323 J/mol, and the Δ H °v is 115 330 J/mol. Enthalpy change for a chemical reaction
Values refer to the enthalpy change in the conversion of liquid to gas at the boiling point (normal, 101.325 kPa). References ... D.R. Lide, (ed.) ...
Ammonia (R-717), with a GWP of <1, remains a popular substitute on fishing vessels and large industrial applications. Ammonia's toxicity in high concentrations limit its application in small-scale refrigeration applications. Propane (R-290) is another example, and has a GWP of 3. Propane was the de facto refrigerant in systems smaller than ...
Std enthalpy change of formation, Δ f H o liquid –169.7 kJ/mol Standard molar entropy, S o liquid: 208.53 J/(mol K) Enthalpy of combustion, Δ c H o liquid –1236.4 kJ/mol Heat capacity, c p: 129.0 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas –125.4 kJ/mol Standard molar entropy, S o gas? J/(mol K) Heat capacity ...