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2. Definitions and main relationships between basic quantities
In the case of a pure fluid, the thermodynamic state is entirely characterized by the knowledge of two quantities, e.g. temperature and pressure, or pressure and volume, etc. In the case of a mixture, the presence of several constituents requires the knowledge of a third quantity to characterize the thermodynamic state. In the case of moist air, this third quantity may be one of the many commonly used to define "humidity": mixing ratio, relative humidity, dew point temperature, wet bulb temperature, etc.
Once we know the temperature, pressure and any one of these quantities, we can determine all the others, as well as the various quantities such as density, mass volume, enthalpy, etc. The aim of this para-graph is to give the main definitions and the relationships we need to know in order to carry out calculations from one quantity to another. The aim of this para-graph...
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The Ultimate Scientific and Technical Reference
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Definitions and main relationships between basic quantities
Bibliography
Standardization
French Standards Association (Afnor)
- Air humidity measurement – Hygrometric parameters - NF X 15-110 - 07-94
- Thermal Environmental Conditions for Human Occupancy - ASHRAE Std 55 - 2004
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
Directory
Hygrometer manufacturers (non-exhaustive list)
Condensation hygrometers
EdgeTech (United States) http://www.edgetechinstruments.com
General Eastern (United States) http://www.gemeasurement.com
...
Organizations
Scientific and Technical Committee for the Climate Industries (COSTIC) http://www.costic.com
Center technique des industries aérauliques et thermiques (CETIAT) http://www.cetiat.fr
Association of Climate, Ventilation and Refrigeration Engineers...
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