What is absolute reference pressure and absolute reference temperature

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SUMMARY

Absolute reference pressure is defined as the pressure measured relative to a perfect vacuum, typically represented as 1.01 bar or 101.3 kPa. Absolute reference temperature is measured in Kelvin, with absolute zero as the baseline, commonly represented as 273 K. The discussion distinguishes between "standard" and "normal" states, clarifying that the former includes conditions like 273+25K and 1.01 bar, while the latter refers to 273 K and 1.01 bar. Understanding these concepts is crucial for accurately measuring compressed air flow rates in various applications.

PREREQUISITES
  • Understanding of thermodynamics and gas laws
  • Familiarity with pressure measurement units (bar, kPa)
  • Knowledge of temperature scales, particularly Kelvin
  • Basic principles of vacuum and atmospheric pressure
NEXT STEPS
  • Research the differences between absolute and relative pressure measurements
  • Study the ideal gas law and its applications in thermodynamics
  • Learn about the significance of absolute zero in temperature measurement
  • Explore the practical applications of compressed air flow rate calculations
USEFUL FOR

Engineers, physicists, and technicians involved in fluid dynamics, HVAC systems, or any field requiring precise measurements of pressure and temperature in relation to vacuum conditions.

Su Solberg
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What is "absolute reference pressure and absolute reference temperature"

I am doinf a test about compressed air flow rate.
There is a parameter called absolute reference pressure and absolute reference temperature.
Are they 1.01bar and 273+20K?
 
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Those what you wrote 273+25 and 1.01bar are the called "standard" state,
There is another one called the "normal" state which is 273 and 1.01,
I don't know absolute can mean here.., probably one of the above two...
 


Not sure but would relative pressure be a pressure relative to an absolute pressure, i.e absolute pressure "being that of space".. conventionally 0 Pa due to a void of particles..Although it does depend what kind of pressure you are talking about, space itself being is probably some form of energy resulting in a pressure "off" space. But i suppose that may beside the point.
In your case, in the test, i would say the reference pressure is with respect to a vacuum. If the atmospheric pressure is adding to the absolute pressure, then you would have to substract the atm pressure (101.3 KPa ) from the relative pressure in order to obtain the absolute pressure (with respect to vacuum). The absolute reference pressure may be directly measured with respect to the vacuum by creating a vacuum.
As for temperature, along the same lines i would say absolute temperature is temperature in kelvin, i.e with respect to absolute zero.
As for : Are they 1.01bar and 273+20K? These would be relative pressure and temperature, relative to a "standard environment".
May be wrong though..

Does that help at all?
 

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