Calculate Isobaric Specific Heat Capacity (Cp) Values of Air - Online Calculator

Specific heat capacity is an important parameter used in air properties calculations, specially in chemical and mechanical engineering. Specific heat capacity is a function of temperature and slightly changes with temperature. In this tutorial, you will learn how to calculate specific heat capacity value, how to use our online calculator and will discuss variation of specific heat capacity with temperature.


Content


Definition of Isobaric Specific Heat Capacity


General definition: Required heat to raise (or reduce) the unit mass of a specific material through unit temperature difference at constant pressure.


Definition with example: Required heat to raise the temperature from 10C of 1kg of dry air at 1 atm.



Isobaric specific heat capacity values of dry air in kJ kg-1 K-1 and kJ kmol-1 K-1 against temperature

Temperature (0C) Temperature (K) Cp (kJ kg-1 K-1) Cp (kJ kmol-1 K-1)
-23.15 250 1.003
26.85 300 1.005 29.15
76.85 350 1.008
126.85 400 1.013 29.37
176.85 450 1.020
226.85 500 1.029 29.83
276.85 550 1.040
326.85 600 1.051 30.44
376.85 650 1.063
426.85 700 1.075 31.14
476.85 750 1.087
526.85 800 1.099 31.83
626.85 900 1.121 32.47
726.85 1000 1.142


variation of Isobaric specific heat capacity values of dry air against temperature



Online Calculator to calculate Isobaric Specific Heat Capacity of Air

Calculated value from this online calculator may be different from the experimented value. Therefore, use several resources to finalize your value if you are going into an engineering designing project, aspects or any thermal modelings.










Example of calculating isobaric specific heat capacity of air using the equation

A function of temperature can be used to calculate isobaric specific heat capacity.

Cp, dry air = a + bT + cT2 + dT3



equation of calculating isobaric specific heat capacity Cp values

Calculate isobaric specific heat capacity of dry air at 26.850C.

  • Use above equation by substituting a, b, c and d values.
  • T = 273.15 + 26.85 = 300K


Calculate Cp in kJ kmol-1 K-1

Cp, dry air = a + bT + cT2 + dT3

Cp, dry air = 28.11 + [0.1967 × 10-2 × 300] + [0.4802 × 10-5 × 3002] + [(-1.966 × 10-9) × 3003]

Cp, dry air = 29.076 kJ kmol-1 K-1



Converting kJ kmol-1 K-1 to kJ kg-1 K-1

Cp, dry air = 29.076 kJ kmol-1 K-1 / 28.97 kg kmol-1

Cp, dry air = 1.004 kJ kg-1 K-1



Have Questions?



Is Specific heat capacity of a flue gas air stream at 5000C temperature is important in transferring heat to water to generate steam?

This hot flue gas air stream has a considerable heat quantity and can transfer some portion of heat to water to generate steam. Quantity of available heat depends on the mass flow rate of flue gas and specific heat capacity of air. When specific heat capacity of air increases, quantity of heat amount also increases.






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