Ammonia Vapor Pressure & Temperature Equations

In the series of physical properties calculation methods, I am now covering Ammonia P & T correlations which are frequently used in refrigeration system design calculations. Or they may be used for designing of heat pumps - yes may be I don't know at this stage if one can use ammonia for heat pump service or not.

Saturation Pressure vs Temperature.

This equation is valid for t = -75 to 70°C. I have limited this equation to this range for better accuracy of calculated data vis a vis comparison with published data.

Pv = A x T^5 + B x T^4 + C x T^3 + D x T^2 + E x T + F

where Pv = vapor pressure in Kg/cm2
T is temperature in Kelvin.

A = -4.5864778 x 10^-11
B = 9.85099347 x 10^-8
C = - 5.7526544 x 10^-5
D = 1.4773233 x 10^-2
E = -1.7847943
F = 83.3895705

Saturation Pressure vs Temperature for t > 70°C.

Pv = 89875.92511 exp (-2706.64791 / T)

where units are same as above.

Saturation Temperature Vs Pressure for P = 0 to 34 Kg/cm2.


T = A x y^5 + B x y^4 + C x y^3 + D x y^2 + E x y + F

Where
A = 0.13493672
B = 0.380555
C = 2.13810444
D = 10.058439
E = 45.5972648
F = 239.1719874

T is in Kelvin

List of other property estimation methods on this Blog.

• Calculate Diffusion Coefficient in Gases


• Calculate Diffusion Coefficient in Liquids


• Heat Capacities of dissolved solids & organic solutions - Quickest methods


• Heat capacities with dissolved solids


• Kinematic viscosity of air Vs Temperature


• Thermal Conductivity of air Vs Temperature


• How to calculate viscosity of liquid mixtures


• Surface Tension


• Viscosities of Pure Gases at Low Pressure - 1


• Viscosities of Pure Gases at Low Pressure - 2


• Viscosities of Pure Gases at High Pressure


• Viscosity of Gaseous Mixture


• Steam Properties - I


• Vapor Pressure Vs Temperature


• Latent Heat Calculation