sat_vapor_pressure: Saturation Vapor Pressure for Water

In iemisc: Irucka Embry's Miscellaneous Functions

Saturation Vapor Pressure for Water

Description

This function solves for the saturation vapor pressure of water using only the temperature of the water in either units of degrees Celsius, degrees Fahrenheit, or Kelvin.

Usage

sat_vapor_pressure(
  Temp,
  units = c("SI", "Eng", "Absolute"),
  formula = c("Huang", "Buck", "IAPWS")
)

Arguments

Temp	numeric vector that contains the temperature (degrees Celsius, degrees Fahrenheit, or Kelvin)
units	character vector that contains the system of units (options are SI for International System of Units, Eng for English units (United States Customary System in the United States and Imperial Units in the United Kingdom), or Absolute for Absolute Units)
formula	character vector that contains the source of the formula used to compute the saturation vapor pressure (options are Huang, Buck, IAPWS)

Details

The simplified equation is expressed as

P_s = \exp{\frac{34.494 - \frac{4924.99}{t + 237.1}}{(t + 105)^1.57}}

for (t > 0 C)

P_s

the saturation vapor pressure (Pa or psi)

t

the water temperature, degrees Celsius

Value

the saturation vapor pressure for water as a numeric vector. The unit for SI and Absolute is Pascal (Pa), but the unit for Eng is pounds per square inch (psi). The units are not returned.

Note

Note: Please refer to the references for the formulas (Huang = Reference 1, IAPWS = Reference 2, and Buck = Reference 3)

Note: Please refer to the iemisc: Comparing Saturated Vapor Pressure Formulas to the Reference vignette for the comparisons to the reference saturated vapor pressure

Author(s)

Irucka Embry

References

1. Huang, J. (2018). "A Simple Accurate Formula for Calculating Saturation Vapor Pressure of Water and Ice", Journal of Applied Meteorology and Climatology, 57(6), 1265-1272. Retrieved Nov 4, 2021, https://journals.ametsoc.org/view/journals/apme/57/6/jamc-d-17-0334.1.xml

2. The International Association for the Properties of Water and Steam. IAPWS SR1-86(1992). "Revised Supplementary Release on Saturation Properties of Ordinary Water Substance", September 1992, http://www.iapws.org/relguide/Supp-sat.pdf

3. Holger Vömel, National Center for Atmospheric Research Earth Observing Laboratory, "Saturation vapor pressure formulations", https://web.archive.org/web/20170623040102/http://cires1.colorado.edu/~voemel/vp.html. Retrieved thanks to the Internet Archive: Wayback Machine

Examples

# Example 1 - Example from the hydraulics package

library(iemisc)

vps <- hydraulics::svp(T = 10, units = "SI"); vps

vps2 <- sat_vapor_pressure(Temp = 10, units = "SI", formula = "Huang"); vps2





# Example 2 - from the Huang Reference

library(iemisc)

sat_vapor_pressure(Temp = c(0.01, seq(from = 20, to = 100, by = 20)), units
= "SI", formula = "Huang")





# Example 3 - compare with saturation_pressure_H2O from aiRthermo

install.load::load_package("iemisc", "units")

Temp <- 40

# create a numeric vector with the units of degrees Celsius
T_C <- set_units(Temp, "degree_C")
T_C

# create a numeric vector to convert from degrees Celsius to Kelvin
T_K <- T_C
T_K

# create a numeric vector with the units of Kelvin
units(T_K) <- make_units(K)

pre <- aiRthermo::saturation_pressure_H2O(drop_units(T_K))
pre

sat_vapor_pressure(Temp = drop_units(T_K), units = "Absolute", formula = "Huang")

iemisc documentation built on Sept. 25, 2023, 5:09 p.m.