R/psychrometric-graph-enthalpy.R

In jinlee86/bems_analysisr_package: EDAS System R Package

#' Enthalpy (h)
#'
#' Calculates the enthalpy of a given moist air state.
#' Eq. 32 - ASHRAE Fundamentals Handbook 2002, Psychrometrics.
#' @param temp.db Vector of dry bulb temperatures [degC].
#' @param hum.ratio Vector of humidity ratios [kg/kg].
#' @family PsychrometricGraph
#' @return Returns a vector of enthalpies [kJ/kg].
#' @export
#' @examples
#' enthalpy(25, 0.010)
#'
#' # Calculating cooling demand
#' density <- 1.2 # density of air (kg/m3)
#' (enthalpy(35, 0.020) - enthalpy(15, 0.010)) * density
#' @author Christoffer Rasmussen
enthalpy <- function(temp.db, hum.ratio) {
  # Enthalpy (eq. 32)
  return(1.006 * temp.db + hum.ratio * (2501 + 1.805 * temp.db))
}