![]() ![]() 8.2 Psychrometric Properties of Moist Air at 1000 kPa Dry Bulb temperature of 200 C = W Twb v h s RH kgw / kg_da C m3 / kgda kJ / kgda kJ / kgda / K % - 0. 8.1 Psychrometric Properties of Moist Air at 101.325 kPa Dry Bulb temperature of 200 C = W Twb v h s RH kgw / kg_da C m3 / kgda kJ / kgda kJ / kgda / K % - 0. In : % run 'fluid_properties/Validation/HAValidation.py' Values here are obtained at documentation build-time using the Humid Air Properties module Mixture specific heat at constant volume per unit humid airĬompressibility factor ( \(Z = pv/(RT)\)) Mixture specific heat at constant volume per unit dry air #import the things you need In : from CoolProp.HumidAirProp import HAPropsSI #Enthalpy (J per kg dry air) as a function of temperature, pressure, # and relative humidity at dry bulb temperature T of 25C, pressure # P of one atmosphere, relative humidity R of 50% In : h = HAPropsSI ( 'H', 'T', 298.15, 'P', 101325, 'R', 0.5 ) print ( h ) 50423.45039107799 #Temperature of saturated air at the previous enthalpy In : T = HAPropsSI ( 'T', 'P', 101325, 'H', h, 'R', 1.0 ) print ( T ) 290.9620924692057 #Temperature of saturated air - order of inputs doesn't matter In : T = HAPropsSI ( 'T', 'H', h, 'R', 1.0, 'P', 101325 ) print ( T ) 290.9620924692057 Table of Inputs/Outputs to HAPropsSI ¶ Input/Output parameters ¶ \ Isothermal Compressibility ¶įor water, the isothermal compressibility is evaluated from Thus the mole fraction of water can be obtained from The humidity ratio \(W\) is the ratio of the mass of water vapor to the mass of air in the mixture. ![]() There are three different variables that can be used to obtain the mole fraction of water vapor without resorting to iterative methods. ![]() Of course, it is not so straightforward to measure the mole fraction of water vapor molecules, so other measures are used. The molar fraction of air is simply \(\psi_a=1-\psi_w\). In the analysis that follows, the three parameters that are ultimately needed to calculate everything else are the dry bulb temperature \(T\), the total pressure \(p\), and the molar fraction of water \(\psi_w\). In the simplest analysis, water and air are treated as ideal gases but in principle there is interaction between the air and water molecules that must be included through the use of interaction parameters.īecause humid air is a mixture of dry air (treated as a pseudo-pure gas) and water vapor (treated as a real gas), three variables are required to fix the state by the state postulate. Humid air can be modeled as a mixture of air and water vapor. It is applicable for pressure from 0.01 kPa up to 10 MPa, in a temperature range from -143.15 ☌ up to 350 ☌ with a humidity ratio from 0 kg of water The code implemented here passes all tests and reproduces the originalĭata with a very high accuracy. The same source has been used in the ASHRAE Handbook 2009 to generate reference saturation property tables. , which describes the outcome of the ASHRAE research project ASHREA-RP1485. The equations implemented in CoolProp are based on a publication by Hermann et al. ![]() If you are feeling impatient, jump to Sample HAPropsSI Code, or to go to the code documentation CoolProp.HumidAirProp, otherwise, hang in there. ![]()
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