Enthalpy of evaporation of water in humidification Calculator

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Humidification

Basics of HMT

Conduction

Convection

Convective Mass Transfer

✖Specific heat of air is the heat required to raise the temperature of a air by one degree to that required to raise the temperature of an equal mass of water one degree.ⓘ Specific Heat of Air [cp]			+10% -10%
✖The Lewis Number is a dimensionless number defined as the ratio of thermal diffusivity to mass diffusivity.ⓘ Lewis Number [L_e]			+10% -10%
✖Absolute Humidity of Air(tw) is the amount of water contained in a parcel of air at wet bulb temperature.ⓘ Absolute Humidity of Air(tw) [Yw]			+10% -10%
✖Absolute humidity of air(atm) is the amount of water contained in a parcel of air at atmospheric temperature.ⓘ Absolute Humidity of Air(atm) [Y∞]			+10% -10%
✖Air temperature is the temperature of the air surrounding an individual and is typically measured in degrees Celsius (°C) or in Kelvin.ⓘ Air Temperature [T∞]			+10% -10%
✖Wet Bulb Temperature is the temperature of the wet bulb and denoted by the symbol Tw.ⓘ Wet Bulb Temperature [T_w]			+10% -10%

✖Enthalpy of evaporation is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas.ⓘ Enthalpy of evaporation of water in humidification [hfg]

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Formula

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Enthalpy of evaporation of water in humidification

Formula

`"hfg" = ("cp"*("L"_{"e"}^0.67))/(("Yw"-"Y∞")/("T∞"-"T"_{"w"}))`

Example

`"-28.763497J/kg*K"=("3J/(kg*K)"*(("4.5")^0.67))/(("6"-"12")/("35"-"14"))`

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Enthalpy of evaporation of water in humidification Solution

STEP 0: Pre-Calculation Summary

Formula Used

Enthalpy of Evaporation = (Specific Heat of Air*(Lewis Number^0.67))/((Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))/(Air Temperature-Wet Bulb Temperature))
hfg = (cp*(L_e^0.67))/((Yw-Y∞)/(T∞-T_w))
This formula uses 7 Variables

Variables Used

Enthalpy of Evaporation - (Measured in Joule per Kilogram K) - Enthalpy of evaporation is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas.
Specific Heat of Air - (Measured in Joule per Kilogram per K) - Specific heat of air is the heat required to raise the temperature of a air by one degree to that required to raise the temperature of an equal mass of water one degree.
Lewis Number - The Lewis Number is a dimensionless number defined as the ratio of thermal diffusivity to mass diffusivity.
Absolute Humidity of Air(tw) - Absolute Humidity of Air(tw) is the amount of water contained in a parcel of air at wet bulb temperature.
Absolute Humidity of Air(atm) - Absolute humidity of air(atm) is the amount of water contained in a parcel of air at atmospheric temperature.
Air Temperature - Air temperature is the temperature of the air surrounding an individual and is typically measured in degrees Celsius (°C) or in Kelvin.
Wet Bulb Temperature - Wet Bulb Temperature is the temperature of the wet bulb and denoted by the symbol Tw.

STEP 1: Convert Input(s) to Base Unit

Specific Heat of Air: 3 Joule per Kilogram per K --> 3 Joule per Kilogram per K No Conversion Required
Lewis Number: 4.5 --> No Conversion Required
Absolute Humidity of Air(tw): 6 --> No Conversion Required
Absolute Humidity of Air(atm): 12 --> No Conversion Required
Air Temperature: 35 --> No Conversion Required
Wet Bulb Temperature: 14 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

hfg = (cp*(L_e^0.67))/((Yw-Y∞)/(T∞-T_w)) --> (3*(4.5^0.67))/((6-12)/(35-14))

Evaluating ... ...

hfg = -28.7634968577051

STEP 3: Convert Result to Output's Unit

-28.7634968577051 Joule per Kilogram K --> No Conversion Required

FINAL ANSWER

-28.7634968577051 ≈ -28.763497 Joule per Kilogram K <-- Enthalpy of Evaporation

(Calculation completed in 00.004 seconds)

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Home » Physics » Heat and Mass Transfer » Humidification » Enthalpy of evaporation of water in humidification

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Created by Nishan Poojary

Shri Madhwa Vadiraja Institute of Technology and Management (SMVITM), Udupi

Nishan Poojary has created this Calculator and 500+ more calculators!

Verified by Anshika Arya

National Institute Of Technology (NIT), Hamirpur

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< 24 Humidification Calculators

Absolute humidity at inside temperature in dehumidification

Go Absolute Humidity (ti) = Absolute Humidity of Air(tg)-(((Liquid Phase Heat Transfer Coefficient*(Temperature at inner surface-Liquid layer temperature))-Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Temperature at inner surface))/(Gas Phase Mass Transfer Coefficient*Enthalpy of Evaporation))

Enthalpy of evaporation in dehumidification

Go Enthalpy of Evaporation = ((Liquid Phase Heat Transfer Coefficient*(Temperature at inner surface-Liquid layer temperature))-Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Temperature at inner surface))/(Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti)))

Liquid phase heat transfer coefficient in dehumidification

Go Liquid Phase Heat Transfer Coefficient = ((Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Temperature at inner surface))+Enthalpy of Evaporation*Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti)))/(Temperature at inner surface-Liquid layer temperature)

Gas phase heat transfer coefficient in dehumidification

Go Gas Phase Heat Transfer Coefficient = ((Liquid Phase Heat Transfer Coefficient*(Inside Temperature-Liquid layer temperature))-(Enthalpy of Evaporation*Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti))))/(Bulk Gas Temperature-Inside Temperature)

Gas phase mass transfer coefficient in dehumidification

Go Gas Phase Mass Transfer Coefficient = ((Liquid Phase Heat Transfer Coefficient*(Inside Temperature-Liquid layer temperature))-Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Inside Temperature))/(Enthalpy of Evaporation*(Absolute Humidity of Air(tg)-Absolute Humidity (ti)))

Bulk gas temperature in dehumidification

Go Bulk Gas Temperature = (((Liquid Phase Heat Transfer Coefficient*(Inside Temperature-Liquid layer temperature))-(Enthalpy of Evaporation*Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti))))/Gas Phase Heat Transfer Coefficient)+Inside Temperature

Liquid layer temperature in dehumidification

Go Liquid layer temperature = Inside Temperature-(((Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Inside Temperature))+Enthalpy of Evaporation*Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti)))/Liquid Phase Heat Transfer Coefficient)

Specific heat of air given gas constant

Go Specific Heat of Air = (((Enthalpy of Evaporation*(Partial Pressure-Partial Pressure in air))/(Gas constant*Density*(Air Temperature-Wet Bulb Temperature)*Mean Temperature*(Lewis Number^0.67))))

Gas constant of water vapor

Go Gas constant = (((Enthalpy of Evaporation*(Partial Pressure-Partial Pressure in air))/((Air Temperature-Wet Bulb Temperature)*Density*Specific Heat of Air*Mean Temperature*(Lewis Number^0.67))))

Temperature of air given gas constant of water

Go Air Temperature = (((Enthalpy of Evaporation*(Partial Pressure-Partial Pressure in air))/(Gas constant*Density*Specific Heat of Air*Mean Temperature*(Lewis Number^0.67))))+Wet Bulb Temperature

Wet bulb temperature given gas constant of water vapor

Go Wet Bulb Temperature = Air Temperature-((Enthalpy of Evaporation*(Partial Pressure-Partial Pressure in air))/(Gas constant*Density*Specific Heat of Air*Mean Temperature*(Lewis Number^0.67)))

Temperature of air during humidification

Go Air Temperature = (((0.622*Enthalpy of Evaporation)/(Specific Heat of Air*(Lewis Number^0.67)))*((Partial Pressure/Total Pressure)-(Partial Pressure in air/Total Pressure)))+Wet Bulb Temperature

Wet bulb temperature of humidification

Go Wet Bulb Temperature = Air Temperature-((0.622*Enthalpy of Evaporation)/(Specific Heat of Air*(Lewis Number^0.67)))*((Partial Pressure/Total Pressure)-(Partial Pressure in air/Total Pressure))

Absolute Humidity of Air at Final Equilibrium Air Temperature

Go Absolute Humidity of Air(ta) = (((Specific Heat of Air+(Absolute Humidity of Air(tg)*Specific Heat of Water Vapor))*(Bulk Gas Temperature-Temperature))/(Enthalpy of Evaporation))+Absolute Humidity of Air(tg)

Gas phase mass transfer coefficient given humidity

Go Gas Phase Mass Transfer Coefficient = (Mass Velocity of Air/Height)*ln((Absolute Humidity at Final Temperature-Humidity of air at entry)/(Absolute Humidity at Final Temperature-Humidity of air at exit))

Height of tower in adiabatic humidification

Go Height = (Mass Velocity of Air/Gas Phase Mass Transfer Coefficient)*ln((Absolute Humidity at Final Temperature-Humidity of air at entry)/(Absolute Humidity at Final Temperature-Humidity of air at exit))

Mass velocity of air per unit area

Go Mass Velocity of Air = (Height*Gas Phase Mass Transfer Coefficient)/ln((Absolute Humidity of Air(ta)-Humidity of Air at Entry(t))/(Absolute Humidity of Air(ta)-Humidity of air at exit))

Partial pressure of water vapor at wet bulb temperature

Go Partial Pressure = ((Convective Heat Transfer Coefficient*(Air Temperature-Wet Bulb Temperature))/(Enthalpy of Evaporation*Convective Mass Transfer Coefficient))+Partial Pressure in air

Convective mass transfer coefficient in humidification

Go Convective Mass Transfer Coefficient = (Convective Heat Transfer Coefficient*(Air Temperature-Wet Bulb Temperature))/(Enthalpy of Evaporation*(Partial Pressure-Partial Pressure in air))

Enthalpy of evaporation for water in humidification

Go Enthalpy of Evaporation = (Convective Heat Transfer Coefficient*(Air Temperature-Wet Bulb Temperature))/(Convective Mass Transfer Coefficient*(Partial Pressure-Partial Pressure in air))

Partial pressure of water vapor in air

Go Partial Pressure in air = Partial Pressure-((Convective Heat Transfer Coefficient*(Air Temperature-Wet Bulb Temperature))/(Enthalpy of Evaporation*Convective Mass Transfer Coefficient))

Heat transfer coefficient in humidification

Go Heat Transfer Coefficient = ((Partial Pressure-Partial Pressure in air)*(Enthalpy of Evaporation*Convective Mass Transfer Coefficient))/(Air Temperature-Wet Bulb Temperature)

Enthalpy of evaporation of water in humidification

Go Enthalpy of Evaporation = (Specific Heat of Air*(Lewis Number^0.67))/((Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))/(Air Temperature-Wet Bulb Temperature))

Specific heat of air during humidification

Go Specific Heat of Air = (Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))*Enthalpy of Evaporation/((Temperature-Air Temperature)*Lewis Number^0.67)

Enthalpy of evaporation of water in humidification Formula

What is humidification?

Humidification is the process in which the moisture or water vapor or humidity is added to the air. Common equipment used in this process is a humidifier. Dehumidification as the term suggests, is the opposite of humidification since dehumidification means removing the moisture from the air. Common equipment used in this process is a dehumidifier.
Humidity is the presence of water vapor or moisture in the air, while relative humidity, on the other hand, is the comparison of the actual moisture or water vapor in the air vs. the total water vapor or moisture that the air can handle.

How to Calculate Enthalpy of evaporation of water in humidification?

Enthalpy of evaporation of water in humidification calculator uses Enthalpy of Evaporation = (Specific Heat of Air*(Lewis Number^0.67))/((Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))/(Air Temperature-Wet Bulb Temperature)) to calculate the Enthalpy of Evaporation, The Enthalpy of evaporation of water in humidification formula is defined as the amount of energy required by the water to change its state from liquid to gas. Enthalpy of Evaporation is denoted by hfg symbol.

How to calculate Enthalpy of evaporation of water in humidification using this online calculator? To use this online calculator for Enthalpy of evaporation of water in humidification, enter Specific Heat of Air (cp), Lewis Number (L_e), Absolute Humidity of Air(tw) (Yw), Absolute Humidity of Air(atm) (Y∞), Air Temperature (T∞) & Wet Bulb Temperature (T_w) and hit the calculate button. Here is how the Enthalpy of evaporation of water in humidification calculation can be explained with given input values -> -28.763497 = (3*(4.5^0.67))/((6-12)/(35-14)).

FAQ

What is Enthalpy of evaporation of water in humidification?

The Enthalpy of evaporation of water in humidification formula is defined as the amount of energy required by the water to change its state from liquid to gas and is represented as hfg = (cp*(L_e^0.67))/((Yw-Y∞)/(T∞-T_w)) or Enthalpy of Evaporation = (Specific Heat of Air*(Lewis Number^0.67))/((Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))/(Air Temperature-Wet Bulb Temperature)). Specific heat of air is the heat required to raise the temperature of a air by one degree to that required to raise the temperature of an equal mass of water one degree, The Lewis Number is a dimensionless number defined as the ratio of thermal diffusivity to mass diffusivity, Absolute Humidity of Air(tw) is the amount of water contained in a parcel of air at wet bulb temperature, Absolute humidity of air(atm) is the amount of water contained in a parcel of air at atmospheric temperature, Air temperature is the temperature of the air surrounding an individual and is typically measured in degrees Celsius (°C) or in Kelvin & Wet Bulb Temperature is the temperature of the wet bulb and denoted by the symbol Tw.

How to calculate Enthalpy of evaporation of water in humidification?

The Enthalpy of evaporation of water in humidification formula is defined as the amount of energy required by the water to change its state from liquid to gas is calculated using Enthalpy of Evaporation = (Specific Heat of Air*(Lewis Number^0.67))/((Absolute Humidity of Air(tw)-Absolute Humidity of Air(atm))/(Air Temperature-Wet Bulb Temperature)). To calculate Enthalpy of evaporation of water in humidification, you need Specific Heat of Air (cp), Lewis Number (L_e), Absolute Humidity of Air(tw) (Yw), Absolute Humidity of Air(atm) (Y∞), Air Temperature (T∞) & Wet Bulb Temperature (T_w). With our tool, you need to enter the respective value for Specific Heat of Air, Lewis Number, Absolute Humidity of Air(tw), Absolute Humidity of Air(atm), Air Temperature & Wet Bulb Temperature and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Enthalpy of Evaporation?

In this formula, Enthalpy of Evaporation uses Specific Heat of Air, Lewis Number, Absolute Humidity of Air(tw), Absolute Humidity of Air(atm), Air Temperature & Wet Bulb Temperature. We can use 2 other way(s) to calculate the same, which is/are as follows -

Enthalpy of Evaporation = (Convective Heat Transfer Coefficient*(Air Temperature-Wet Bulb Temperature))/(Convective Mass Transfer Coefficient*(Partial Pressure-Partial Pressure in air))
Enthalpy of Evaporation = ((Liquid Phase Heat Transfer Coefficient*(Temperature at inner surface-Liquid layer temperature))-Gas Phase Heat Transfer Coefficient*(Bulk Gas Temperature-Temperature at inner surface))/(Gas Phase Mass Transfer Coefficient*(Absolute Humidity of Air(tg)-Absolute Humidity (ti)))

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