Logarithmic mean temperature difference Calculator

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Heat exchanger

Basics of HMT

Conduction

Convection

Convective Mass Transfer

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Transverse Fin Heat Exchanger

✖Heat exchanged is the amount of heat transferred between two objects.ⓘ Heat exchanged [Q]			+10% -10%
✖Correction Factor is that which is multiplied with the result of an equation to correct for a known amount of systematic error.ⓘ Correction Factor [f]			+10% -10%
✖Overall heat transfer coefficient is the overall convective heat transfer between a fluid medium (a fluid) and the surface (wall) flowed over by the fluid.ⓘ Overall Heat Transfer Coefficient [U]			+10% -10%
✖The area is the amount of two-dimensional space taken up by an object.ⓘ Area [A]			+10% -10%

✖Logarithmic Mean Temperature Difference is the log of the mean of the temperature values.ⓘ Logarithmic mean temperature difference [ΔT_m]

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Formula

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Logarithmic mean temperature difference

Formula

`"ΔT"_{"m"} = "Q"/("f"*"U"*"A")`

Example

`"0.04"="50W"/("0.5"*"50W/m²*K"*"50m²")`

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Logarithmic mean temperature difference Solution

STEP 0: Pre-Calculation Summary

Formula Used

Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area)
ΔT_m = Q/(f*U*A)
This formula uses 5 Variables

Variables Used

Logarithmic Mean Temperature Difference - Logarithmic Mean Temperature Difference is the log of the mean of the temperature values.
Heat exchanged - (Measured in Watt) - Heat exchanged is the amount of heat transferred between two objects.
Correction Factor - Correction Factor is that which is multiplied with the result of an equation to correct for a known amount of systematic error.
Overall Heat Transfer Coefficient - (Measured in Watt per Square Meter per Kelvin) - Overall heat transfer coefficient is the overall convective heat transfer between a fluid medium (a fluid) and the surface (wall) flowed over by the fluid.
Area - (Measured in Square Meter) - The area is the amount of two-dimensional space taken up by an object.

STEP 1: Convert Input(s) to Base Unit

Heat exchanged: 50 Watt --> 50 Watt No Conversion Required
Correction Factor: 0.5 --> No Conversion Required
Overall Heat Transfer Coefficient: 50 Watt per Square Meter per Kelvin --> 50 Watt per Square Meter per Kelvin No Conversion Required
Area: 50 Square Meter --> 50 Square Meter No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

ΔT_m = Q/(f*U*A) --> 50/(0.5*50*50)

Evaluating ... ...

ΔT_m = 0.04

STEP 3: Convert Result to Output's Unit

0.04 --> No Conversion Required

FINAL ANSWER

0.04 <-- Logarithmic Mean Temperature Difference

(Calculation completed in 00.004 seconds)

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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 Sagar S Kulkarni

Dayananda Sagar College of Engineering (DSCE), Bengaluru

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< 25 Heat exchanger Calculators

Logarithmic mean temperature difference for single pass counter flow

Go Logarithmic Mean Temperature Difference = ((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)-(Entry Temperature of Cold Fluid-Exit Temperature of Hot Fluid))/ln((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)/(Entry Temperature of Cold Fluid-Exit Temperature of Hot Fluid))

Mass flow rate of cold fluid

Go Mass Flow Rate of Cold Fluid = (Effectiveness of Heat Exchanger*Smaller Value/Specific heat of cold fluid)*(1/((Exit Temperature of Cold Fluid-Entry Temperature of Cold Fluid)/(Entry Temperature of Hot Fluid-Entry Temperature of Cold Fluid)))

Specific heat of cold fluid

Go Specific heat of cold fluid = (Effectiveness of Heat Exchanger*Smaller Value/Mass Flow Rate of Cold Fluid)*(1/((Exit Temperature of Cold Fluid-Entry Temperature of Cold Fluid)/(Entry Temperature of Hot Fluid-Entry Temperature of Cold Fluid)))

Mass flow rate of hot fluid

Go Mass Flow Rate of Hot Fluid = (Effectiveness of Heat Exchanger*Smaller Value/Specific heat of hot fluid)*(1/((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)/(Entry Temperature of Hot Fluid-Entry Temperature of Cold Fluid)))

Specific heat of hot water

Go Specific heat of hot fluid = (Effectiveness of Heat Exchanger*Smaller Value/Mass Flow Rate of Hot Fluid)*(1/((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)/(Entry Temperature of Hot Fluid-Entry Temperature of Cold Fluid)))

Heat transfer surface area for unit length of matrix in storage type heat exchanger

Go Surface Area = (Location factor*Specific heat of fluid*Mass Flowrate)/(Convective Heat Transfer Coefficient*Distance from Point to YY Axis)

Convective heat transfer coefficient of storage type heat exchanger

Go Convective Heat Transfer Coefficient = (Location factor*Specific heat of fluid*Mass Flowrate)/(Surface Area*Distance from Point to YY Axis)

Specific heat of fluid in storage type heat exchanger

Go Specific heat of fluid = (Convective Heat Transfer Coefficient*Surface Area*Distance from Point to YY Axis)/(Location factor*Mass Flowrate)

Mass Flowrate of Fluid in Storage type Heat Exchanger

Go Mass Flowrate = (Convective Heat Transfer Coefficient*Surface Area*Distance from Point to YY Axis)/(Specific heat of fluid*Location factor)

Location factor at distance X of heat exchanger

Go Location factor = (Convective Heat Transfer Coefficient*Surface Area*Distance from Point to YY Axis)/(Specific heat of fluid*Mass Flowrate)

Convective heat transfer coefficient of storage type heat exchanger given time factor

Go Convective Heat Transfer Coefficient = (Time Factor*Specific heat of matrix material*Mass of Solid)/(Surface Area*Total Time Taken)

Heat transfer surface area for unit length given time factor

Go Surface Area = (Time Factor*Specific heat of matrix material*Mass of Solid)/(Convective Heat Transfer Coefficient*Total Time Taken)

Time factor of storage type heat exchanger

Go Time Factor = (Convective Heat Transfer Coefficient*Surface Area*Total Time Taken)/(Specific heat of matrix material*Mass of Solid)

Time taken for storage type heat exchanger

Go Total Time Taken = (Time Factor*Specific heat of matrix material*Mass of Solid)/(Surface Area*Convective Heat Transfer Coefficient)

Mass of solid per unit length of matrix

Go Mass of Solid = (Convective Heat Transfer Coefficient*Surface Area*Total Time Taken)/(Time Factor*Specific heat of matrix material)

Specific heat of matrix material

Go Specific heat of matrix material = (Convective Heat Transfer Coefficient*Surface Area*Total Time Taken)/(Time Factor*Mass of Solid)

Entry temperature of cold fluid

Go Entry Temperature of Cold Fluid = Entry Temperature of Hot Fluid-(Heat exchanged/(Effectiveness of Heat Exchanger*Smaller Value))

Entry temperature of hot fluid

Go Entry Temperature of Hot Fluid = (Heat exchanged/(Effectiveness of Heat Exchanger*Smaller Value))+Entry Temperature of Cold Fluid

Heat exchanged NTU method

Go Heat exchanged = Effectiveness of Heat Exchanger*Smaller Value*(Entry Temperature of Hot Fluid-Entry Temperature of Cold Fluid)

Overall heat transfer coefficient given LMTD

Go Overall Heat Transfer Coefficient = Heat exchanged/(Correction Factor*Area*Logarithmic Mean Temperature Difference)

Logarithmic mean temperature difference

Go Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area)

Correction factor in heat exchanger

Go Correction Factor = Heat exchanged/(Overall Heat Transfer Coefficient*Area*Logarithmic Mean Temperature Difference)

Area of heat exchanger

Go Area = Heat exchanged/(Overall Heat Transfer Coefficient*Logarithmic Mean Temperature Difference*Correction Factor)

Heat exchanged

Go Heat exchanged = Correction Factor*Overall Heat Transfer Coefficient*Area*Logarithmic Mean Temperature Difference

Capacity Ratio

Go Heat capacity ratio = Minimum heat capacity/Maximum heat capacity

Logarithmic mean temperature difference Formula

Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area)
ΔT_m = Q/(f*U*A)

What is Heat exchanger

A heat exchanger is a system used to transfer heat between two or more fluids. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.

How to Calculate Logarithmic mean temperature difference?

Logarithmic mean temperature difference calculator uses Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area) to calculate the Logarithmic Mean Temperature Difference, The Logarithmic mean temperature difference formula is defined as the log of the mean difference of the temperature values. Logarithmic Mean Temperature Difference is denoted by ΔT_m symbol.

How to calculate Logarithmic mean temperature difference using this online calculator? To use this online calculator for Logarithmic mean temperature difference, enter Heat exchanged (Q), Correction Factor (f), Overall Heat Transfer Coefficient (U) & Area (A) and hit the calculate button. Here is how the Logarithmic mean temperature difference calculation can be explained with given input values -> 0.04 = 50/(0.5*50*50).

FAQ

What is Logarithmic mean temperature difference?

The Logarithmic mean temperature difference formula is defined as the log of the mean difference of the temperature values and is represented as ΔT_m = Q/(f*U*A) or Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area). Heat exchanged is the amount of heat transferred between two objects, Correction Factor is that which is multiplied with the result of an equation to correct for a known amount of systematic error, Overall heat transfer coefficient is the overall convective heat transfer between a fluid medium (a fluid) and the surface (wall) flowed over by the fluid & The area is the amount of two-dimensional space taken up by an object.

How to calculate Logarithmic mean temperature difference?

The Logarithmic mean temperature difference formula is defined as the log of the mean difference of the temperature values is calculated using Logarithmic Mean Temperature Difference = Heat exchanged/(Correction Factor*Overall Heat Transfer Coefficient*Area). To calculate Logarithmic mean temperature difference, you need Heat exchanged (Q), Correction Factor (f), Overall Heat Transfer Coefficient (U) & Area (A). With our tool, you need to enter the respective value for Heat exchanged, Correction Factor, Overall Heat Transfer Coefficient & Area 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 Logarithmic Mean Temperature Difference?

In this formula, Logarithmic Mean Temperature Difference uses Heat exchanged, Correction Factor, Overall Heat Transfer Coefficient & Area. We can use 1 other way(s) to calculate the same, which is/are as follows -

Logarithmic Mean Temperature Difference = ((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)-(Entry Temperature of Cold Fluid-Exit Temperature of Hot Fluid))/ln((Entry Temperature of Hot Fluid-Exit Temperature of Cold Fluid)/(Entry Temperature of Cold Fluid-Exit Temperature of Hot Fluid))

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