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Log Mean Temperature Difference for Counter Current Flow Formula

GoLog Mean Temperature Difference for CoCurrent Flow Formula

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The Log Mean Temperature Difference (LMTD) is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger. Check FAQs

LMTD = \frac{(T ho - T ci) - (T hi - T co)}{\ln (\frac{T ho - T ci}{T hi - T co})}

LMTD - Log Mean Temperature Difference?T_ho - Outlet Temperature of Hot Fluid?T_ci - Inlet Temperature of Cold Fluid?T_hi - Inlet Temperature of Hot Fluid?T_co - Outlet Temperature of Cold Fluid?

Log Mean Temperature Difference for Counter Current Flow Example

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Here is how the Log Mean Temperature Difference for Counter Current Flow equation looks like with Values.

Here is how the Log Mean Temperature Difference for Counter Current Flow equation looks like with Units.

Here is how the Log Mean Temperature Difference for Counter Current Flow equation looks like.

19.5762 = \frac{(20 - 5) - (35 - 10)}{\ln (\frac{20 - 5}{35 - 10})}

19.5762K = \frac{(20K - 5K) - (35K - 10K)}{\ln (\frac{20K - 5K}{35K - 10K})}

19.5762 = \frac{(20 - 5) - (35 - 10)}{\ln (\frac{20 - 5}{35 - 10})}

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Log Mean Temperature Difference for Counter Current Flow Solution

Follow our step by step solution on how to calculate Log Mean Temperature Difference for Counter Current Flow?

FIRST Step Consider the formula

LMTD = \frac{(T ho - T ci) - (T hi - T co)}{\ln (\frac{T ho - T ci}{T hi - T co})}

Next Step Substitute values of Variables

∴

LMTD = \frac{(20K - 5K) - (35K - 10K)}{\ln (\frac{20K - 5K}{35K - 10K})}

Next Step Prepare to Evaluate

∴

LMTD = \frac{(20 - 5) - (35 - 10)}{\ln (\frac{20 - 5}{35 - 10})}

Next Step Evaluate

∴

LMTD = 19.5761518897122K

LAST Step Rounding Answer

∴

LMTD = 19.5762K

Log Mean Temperature Difference for Counter Current Flow Formula Elements

Variables

Functions

Log Mean Temperature Difference

The Log Mean Temperature Difference (LMTD) is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger.

Symbol: LMTD

Measurement: TemperatureUnit: K

Note: Value should be greater than 0.

Formulas to find Log Mean Temperature Difference

Outlet Temperature of Hot Fluid

Outlet Temperature of Hot Fluid is the temperature at which the hot fluid exits the heat exchanger.

Symbol: T_ho

Measurement: TemperatureUnit: K

Note: Value should be greater than 0.

Formulas to find Outlet Temperature of Hot Fluid

Inlet Temperature of Cold Fluid

Inlet Temperature of Cold Fluid is the temperature at which the cold fluid enters the heat exchanger.

Symbol: T_ci

Measurement: TemperatureUnit: K

Note: Value should be greater than 0.

Formulas to find Inlet Temperature of Cold Fluid

Inlet Temperature of Hot Fluid

Inlet Temperature of Hot Fluid is the temperature at which the hot fluid enters the heat exchanger.

Symbol: T_hi

Measurement: TemperatureUnit: K

Note: Value should be greater than 0.

Formulas to find Inlet Temperature of Hot Fluid

Outlet Temperature of Cold Fluid

Outlet Temperature of Cold Fluid is the temperature at which the cold fluid exits the heat exchanger.

Symbol: T_co

Measurement: TemperatureUnit: K

Note: Value should be greater than 0.

Formulas to find Outlet Temperature of Cold Fluid

The natural logarithm, also known as the logarithm to the base e, is the inverse function of the natural exponential function.

Syntax: ln(Number)

Other Formulas to find Log Mean Temperature Difference

Go Log Mean Temperature Difference for CoCurrent Flow

LMTD = \frac{(T ho - T co) - (T hi - T ci)}{\ln (\frac{T ho - T co}{T hi - T ci})}

Other formulas in Basics of Heat Transfer category

Go Logarithmic Mean Area of Cylinder

A mean = \frac{A o - A i}{\ln (\frac{A o}{A i})}

Go Heat Transfer Coefficient based on Temperature Difference

h ht = \frac{q}{ΔT Overall}

Go Hydraulic Radius

r H = \frac{A cs}{P}

Go Equivalent Diameter of Non-Circular Duct

D e = \frac{4 \cdot A cs}{P}

How to Evaluate Log Mean Temperature Difference for Counter Current Flow?

Log Mean Temperature Difference for Counter Current Flow evaluator uses Log Mean Temperature Difference = ((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)-(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid))/ln((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)/(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid)) to evaluate the Log Mean Temperature Difference, The Log Mean Temperature Difference for Counter Current Flow in is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold streams at each end of the exchanger. Log Mean Temperature Difference is denoted by LMTD symbol.

How to evaluate Log Mean Temperature Difference for Counter Current Flow using this online evaluator? To use this online evaluator for Log Mean Temperature Difference for Counter Current Flow, enter Outlet Temperature of Hot Fluid (T_ho), Inlet Temperature of Cold Fluid (T_ci), Inlet Temperature of Hot Fluid (T_hi) & Outlet Temperature of Cold Fluid (T_co) and hit the calculate button.

FAQs on Log Mean Temperature Difference for Counter Current Flow

What is the formula to find Log Mean Temperature Difference for Counter Current Flow?

The formula of Log Mean Temperature Difference for Counter Current Flow is expressed as Log Mean Temperature Difference = ((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)-(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid))/ln((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)/(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid)). Here is an example- 19.57615 = ((20-5)-(35-10))/ln((20-5)/(35-10)).

How to calculate Log Mean Temperature Difference for Counter Current Flow?

With Outlet Temperature of Hot Fluid (T_ho), Inlet Temperature of Cold Fluid (T_ci), Inlet Temperature of Hot Fluid (T_hi) & Outlet Temperature of Cold Fluid (T_co) we can find Log Mean Temperature Difference for Counter Current Flow using the formula - Log Mean Temperature Difference = ((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)-(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid))/ln((Outlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid)/(Inlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid)). This formula also uses Natural Logarithm (ln) function(s).

What are the other ways to Calculate Log Mean Temperature Difference?

Here are the different ways to Calculate Log Mean Temperature Difference-

Log Mean Temperature Difference=((Outlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid)-(Inlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid))/ln((Outlet Temperature of Hot Fluid-Outlet Temperature of Cold Fluid)/(Inlet Temperature of Hot Fluid-Inlet Temperature of Cold Fluid))

Can the Log Mean Temperature Difference for Counter Current Flow be negative?

No, the Log Mean Temperature Difference for Counter Current Flow, measured in Temperature cannot be negative.

Which unit is used to measure Log Mean Temperature Difference for Counter Current Flow?

Log Mean Temperature Difference for Counter Current Flow is usually measured using the Kelvin[K] for Temperature. Celsius[K], Fahrenheit[K], Rankine[K] are the few other units in which Log Mean Temperature Difference for Counter Current Flow can be measured.

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Log Mean Temperature Difference for Counter Current Flow Formula

​GoLog Mean Temperature Difference for CoCurrent Flow Formula

Log Mean Temperature Difference for Counter Current Flow Example

Log Mean Temperature Difference for Counter Current Flow Solution

Log Mean Temperature Difference for Counter Current Flow Formula Elements

Other Formulas to find Log Mean Temperature Difference

Other formulas in Basics of Heat Transfer category

How to Evaluate Log Mean Temperature Difference for Counter Current Flow?

FAQs on Log Mean Temperature Difference for Counter Current Flow

Variable Name

GoLog Mean Temperature Difference for CoCurrent Flow Formula