Number of transfer units Calculator

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Heat exchanger

Basics of HMT

Conduction

Convection

Convective Mass Transfer

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Transverse Fin Heat Exchanger

✖The area is the amount of two-dimensional space taken up by an object.ⓘ Area [A]			+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%
✖Smaller value of mass flowrate of hot fluid * specific heat of hot fluid and mass flowrate of cold fluid * specific heat of cold fluid.ⓘ Smaller Value [C_min]			+10% -10%

✖The number of transfer units is defined as ratio of overall thermal conductance to smaller heat capacity rate. NTU designates non-dimensional heat transfer size or thermal size of the exchanger.ⓘ Number of transfer units [NTU]

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Formula

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Number of transfer units

Formula

`"NTU" = "A"*"U"/"C"_{"min"}`

Example

`"33.33333"="50m²"*"20W/m²*°C"/"30"`

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Number of transfer units Solution

STEP 0: Pre-Calculation Summary

Formula Used

Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value
NTU = A*U/C_min
This formula uses 4 Variables

Variables Used

Number of Transfer Units - The number of transfer units is defined as ratio of overall thermal conductance to smaller heat capacity rate. NTU designates non-dimensional heat transfer size or thermal size of the exchanger.
Area - (Measured in Square Meter) - The area is the amount of two-dimensional space taken up by an object.
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.
Smaller Value - Smaller value of mass flowrate of hot fluid * specific heat of hot fluid and mass flowrate of cold fluid * specific heat of cold fluid.

STEP 1: Convert Input(s) to Base Unit

Area: 50 Square Meter --> 50 Square Meter No Conversion Required
Overall Heat Transfer Coefficient: 20 Watt per Square Meter per Celcius --> 20 Watt per Square Meter per Kelvin (Check conversion here)
Smaller Value: 30 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

NTU = A*U/C_min --> 50*20/30

Evaluating ... ...

NTU = 33.3333333333333

STEP 3: Convert Result to Output's Unit

33.3333333333333 --> No Conversion Required

FINAL ANSWER

33.3333333333333 ≈ 33.33333 <-- Number of Transfer Units

(Calculation completed in 00.004 seconds)

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< 8 NTU Relations Calculators

NTU relation of heat exchanger with one shell pass and 2, 4, 6 tube pass

Go Number of Transfer Units = -((1+Heat capacity ratio^2)^-0.5)*(ln(((2/Effectiveness of Heat Exchanger)-1-Heat capacity ratio-((1+Heat capacity ratio^2)^-0.5)))/((2/Effectiveness of Heat Exchanger)-1-Heat capacity ratio+((1+Heat capacity ratio^2)^-0.5)))

NTU relation of double pipe counter flow heat exchanger

Go Number of Transfer Units = (1/(Heat capacity ratio-1))*(ln((Effectiveness of Heat Exchanger-1)/(Heat capacity ratio*Effectiveness of Heat Exchanger-1)))

NTU relation of double pipe counter flow heat exchanger with Cmax mixed and Cmin unmixed

Go Number of Transfer Units = -ln(1+(1/Heat capacity ratio)*(ln(1-Heat capacity ratio*Effectiveness of Heat Exchanger)))

NTU relation of double pipe counter flow heat exchanger with Cmax unmixed and Cmin mixed

Go Number of Transfer Units = (-1/Heat capacity ratio)*(1+(Heat capacity ratio*(ln(1-Effectiveness of Heat Exchanger))))

NTU relation of double pipe parallel flow heat exchanger

Go Number of Transfer Units = (-ln(1-(1+Heat capacity ratio)*Effectiveness of Heat Exchanger))/(1+Heat capacity ratio)

Number of transfer units

Go Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value

NTU relation of double pipe counter flow heat exchanger given C equal to 1

Go Number of Transfer Units = Effectiveness of Heat Exchanger/(1-Effectiveness of Heat Exchanger)

NTU relation of heat exchanger given all exchanger C equal to 0

Go Number of Transfer Units = -ln(1-Effectiveness of Heat Exchanger)

Number of transfer units Formula

Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value
NTU = A*U/C_min

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 Number of transfer units?

Number of transfer units calculator uses Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value to calculate the Number of Transfer Units, The Number of transfer units formula is defined as the amount of energy units transferred between the fluids in the heat exchanger. Number of Transfer Units is denoted by NTU symbol.

How to calculate Number of transfer units using this online calculator? To use this online calculator for Number of transfer units, enter Area (A), Overall Heat Transfer Coefficient (U) & Smaller Value (C_min) and hit the calculate button. Here is how the Number of transfer units calculation can be explained with given input values -> 33.33333 = 50*20/30.

FAQ

What is Number of transfer units?

The Number of transfer units formula is defined as the amount of energy units transferred between the fluids in the heat exchanger and is represented as NTU = A*U/C_min or Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value. The area is the amount of two-dimensional space taken up by an object, 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 & Smaller value of mass flowrate of hot fluid * specific heat of hot fluid and mass flowrate of cold fluid * specific heat of cold fluid.

How to calculate Number of transfer units?

The Number of transfer units formula is defined as the amount of energy units transferred between the fluids in the heat exchanger is calculated using Number of Transfer Units = Area*Overall Heat Transfer Coefficient/Smaller Value. To calculate Number of transfer units, you need Area (A), Overall Heat Transfer Coefficient (U) & Smaller Value (C_min). With our tool, you need to enter the respective value for Area, Overall Heat Transfer Coefficient & Smaller Value 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 Number of Transfer Units?

In this formula, Number of Transfer Units uses Area, Overall Heat Transfer Coefficient & Smaller Value. We can use 7 other way(s) to calculate the same, which is/are as follows -

Number of Transfer Units = (-ln(1-(1+Heat capacity ratio)*Effectiveness of Heat Exchanger))/(1+Heat capacity ratio)
Number of Transfer Units = (1/(Heat capacity ratio-1))*(ln((Effectiveness of Heat Exchanger-1)/(Heat capacity ratio*Effectiveness of Heat Exchanger-1)))
Number of Transfer Units = Effectiveness of Heat Exchanger/(1-Effectiveness of Heat Exchanger)
Number of Transfer Units = -ln(1+(1/Heat capacity ratio)*(ln(1-Heat capacity ratio*Effectiveness of Heat Exchanger)))
Number of Transfer Units = (-1/Heat capacity ratio)*(1+(Heat capacity ratio*(ln(1-Effectiveness of Heat Exchanger))))
Number of Transfer Units = -((1+Heat capacity ratio^2)^-0.5)*(ln(((2/Effectiveness of Heat Exchanger)-1-Heat capacity ratio-((1+Heat capacity ratio^2)^-0.5)))/((2/Effectiveness of Heat Exchanger)-1-Heat capacity ratio+((1+Heat capacity ratio^2)^-0.5)))
Number of Transfer Units = -ln(1-Effectiveness of Heat Exchanger)

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