TEMA Type E Heat Exchanger Design

This Excel spreadsheet helps you design a TEMA Type E heat exchanger. The spreadsheet uses the Bell-Delaware method to calculate the overall heat transfer coefficient and the shell-side pressure drop.

TEMA Type E heat exchangers are the basis of many other designs. They offer a single pass, with liquid entry and exist on opposing sides of the shell

The spreadsheet allows you to pick from a triangle, square or rotated square tube placement, and specify the precise geometry of the shell, and then calculates the shell-side pressure drop and heat transfer coefficient accordingly.

The spreadsheet contains several empirical correlations, including those to calculate the Colburn J factor (used in determining the shell-side friction factor) and the pressure drop.

In the Bell-Delaware method, the shell-side heat transfer coefficient is the ideal heat transfer coefficient for cross-flow across a tube bank, multiplied by several correction factors as follows

The correction factors adjust the ideal heat transfer coefficient for leakage effects, bundle bypass, baffle spacing, and baffle cut. The correction factors are all calculated inside the spreadsheet for your convenience. The product of all the correction factors are equal to about 0.6 for an efficiently designed heat exchanger.

The spreadsheet is easy to use. Simply enter the process parameters (i.e. flowrates, temperatures, etc) and the geometrical parameters (number of tube passes, shell dimensions etc) in the pink cells.  You will need to equalize heat transfer across the shell-side and tube-side streams by varying a process parameter (this is indicated inside the spreadsheet).

Temperature Dynamics of Heated Tanks Connected in Series

This Excel spreadsheet models the temperature dynamics of a feed stream heated in three tanks connected in series. Each tank has a heating coil at a fixed temperature, and it is assumed that each tank is perfectly mixed

The temperature dynamics are modeled by these three differential equations.

• M is the mass of liquid in each tank (kg)
• T0 is the temperature of the feed stream (K)
• T1(t), T2(t) and T3(t) are the temperatures in each tank
• Ts is the temperature of the heating coil
• W is the flowrate of the feed stream (kg s-1)
• Cp is the specific heat capacity of the feed stream (J kg-1 K-1)
• U is the overall heat transfer coefficient (W m-2 K-1)
• A is the heat transfer area (m2)
The three differential equations were solved analytically to give symbolic equations for the three temperatures T1(t), T2(t) and T3(t) . These  equations were then translated into Visual Basic and implemented in Excel.

The spreadsheet also gives the steady-state temperature Tn of the nth tank connected in series, as predicted by this equation.

Double Pipe Heat Exchanger

This Excel spreadsheet helps you design a double pipe heat exchanger (also known as a concentric tube heat exchanger). Double pipe heat exchangers are often used in the chemical, food processing and oil & gas industries. They have a particular advantage when close temperature approaches are needed or in high pressure applications.

The spreadsheet will give you important design parameters, such as the overall heat transfer area, the length required, pressure drops, fluid velocities and much more.  The spreadsheet uses the
• Gnielinski correlation for the heat transfer coefficient of the shell side and tube side fluids (hh and hc). The Gnielinski correlation is valid for 0.5 ≤ Pr ≤ 2000 and 2300 ≤ Re ≤ 56.It gives the heat transfer coefficient in terms of the friction factor, the Reynolds number and the Prandtl number.
• Filonenko correlation for the friction factor (valid for smooth pipes in turbulent flow with 104 ≤ Re ≤ 107).
The equations for the heat transfer coefficients, the friction factor, the length of the heat exchanger and the overall heat transfer coefficient are given below

 Double Pipe Heat Exchanger Equations

• Nu is the Nusselt Number
• Re is the Reynolds Number
• f is the friction factor
• Q is the rate of heat transfer (determined from a heat balance)
• dic is the internal diameter of the inner pipe
• doc is the external diameter of the inner pipe
• kp is the thermal conductivity of the pipe material
• hc is the heat transfer coefficient of the cold fluid (in the inner pipe)
• hh is the heat transfer coefficient of the hot fluid (in the outer pipe)
• ΔTLMTD is the log mean temperature difference
The Excel spreadsheet uses variable names in the formulas to help you better understand the equations. Generally, the suffixes h and c represents quantities defined for the hot and cold streams respectively (e.g. hh is the heat transfer coefficient for the hot stream, hc is the heat transfer coefficient for the cold stream)

 Named variables

INSTRUCTIONS

Step 1. Enter your parameters. The spreadsheet will calculate initial values of the heat transfer coefficients, the rate of heat transfer across both fluids, and the length of the heat exchanger. Provide an initial guess for the parameter (i.e. mass flowrate) you will change in Step 2.

Step 2. Equalize heat transfer across both streams. The rate of heat transfer across the shell side and tube side fluids must be the same. You must use Goal Seek to make the difference between the two rates of heat transfer equal to zero by changing a design parameter (e.g. mass flowrates)

 Goal Seek

You have now established important design parameters, such as the fluid velocities, the tube-side and shell-side pressure drops, Prandtl numbers, the length of the heat exchanger and so on.

 Intermediate Calculations and Results

Find Orifice Diameter for Specific Operating Parameters

These Excel spreadsheets will help you find the orifice size for an orifice flow meter, given various design parameters like the desired pressure drop, fluid properties etc. All the spreadsheets use industry-standard designs, such as ISO 5167 and ASME MFC-14M-2001

First, decide what type of orifice you're designing and download the appropriate Excel Spreadsheet (read the articles for the equations and valid operating conditions)

I'll illustrate the calculation process with an example problem (but the principles are the same for the other spreadsheets). All the spreadsheets require Excel's Goal Seek functionality because the calculations are iterative.

We will now find the orifice diameter for a small-bore liquid flow meter under the following conditions
• Pipe diameter: 0.042m
• Density: 1000 kg m -3
• Viscosity: 0.001 Pa s
• Desired pressure drop: 30 Pa
• Flange taps
Step 1: Define the parameters as specified above, and also include an initial guess value for the orifice diameter.

Step 2: Go to Data > What If Analysis > Goal Seek. Set the difference in the guess and calculated values of the Reynolds number to zero by varying the orifice diameter.

As soon as you click OK, Excel will give the correct orifice size, as well as other parameters, like the flowrate, orifice coefficients, Reynolds Numbers etc.

Small-Bore Gas Orifice Meter Flow Calculator

This Excel spreadsheet calculates the flowrate from a small-bore gas orifice meter using the ASME MFC-14M-2001 standard. This calculator is valid for pipe diameters of less than 40 mm (other restrictions are given below).

The equations are as follows

• C is the discharge coefficient. D1 has to be supplied in m
• D1 and D2 are the diameter of the pipe and orifice respectively (m)
• A1 and A2 are the cross sectional areas of the pipe and orifice (m2)
• ΔP is the pressure drop across the orifice (Pa)
• P1 and Pstd are the upstream pressure and standard pressure
• T and Tstd are the gas temperature and standard temperature is the
• ρ is the gas (kg m-3)
• μ is the gas viscosity (Pa s)
• V1 is the liquid velocity in the pipe (m s-1)
• Re1 is the Reynolds Number in the pipe
• β is the diameter ratio
• MW is the molecular weight of the gas (kg mol-1)
• R is the universal gas constant (8314 J kmol-1 K-1)
• γ is the specific heat ratio
• e is the gas expansivity
• Q is the volumetric flowrate (m3s-1)
• Qstd is the volumetric flowrate at standard conditions (m3s-1)
The spreadsheet uses the ideal gas law to calculate the gas density (you just have to supply the molecular weight, pressure and temperature of the gas).

Note these restrictions to the validity of the equations
• Corner Taps: 0.1 < β < 0.8 and 12 mm < D< 40 mm
• Flange Taps: 0.15 < β < 0.7 and 25 mm < D< 40 mm
• D2 > 6 mm
• Re >1000
Additionally, the discharge coefficients are only valid for the tap configurations illustrated below (as specified by the ASME MFC-14M-2001 standard).

You can choose either Corner or Flange taps with a drop-down menu in the spreadsheet, and Excel automatically uses the correct correlation for the discharge coefficient.

These equations (like nearly all orifice flow meter calculations) require an iterative solution. This is easily done with Excel's Goal Seek.  All you have to do is click a button.

Goal Seek uses an initial guess value for the Reynolds Number to calculate the discharge coefficients, and uses this to calculate the flowrate. The calculated flowrate is then used to calculate the Reynolds Number.  Goal Seek then automatically adjusts the guess and calculated values of the Reynolds number until they are the same.

Small-Bore Liquid Orifice Flow Meter Calculator for Excel

This Excel spreadsheet calculates the liquid flowrate from a small-bore orifice meter using the equations defined in ASME MFC-14M-2001. The calculation is iterative, but the spreadsheet is conveniently set up to use Excel's Goal Seek functionality by simply clicking a button.

The equations implemented in the spreadsheet are sourced from ASME MFC-14M-2001 and are given below.

The notation is given below.
• C is the discharge coefficient. D1 must be supplied in m.  The equation differs for flange taps and corner taps, but a menu in the spreadsheet allows you to pick between the two.
• D1 and D2 are the diameter of the pipe and orifice respectively (m)
• A1 and A2 are the cross sectional areas of the pipe and orifice (m2)
• ΔP is the pressure drop across the orifice (Pa)
• ρ is the density of the liquid (kg m-3)
• V1 is the liquid velocity in the pipe(m s-1)
• Re1 is the Reynolds Number in the pipe
• β is the diameter ratio
• μ is the liquid viscosity (Pa s)
• Q is the volumetric flowrate (m3s-1)
The correlations for the Flange Taps and Corner Taps discharge coefficient are only valid for the following configurations.

The equations are only valid under the following conditions
• Corner Taps: 0.1 < β < 0.8
• Flange Taps: 0.15 < β < 0.7
• 25 mm < D1 < 50 mm
• 6 mm < D2
• Re > 1000
A β of between 0.3 and 0.7 is practical; below this, the pressure drop is too large for economical operation, and above this, the pressure drop is not large enough for an accurate reading.

The Excel spreadsheet will also calculate the static pressure loss and the head loss from a distance D1 upstream and 6 D1 downstream of the orifice.

The spreadsheet is free, and none of the cells are hidden, locked or password protected. Please visit this website regularly for more exclusive, professionally prepared Excel spreadsheets for engineering.