## Shell & tube heat exchanger design

Shell and tube heat exchangers are very popular and commonly used heat transfer equipment in the process industry. This type of heat exchangers consists of metal tubes passing through another metal enclosure, which is referred to as the 'shell'.

There are many subtypes of shell and tube exchangers created by different configurations of the shell and tube arrangement. This versatility is one of the reasons why shell and tube exchangers are so popular among process design engineers.

Design of shell and tube exchangers is commonly governed by the standards created by TEMA (Tubular Exchangers Manufacturers Association).

## Shell & tube heat exchanger calculations

Normally, a process design engineer is responsible to create the process datasheet for a shell & tube exchanger, with details like - service, heat duty, utility, allowable pressure drop on shell & tube sides, operating and design T & P conditions and the type of shell and tube heat exchanger to be used.

To determine these design parameters, a few calculations must be performed for the shell and tube heat exchanger.

Here are some calculators, guidelines and calculators to help you with those shell & tube heat exchanger calculations.

## Equations for the shell & tube exchangers

Here is a list of important equations for the design calculations for a shell & tube heat exchanger.

## Calculators

As a general practice, the design of shell & tube heat exchanger is done in an iterative manner. In each iteration you need to calculate how the exchanger performs. Following calculators can help you with these heat exchanger sizing calculations.

*Note all of the following calculators are for demo. To access the actual working calculators, you will need to create a login on EnggCyclopedia.*

- Here's a shell & tube heat exchanger sizing calculator to help you calculate the required heat transfer area based on inlet/outlet temperature values on shell and tube sides.
**This calculator is for sizing the tubeside flow based on a fixed shell side flow**. Other required inputs are - flow rate, density, viscosity, specific heat values for fluids on shell and tube sides. - This other calculator for shell side flow will help you calculate the required surface area as well as the shell side flow,
**when you have fixed conditions on the tube side**. Other required inputs are - flow rate, density, viscosity, specific heat values for fluids on shell and tube sides. - This quick LMTD calculator helps to quickly get LMTD value for an exchanger.
- Then there is another calculator for LMTD correction factor.
- Apart from these, you will also need to calculate the pressure drop on the shell and tube sides for your process datasheet. This calculator is for shell side pressure drop calculation.
- You can use this calculator to determine tubeside pressure drop.

Apart from these calculators, you can always use a heat exchanger design software to build a model of your heat exchanger design and then to simulate its performance.

## Tutorials

Here are some step by step guided tutorials about how to use those calculators for shell & tube heat exchanger calculations.

- Calculation of overall heat transfer coefficient
- Calculation of insulation thickness for furnace wall
- LMTD calculation tutorial
- Calculating LMTD when the formula fails
- Tutorial - Heat Exchanger shellside pressure drop calculation
- Tutorial - Heat Exchanger tubeside pressure drop calculation

## Tips and pointers for shell & tube exchanger design

- The shell side baffles are used to promote crossflow and enhance the heat transfer between the two fluids. The spacing between shell side baffles has an important impact on the degree of heat transfer. You can use these guidelines to select the optimal shell side baffle spacing. It is generally recommended to consider baffle spacing between 0.3 to 0.6 times of shell ID, as per the TEMA standards.
- Heat exchanger approach temperature is an important factor influencing the design of an exchanger. It is advisable to carefully consider the selected utility and corresponding approach temperature, before actually proceeding with the sizing calculations.