Shell & Tube Heat Exchanger
Overview
The shell and tube heat exchanger is commonly used in the food and chemical process industries.
This type of exchanger consists of a number of tubes in parallel enclosed in a cylindrical shell.
Heat is transferred between one fluid flowing through the tubes and another fluid flowing
through the cylindrical shell around the tubes.
August 2020
In this miniature exchanger, baffles inside the shell increase the velocity of the fluid and hence
the rate of heat transfer. The exchanger has one shell and seven tubes with two transverse
baffles in the shell.
The exchanger is mounted on a PVC base plate which incorporates four holes, which locate it on
four studs at the left hand end of the HT30XC service unit. The PVC base plate is secured to the
service unit using thumb nuts. In normal operation the hot fluid from the hot water circulator
enters the header at one end of the shell and passes through the bundle of stainless steel tubes.
The cold fluid from the cold water supply passes through the cylindrical shell. This arrangement
minimises heat loss from the exchanger without the need for additional insulation and allows
the construction of the exchanger to be viewed.
A length of flexible tubing is attached to each fluid inlet/outlet, terminated with a ferrule. This
allows rapid connection to the appropriate fittings on the HT30XC service unit, and conversion
from concurrent (flows in same direction) to countercurrent (flows in the opposite direction)
operation. Besides, the temperature of hot flow and the flow rate can be changed. These
instructions were adapted from Shell and Tube Heat Exchanger Instruction Manual, available on
ILearn (Issue 3, 2013).
Objectives
• Observe the different behavior of a system under countercurrent to concurrent
operation;
• Draw graphs to visualize the relationship between:
o Flow rate and temperature (countercurrent) o
Flow rate and temperature (concurrent)
Relate the experiments to the theory learned in class;
.
Materials and Method
The students for a given tutorial session will be split into groups of 5, 6 or 7 students. Each
student has a task; each task contributed to the operation and success of the experiments. The
tasks are as follows:
1. To demonstrate indirect heating or cooling by transfer of heat from one fluid stream;
2. To perform an energy balance across a Shell and Tube Heat Exchanger and calculate the
Overall Efficiency at different fluid flowrates;
3.
To demonstrate the differences between concurrent flow and countercurrent flow and
the effect on heat transferred and temperature efficiencies;
4.
To determine the Overall Heat Transfer Coefficient for a Tubular Heat Exchanger using
the Logarithmic Mean Temperature Difference to perform the calculations (for
concurrent and countercurrent flow);/n5. To investigate the effect of changes in hot and cold fluid flowrate on the Temperature
Efficiencies and Overall Heat Transfer Coefficient.
Experiment A-Fluid to Fluid Heat Transfer in Concurrent flow
Turn on the apparatus heater and pump in concurrent flow. Set the cold water flow rate to 1
liter/min, set the tank temperature to 50 °C and wait until it goes to be stable. Then write down
the temperatures (T₁, T2, T₁, T₁,) every 30 secs for 3 mins via setting the hot flow rate of 3
liter/min, 2 liter/min, 1 liter/min.
Write down your results; Comment on the changes in temperature difference and when the
flow of how flow is increased; Calculate the overall efficiency; Calculate the temperature
efficiency; Calculate the LMTD temperature and overall heat transfer coefficient;
Table 1 Different temperatures when cold flow rate of 1 liter/min and Temp Hot In is 50°C
T₂
T₁
T₁
Sample
Hot flow Time T₁
rate (l/min)
(Sec)
1
1
1
1
1
1
1
2
2
2
2
2
2
2
3
3
3
3
3
3
3
0
30
60
90
120
150
180
0
30
60
90
120
150
180
0
30
60
90
120
150
180/n3
3
3
Table 2 Different temperatures when cold flow rate of 1 liter/min and Temp Hot In is 60°C
Sample
Hot flow
T₂
T₁
T₂
rate (l/min)
1
1
1
1
1
1
1
2
2
2
2
2
2
2
3
3
3
3
3
120
150
180
3
3
Time T₁
(Sec)
0
30
2
60
90
120
150
180
0
30
60
90
120
150
180
0
30
60
90
120
150
180/nExperiment B-Fluid to Fluid Heat Transfer in Countercurrent flow
Turn on the apparatus heater and pump in countercurrent flow. Set the cold water flow rate to
1 liter/min, set the tank temperature to 50 °C and wait until it goes to be stable. Then write down
the temperatures (T₁, T2, T3, T4,) every 30 secs for 3 mins via setting the hot flow rate of 3
liter/min, 2 liter/min, 1 liter/min.
Write down your results; Comment on the changes in temperature difference and when the flow
of hot flow is increased; Calculate the overall efficiency; Calculate the temperature efficiency;
Calculate the LMTD temperature and overall heat transfer coefficient (U);
Table 3 Different temperatures when cold flow rate of 1 liter/min and Temp Hot In is 50 °C
Sample
T₂
T₁
T₁
Hot flow Time T₁
rate (l/min) (Sec)
3
Table 4 Different temperatures when cold flow rate of 1 liter/min and Temp Hot In is 60°C
Sample
T₂
T₁
T₁
Hot flow Time T₁
rate (l/min) (Sec)/nLab Report
The lab report must contain a short and clear introduction (2) containing the fundamentals of
the experiments ran during this practical session, a schematic drawing (do not copy, make your
own) of the equipment used (2) and a brief description of the methodology (2), the tables and
graphs obtained from your results (2), a discussion of your results addressing the points made
throughout these guidelines (5), a conclusion based on your discussion (1) and the references
used in your work (1).
