Diploma project report

DOUBLE PIPE HEAT EXCHANGER 2017
SLIET,LONGOWAL 1
SANTLONGOWALINSTITUTEOF ENGINEERING&
TECHNOLOGY,LONGOWALSANGRUR(PUNJAB)
PROJECT REPORT
ON
DOUBLE PIPE HEAT-EXCHANGER
GUIDED BY: - SUBMITTED BY: -
Dr. H.R GHATAK RAJNIKANT (SL/14/0003)
PROFESSOR PANKAJ KUMAR (SL/14/0682)
[DEPT. OF CHEMICAL TECH.
SLIET, LONGOWAL,PUNJAB]

SLIET,LONGOWAL 2
DOUBLE PIPE HEAT EXCHANGER

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ACKNOWLEDGEMENT
We would like to express profound gratitude and appreciation to our
project guide Dr. H.R GHATAK and our project in-charge Dr. AMIT
RAY for his invaluable support, encouragement, supervision and useful
suggestions throughout the project work. His moral support and
continuous guidance enabled us to overcome our dough and complete
our work successfully
We are grateful for the cooperation and constant encouragement
from our honorable Head of Department of chemical technology Mr.
S.M. Ahuja. His regular suggestions made our work easy and proficient.
Last but not least, I am thankful and indebted to all the faculty
members of chemical department and friends who helped us directly or
indirectly in completion of this project.
Thanks to all

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ABSTRACT
A heat exchanger may be defined as equipment which transfers the
energy from a hot fluid to a cold fluid, with maximum rate and
minimum investment and running cost. The rate of transfer of heat
depends on the conductivity of the dividing wall and convective heat
transfer coefficient between the wall and fluids. They are commonly
used in practice in a wide range of applications, from heating and air-
conditioning systems in a household, to chemical processing and power
production in large plants.
This project aims to construct the most common type of heat exchanger
“DOUBLE PIPE HEAT EXCHANGER”.

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CERTIFICATION
SANT LONGOWAL INSTITUTE OF
ENGINEERING & TECHNOLOGY
This is to certify that work presented in the project titled ‘DESIGN OF
DOUBLE PIPE HEAT EXCHANGER’ submitted to the department of
Chemical Technology of SLIET is an authentic record of our own work
carried out during the period of 6th semester under supervision of project
guide Dr. H.R GHATAK, Department of Chemical Technology, SLIET.
RAJNI KANT (DCT/1411003) …………….
PANKAJ KUMAR (DCT/1411045) .…………....
………………………… ……………………….
(Sign. Of Project In-charge) (Sign. Of Project Guide)
…………………………….
(Sign. Of H.O.D.)

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CONTENTS
Ch. no Title
1. INTRODUCTION
1.1 Definition of heat transfer.
1.2 Various modes of heat transfer.
1.3 Heat exchanger.
1.4 Classification of heat exchangers.
2. INTRODUCTION ABOUT DOUBLE PIPE HEAT
EXCHANGER
2.1 Double Pipe Heat Exchanger Design
2.2 Introduction
2.3 General configuration and characteristics of double pipe
2.4 Counter flow and parallel flow in a double pipe exchanger.
3. OBJECTIVE
3.1 LMTD
3.2 EFFICIENCY
3.2 OVERALL HEAT TRANSFER AREA
4. EQUIPMENTS AND THEIR SPECIFICATION
5. WORKING PROCEDURE OF DOUBLE PIPE HEAT
EXCHANGER
5.1 Experimental setup
5.2 Procedure
5.3 calculation

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6. Advantages, Disadvantage and Application
CONCLUSION
REFERENCE
CHAPTER-1
INTRODUCTION

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1.1 HEAT TRANSFER
Heat transfer, also referred to simply as heat, is the movement of thermal
energy from one thing to another thing of different temperature. These
objects could be two solids, a solid and a liquid or gas, or even within a
liquid or gas. There are three different ways the heat can transfer:
conduction (through direct contact), convection (through fluid
movement), or radiation (through electromagnetic waves). Heat transfer
occurs when the temperatures of objects are not equal to each other and
refers to how this difference is changed to an equilibrium state.
Thermodynamics then deals with things that are in the equilibrium state.
OR
Simply we can say heat transfer is energy transfer due to temperature
difference.
OR
Temperature represents the amount of thermal energy available with the
molecules of substances.
HEAT FLUX
Heat flux or thermal flux is the rate of heat energy transfer through a
given surface per unit time. The SI derived unit of heat rate is joule per
second, or watt. Heat flux density is the heat rate per unit area.
In SI units, heat flux density is measured in [W/m2]. The dimensional
unit is [MT -3].heat rate is a scalar quantity, while heat flux is

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a Victoria quantity. To define the heat flux at a certain point in space,
one takes the limiting case where the size of the surface becomes
infinitesimally small.
1.2 VARIOUS HEAT TRANSFER MODES: -
There are three types of heat transfer modes
1. Convection
2. Conduction
3. Radiation
1. CONVECTION
Convection is a transfer of heat energy between a solid surface and
the nearby liquid or gas in motion.
The presence of bulk motion
fluid is necessary.
2. CONDUCTION
Conduction refers to the heat transfer that occurs across the
medium.
Medium can be solid be or fluid and heat occurring through the
matter without bulk motion of the matter
3. RADIATION

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Radiation takes places intervening. There is net heat transfer
between two surfaces at different temperature
HEAT EXCHANGER
A heat exchanger may be defined as equipment which transfers
the energy from a hot fluid to a cold fluid, with maximum rate and
minimum investment and running cost. The rate of transfer of heat
depends on the conductivity of the dividing wall and convective
heat transfer coefficient between the wall and fluids. The heat
transfer rate also varies depending on the boundary conditions such
as adiabatic or insulated wall conditions.
1.4 CLASSIFICATION OF HEAT EXCHANGER
HEAT EXCHANGER
Recuperators Regenerators
Direct contact type Indirect contact type Fixed-matrix regenerator Rotary regenerator
Tabular Plate Extended surface Drum Type
Double Pipe Gasketed plate Plate fin Disk Type
Spiral Tube Spiral plate Tube fin

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Shell &Tube Lamella
CHAPTER-2
INTRODUCTION ABOUT DOUBLE PIPE
HEAT EXCHANGE

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1.1 INTRODUCTION
In double pipe heat exchanger design, an important factor is the type of
flow pattern in the heat exchanger. A double pipe heat exchanger will
typically be either counter flow or parallel flow. Cross flow just doesn't
work for a double pipe heat exchanger. The flow pattern and the
required heat exchange duty allow calculation of the log mean
temperature difference. That together with an estimated overall heat
transfer coefficient allows calculation of the required heat transfer
surface area. Then pipe sizes, pipe lengths and number of bends can be
determined.
1.2 Double Pipe Heat Exchanger Design
Double pipe heat exchanger design is rather straightforward. It uses one
heat exchanger pipe inside another. After determining the required heat
exchanger surface area, for either counter flow or parallel flow, the pipe
sizes and number of bends for the double pipe heat exchanger can be
selected.

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1.3 GENERAL CONFIGURATION AND
CHARACTE RISTICS OF A DOUBLE PIPE
A double pipe heat exchanger, in its simplest form is just one pipe inside
another larger pipe. One fluid flows through the inside pipe and the other
flows through the annulus between the two pipes. The wall of the inner
pipe is the heat transfer surface. The pipes are usually doubled back
multiple times as shown in the diagram at the left, in order to make the
overall unit more compact.
The term 'hairpin heat exchanger' is also used for a heat exchanger of the
configuration in the diagram. A hairpin heat exchanger may have only
one inside pipe, or it may have multiple inside tubes, but it will always
have the doubling back feature shown. Some heat exchanger
manufacturers advertise the availability of finned tubes in a hairpin or
double pipe heat exchanger. These would always be longitudinal fins,
rather than the more common radial fins used in a cross flow finned tube
heat exchanger.
2.4 Counter flow and Parallel Flow in a Double Pipe Heat
Exchanger
A primary advantage of a hairpin or double pipe heat exchanger is that it
can be operated in a true counter flow pattern, which is the most
efficient flow pattern. That is, it will give the highest overall heat
Transfer coefficient for the double pipe heat exchanger design.

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Double pipe heat exchangers can handle high pressures and temperatures
well. When they are operating in true counter flow, they can operate
with a temperature cross, that is, where the cold side outlet temperature
is higher than the hot side outlet temperature.
For example, in the diagrams in this section, consider Fluid 2to be the
hot fluid and Fluid 1 to be the cold fluid. Then, in the counter flow
diagram at the left, you can see that the cold side outlet temperature,
T2out, can approach the hot side entering temperature, T1in, which is

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higher than the hot side outlet temperature, T2out. For the parallel flow
shown at the right, T2out can only approach T1out; it could not be greater.
CHAPTER-3
OBJECTIVE

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LMTD (LOG MEAN TEMPERATURE DIFFRANCE)
The logarithmic mean temperature difference (also known
as log mean temperature difference or simply by
its initialize LMTD) 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 feeds at
each end of the double pipe exchanger. The larger the LMTD,
the more heat is transferred. The use of the LMTD arises
straightforwardly from the analysis of a heat exchanger with
constant flow rate and fluid thermal properties.
We assume that a generic heat exchanger has two ends
(which we call "A" and "B") at which the hot and cold
streams enter or exit on either side; then, the LMTD is
defined by the logarithmicmean as follows
LMTD= ∆ TA - ∆ TB
Ln (∆TA ∕ ∆TB)
OVERALL HEAT TRANSFER AREA= 𝝅𝒅𝒍

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Where
d: -diameter of inner pipe
l: -length of the inner pipe
EFFICIENCY
n𝟏 = 𝟏𝟎𝟎%
(𝐓𝟏 − 𝐓𝟐)
(𝐓𝟏 − 𝐭𝟐)
n𝟐 = 𝟏𝟎𝟎%
(𝐭𝟐 − 𝐭𝟏)
(𝐓𝟏 − 𝐭𝟐)
MEAN EFFICIENCY
nm=(n1+n2)/2

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CHAPTER-4
EQIPMENTS USE AND THERE
SPECIFICATION
A. PVC PIPE
We are using PVC pipe as
External pipe,
Length of pipe=60.96cm

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External diameter=11.13cm
B. ALUMINIUM PIPE
Aluminum pipe used
As an internal pipe or
Concentric pipe.
Length >60.96cm
External diameter =2.8cm
Internal diameter =2.6cm
We are using aluminum pipe
because of its better heat
conductivity as compares to iron.
C. MOTOR PUMP
Quantity =2pcs.
RPM=2800
Motor pump use to pumps
The water into the external
Pipe and internal pipe
D.CAPS
Quantity =2pcs
Caps are use at the both
Ends of heat exchanger

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E. BALL
Quantity=2pcs
Ball valve used at the outlet
of both of pipe.to control
the flow of heat exchanger

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CHAPTER-5
WORKING PROCEDURE OF DOUBLE
PIPE HEAT EXCHANGER

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Experimental Setup
The hot fluid is hot water, which is obtained from an electric
geyser. Cold water flows through the inner tube, in one
direction. Hot fluid is hot water, which flows through the
annulus. Control valves are provided so that direction of cold
water can be kept parallel or opposite to that of hot water. Thus,
the heat exchanger can be operated either as paralle1 or counter
flow heat exchanger. The temperatures are measured with
thermometer. Thus, the heat transfer rate, heat transfer
coefficient, LMTD and effectiveness of heat exchanger can be
calculated for both parallel and counter flow.
WORKING
First supply the electricity to the pump it would pumps the water
(hot & cold). when cold and hot water enters into the inner pipe and
outer pipe respectively. Hot water flows through the annular space
where as cold water flows through the internal pipe. because
internal pipe is made up of aluminum it will conduct some heat from
annular space hot water to internal pipe by the conduction.

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It results that an internal pipe water gains some heat form the
annular space water (which lose some temperature). And both fluids
get flash out through outlets.
PROCEDURE
i. First of all, connect the both inlets of exchanger to the motor
pumps & supply electricity.
ii. Initially measure the temperature of both (inlet & outlet)
iii. Keep the both valves opened so that arrangement in parallel
flow

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iv. Let the fluid flows through the pipes and then after 1 min. cut
the pumps supply.
v. After that take, the readings from outlets.
vi. Repeat the above procedure to get the better reading.
CALCULATION
Calculation for Logarithmic Mean Temperature Difference
(LMTD)
∆TLM =
∆𝑻𝟏−∆𝑻𝟐
𝐥𝐧[∆𝑻𝟏/∆𝑻𝟐 ]
T1= 55 T2=50°C
t1=31°C t2= 33 °C
∆T1 = 𝟓𝟓 − 𝟑𝟑 = 𝟐𝟐°𝐂 , ∆T2 = 𝟓𝟎 − 𝟑𝟏 = 𝟏𝟗°𝐂
∆TLM = 22-19
ln[𝟐𝟐/𝟏𝟗 ]
= 20.54°C
33°𝐂 COLD
OUT
50°𝐂 HOT
OUT

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CALCULATION FOR CORRECTION FACTOR
R =(T1 - T2 ) / (T2 - t1) P = (t2 - t1)/(T1-t1)
= (55-50) / (50-31) = (33-31) / (55-31)
= 0.26°C = 0.083°C
CORRECTION FACTOR
𝑭 = √𝑹𝟐 + 𝟏 ln (1-P 1-PR)
(R-1) ln [2-P {R+1- (√𝑹𝟐 + 𝟏)}]
[2-P {R+1+ (√𝑹𝟐 + 𝟏)}]
= √𝟎.𝟎𝟔 + 𝟏 (−𝟎.𝟎𝟔𝟒)
-0.74*0.114
= 0.083
0.084
55°𝐂
HOT IN
31°C
COLD IN
1
2

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F = 0.98
∆TM = F*∆TLM
= 0.98*20.54
= 20.12 ( CORRECTED LMTD)
Calculate efficiency, ῃ
n1 = 100%
(T1 − T2)
(T1 − t2)
n1 = 100%
(55 − 50)
(55 − 33)
= 29.41%
n2 = 100%
(t2 − t1)
(T1 − t2)
n2 = 100%
(33 − 31)
(55 − 33)
= 9.09%
MEAN OF EFFICIECNCY
nm = (n1 + n2)/2

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(29.41+9.09)/2
= 19.25%
Calculate heat transfer area, A
A= π*d0*l
= 3.14*0.028*0.609
= 0.053 m2

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CHAPTER-4
ADVANTAGES & DISADVANTAGES
OR APPLICATIONS OF DOUBLE PIPE
HEAT EXCHANGER
Advantages and Disadvantages
Advantages Disadvantages

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Suited to high pressure
applications.
Limited to low heat duties
requiring surface areas less than 47
m2
Standardization, simplifies
maintenance, servicing and
stocking of parts.
Flow pattern is strictly counter
flow; there is no cross flow.
Flexibility, units can be added or
removed as required.
As units are added on the
possibility of leakage increases
because of the number of
connections increases.
Modular type construction.
DoublePipe Heat Exchanger Applications:
 Because of compact size, it can be used in applications
where space limitation is present such as marine cooling
systems, cooling of lubrication oil, central cooling and
industrial applications.
 In HVACs, due to their compact structure and greater heat
transfer rate.
 Used in chemical reactors because of high heat transfer
capacity.

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 In cryogenic applications for liquefaction of gases.
 Used in hydro carbon processing for the recovery of CO2,
cooling of liquid hydrocarbons, also used in polymer
industries for cooling purposes.
 Pasteurization
 Digester heating
CONCLUSION
The fabricated heat exchanger is conducted for water to water heat
transfer application. Double pipe heat exchanger has been analyzed in
terms of temperature variation.
The readings (inlet outlets temperatures after the process) obtained from
the experimental investigation of heat exchanger operated in different
temperature are calculated & presented. The tube side flow (cold water
flow) is varied and same time annular side flow rate is maintained
constant to obtained the better heat transfer.
We have done above all process through both flow (counter & co-
current) and we see that LMTD is more efficient in counter current flow

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than co-current flow as experimentally proved that the counter flow heat
exchanger is more efficient than the parallel flow.
Efficiency obtained after calculation around 21% it may be increase by
the increase the process duration or to stay the hot water into the annular
space.
NOMENCLATURE
∆TLM :- LOG MEAN TEMPEATURE DIFFRANCE
T1:- Hot water inlet
T2:- Hot water outlet
t1:- cold water inlet
t2:- cold water outlet
F:- correction factor
R:-Ratio of fall in temperature hot fluid to rise in cold fluid
P:-Heating effectiveness
ῃ1:- annular pipe efficiency
ῃ𝟐:- internal pipe efficiency

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ῃm:- Mean efficiency
REFERANCE
 www.webbusterz.org
 www.google.com
 checalc.com/solved/doublePipe.html
 Double pipe heat exchanger Wikipedia
 Unit Operations of Chemical Engineering (McCabe smith)

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