Thermalfluid Lab – MEC 554 / LSRC / SCA Rev. 01-2017
UNIVERSITI TEKNOLOGI MARA
FACULTY OF MECHANICAL ENGINEERING
Program
: Bachelor of Engineering (Hons.) Mechanical
Course
: Thermalfluids Lab
Course Code
: MEC 554
Lecturer/Tutor Name : PM DR. RAMLAN ZAILANI
Group
: EMD5M2B2
Lab Report
Experiment’s
Tittle
CONCENTRIC TUBE HEAT EXCHANGER
Bil
Student Name
Student ID
1.
Ahmad Syamil Bin Shahruddin
2019654456
2.
Akmal Syazli Bin A’Aziyuddin
2019689028
3.
Alif Ikhwan Bin Khairunnizam
2019452212
4.
Alisa Afzan Binti Mohd Rasani
2019695932
Lab Session
: 7 December 2020
(Date)
Submission of Report : 13 December 2020
(Date)
Approved by:
Received by:
Assessment Rubric: Technical Content. 60 marks
Scale
1
Criteria
Poor
1. Introduction
(10 marks)
•
•
2. Experimental
Procedure
(10 marks)
•
•
3. Data / result and
Sample Calculation
(20 marks)
•
4. Discussion and
Conclusion
(20 marks)
•
•
2
3
4
5
Acceptable
Unable to generate a complete
theoretical formula i.e. only
writing the final formula.
Make many errors in
applications of engineering
principles and concepts.
•
Unable to produce and
appropriate procedure to run
the experiment.
Having no objective(s).
Would not allow experiment
to achieve any goals.
•
Unable to present
experimental result using
appropriate tables, charts,
graphs or other presentation
formats.
Unable to relate theoretical
analysis with experimental
result and their practical
implication.
Unable to come out a clear
and understandable
conclusion.
•
•
•
•
•
Excellent
Adequately generate theoretical
formula with small errors.
Make some but tolerable errors
in applications of engineering
principles and concepts.
•
Adequately produce an
appropriate procedure to run
the experiment i.e. missing
steps in procedure.
Having objective(s). Would
allow experiment to achieve
most goals.
Adequately present
experimental result using
appropriate tables, charts,
graphs or other presentation
formats.
Adequately relate theoretical
analysis with experimental
result and their practical
implication.
Conclusion is not clear, but
yet, understandable in such
manner.
•
•
•
Student capable to generate a
complete theoretical formula
from the beginning.
All
relevant
engineering
principles and concepts are
accurately and comprehensively
demonstrated and applied.
Student capable to produce a
detailed procedure to run the
experiment.
Objective clearly defined. Would
allow experiments to achieve
goals.
•
Students capable to articulate
experimental result using
appropriate tables, charts, graphs
or other presentation formats.
•
Students capable to relate
theoretical analysis with
experimental result and their
practical implication. Student
capable to express a clear
and concise conclusion.
•
Assessment Rubric: Writing Performance Level. 20 marks
Scale
1
Criteria
Poor
2
3
4
5
Acceptable
Excellent
1. Structure
(5marks)
•
Paragraphs are poorly
organized; use of sections is
illogical and hinders
document navigation.
•
Paragraphs are usually well
organized; use of sections is
logical and generally allows
easy document navigation.
•
All paragraphs are well
organized; use of sections is
logical and allows easy
navigation through the document.
2. Graphics, figures,
tables and equations.
(5marks)
•
Figures, tables and equations
are not clearly or logically
identified and fail to support
the text.
•
Some figures, tables and
equations are logically
identified and adequately
support the text.
•
All figures, tables and equations
are clearly and logically
identified and strongly support
the text.
3. Mechanics
(5marks)
•
Sentences are poorly written;
numerous incorrect word
choices and errors in
grammar, punctuation and
spelling.
•
Sentences are generally well
written; a few incorrect word
choices and errors in grammar,
punctuation and spelling.
•
Sentences are well written; there
are no incorrect word choices
and the text is free of errors in
grammar, punctuation and
spelling.
4. Formatting and
references (5marks)
•
Report is formatted poorly
and lacks a quality cover
page and index.
Fails to correctly report any
sources or to utilize
appropriate citation forms.
•
Formatting of the report is
genarally consistent and
adequate,includes a quality
cover page and index. Most
sources are correctly
reported; appropriate citation
forms are genarally utilized.
•
Formatting of the report is
professional and includes a
professional cover page and
index.
All sources are correctly
reported; appropriate citation
forms are utilized thoughout.
•
•
•
FACULTY OF MECHANICAL ENGINEERING
UNIVERSITI TEKNOLOGI MARA
40450 SHAH ALAM
SELANGOR DARUL EHSAN
Tel: 03-55435190 Fax: 03-55435160
_
_
REPORT ASSESSMENT FORM
Experiment’s Title:
_
CONCENTRIC TUBE HEAT EXCHANGER
Prepared by:
_
Bil
Name
1. Ahmad Syamil Bin Shahruddin
2. Akmal Syazli Bin A’Aziyuddin
3. Alif Ikhwan Bin Khairunnizam
4. Alisa Afzan Binti Mohd Rasani
No Technical Report
1 Introduction
2
3
4
Experimental
Procedures
Data/result/sample of
calculation
Discussion and
Conclusion
No Writing Performance
1 Structure
2
3
4
Graphics/Figures/Tabl
es
Mechanics
Formatting and
references
Course
Outcome
Matrix No
2019654456
2019689028
2019452212
2019695932
Assessment
FULL MARK
CO2
10
C02
10
CO2
20
CO2
20
TOTAL
60
Course
Outcome
GIVEN MARK
/60
Assessment
FULL MARK
GIVEN MARK
CO3
5
C03
5
CO3
5
CO3
5
TOTAL
20
/20
80
/80
TOTAL MARKS
Table of Contents
1.0 INTRODUCTION ............................................................................................................ 2
2.0 OBJECTIVE ..................................................................................................................... 2
3.0 THEORY ........................................................................................................................... 2
4.0 APPARATUS .................................................................................................................... 3
5.0 PROCEDURE ................................................................................................................... 4
6.0 RESULT ............................................................................................................................ 6
7.0 DISSCUSSION AND CONCLUSION .......................................................................... 12
8.0 REFERENCES ............................................................................................................... 18
9.0 APPENDIX...................................................................................................................... 19
1.0
INTRODUCTION
Heat exchanger is a device which transfers heat from one medium to another, a
Hydraulic Oil Cooler or example will remove heat from hot oil by using cold water or air.
Alternatively, a Swimming Pool Heat Exchanger uses hot water from a boiler or solar heated
water circuit to heat the pool water. Heat is transferred by conduction through the exchanger
materials which separate the mediums being used. A shell and tube heat exchanger pass fluid s
through and over tubes, where as an air-cooled heat exchanger passes cool air through a core
of fins to cool a liquid.
Heat exchangers 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. Heat exchangers differ from mixing chambers in that they do not
allow the two fluids involved to mix. Heat transfer in a heat exchanger usually involve s
convection in each fluid and conduction through the wall separating the two fluids. In the
analysis of heat exchangers, it is convenient to work with an overall heat transfer coefficient U
that accounts for the contribution of all these effects on heat transfer. The rate of heat transfer
between the two fluids at a location in a heat exchanger depends on the magnitude of the
temperature difference at that location, which varies along the heat exchanger.
2.0
OBJECTIVE
Demonstrate the effect of flow rate variation on the performance characteristics of a
counter-flow concentric tube heat exchanger.
2
3.0
THEORY
The effect of various flow rate on the performance characteristic of counter and parallel flow
concentric tube heat exchanger can be find using these formulas.
Power Emitted = Vh ρh Cph ( Th,in – Th,out )
(Vh is the volumetric flow rate of the hot fluid)
Power Absorbed = Vc ρc Cpc ( Tc,out – Tc,in )
(Vc is the volumetric flow rate of the cold fluid)
Power Lost = Power Emitted – Power Absorbed
Logarithmic mean temperature difference (ΔTm):
ΔTm = (ΔT1 – ΔT2 ) / ln (ΔT1 /ΔT2 )
= [ (Th,in – Tc,out ) – (Th,out – Tc,in ) ] / ln [(Th,in – Tc,out ) / (Th,out -Tc,in )]
Overall efficiency (η)
η = (Power Absorbed / Power Emitted) × 100
Efficiency of the cold medium:
ηc = (Tc,out – Tc,in ) / (Th,in – Tc,in ) × 100
Efficiency of the hot medium :
ηh = (Th,in – Tc,out ) / (Th,out -Tc,in ) × 100
Mean temperature efficiency :
ηmean = ( ηc + ηh ) / 2
Overall heat transfer coefficient (U):
U = Power Absorbed / As . ΔTm
3
4.0
APPARATUS
Apparatus that was used for this experiment:
i.
5.0
i.
Concentric Tube Heat Exchanger.
PROCEDURE
The hot water temperature has been set to between range of 55℃to 65℃by changing the dial
and the LED light was automatically off.
ii.
The volume flow rate of the hot water had been set to 1000𝑐𝑚 3 𝑚𝑖𝑛−1 by adjusting the valve.
iii.
The volume flowrate of the cold-water also had been set up to 2000𝑐𝑚 3 𝑚𝑖𝑛−1 by using the
valve.
iv.
The stopwatch had been started.
v.
All the temperature on the board had been recorded after 5 minutes.
vi.
Step ii. had been repeated by using different volume flow rate of hot water, 2000𝑐𝑚 3 𝑚𝑖𝑛−1,
3000𝑐𝑚3 𝑚𝑖𝑛−1 and 4000𝑐𝑚 3 𝑚𝑖𝑛−1 by using the valve while the cold-water volume
flowrate remains constant.
vii.
Parallel flow data had been recorded.
viii.
All the volumetric valve had been turned off.
4
Figure 1: Valve that were used to change the configuration
ix.
The valve on the board in Figure X had been configured to counter flow configuration.
x.
Step i. until vi. had been repeated and the counter flow data had been recorded
xi.
Parallel flow data and the counter flow data had been tabulated and the heat transfer
coefficient had been calculated for each heat exchanger configuration.
5
6.0
RESULT
Hot water temperature: 64o C
Fixed cold water flow rate: 2000 cm3 /min
Additional info: Tube Specification
1. Heat transmission length: 1.5m
2. Heat transmission area: 0.067 m2
3. Tube outer diameter: 15 x 0.7 mm (thin-wall)
4. Shell outer diameter: 22 x 0.9 mm (thin-wall)
5. Insulation thickness: 20mm
Parallel flow
Hot water Hot water Hot water Hot water Cold water in, Cold water mid, Cold water
oC
oC
flow rate, in, o C
mid, o C
out, o C
out, o C
cm3 /min
1000
64
47
39
27
29
30
2000
64
48
41
27
30
31
3000
64
48
41
27
30
32
4000
64
49
42
27
31
33
6
Counter flow
Hot water Hot water Hot water Hot water Cold water Cold water mid, Cold water
oC
flow rate, in, o C
mid, o C
out, o C
in, o C
out, o C
cm3/min
1000
64
47
39
27
29
31
2000
64
50
42
27
31
34
3000
64
51
43
28
32
35
4000
64
50
43
28
32
35
Sample Calculation
-
Assume for 1000 cm3 /min hot water volumetric flow rate.
Refer table A-2 Boiling and Freezing Point Properties for liquid properties.
7
Parallel flow
Interpolate to find 𝜌𝑐and𝜌ℎ,
8
9
10
Hot wate r Power
flow rate
Emitted
(cm3 /min)
(W)
Power
Absorbed
(W)
Power
Lost
ΔT1
ΔT2
ΔTm
U
(%)
(˚C)
(˚C)
(˚C)
W/(m2 .˚C)
Efficiency
η
(W)
1000
1709
416.8
1292.2 24.39
37
9
19.81
314.03
2000
3147.1
555.3
2591.8 17.6
37
10
20.6
402.3
3000
4720.6
694.1
4026.5 14.7
37
9
19.8
523.2
4000
6020.5
832.9
5187.6 13.8
37
9
19.8
627.8
Power
Power
ΔT1
ΔT2
ΔTm
U
(%)
(˚C)
(˚C)
(˚C)
W/(m2 .˚C)
Counter Flow
Sample Calculation
“Same as Parallel Flow”
Hot wate r Power
flow rate
Emitted
(cm3 /min)
(W)
Absorbed
(W)
Lost
Efficiency
η
(W)
1000
1710.4
555.3
1155.1 32.5
33
12
20.8
398.5
2000
3010.3
971.7
2038.6 32.3
30
15
21.6
671.4
3000
4310.1
971.4
3338.7 22.5
29
15
21.2
683.9
4000
5746.9
971.4
4775.5 16.9
29
15
21.2
683.9
11
7.0 DISCUSSION
AND
CONCLUSION
AHMAD SYAMIL BIN SHAHRUDDIN
2019654456
DISCUSSION
By referring to the result that was calculated, it is shown that the counter flow is better
than parallel follow in factor of heat exchanger.
When the water flow rate increases from
1000cm3 /min to 4000cm3 /min, the power emitted by counter flow bit lower than parallel flow.
When looking in term of efficiency, counter flow has higher efficiency. For flow rate of
4000cm3 /min, counter efficiency is 16.9% mean while parallel flow is 13.8%. This is because
counter flow make use every power that is emitted so the power loss will be reduced.
When looking into heat transfer coefficient, counter flow has larger value than the
parallel flow. This is because, logarithmic mean temperature difference counter flow ranged
between 20.8℃ to 21.6℃ meanwhile for parallel flow ranged between 19.8℃ to 20.6℃.
There are some errors that can be found during this experiment and will affects the
recorded result. Systematic is one of the error that is found where this error comes from the
equipment itself. In order to prevent and reduce this error, scheduled maintenance must be done
for the equipment. In addition, other errors is human error. This is because this error happens
when trying to read the level of volume flow of water into desired value. In order to reduce this
error, the eyes must be perpendicular to the measurement level.
CONCLUSION
For the conclusion based on the result, when volume flow rate increase, the power
emitted and absorbed for each flow increase too. Next, counter flow is the best option for heat
exchanging mechanism because it has higher efficiency than parallel flow. In addition, the heat
transfer coefficient changes when the volume flow rate increase. After that, when choosing a
flow that will be used for heat exchange, counter flow is the most suitable option because it
has better performance than parallel flow. For the recommendation, other type of flow may be
observed and compared between parallel and counter flow to see which flow is better in term
of efficiency, and heat transfer coefficient.
13
AKMAL SYAZLI BIN A’AZIYUDDIN
2019689028
DISCUSSION
Based on the outcome, the counter flow can be shown to have a greater heat exchanger
factor compared to the parallel flow. As the volumetric flow rate rises from 1000 to 4000, the
power emitted by the counter flow can be shown to be less than the parallel power. The overall
power emitted is 5746.9W for the counter flow, while the power emitted for parallel flow is
greater than the counter flow of 6020.5W. Meanwhile in terms of power consumed and power
lost, counter flow effectively makes use of any power emitted with each flow, making each
volumetric flow rate's power loss smaller than the parallel flow power lost. In manufactur ing,
saving more capital would ultimately be a top priority for both of them, so a commodity that
can use less intakes such as power or electricity will be chosen to conserve more cash while
having the good quality. So a counter flow is a safer alternative rather than parallel flow in this
experiment.
Meanwhile the average efficiency in counter flow is again more desirable. Compared
to parallel flow, counter flow has a higher efficiency, with the maximum measured average
efficiency being 32.5 percent for a counter flow and 24.39 percent for parallel flow. For both
parallel flow and counter flow, the efficiency is diminished linearly as the volumetric flow rate
is increased. A parallel flow has a lower value compared to a counter flow in terms of the
logarithmic mean temperature. The counter flow has a value of 20 to 21, while the logarithmic
mean temperature range is between 19 and 20 for parallel flow. In this case, a smaller value is
expected than a larger value, such that the total coefficient of heat transfer is greater depending
on the formula to obtain the coefficient of heat transfer; the logarithmic mean temperature is
divided by the power consumed to obtain the coefficient of heat transfer. The value of the
counter flow heat transfer coefficient is also greater than the parallel flow value. As the
volumetric flow rate is increased, the heat transfer coefficient increases linearly for all flows.
There may be a few variables that lead to the experiment's mistake, which is the
structural mistake and the individual mistake. Systematic error is an error created by the
computer itself while human error is caused by the human being himself.
So the
methodological mistake that resulted in this experiment is where the original flow temperature
is changed. During the parallel flow, the temperature tends to rise during the experiment, which
can affect the measured and determined results. Meanwhile when changing the volumetric flow
rate, human error is involved. It is perhaps very difficult to achieve the exact value since the
eyes will not be perpendicular to the scale.
14
AKMAL SYAZLI BIN A’AZIYUDDIN
2019689028
CONCLUSIONS
It can be stated on the results of the experiment that:
1) Increasing the volumetric flow rate would increase the power produced and
consumed by both counter flow and parallel flow, and will definitely influence either
of the volumetric flow rate and reduce the power lost.
2) The counter flow performance is greater than parallel flow, making the flow a safer
alternative for a heat exchanger device. In addition, the coefficient of heat transfer is
often altered as the volumetric flow rate is increased.
3) Overall, when it comes to making a decision with parallel flow, counter flow has a
greater heat exchanger efficiency factor.
Using another kind of flow that is in series, for recommendation, to compare the output factor
of the heat exchanger when adjusting the volumetric flow rate.
15
ALIF IKHWAN BIN KHAIRUNNIZAM
2019452212
DISCUSSION
From the result, it can be observed that the counter flow has a good performance of heat
exchanger factor comparing to parallel flow. When the volumetric flow rate is increase from
1000cm3/min to 4000cm3 /min it can be observed that the power emitted by the counter flow is
smaller than the parallel. For the parallel flow, the highest power emitted is 6020.5W while for
the power emitted for parallel flow is higher than counter flow which is 5746.9W. Next, in
term of power absorbed and power lost, basically counter flow make used of every power that
is emitted for each flow making the power loss of each of the volumetric flow rate to be lesser
than the power losses of parallel flow.
Therefore, the overall efficiency is much higher for counter flow compare to parallel
flow. Counter flow has a higher efficiency comparing to the parallel flow which the highes t
overall efficiency calculated is 32.5% for a counter flow and 24.39% for parallel flow. For
parallel flow, when the volumetric flow rate is increases, the efficiency is increases too. Then,
for counter flow, the efficiency of the system decreases when the volumetric flow rate in
increases. In term of the logarithmic mean temperature, a counter flow has a smaller difference
comparing to parallel flow. Counter flow has a range of 20℃ to 22℃ while for parallel flow
the range of the logarithmic mean temperature is between 19℃ until 21℃. In this experiment,
a small value is needed compare to a larger value so that the overall heat transfer coefficie nt
will be higher based on the formula to obtain the heat transfer coefficient. Lastly, the value for
the heat transfer coefficient for counter flow is greater than the parallel flow. The heat transfer
coefficient increased linearly for both of the flow when the volumetric flow rate is increased.
CONCLUSION
In conclusion, when the volumetric is increase, the power emitted and absorbed for both
counter flow and parallel flow will increase linearly. Then, the power lost for each of
volumetric flow rate will be decreases. Next, the efficiency of the counter flow is higher than
compare to the parallel flow. This shows counter flow is the most suitable option for the heat
exchanger system. After that, the heat transfer coefficient is affected when the volumetric flow
rate is increases. Lastly, we can see that counter flow has a great performance factor compare
to the parallel flow in the heat exchanger system.
16
ALISA AFZAN BINTI MOHD RASANI
2019695932
DISCUSSION
According to result that had been obtained, it shows that counter flow heat exchanger
is better than parallel flow heat exchanger. The value of volumetric flow rate increase from
1000cm3 /min to 4000cm3 /min showing that power emitted by the counter flow heat exchanger
is lower than parallel flow heat exchanger. When the value of volumetric flow rate is
4000cm3 /min for the counter flow heat exchanger the value of power emitted is 5746.9W.
Meanwhile the power absorbed is 9710.4W and its efficiency is 16.9% higher than parallel
flow heat exchanger efficiency, 13.8%. This is because counter flow heat exchanger uses all
power that is emitted and results to decrease of total power lost. The logarithmic mean
temperature for counter flow heat exchanger is higher compare to parallel flow heat exchanger
which is between 20.8℃ to 21.6℃ while for parallel flow is 19.8℃ to 20.6℃. In this case
there are a few reasons for errors occur in this experiment. First error is systematic error that
caused by the equipment when the initial temperature of the flow is adjusted. Second the error
that caused by the person who execute the experiment which is the human error when adjusting
the volumetric flow rate. This is because it is quite hard to read the exact value as the eye might
not be perpendicular to the scale.
CONCLUSION
For the conclusion, it can conclude that, the value of power emitted and also power
absorbed depend on the value of volumetric flow rate. When the value of volumetric flow rate
for both type of heat exchanger increases the value of power emitted and absorbed also
increase. The efficiency for counter flow heat exchanger is bigger compare to parallel flow
heat exchanger. So counter flow heat exchanger is the best option for a heat exchanger system
compare to parallel flow heat exchanger. Besides counter flow heat exchanger also has a batter
heat exchanger performance factor compare to parallel flow heat exchanger.
recommended to use series type of flow for heat exchanger.
17
It is
8.0
REFERENCES
1) Chris, W. (2016, November 12). How do heat exchangers work? Retrieved October
30, 2017, from http://www.explainthatstuff.com/how-heat-exchangers-work.html
2) Dam, G. (n.d.). HEAT TRANSFER - PRINCIPLES & EQUIPMENT - FACTORS
AFFECTING HEAT TRANSFER. Retrieved October 30, 2017, from
http://articles.compressionjobs.com/articles/oilfield-101/1856-heat-exchangersboilers-furnaces?start=8
3) Heat Exchanger Flow: Cross flow, Parallel flow, Counter Flow Heat Exchangers.
(2010, January 28). Retrieved October 30, 2017, from
http://www.brighthubengineering.com/hvac/62410- heat-exchanger-flow-patterns/
4) Parallel Heat Flow Exchanger. (n.d.). Retrieved October 30, 2017, from
https://www.brazetek.com/articles/112-parallel- flow-heat-exchangers
5) What is a Heat Exchanger? (n.d.). Retrieved October 30, 2017, from
http://www.thermex.co.uk/news/blog/160-what-is-a-heat-exchanger
6) What is a Heat Exchanger? (n.d.). Retrieved October 30, 2017, from
http://www.thermex.co.uk/news/blog/605-why-counter- flow-heat-exchangers-aremore-efficient
9.0 APPENDIX
Figure 1: Valve that were used to change the configuration
Figure 2: Concentric Tube Exchanger