Engineering Computer Systems Management

Lets shake hand if you are 100% sure

Engineering Computer Systems Management – 767425

Project #1
(Due date: Monday 19 August 2013)

The aim of this project is for you to discover how to use a spreadsheet to “model” a typical engineering
problem, in this case a heat transfer situation. And to discover how this model can be used to solve
problems that would otherwise require lengthy analytical or trial and error solutions.

The model can then
be used as a design/analysis tool to try out various “what if” scenarios.

Hot oil is used as an alternative to steam for providing process heat in some industries. In our scenario the
hot oil is being pumped to the process equipment through an insulated pipe and we want to determine the
rate of heat loss per metre of pipe. The pipe is made from mild steel and is insulated with fibreglass and
clad with stainless steel. Heat is being lost from the stainless steel cladding surface by convection and by

radiation. The initial problem is to determine the heat loss ̇ and cladding surface temperature for
various thicknesses of the fibreglass insulation.

Heat Transfer Situation:

The following data is given:

hot oil temperature, …………………………………………………… 180°C

steel pipe internal diameter,

…………………………………………….. 80 mm

steel pipe external diameter,
……………………………………………. 90 mm

pipe length, ……………………………………………………………………… nominal, 1 m

inside convection heat transfer coefficient, …………………………. 50 W/m

2
°C

steel pipe thermal conductivity, …………………………………….. 35 W/m°C

initial fibreglass insulation thicknesses ……………………………………. 25 mm

insulation thermal conductivity, ……………………………………… 0.039 W/m°C

stainless steel cladding thickness …………………………………………… 2.6 mm

stainless steel cladding thermal conductivity, …………………… 14 W/m°C

stainless steel emissivity,
………………………………………………. 0.2

outside convection heat transfer coefficient,
……………………… 18 W/m

2
°C

ambient/surrounding surface temperature, …………………….. 22°C

Relevant formulae:

̇ ̇ ̇ ̇

̇
( )

∑(
(

)

)

̇ ( ) ̇ (

)

stainless steel cladding

steel pipe

fibreglass insulation

𝑇
𝑇

𝑟

𝑟3

𝑟
𝑟

�̇�

�̇�

�̇�

�̇� 𝑇

At first glance this looks to be a relatively simple problem, however to solve it we need to find the surface

temperature, before we can find the heat loss, ̇ . To solve for analytically would require the
solution of a polynomial (quartic) equation. With the spreadsheet we can solve this fairly easily using a trial
and error approach or using one of the advanced tools available in Excel to automate this process…

Specific requirements:
You are required to:

 Set up a spreadsheet model of the heat transfer situation, using Microsoft Excel, as detailed below.

 Write a Report (Word document) with comments and results as also detailed below.

1. Spreadsheet Model
Set up your spreadsheet model of the heat transfer situation with an area for input values (all of the

data given above), an area for intermediate answers (eg radii, ̇ , ̇ , ̇ ), and an area for the

final results, and ̇ . Your model should be set up to be as flexible as possible to produce

answers for and ̇ for a given insulation thickness. (Imagine other engineers might use your
spreadsheet as a tool for similar heat loss situations, so make it clear, easy to use and helpful).

In your Report (Word document) :

 Explain how you set up the spreadsheet and what “advanced” functions or tools you used, and how

you used them to solve for s and ̇loss for a given insulation thickness.

 Provide a table summarising your results ( and ̇ ), for the following insulation thicknesses:
25 mm, 50 mm, 75 mm and 100 mm.

2. Further Analysis
Use your spreadsheet model to determine the thickness of insulation required to give a cladding
surface temperature of say 50°C.

In your Report (Word document) :

 Briefly explain how you used your model to do this.

 State the thickness of insulation required.

3. “What if” analysis
Set the insulation thickness to 75mm and then use your model to investigate the following “what if”

situations (ie what happens to surface temperature, and heat loss, ̇ if the following changes
occurred).

 What if the cladding emissivity changed to 0.4 or even 0.8 over a period of time as the stainless
steel became more oxidised?

 What if the insulation deteriorated over a period of time so that the thermal conductivity increased
to a value of say 0.06 or 0.1 W/m°C?

 What if the hot oil temperature increased to 250°C or decreased to 120°C?

 What if the stainless steel cladding was broken off?

 What if the temperature of the surroundings drops to 10°C or increases to 30°C?

 What if the outside convection heat transfer coefficient drops to 12 W/m
2
°C or increases to

50 W/m
2
°C.

 What if the inside convection heat transfer coefficient drops to 30 W/m
2
°C or increases to

100 W/m
2
°C

In your Report (Word document) :

 For each “what if” situation provide a table with original values and new values of and ̇ and
discuss whether or not you think the change is significant.

 Write a summary of your “What if” analysis ie discuss the main factors that affect the rate of heat
loss for an insulated hot oil pipe like this … (use your results from the above “What if” analysis).

4. Comments and Conclusion
In your Report add a Comments and Conclusions section and briefly comment on the following:

 The advantages/disadvantages of setting up a problem like this on a spreadsheet compared to
using a calculator and /or hand calculations.

 Could the spreadsheet you set up be used for other “what-if” scenarios?

 What are some of the dangers of setting up a problem like this on a spreadsheet, and other people
using it?

Note: Marks will also be awarded for layout (of spreadsheet model) and overall ease of use. Bonus
marks may be awarded for additional helpful features…

5. Submit the spreadsheet and supporting document for marking by 4:00 pm, Monday 19 August 2013,
using AUTonline. Instructions for doing this are provided below and in the Assessments area on
AUTonline for this paper.

Instructions: How to submit Project #1…..

1. Once you have completed Project #1, log on to AUTOnline and select this paper: Engineering

Computer Systems Management

2. Click the “Projects” button on the menu

3. Select “Project 1 – Excel Model”

4. Click this item:

5. In the section “2. Assignment Materials”…

 To attach your Project files (spreadsheet and word document), alongside “Attach File” click

the button and select your Project #1 spreadsheet that you are handing

in for marking, then click the button. This will attach the file ready for
submitting.

 Repeat the previous step and add your Project #1 Word document (Report) that you are
handing in for marking.

 If you make a mistake click the link (under “Attached files”) to remove the
incorrect file and then repeat the above steps to add the correct file(s).

 Enter a brief comment about your assignment if you wish…

6. Once you have attached the two files you are submitting for Project #1 then in section “3.

Submit”, click the button to submit the two files to your lecturer for marking.

7. Once you have submitted your Project you cannot resubmit it. If you have made an error or

mistake after you have clicked the button you will need to see your lecturer to reset
your Project #1 account.