ENGR 103 - Spring 2016
Freshman Engineering Design Lab
Freshman Engineering Design Lab
“Solar Water
Heating System”
Project Design
Proposal
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Date
Submitted: April 07, 2016
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Group
Members {Jonathan Altland, jsa65@drexel.edu}
{Pooja
Anantha, pa327@drexel.edu}
{Kerianne
Chen, kmc492@drexel.edu}
{Manyah
Kohli, mk3336@drexel.edu}
{Abigail
Martin, aem374@drexel.edu}
Technical
Advisor {John Speidel, speidel@drexel.edu}
Abstract:
Heat pipes are
used to transfer heat and energy to regulate temperatures. This project
utilizes solar energy and electricity to heat water. The goal of the project is
to design, test, and produce a heat pipe that will raise water temperatures to
prevent freezing in outdoor water storage units. Heat pipes will be extensively
researched to ensure that the system will match or surpass the abilities of
previous projects. An outer Pyrex glass tube with an inner vacuum layer will be
constructed and sealed to prevent heat loss. Copper tubing will be welded into
a pipe that holds the working fluid, water, and withstands high temperatures
and pressures caused by the water evaporation and condensation. An aluminum
sheet is attached to the outside to better conduct heat. A wire mesh wick will
transfer the water through capillary pressure from the condensation portion to
the evaporation portion of the pipe. The entire system will either be powered
with solar energy or electricity. Challenges will include learning the
machinery and finding the best design. The temperatures will be tested using
LoggerLite software both with and without water to determine how well it
transfers heat, and how long the process takes to heat water. Testing will be
done on the range of temperatures the system can operate under, and the optimal
energy for the device. The deliverables will include testing data, as well as a
working heat pipe of 12” length and 1” diameter which conducts solar and
electrical energy to heat water.
1
Introduction
This project is
tasked with designing, creating, and testing a heat pipe. A heat pipe is
basically a heat transfer device that works on the principles of thermal
conductivity and phase transition, combined, to efficiently manage the transfer
of heat between two solid interfaces. The system will be one which is used to
heat water through both solar energy and electricity. In order to complete this
project, ideas will be brainstormed for creating the most efficient heating
system possible. Once the idea has been finalized, the materials will be
ordered and construction of the heating system can begin. Throughout the construction
process, tests will be made to determine the efficiency of the system. These
tests will identify any flaws in the system and allow for immediate analysis of
the problem. This testing and modification stage will continue until the
heating system has reached its optimal efficiency. At the end of this project,
there will be a working prototype of the heating system which can be tested to
show how well the system functions.
2
Deliverables
At the
conclusion of this lab, a heating pipe capable of collecting solar energy and
heating water will be produced. With temperature testing, a range of
temperatures will be produced as well as time and energy required to produce
the amount of heat to raise the temperature of the water. In regular solar
thermal water heating applications, an individual absorber tube of an evacuated
tube collector is about 40% more efficient as compared to more traditional
solar water collectors like flat plates. It is mainly due to the vacuum that
exists within the tube, which slows down convective and conductive heat loss.
3
Technical Activities
3.1
Design Pipe
3.1.1
Vacuum Sealed Glass Layer
The pipe has a layer of glass providing a vacuum sealed layer
surrounding the pipe to best conserve heat, and facilitate the vaporization of
the working fluid at lower temperatures. The glass layer around the pipe allows
the system to absorb heat from all directions with the same effectiveness. A
glass layer also allows the sunlight to better reach and heat up the copper
pipe.
3.1.2
Copper Pipe
The copper pipe provides the best conductivity for the system. An
aluminum sheet on the outside of the pipe will best collect and transfer heat
absorbed from sunlight and other external sources.
3.1.3
Wire Mesh Wick
On the inner layer of the pipe a layer of wire screen mesh will
transport the water through capillary action, and conduct heat from one end of
the pipe to the other. The wick will be held against the walls of the pipe with
tension created by the mesh itself.
3.2
Construction of System
3.2.1
Vacuum Sealed Glass Layer
The vacuum sealed glass layer will be constructed by sealing a Pyrex
tube with a plug and adhesive at both ends. One end will be designed for the
heat pipe to fit securely inside of the vacuum tube. The plug and adhesive will
be able to withstand the pressures and temperatures at which the system will
operate.
3.2.2
Copper Pipe
The copper pipe will be created from weld-able copper tubing which
is 0.25” in diameter. The tubing will be cut to a length of 12” to function as
the main body of the heat pipe. The tubing will be welded closed at one end and
then filled with the working fluid (water). The tubing will then be sealed on
the other end. An aluminum sheet will be attached to the copper pipe to aid in
the heat absorption within the vacuum sealed glass tube.
3.2.3
Wire Mesh Wick
The wick for the system is made from aluminum wire cloth. The wire
cloth is attached to the inside of the copper tubing and aids in the movement
of the working fluid through the system. The cloth will be attached to the
interior of the tube before the working fluid is added to the copper tube.
3.3
Testing and Modifications
In order to test the heating system, Vernier temperature probes
will be used to test the change in temperature. The efficiency the heat pipe
system will be determined based on the temperature change and how fast that
change occurs. The greater the temperature change in a smaller amount of time
represents a more efficient system.
4
Project Timeline
In order to provide structure and keep the project on task,
a timeline was created to show when each of the major tasks need to get done.
This timeline is shown below in Table 1.
Table 1: Project Timeline
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Week
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|||||||||
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Task
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1
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2
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3
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4
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5
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6
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7
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8
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9
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10
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Form groups and brainstorm ideas for project
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x
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Continued research and more detailed design of the
system
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x
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x
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x
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x
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Order materials for construction (includes shipping
time)
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x
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x
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x
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Construction of heating system (includes learning
machinery)
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x
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x
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x
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Testing and modifications to the system
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x
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x
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x
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Final report preparation
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x
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x
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5
Facilities and Resources
Materials:
- Copper piping, 0.014”
thickness, 0.25” outer diameter
- Working Fluid: Water
- Glass tubing, Pyrex,
0.157” thickness, 1” outer diameter, 0.69” inner diameter
- Aluminum sheet 0.04”
thickness, 0.5”x12”
- Aluminum Wire Cloth,
0.018 Wire diameter, 12”x12”
- Lathe
- Band saw
- Welding equipment
- Temperature probes
- Logger Lite software
Heating pipes
are composed of three components: heat pipe working fluid, heat pipe envelope,
and heat pipe wick. The working fluid transfers heat by evaporation and
condensation, the envelope contains the working fluid. The wick returns the
liquid from the condenser to the evaporator using capillary forces. The working
fluid is selected after the operating temperature is known, and the envelope
and wick materials are selected after testing their compatibility with the
working fluid. Compatibility between materials is determined through
experimental tests. Some examples of compatible envelope/ working fluid system
include copper/ water, copper/ methanol, and titanium/ monel.
The materials used depend on the operating temperature range. The
operating temperature of the working fluid will be at minimum above 25 degrees
Celsius, and the corresponding compatible envelope/ working fluid system that
will be used is copper/ water. The glass tubing contains the copper tube on the
inside, which contains the working fluid that is water. The aluminum sheet acts
as an external heat absorber, and it is attached to the copper tube. The lathe,
band saw, and welding equipment will be used to construct this system.
Temperature probes are used to monitor the temperature of the water. The
LoggerLite software will be used to collect and save data for future analysis.
6
Expertise
For this
project, the heating system will require several skills to create a functioning
system. For the design of the pipe, knowledge and research into how heat pipes
operate will be necessary to create an effective design. In order to actually
construct the system, the machine shop will be used for several tasks. Use of
lathe, band saw, and welding equipment will be integrated into the construction
process. To test the efficiency, temperature probes will be used along with
Vernier software, either LoggerPro or LoggerLite to record the temperature as
the heating system runs.
7
Budget
For this
project, the projected budget was composed of three items; heat pipe materials,
testing materials, and shipping costs. This budget can be seen below in Table
2.
Table 2: Projected Budget
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Category
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Projected Cost
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Heat Pipe Materials
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$59.29
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Testing Materials
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$39
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Shipping Costs
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$21
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TOTAL
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$119.29
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7.1
Heat Pipe Materials
For the physical
construction of the heat pipe system, we will need glass tubing, copper piping,
and aluminum sheeting. The specifications and prices for each of these items
are show below in Table 3.
Table 3: Heat Pipe Materials
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Item
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Dimensions
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Price
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Supplier
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Pyrex glass tubing
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0.157” thickness, 1” outer diameter, 12” length
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2 @ $21.62
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McMaster 8729K49
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Copper piping
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0.014” thickness, 0.25” outer diameter, 12” length
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$2.68
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McMaster 7190K57
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Aluminum sheeting
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0.04” thickness, 2”x24”
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$5.53
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McMaster 89015K161
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Aluminum Wire Cloth
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16
x 16 Mesh, .018" Wire Diameter
12”x12”
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$7.84
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McMaster 9227T61
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TOTAL: $59.29
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7.2
Testing Materials
In order to test how efficient the heat pipe is, the temperature
will be recorded as the system runs using a Vernier temperature probe and
LoggerLite software. The temperature probe which will be used is called Go-Temp
and can be connected directly to computers and the data is recorded through the
free LoggerLite software. The Go-Temp probe is $39 from vernier.com.
7.3
Shipping Costs
Shipping costs include the shipping from mcmaster.com and
vernier.com. Vernier’s shipping is $11 and McMaster’s shipping will be around
$10.
8
References
"Capillary
Wick Designs and Structures in Heat Pipes", Global Digital Central,
2014. [Online]. Available:
https://www.thermalfluidscentral.org/encyclopedia/index.php/Capillary_Wick_Designs_and_Structures_in_Heat_Pipes.
[Accessed: 07- Apr- 2016].
“Fluid/Envelope/Wick Compatibility”.
Advanced Cooling Technologies,Inc. Lancaster, Pennsylvania., 2016
F. Mahjouri, "Vacuum Tube Liquid-Vapor (Heat-Pipe)
Collectors", Thermo Technologies, 2016. [Online]. Available:
http://www.thermomax.com/Downloads/Vacuum%20Tube%20Paper.pdf. [Accessed: 07-
Apr- 2016].
“Heat Pipe Materials,
Working Fluids, and Compatibility”. Advanced Cooling Technologies,Inc.
Lancaster, Pennsylvania., 2016
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