Weekly Progress

Week One:

In week one, we decided on the project we were most passionate about and investigated the problems present with building an apparatus like this one.

Possible Problems:
Difficulty to capture enough solar energy to effectively heat a solar coil enough to boil water (this will require further investigation and experiment in future weeks)
Price of solar panels on a small or large scale
Using the apparatus when the sun goes down, which would require storage of energy

We also drew a model of all of the parts needed and created an early estimate of the price of items needed to make the apparatus.

Week Two:

After some calculations, we realized that the system containing a solar panel to heat a heating coil wouldn't work because it requires 747 watts of power to boil the water. We would be able to get 5 watts maximum from each solar panel, and the price of this system would be simply too high. We had to go back to the "drawing board".

Through some more research and discovering this video, we decided that we wanted to pursue a system using directed light from the sun at a container to achieve boiling. This decision meant that we needed to reconsider everything we had done so far.

Calculations:
Q = mcdeltaT
m = 1000 g
c = 4.184
deltaT = 60 degrees Celsius (assuming room temperature in Africa at 40 degrees C)
Q = 250,000 J

Calculating amount of output for our proposed system:
milliJoules created by our system = solar constant*Adish*Time(seconds)
solar constant = 1.361 kW/m^2 = 136 mW/cm^2
Adish = pi*r^2, we did this to simplify calculations as the surface area of a concave dish is tough to calculate      
Time will be 3600 s, an hour
We decided on a dish with radius, r = 16.51 cm

mJ = 136*16.51^2*pi*3600 = 422180 J

Finding amount of water boiled with this amount of energy:
Q = 422180 J
422180 = m(4.18)*(60)
m = 1683 g/hr = 1.683 L/hr

Because we want about ten liters per 12 hour day, this is an acceptable amount of output created for our system. We intend to use this system.

Week Three:

With our general planning done, we're beginning to solidly work on designing the process. We spent this week solidifying our intended design and looking for products to buy to complete the design. We've decided that we'll be building the apparatus with the mirror out of PVC piping and using a standard aluminum cooking pot to boil the water out of.

We intend to use a tripod along these lines to hold up the aluminum pot and air duct material to direct the water vapor to another bucket, where it will condense.

We also designed the way that the aluminum pot will be refilled. We intend to use a duct reducer (this) attached to the top of the pot, where it will funnel the water vapor into the ducting. At the point where the ducting meets the smaller end of the funnel, we intend to use Velcro to attach it. This way, the ducting can be removed by the user when they need to refill the pot.

Materials along with general prices:
Heating duct material: $15-20
PVC Pipe/PVC glue (one of our group members already has this): $20
2 quart pot: $10-15
Coffee Filter/Other Filtration: Free (we have these)
Pot to hold pure water: $10
Velcro Strips: $5

Total Estimated Price: $65-70

We officially delegated the roles of the group into the following subgroups:
Building the apparatus to hold the kettle and the mirror: Greg and Malik
Creo designs of that apparatus: Greg and Malik
Building the distillation apparatus: Brian, Sarah, Billy
Calculations: Billy and Sarah
Flow chart of the major processes: Brian

At the suggestion of Dr. Herczfeld, we drew a flow chart of the major systems involved in the process.

Week Four:

This week, we're working on solidifying our designs and drawing them in Creo Parametric before beginning to build. Also, we're redoing calculations and searching for more possible downfalls of our design.


Over the past week, we received the parabolic mirror and also purchased the heating tubes and duct reducer for the final design. We plan on going to Home Depot and purchasing the remaining materials by the end of this week so we can begin building officially by next week.

We used the information provided by this website:
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

We intend to use an infrared thermometer to measure the change in temperature between the inside and outside in order to have enough information to find the heat transfer per unit area. This will give us a good idea of how much energy the aluminum will allow to be transferred through the surface.

Also, to prepare for the build, we estimated how much the aluminum pot and water system would weigh (how much force our stand would have to hold up). The calculations are as follows (assuming 1.5 liters of water in the pot at any given time):

Total Mass = weight of pot + weight of water = 230 grams (from the website for the pot) + (1.5 Liters * (1000 mL/L) * (1 g/mL)) = 1730 grams = 1.73 kilograms

Gravitational Force pulling the pot down = m*g = (1.73 kg)*9.8 = 16.9 N

16.9 N is not a very strong force and should not be difficult to support using a simple stand made out of PVC piping.

Week Five

This week mostly involves getting the materials needed to build the apparatus. During class time, Malik and Gregory went to Home Depot to buy the PVC piping and other materials needed to begin building. Building will begin this week.

Materials Acquired:

Pictured: Heating duct material, PVC piping of multiple sizes, PVC T joints, Velcro Strips, Heating duct band

List of things to accomplish this week:

• Gather materials/inventory
• Build rudimentary base to hold mirror for experiments
• Update Calculations
• Prepare for thermometer test
• Measure focal point of the mirror
• Decide how to test final water quality

Week Six:

During lab period, Sarah, Brian, and William are going to work in Myers Hall on building the apparatus to hold up the pot while Malik and Gregory work on finishing their design. The Creo Parametric design is almost finished, but needs final touches. 

Roles for final report:

Malik: Abstract, Problem Overview

Brian: Existing Solutions, Project Objectives

Gregory: Project Timeline, Project Budget

William: Results, Future Work

Sarah: Abstract, assist other people with any problems they have

Additional Supplies Needed:
Drill/PVC cutter
Elbow joints for PVC
More PVC (thinner than 1 inch)
Screws
Command Hooks (maybe)
Duct tape

Progress of the Sarah/Brian/William group:

Pot connected to duct reducer and heating duct

The pot, connected to a duct reducer with velcro strips and connected to heating ducts 

Progress on the stand for the pot

Week Seven:

In week seven, the project has reached the point where building is the focal point of our progress. The build has been coming along fairly well, as the adjustable stand for the mirror is built. 

Pictured above is the stand for the mirror, built using PVC pipe connected with PVC glue

During lab period, the group left early to go work on building the stand for the pot. In the time there, we constructed the stand, again using PVC piping and glue. We did, however, run into a problem with the size of the pot we had intended to use. It is too big, and our duct reducer will not fit onto it correctly. We intend, over the next week to check multiple shops for smaller pots that will fit the duct reducer. 

Our progress on the stand for the pot:

We used PVC piping and various joints to construct the stand as shown above. We intend to drill through the T-joint in the middle to connect a system to hold up a pot once we are able to locate and purchase a sizable one. 

Throughout the week, we've searched multiple stores in the local Philadelphia area for the correct size pot, but to no avail. 

We intend to go as a group during week eight to search for a pot. At this point in the term, our build is virtually finished and simply requires a correct size pot, testing, and general adjustments to achieve maximum efficiency. 

Week Eight:

We were unable to find a pot to buy, but we decided on a stainless steel bowl that we will cover in aluminum foil. After purchasing the bowl and the aluminum foil, we constructed the system completely, with only minor adjustments to make by the end of the term. 

Here are pictures of the completed design:

The full build, completed but missing the mirror, which would typically rest on the PVC stand on the ground

Close up of the bowl, covered in aluminum foil, and the duct reducer and the heating duct that are attached to the bowl

Above view, showing how the bowl hangs and how it is fastened at the top. It is connected using ribbon (which was a temporary solution just for testing purposes, as we didn't have actual nylon rope), and at the top is fastened by tying the ribbon through a small loop of PVC.

The small loop of PVC with ribbon tied through it

Important Note:

These pictures aren't of a completely finished project, as the ribbon needs to be replaced by rope. We only used the ribbon in order to have the apparatus built in order to test it. The ribbon won't hinder the production of the build, but doesn't look professional and is considerably less durable than the nylon rope we intend to use. 

Testing Progress:

We completed the project Tuesday night, and haven't been able to test yet this week. We tried a few times to use it outside, but it's been too cloudy for a reasonable test. When we tried, the sun simply wasn't shining well enough because it was obscured by clouds. We intend to test the build at the next sunny day.  

Week Nine:

This week, testing is our highest priority. We really need a sunny day to test the build before week ten, and the weather forecast for the next ten days seems ominous, as virtually every day will be cloudy. We will continue to be vigilant and test whenever we can.

Also, we've purchased the nylon rope and intend to replace the ribbon with the rope tonight (Tuesday night). 

 

The type of nylon rope we decided to use. One eighth inch is plenty of width and the weight it is supporting is far less than the 90 lbs the product says it can hold.

In order to be able to test our project, we obtained 200-watt halogen lights to simulate sunlight. Results were unfortunate, as the testing resulted in no boiling or vapors. We intend to test using actual sunlight on the next available day. 

Week 10

Fortunately, sunlight was abundant early this week. Through our testing, we've discovered that while our project can heat water a considerable amount (25 degrees Celsius), it is unable to boil water, which is an integral part of the entire project.

The temperature of the water after testing (45 degrees Celsius)

The physical bubbling in the water following our testing

The full build, including mirror and clean water containing pot

Results

While the project was overall unsuccessful because it is unable to heat water effectively to boil it, it was successful in many other ways. It managed to create bubbles, which shows that with improvements to the system it could completely boil the water as intended. Also, it is a compact and portable prototype that can easily be transported, and we are even going to take it to the site of our presentation because it's compact. 

Possible Improvements:

A more conductive metal container would have given us more heat transfer through the metal, which would have resulted in a higher temperature of water. This lack of conductivity could have made the difference between boiling water and just lightly bubbling water. 

Another improvement we could have made would have been to purchase or construct a larger reflector, as more surface area would have resulted in more heat transfer. 

Together, these two improvements could have made the difference between success and failure to boil water.