Potentially Interesting Projects

Bicycle-powered blender

bicycle-powered blender: improve the design, test, and market the product.  The youth group associated with GrupoFenix has been provided with a design for a bicycle-powered blender.  The design makes the bike unrideable.  The group is interested in a design that can be made locally, allows the bike to work when not blending, and does a good job making smoothies.  A good, affordable, locally-craftable bike stand is a key part of this project and would allow this group to explore other bike-powered devices.  One other that is of particular interest is a bike charger for cell phones and similar low power devices.

Organization

·       Works in Nicaragua

o   Primarily in the capital city of Managua and a city in one of the poorest regions, Sabana Grande

·       In the Sabana Grande region, there is a large deforestation problem, limiting access to resources

·       Organization came to being in 1996 and focused a lot on developing and introducing solar-powered devices

·       Many other organizations have come into being around grupofenix

Local community

·       Nicaragua is an agriculture-based economy

·       High unemployment and economically unstable

·       Inequalities in the distribution of wealth

·       Land area of the entire country is slightly smaller than new york

o   Managua – the capital city is the largest in terms of population and size

o   Economy is based mainly on trade and industry

o   Sabana Grande -  80% of the population get an income from agriculture only

o   Tropical climate with many dry spells; but high levels of solar radiation

o   97% of the national consumption of the forests went towards cooking; using wood burning stoves

Existing solutions to the problem – the current design involves a bicycle with only one wheel, not a unicycle, so obviously, a bicycle with only one wheel is not able to be ridden.  The reason that this bicycle is stationary is because the blender is simply sitting on top of a platform, with nothing to hold it to the bicycle or make sure that it does not fly off when it is in use.  A method of securing the blender to the bicycle while retaining complete function is necessary to make the bicycle successfully have multiple purposes. 

·       a bicycle dynamo; get the rotational power from the spokes instead of the wheel, serves more bicycles, and allows the bicycle to be ridden while blending

·       Secure the blender and ensure that the blender does not lose connection with the wheels while in motion

·       Having a platform on the front of the bicycle allows the people to see the smoothie as it is being made

·       For stability there would have to be a way to encase the blender to keep it stationary

Questions:

·       Will people find it useful to blend and ride at the same time, or is the idea to have a bicycle that can serve two separate functions?

·       Is making smoothies and blending food a way in which people can establish a source of income?

·       Do people have access to many different types of blenders, or are they standard?

Sources:

Grupofenix.org

http://www.gcsescience.com/pme21.htm

http://www.solarenergy.org/sabana-grande-nicaragua

http://rockthebike.com/fender-blender-bike-blenders/

Solar Cooker Stand

Develop new design for stands for solar cookers that is easier to build and more cost efficient (see attachment).  The current design requires a lot of metalworking, and the tools available are insufficient for the work.  Research online should allow you to find pictures of the existing grupofenix solar cooker stand.  A stand that can be easily rotated to keep the cooker pointed to the sun during the day would be a real improvement.

The background for the solar cooker stand is the same as the blender because the same group, grupofenix is in charge of both projects.  Same organization and local community, Nicaragua, the city and a poor suburb.  However, cooking with a solar cooker implies that there is a lot of available space so the community in which we will be focusing will be the more rural area as opposed to the city.

The current stand is stationary, unable to be rotated, and very difficult to reposition because the stand gets so hot during the day. 

A larger surface to collect sun would be good, having the pot at the focal point of an ellipse would greatly increase the efficiency of the cooker, but a rotation device would be most effective if it did not conduct heat, so it could be easily manipulated during the points of the day that are hottest and when people most need to rotate their pots.  A ball and joint system that had the ability to lock in place would be most effective.    

Questions:

·       How long does it generally take people to cook a meal?

·       How long many times would the solar cooker need to be moved?

·       Are people moving the cooker much more than in and out of their houses?

Sources:

Grupofenix.org

http://www.solarcookers.org/index.html

www.ccathsu.com/files/handouts/Parabolic%20Solar%20Cookers.pdf

Water Purification System

LSI in Indonesia: identify appropriate water purification for villagers in West Sumatra, Indonesia, including determining how to reach scale (see attachment)

LSI group:

·       Involved in a very wide range of industries that are primarily devoted to clients in South East Asia and Indonesia

·       The organization began under the premise of helping businesses succeed

·       There are many large-scale projects involving water purification, such as the ozone-protecting water filtration devices that are currently being implemented in Connecticut

·       In addition to helping promote water filtration, LSI is also taking steps to improve the overall Indonesian economy

Region is West Sumatra, Indonesia – an area that is on the western coast of the Island and one that is prone to earthquakes

·       The public health services in the region are not adequately equipped to deal with natural disasters and keep an appropriate level of public sanitation

·       Iodine deficiency leads to nutritional deficiencies in the population, but also makes it hard to purify water

·       Tropical Rainforest climate, but there have been cases of extreme whether that destroy the agricultural crop

·       Agricultural-based economy for those who are inland, but fishing dominates on the coast

·       The main problem is getting clean water access to the more rural areas of the province

·       The water comes directly from rivers and streams, and is unpurified

·       Traditionally, village elders have a large say in the future of their villages

Existing solutions are solar stills, and solar ultraviolet water distillation methods.  Reaching large portions of the community is very difficult

·       Certain types of filters are available for filtering water, ranging from large space-consuming filters to tablets that filter individual servings of water

·       Carbon filtration devices allow only certain elements of the water to pass through, it will even filter out bacteria, and the resulting water also tastes fresh

·       A combination of sand and charcoal also allows filters water.  Sand and charcoal are natural materials that may be available in the region of west Sumatra

·       Three stages of water cleaning, layer of sand sifts out large impurities; the porous charcoal filters out the smaller impurities, lastly an activated carbon filter kills the reaming bacteria and leaves the water tasting fresh and drinkable. 

Questions:

·       Do the people have access to sand and charcoal?

·       Are the villagers aware that they need to filter their water?

·       How much power do the elders have over the village?

·       Would the people have a difficult time adapting to the lifestyle changes necessary to filter water before drinking?

Sources:

http://store.wavesforwater.org/

http://lsigroup.org/

BMC Research Notes. 2011, Vol. 4 Issue 1, p81-85. 5p. article

Asia Pacific Journal of Clinical Nutrition. Feb2001, Vol. 10 Issue 1, p10-16. 7p. 4 Charts, 1 Graph

Marine Micropaleontology. Oct2007, Vol. 65 Issue 1/2, p96-112. 17p.

Cook Stove

Blog Post – Cook stove

A few weeks ago we were presented with the challenge of designing a charcoal cook stove to be used in Nicaragua.  The goal of the stove would be to reduce the harmful emissions and gasses that currently fill homes as a result of cooking.  By virtue of the charcoal its self, the emissions are reduced, so we needed to design a stove that would have the same or better cooking capacity and efficiency when compared to the current wood stoves that are used. 

Initially, we developed a few main categories to focus our design efforts:

·      Good heat control

·      Effective ash disposal

·      Multi-purpose cooking surface

·      Solid structure

·      Aesthetically pleasing

In order to create a successful stove, it was determined that we would need pick a specific point we wanted to focus on, and leave the rest to become details around that point. 

Some of our original brainstorming.

Knowing that aesthetics are an important factor in a product’s success rate in the third world, we chose to focus on a stove that would appear large and powerful, but be efficient and ensure that the entire physical stove had a purpose.  We began with a very simple box design that would be large enough to hold two pots.  Given the fact that the current Nicaraguan cook stoves have the capability of cooking two pots at once, we felt that having only one cooking surface would be viewed as a down-grade and not amply used.  Furthermore, once we determined that there would be room to cook two separate items, we decided to make a stove with two different cooking surfaces.  One surface would be for pots and large items that cannot fall through a grated surface, and the other would be a solid surface, like a hot plate, on which people could cook tortillas, or keep things away from the flame if necessary.  Because there were two distinct cooking surfaces, we also wanted to be able to isolate one surface if only one pot was being cooked.  To do this, we needed to split the large box into two smaller compartments.  By simply putting a metal divider down the middle of the stove, we figured we could accomplish this task.  Thus, in choosing to focus on the aesthetics, we had already began to incorporate other important factors. 

            Once we had a basic design, a box-like structure that had a multi-purpose cooking surface, there were two other main points we had to consider.  Heat flow, and ash disposal are two points that could either make or break the functionality of our stove.  With inadequate heat flow, the stove would be inefficient, and people would have to burn more charcoal than necessary to cook, thus increasing the gaseous emissions, and giving people a product that is not as good as what they currently have.  Additionally, if the ashes are not contained properly, people are left with a mess in their kitchen and an unsanitary and unpleasant eating environment.  To tackle the problem of heat flow, we wanted to make sure that the charcoal was close to the cooking surface and only small amounts of useable heat escaped.  Our initial thinking was that having a box structure would be relatively good at insulating, and if the charcoal was close to the surface, it was almost guaranteed that all possible heat was being captured.  So given that we would not have a problem with insulation, we wanted to have a way to change the temperature of the stove, by letting some of the heat escape.  We sketched different doors that would slide along the side of the stove, with adjustable heights to let more or less air out, then we moved to vents that would be around a half inch on each portion of the stove, but we determined that the construction of the vents would be too difficult, and very hard to replicated or repair.  We concluded that we would have quarter circle doors that would rotate 90 degrees to reveal a quarter circle hole in the side of the stove.  In the final design and testing phases, we found that our vision did not match our product, and heat flow (in terms of insulation) was in fact the weakest element of our design. 

The problem of Ash disposal was definitely our most heavily deliberated and very unclear in our initial design.  Our original box shape did not incorporate any form of stand, or collection mechanism for the ashes.  We originally were thinking that the ash would just fall out of the bottom, but we weren’t sure where it would go.  As we observed other stove designs, both online and in the class room, we quickly realized that having a box sitting on the ground, with no airflow from the bottom, and no place for the ashes to fall would be a problem.  We spent some time thinking about different mechanisms, like trays, and collection bins; however, we encountered many trade offs between the difficulty to manufacture these items and the minor function they would serve.  So we went back and asked ourselves if it was truly necessary to have a way of cleanly disposing the ashes.  Obviously we all agreed that we couldn’t just have them flying everywhere, they would have to be contained, but it would be okay if they just fell to the ground.  Then we determined that there would be bricks available in Nicaragua, and it would be reasonable to assume everyone has access to bricks.  Thus, we would use bricks to elevate our stove, form a base, and a closed area in which the ashes would fall. 

Our final sketch:

The sketch has vents, as opposed to quarter-circle doors for increased airflow.

   

         

As we moved on to our cardboard sketch, we realized how limited we were in terms of our ability to connect materials, meaning that the stove would have to be held together by rivets so everything would have to be at right angles with extra material to make the folds.

Before we began to build or stove, now named the Power Stove 2, (PS2), we determined the made our final detentions and chose to have the sides composed of two pieces of sheet metal with a piece of Masonite in the middle for extra support and insulation.

Dimensions:                                       Materials:

2 feet long                                          Sheet metal; around the sides and the alternative cooking surface

1 foot wide                                         Masonite; around the side

6 inches wide                                    Chicken wire; top and bottom grates

                                                            Metal rods; to support the pot on the top grate

                                                            Rivets; to hold the stove together

Cost of stove;

Sheet metal:

Used approximately 72 inches X 14 inches for the base, 2(10X10) for the cooking surface; costs approximately $0.02 for 1 square inch; used 1208 square inches, costs $24.16

Masonite:

Used approximately 72 inches X 5 inches for insulating the sides; costs approximately $0.02 for 1 square inch; used 360 total inches

$7.2

Chicken Wire:

Used 12 inches X 24 inches for both the top and bottom grates, so there were a total of 2(12 X 24) square inches; costs $0.005, half of a penny, per square inch, total of 576 square inches

$2.88

Metal Rods

Used a total of 84 inches (7 feet) of metal rods that were 1/8 inch in diameter; cost is $0.63 per foot of rod

$4.41

Rivets

Used a total of 20 rivets

$1.28

Total cost of our stove = $39.93

Our final design consist of two layers of sheet metal, 6 inches tall, with a piece of Masonite in-between.  There are two vents on the front of the stove that can be opened or closed as much or as little as one wishes.  The vents are large enough to add charcoal to the fire without needing to take off the top grate.  There is one piece of sheet metal in the middle of the stove that serves as a divider between the two sections of the stove, to ensure that if one is only using half of the stove, only one half of the stove will be heated.  The bottom of the stove is simply one sheet of chicken wire attached to the base of the sides that have been folded over to allow the pieces of the stove to fit together properly.  The chicken wire is attached to the stove by woven small wire.  The top grate is completely removable.  It consists of a piece of chicken (1 foot by 2 feet) wire with 10-inch metal rods attached (by weaving the rods through the wire) at approximately 4-inch increments.  On one half of the top, however, there are two pieces of 10 X 10 inch sheet metal sandwiched together with rivets that serve as an alternative-cooking surface for items like tortillas. 

The final design of our stove was much larger than we had anticipated.  The stove can definitely hold any sized pot, and will be able to support it, however, it may be slightly inefficient for heating up small pots.  The bottom is very open and there is a lot of airflow, so all of the heat is not funneled upwards toward the desired location.  Thus, the vents were not entirely necessary for airflow, however, they were very good for accessing the charcoal & fire without needing to take the entire stove apart.  When we tested our stove, we loaded the charcoal through the vents and re-lit the flame using the vents while our pot was still sitting on the stove.  Shortening the body of the stove would have also made the stove more efficient, seeing that the charcoal would be closer to its targeted destination.  Our brick base did adequately contain the ashes (although there were hardly any to contain) and having the bricks along the sides of the stove served as an extra layer of insulation and support.  Overall, our stove successfully supported the pot and would have (most likely) done an adequate job boiling the water, if the weather was more like Nicaragua.  Aesthetically, we succeeded in producing a powerful-looking product, one that looks like it will function well and is desirable to have as an object in one’s home.  We have a multi-purpose cooking surface and effective ash disposal.  The only point for which we were slightly off the mark was the effective heat control.  We thought we were going to need a way to lower the heat, but it turns out that we now need a way to keep it hot!

 

Class topics of interest

Examples of successful/ unsuccessful development work with a technology focus

In every career path, people inevitably learn from their mistakes.  In a way, I feel that making unsuccessful designs, effectively making mistakes, is the most important aspect of developing a successful product.  Therefore, unsuccessful development work is necessary for successful work.  On the other hand, an unsuccessful products in developing countries can have detrimental effects by not only wasting money, but also discouraging populations about what products will be available for their future.  I see these two situations of unsuccessful design to be very different, one is caused by creativity, trial and error, and the other is caused by carelessness.  I am interested in discussing what makes development work successful and unsuccessful, and if unsuccessful work is due to an inherent design flaw or a neglect to consider who would be using the product.

Furthermore, we have already discussed the challenge engineers face of designing for people who are removed from themselves, and I would like to see how the most successful development work has tackled this problem.  Before looking into the answer, I have a hunch that the greatest success will come from those who have truly engaged with the targeted population and involved them in the design process.  If a community cannot get excited about a product, and does not feel like it is their own, I believe that it will be much harder for a product to have success. 

The lack of technology in developing nature indisputably contributes to a lower living standard, and I see it as developed nations’ responsibility to act as a catalyst for nations to develop their own technologies.  I would find it very interesting to look into the correlation, if any, between successful / unsuccessful development work and giving technologies to countries versus helping them develop / create these technologies themselves. 

Solar Panel Testing

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To understand the variables attached to solar panels, we explored how different distances, positions and surface areas affected the voltage and current captured in the solar panel.  Additionally, we were tasked with finding the resistor that will maximize voltage and current.  We used a 50-watt bulb to serve as the sun, and offering a light source.  In a 100% efficient solar panel, all 50 watts would be captured and converted to useable power.  We measured the current to be 54.9 milliamps, which converts to .055 amps, and the voltage at .5 volts.  To get the wattage produced by this current and voltage, we would multiply the two quantities, .055 * .5 = .0275 watts.  Out of a possible 50 watts, only .0275 watts were captured, yielding a 5.5*10^-4% efficiency.  This efficiency would be the case if the wattage the bulb required was exactly equal to the wattage it put out.  However, the bulb its self is not 100% efficient.  We noticed that the bulb generates a significant amount of heat and in conjunction with the amount of useable light given off by the bulb, the light that reaches the solar panel is much less than 50 watts.  The average cheep solar panel is around 10% efficient, and knowing that the wattage of useable light available to the solar panel is much less than 50 for a variety of reasons, we can conclude that the panel is probably around 10% efficient.  The panels are not as horrible as we first calculated, but they are will clearly not be used by NASA.  The next experiment we conducted using the solar panels was to add resistors to the circuit and find the resistor that yielded the highest current and voltage.  We tested a total of 8 resistors and fount that they all were very close to the ideal current and voltage, that measured with no resistor in place.  The resistors ranged from 10 ohms to 100 killi-ohms, however we focused primarily on resistors with orders of magnitude from 1 killi-ohm to 100 killi-ohm.  Within the primary resistors we tested, our average resistance was 26.6 ohms and we found that there was an average current of 51.8 milli amps and average voltage of .58 volts.  Ideally, we would have liked to find a resistor that yielded a current and voltage equal to when there was no resistor present, 54.9 mA and .50 V.  However, because no resistor will be ideal, we will choose the resistor with the current and voltage reading closest to 54.9 an .50 to be our "best" resistor.  The 10 ohm resistor yielded a current and voltage that was significantly different from the other data compiled.  Originally, I suspected that this point was an outlier; however, upon further examination, this may not be the case.  According to the mathematical formula, V = IR ( Voltage = Current * Resistance), a larger resistance will yield a higher voltage, which is consistent with our data, the voltage of the circuit is smallest with the smallest resistor.  Although the formula V=IR can be rearranged to say V/R = I, which would suggest that a smaller resistance should yield a larger current, if you have a small voltage, the current should be small as well.  The last test we conducted was to test the effects of "bird poop" on the current and voltage of the solar panel.  We found that the effect of covering one spot on the solar panel had the same effect on the current and voltage as covering half of the panel.  Each component, current and voltage, decreased dramatically when just a speck of the panel was covered.  We concluded that this is due to the interconnected-nature of the solar panel. 

Resistor	Current	Voltage
No resistor	54.9 mA	.50 V
1.2 k ohms	53.9 mA	.49 V
4.7 k ohms	54.2 mA	.48 V
10 k ohms	49.1 mA	.47 V
15 k ohms	53.9 mA	.48 V
22 k ohms	49.1 mA	.47 V
33 k ohms	50.8 mA	.48 V
100 k ohms	51.8 mA	.48 V
10 ohms	38.8 mA	.38 V