Presentation on "Engineers solve the problems of the world"

I made this talk I made to deliver to a high school class on "Introduction to Engineering." In it, I detail some of my adventures as an engineer through Latin America, hoping to inspire the next generation of engineers and problem solvers who will make our world a better place.

Engineers solve the problems of the world

Promoting wind energy

In the weeks before the Guiness World Record installation and during the installation itself, there was a great deal of media attention for this project. WindAid was in the Peruvian news, including TV and newspapers. This just goes to show that breaking a world record is one way to bring the public’s attention to not only renewable energy, but also climate change. Here are some links:

Instalarán turbina de viento más alto del mundo en nevado Pastoruri (Récord Guinness)
Installation of highest wind turbine gets a mention in the World Guinness Book of Records
HUARAZ INSTALAN GENERADOR DE ENERGÍA ELÉCTRICA EN EL NEVADO PASTORURI

The highest altitude wind turbine in the world

Last month WindAid embarked upon a project to break a Guiness World Record of the highest altitude wind turbine in the world.  This installation was done at the entrance to the Pastoruri Glacier in the state of Ancash of Peru, at the elevation of 4882 meters.  This wind turbine installation achieves several things.  It provides electricity to the two women who live there, such that they are able to have light in their homes after dark.  Also, it provides electricity for the nearby buildings, some of which serve as places to sell souvenirs for tourists visiting the park.  None of this area has had electricity before.  This project to put the highest altitude wind turbine in the world at this park also provides more publicity for wind energy in Peru and also brings more attention to the melting of the Pastoruri Glacier, and this attention will hopefully lead to more renewable energy and actions to prevent glacial melt in the future.

La mes pasada WindAid empezó un proyecto a romper un Record Guiness por la turbina eólica mas alto en el mundo.  Esto instalación estuvo en la entrada de la Pastoruri glacier en el estado de Ancash en Perú a 4882 metros alto.  Esto instalación es para algunos cosas.  Da electricidad para las dos mujeres que viven allá para que ellas pueden tener luz en su casa cuando oscuro.  Tambien esto da luz para los otros edificios cerca que usan por vender cosas para turistas y otras funciones.  Todos estos edificios y casas nunca han tenido luz antes.  Esto proyecto tambien hace mas publicidad para energia eólica en Perú y tambien mostra el mundo de la deterritido de Pastoruti.  Esperamos que esto atención es bueno para mejorar mas energia removable y traer acciónes a parar deterritido de glaciers en el futuro.

Engineering and learning languages

I was once asked to give a talk on integrating engineering and the liberal arts, and I chose the theme "Filling a leader's toolbox..."

I was recently thinking about the process of learning languages, and how this concept of filling your toolbox and engineering a solution with what you have parallels the process of speaking to others in a new language.  Sure, there is the engineering design process where you find a problem, spend some time brainstorming ideas, select a solution, build a prototype to test and evaluate the results, and then reiterate and repeat until you have an optimal solution.  This is the process by which most teams follow when building a robot for the FIRST robotics competition.  But there is another process that occurs during the robotics competition.  Unexpected events occur, for example things break or you discover something else is needed, and you are forced to engineer a solution with only the parts and tools you can find on hand.  Therefore, it is important to stock your toolbox and inventory well, but also to be creative in engineering solutions with limited tools and hardware.  This was always the type of engineering I enjoyed the most, and I've found that it's helped me speak to others in new languages.  In my experience, I have found that with only a very limited vocabulary, it is possible to communicate almost all things I want to say, as long as the words in the vocabulary are chosen carefully.  For example, at a restaurant if I want to ask for the check but don't know the word for check, I can ask to pay; or if I don't know the word for pay, I can ask to give you money.  Sure the solution may not always be the most elegant, but it works and gets the message across.  And, at least for me, trying to sustain a conversation with a limited vocabulary in a new language is almost as exciting as engineering solutions to fix a robot during a fast-paced robotics competition.

Recientemente, pensaba de el proceso de aprender idioma y como esto proceso es similar de el proceso de conseguir herramientas y deseñar una solución con que tienes.  Claro hay un proceso de deseño ingeniero con pasos que incluyen buscar una problema, hacer ideas, elegir una solucion, construir un prototipo por experimentar y evaluar como es, y finalmente repetir otra vez y otra vez hasta encontrar una solución optima.  Esto es el proceso que la mayoria del equipos usan para construir robotes por la internaciónal competición de FIRST.  Pero, hay un otra proceso en la competición cuando no hay tiempo para pensar mucho y necesita arregular algo o hacer algo nuevo y tienes que hacer una solución con solo que tu tienes.  Por esto, es importante tener herramientas utiles, y tambien es importante saber como usarlos con mucho creatividad.  Esto es el tipo de ingenieria que me gusta mas y he encontrado que con saber un vocabulario pequeño es posible comunicar casi todos cosas que quiero decir.  Por ejemplo, en una restarante, si quiero pedir por la cuenta pero no se la palabra “cuenta” puedo decir “puedo pagar” o “puedo darlo dinero.”  Claro la solución no es bonita pero es suficiente bien para funcióna.  Y para mi, intentar a seguir una conversación con un vocabulario pequeño es divertido como arreglar un robot en una competicion rapido.  

Como hacer un alabe grande

Por la construción de los alabes por las turbinas grandes, hay algunas pasos. 

Primera, el alabe es hecho en un molde con puma y fibra de vidrio.  Despues de la puma, tenemos que cortar partes que no importa y lijar mucho.  Y despues de esto, el alabe es cubrierto con fibra de carbono y resina, y puesto en el molde otra vez. 

Despues de sacamos el alabe de el moldo, todavia hay muchos pasos.  Otra vez, hay partes de el molde que no queremos y tenemos que cortar.  Y entonces necesitamos lijar mas.

El molde usamos falta el geometria correcto.  Entonces tenemos que soldar un poco de metal para que el alabe es en el correcto posición cuando colocamos en el generator.

El proximo paso es a pintar el alabe.  Y entonces podemos instalarlo si son balanceado con los otros alabes.  A veces hay un paso adicional si necesitamos hacer huecos chinos (huecos mas ancho, como los ojos de chinos) a colocar con el generator.  

Tal vez escribiré estas instruciónes en ingles y mas de como hacer una turbina mas tarde. (Maybe later I will write these instructions in English and more about how to make wind turbines.)

Mas sobre luz por comunidades rurales

Como prometí, una historia pasada en español.

Sería interesante examiner si una molina pequeña es suficiente para hacer luz por una pueblo pequeño cuando pensamos la cuesta de instalacíon.  Una molina de dos punto cinco kilovatios cuesta casi tres mil nuevo soles.  Los alternativas incluyen generatores, paneles solares, conexion de la red electrica o siguiendo sin luz.

Mira la última alternitiva primera.  Una familia todavía sin luz que necesita hacer cosas cuando es oscuro necesita pagar uno a dos nuevo soles cada día por velas o otro tipo de luz de fuego.  Entonces necesitan trenta a seisenta nuevo soles cada mes.  En mas o menos un año, ellos pagarían la misma cuesta por la molina que puede hacer luz por mas tiempo de esas velas podria.

Generatores son populares por familias y empresas en Perú que son sin luz.  Esos generatores cuestan mas o menos quinentos nuevos soles cada mez a functionar.  Como se puede ver, despues de seis meses la cuesta por un generator por lo mismo tiempo es igual de una molina, y con la molina despues de seis meses la luz sería gratis.

Tambien podemos pensar como conectar un pueblo a la red electrica.  Pero por pueblos con solos unas pocas familias, esta es muy caro por cada famila y sería mucho mas caro de si cada famila tiene una molina porque normalmente estas familias no necesitan mucha luz.

Paneles solares tambien son una buena opcion.  Pero desvantajes son hacer limpio siempre y la cuesta.  Sistemas con dos tipos de energia con sol y viento pueden ser muy bien ideas especialmente si hay apoyo por los dos sistemas.

Siempre hay la pregunta quien paga por la technologia por estas comunidades.  Claro que las familias pagan si pueden y pueden pagar todo cuando comienzo o poco a poco cada vez hasta pagan por todo.  Sabemos la opcion poco a poco es posible porque ellos pueden pagar por velas ahora.  Esto es similar de como la empresa vende las estufas en Guatemala donde las familias pueden pagar la cuesta la misma cada mes como ya necesitado ahora por un estufa peor, entonces ellos no se sientan la diferencia en la cuesta y solo ven la diferencia en la estufa nueva.  Y technologias por regular cuando las familias pagan pueden ayudar tambien.  Una otra opcion es usar plata de el goviernmento por las comunidades sin luz.  Esto puedo ser bien por personas que queiren estar en el goviernmento pero puede ser muy dificil a ganar esta plata.  

Energía en una isla

Las islas flotante en Laguna Titicaca tienen luz. En la isla que viajamos, hay ocho familias y ellos pasan tiempo pescando y buscando huevos de aves y haciendo cosas para vender por turísticos. La luz en las casas es de paneles de sol y es sólo para luz en las noches por las familias a tener mas tiempo para hacer más cosas.

The floating islands on Lake Titicaca have electricity. In the island that we went to, there were eight familis who spent time fishing, collecting bird eggs and making artesional crafts for tourists. The electricity in the houses is from solar panels and it is only used for light in the evenings so the people can have more time to make crafts.

Energía de España

Este semana yo conocí dos amigas de españa.  Los dos tienen doctorados y una estudiaba energía renovable en españa.  Yo la pregunté ella de la energía en españa y aprendia que la mayoria todavia es de combustíbles de petroleum y gases, y carbón es raro.  Pero ella dijo que tambien hay mucha energía de viento en españa, y a veces mas o menos seisento por cento de la energía en españa es de viento.  ¡Que chevere!  Hay energia hidroelectrica tambien.

                 

This week I met two postdocs from Spain.  One was studying renewable energy in Spain, so we got to talking about where energy comes from there.  Primarily the power plants use petroleum or gas, and carbon is rare.  Wind energy is apparently utilized well there though, and at times it’s possible to get up to 60% of the country’s energy from wind.  There is some hydroelectric power too.

More on rural electrification

It might be interested to examine whether a simple small-scale wind turbine is sufficient for providing power to a small community and consider the costs of implementation.  The cost of a small 2.5 kW wind turbine could be about 3000 soles.  The alternatives include generators, solar panels, connecting the community to the electric grid, or remaining without electricity. 

Considering the last alternative listed first, for a family to remain without electricity, but want to have light to do things after dark, a family would pay around 1 to 2 soles per day for candles, leading to 30 to 60 soles per month.  In more or less one year, they would end up paying the same as for a wind turbine that could power lights for longer than these candles would last. 

Generators are quite popular for families and businesses in Peru without electricity.  These can cost about 500 soles per month to operate.  This means that after six months, the amount paid to operate a generator for that time could have been used on a turbine which would produce free energy after this time. 

We can also think about connecting communities without electricity to the national grid, however, for communities with only a few number of houses, this can be very costly per family, and be much more expensive than implementing a small wind turbine since these families typically do not need much power.

Solar panels are an option.  Some disadvantages to consider are maintenance (keeping them clean), and cost.  Bi-energy systems with solar and wind can be an excellent idea, especially if there is local support for both systems.

There is also always the question of how the technology for rural electrification is paid for.  Of course the families can pay if they are able to either by paying the money up front or a little at a time (and since they can currently pay for candles, the latter method is obviously feasible).  This is similar to how the stoves in Guatemala were sold by the company; they priced the stove with a payment plan that the families would not see any difference in what they were paying per month but would only see the difference in having a newer device.  And technologies that can be used to automatically meter and control the payments can help.  Another method is to obtain government money for electrifying rural communities.  This could be advantageous for politicians to support to get the support of communities, but the implementation of getting government funds to actually pay for the technologies can be difficult.  

Voy a escribir en español mas tarde.

Teaching clean energy in Peru

We recently went down to Lima to fix a wind turbine at a school that has been installed there a few years ago.  We had to install new blades on an existing turbine body that was at the school, so we would not be able to balance the blades on the existing disc for the turbine, a step that is usually done inside the shop where there is no wind and we don’t have to be standing on a roof.  To make this step easier, we tried a new method for preparing the blades.  The original method included adding weight near the center to make sure all of the blades were of the same weight, and then adding weight to places on the disc as necessary to balance the blades.  In the new preparation, when adding weight to make all blades the same weight, the weight was added in strategic locations to make the center of mass of each blade in the same location.  We determined the center of mass by balancing the blades on a fulcrum along two separate lines.  To add weight, holes were drilled into the blades and the appropriate amount of lead was added before filling the holes up with resin.  This new method helped us balance the blades at the site in half a day!  This is a big improvement to the old method.

Nosotros fuimos a Lima para aregular una molina en una escuela que instaló hace pocas años y rompió.  Tenemos que instalar alaves nuevas en una molina que esta en la escuela.  Por esto, no podemos balancear las alaves adentro la fabrica donde no hay viento y no necesitamos estar arriba un techo.  Para majorar el paso de balancear, hicemos un metodo nuevo por la preperación.  En la metodo original, todos tres alaves son lo mismo peso, y si no balancean, ponemos mas peso donde necesita.  Pero in el metodo nuevo, ponemos peso in lugares especial en las alaves para hacer el centro de masa en lo mismo lugar en cada alave.  Encontramos el centro de masa por balanceando la alave, entonces poner mas peso por haciendo huecos y llenar con plomo antes de lenar los huecos con resin otra vez.  Esto metodo nuevo nos ayuda balancear las alaves a la escuela en solomente una media dia.  Mucho mejor de el metodo viejo.

 

The story behind the wind turbine at the school is also pretty interesting.  This wind turbine is at a secondary school that is called “the best secondary school in Peru, and possibly South America.”  The school has a book chosen as its community reading assignment, where everyone at the school reads the book and then the classes can have discussions about it.  A few years ago, the book chosen was The BoyWho Harnessed the Wind, about a boy in a remote African village who heard about wind energy and spent a lot of time reading old books and trying to build a wind turbine from metal scraps he could find.  A student at the school after reading this book then approached the science teacher and suggested that students learn to build wind turbines.  The teacher did just that in her classroom, and went a step further and they found WindAid who helped put a turbine in the school.  The turbine is now a beacon for clean energy.  The science teacher made and teaches an environmental science class and is promoting clean renewable energy as much as she can, her main motivation being that because this is the best school in Peru, she could be teaching the future presidents of Peru, so educating them about clean energy and showing them why it is beneficial can really help the policies that improve the lives of the Peruvians of tomorrow.  I thought this was an interesting story showing how literature, science, engineering, and policy are intertwined.

La historia de porque la escuela tiene una molino es interesante tambien.   La molina esta en una escuela secondaria que se llama “la mejor escuela en Peru, y posiblemente America del Sur.”  La escuela tiene un libro por la comunidad que todos leen y discutimos en las clases.  Haces unas años, el libro fue “El Niño que Empleó la Viento,” sobre un niño de un pueblo de Africa que leó muchas libros de ciencia y trató de contruir una molina con basura de metal.  Dispues de leyo esto libro, un estudiante en la escuela preguntó la maestra de ciencia puede ella enseñar la clase sobre molinas.  La maestra hizo esto, y tambien conosció a WindAid y todos podemos una molina en la escuela. La turbina es un simbolo de energía renovable.  La maestra hizo una clase de ciencia de el medio ambiente y quere favorecer energía limpia y renovable mucho porque esta es la mejor escuela en Peru y posiblemente hay estudiantes que seré presidentes en el futuro.  Entonces, es muy importante enseñarlos sobre energía limpia y mostrarlos como esta energía puede mejorar las vidas de la gente.  Yo pienso esta historia es una bien ejemplo que muestra como literatura, ciencia, ingeneria, y politica mezclan/.

Reporte de la estufa investigación

Just like real scientific research, my analysis and report on the experiments I did for the rocket stove took several weeks to finish after performing the experiments.  In addition to the soot measurements, I also measured water boiling time and the temperature distribution of the stove. 

Como todas investigaciónes de ciencia, mi anailis y reporte de los experimentos de las estufas terminan algunas semanas despues de terminando los experimentos.  Ademas de examiné la hollín, medí el tiempo necessario hervir agua y la distribución de la temperatura en la estufa. 

                                                                                          

The water took the longest boil when the stove was started from a cold start.  When the water boiling test was repeated when the stove was lit when it was already hot, the same amount of water too half the time to boil.  Decreasing the time to boil to half again was possible by putting the pot inside the stove (see photo).  This is why many wood-burning stoves have pot skirts.

Agua necesitó mas tiempe hervir cuando la estufa encendió de una frio tiempo.  Menos tiempo necesitó cuando la estufa encendió cuando ya estaba caliente (un medio de la otra tiempo encendió de la frio estufa).  Es posible reducir el tiempo necisario hervir a medio otra ves si pone el olla adentro la estufa (mira la foto).  Esto es la razon que muchas estufas de leñs tienen faldas de ollas.

The different temperatures of the surface of the stove were studied with an infrared temperature sensor, and also with a much more real world test of tortilla making.  When putting enough wood in the stove to get the rear burners to sufficient cooking temperature, the front burner will burn the tortillas very quickly.  But the rear burners of the stove are not hot enough for cooking tortillas when the front burner was set to the ideal heat for not burning the tortillas (by using less wood).  I did find a great way to make use of the rear burners when the front burner was at low heat; when open, the rear burners were perfect for roasting marshmallows and making s’mores.

Estudié la distribución de la temperatura en la plancha usando una herrmienta de temperatura como infraroja, y tambien hice un otra experimento mas real para hiciendo tortillas.  Cuando puse suficiente leña en la estufa para hacer la plancha altras suficiente caliente, la fronte de la plancha es demaciado caliente y las quemaré las tortillas muy rapido.  Pero cuando la fronte de la plancha puede cocinar tortillas bien como menos leña, la plancha altras falta suficiente calor y no puede cocinar.  Yo encontré una bien opción por la plancha altras cuando la fronte de la plancha puede cocinar tortillas bien; la plancha altras esta perfecto para hacer angelitos asado (o malvaviscos tostados) y u’p’mas**.

** s’mores = some more = un poco mas = u’p’mas

This stove study was on the stove designed by Alterna.  The other stoves I worked on with my Spanish school in Guatemala are discussed in their blog, including a post on our talk about soot!  

In Peru, I haven’t seen many cookstoves.  In communities near the ocean where ceviche is common, cooking isn't necessary for this dish.  Gas is also very cheap in Peru, so many families use gas stoves.  I did see some three-stone fire pits for making chicha morada in one of the electricity-free houses.  And we did build a campfire at a lagoon in the desert that would have been perfect for making s’mores and roasting fish.

Field installations

Many communities in Sechura, Peru are without electricity, at least not connected to the main grid.  We recently took a trip out there to install and maintain wind turbines for some of these communities.  Here are some short summaries, more to come later.  (Hay muchas comunidades en Sechura Peru que no tienen luz de la principal luz fuente.  Viajamos a las comunidades a instalar y arregular molinos por algunas comunidades.  Aqui yo escribo un poco sobre esta viaje, y mas a venir pronto.)

A small group of about five houses got a new wind turbine last week that we put up.  This was supposed to be the site for a pilot test of a new method to fund the wind turbines.  A meter was planned to be installed on each house that was connected to the generator, and this meter would be capable of measuring and controlling the amount of energy coming through to the house.  After a month of letting the community use the energy from the turbine for free, they would switch to having to pay a fee for the energy they use, which would eventually pay off the cost of the wind turbine, and any future excess would go back into the community for maintenance or a new turbine.  Though, based on the remote location of this community, it was not actually chosen for the pilot test of this meter technology.

Playa Blanca, a community of 49 houses near in Sechura was chosen to be the final location for the pilot test of this meter technology.  The people in this community were very excited to get a new wind turbine, and they were interested in being able to pay for the energy, therefore, this meter technology would facilitate the payment logistics.  And the meter would help ensure that families only paid for what they needed and/or could afford, and the cost could be chosen to be an improvement for the alternatives.  For examples, families who currently only needed light in the evenings could be paying less to get enough electricity to turn on an LED for several hours a night than to buy one or two candles a night (1 sole each).  Or a family who is accustomed to having electricity for a television, from a diesel generator, could be paying less for the energy from a wind turbine than to operate their generator.  Playa Blanca also has some of the best wind resources in the world, according to NASA data, so this is an excellent place to put in small scale wind turbines for the communities here.  The closest city connected to the main electricity grid is 40 kilometers away, and it is actually more cost effective to put in small scale wind turbines than to connect this community to the grid. 

We also visited a house that had already arranged to purchase a wind turbine.  His wind turbine was installed, and he was making payments of about 500 soles per month, collected in person.  This works well because the owner is very interested in making payments for his wind turbine, and WindAid is willing to come by and collect money on a regular basis.  However, this model runs into problems if either of these situations is not present, and this would be where the meter type of system would be of great help.  Many Peruvians seems to want to pay for electricity.  Before having wind turbines, many already have televisions or other electricity-powered appliances run on generators, which are expensive to operate, or batteries, which are expensive in time and money to get recharged in the nearest town.  This guy with the wind turbine loves his television and was excited to show it off to us.

We stopped by another small roadside restaurant off of the Pan American highway (forgot to take a photo).  The owner sold us some cold drinks, and mentioned how she was paying 500 soles a month to operate her diesel generator for the lights in her restaurant.  She saw our wind turbine propaganda (hats, stickers on the car, etc.) and was very interested in the product.  She could easily switch to paying 500 soles per month as a payment for a turbine and then never have to pay it again once the cost of the turbine (about 3000 soles) was paid off.

La finca de café

Here’s an overdue story about a trip to a coffee plantation led by my Spanish school in Xela.  We learned about the coffee making process, involving stuff about heat transfer.  First, we learned about differences between red and green coffee beans.  The red ones can be peeled and opened, and the green ones cannot, meaning that they have to be processed as is.  The green ones are usually the ones that get dried and made into instant coffee.

Hace algunas semanas, mi escuela de español en Xela fue a una viaje de la finca de café.  Nosotros aprendemos como preparar café y cosas en esto proceso sobre transferencia de calor.  Primera, aprendemos que es la diferencia de cafés rojos y verdes.  Podemos abrar los cafés rojos, pero no podemos abrar los cafés verdes.  Los cafés verdes necesitan preparar como fueron y a menudo estos es lo que cambiar a café instante. 

We saw three different methods of drying the coffee beans.  One is a machine from Germany (photo below left), where the coffee spins in circles while heat is allowed into the system.  Another method involves putting the coffee beans in a large pile above a grate where heat comes in through the bottom, and workers crawl through the mixture to distribute the heat and let the moisture evaporate through the top.  The last method is to let the coffee beans dry outside (photo below right), though if there is any chance of rain overnight these must be collected every night and put back out.  The machine from Germany is obviously the best method because it dried the coffee fast, within hours, and requires minimal input.  The method with the workers mixing the coffee is bad for the workers’ health, and they are always sick when working in this process.  The coffee drying outside takes days.  I asked why they don’t just build another machine like the German one.  My teacher said he wasn’t sure but it could be that the plantation owners don’t want to invest in one and take away jobs for the workers. 

Vemos tres opciónes para secar los cafés.  La primera opción es una máquina de Alemania (foto abajo a la izquerda).  Los cafés dan vueltas mientras calor entra la máquina.  La segunda opción es una caja donde calor entra en el piso de la caja, y trabajadores caminan en los cafés para mezclar.  La ultima opción es solamente poner los cafés afuera para secar (foto abajo a la derecha), pero si hay lluvia necesitan mover los cafés para que los no son mojados.  La máquina de Alemania es mejor porque los cafés secan mas rapido de las otra opciónes y no necesita mas trabajo.  La segunda opción (como la caja) es muy mal por la salud de los trabajadores y ellos siempre estan enferma.  La ultima opción (los cafés afuera) es muy lento.  Yo pregunté ‘¿porque ellos no construyen una otra máquina de Alemania?’   Mi maestro respondó ‘es una buen pregunta’ y el dijo posiblemente porque los dueños no lo queren y quieren trabajos por mas personas.

The final dried coffee beans of the best quality are the whitest ones, as shown below.  Almost all of the good coffee coming from Guatemalan coffee plantations are exported. 

La ultima paso de los cafés mejores es en la foto abajo donde son muy blancos.  La mayoria de los cafés mejores venden en otra paises.

Technology distribution models

It was interesting to learn about the different distribution models for the stoves in Guatemala.  Recall that the Spanish school developed a very cheap and easy safe stove that could be provided to families for little to no cost.  The company I volunteered with had a different model, of selling the stove to families, and any family could purchase one, and while the costs were on the higher end, the families could pay in payment plans where each month their fee was estimated to be equal to the amount that they would typically pay for extra wood for a non-fuel-efficient stove.

Es muy interesante aprender sobre las diferente modelos de distribución por las estufas en Guatemala.  La estufa de la escuela tenía una deseño por la estufas que es muy barrato y facil.  Entonces las familias podían recebir las estufas por menos o nada cuesta.  Las estufas de la compania distribieron con un otra modelo.  La compania vendía estas estufas a alguien familia.  La cuesta era mas de un tradicional estufa, pero las familias podía pagar un poco cada mes, y la cuesta por una mes es la misma de la cuesta por la leña por un estufa tradiciónal. 

Neither of these models are better.  They each have tradeoffs and serve different markets, and having both types of models helped ensure a larger population of Guatemalans with safe stoves.  Sustainable distribution models for safe stoves, and other types of technologies for improving quality of life in rural areas, are sometime more difficult that the engineering of the technologies, though often these concepts are intertwined. 

No modelo es major.  Cada modelo tiene un diferent propósito y cada modelo tiene intercambios.  Mas modelos es mejor por los Guatemaltecos porque mas familias reciben estufas.  Modelos de distribución que son sostenible de estufas y otra tipos de tecnologia es una problema y a menudo haciendo un bien modelo es mas dificil que la deseño de ingenieria, pero ambos son conectado. 

When I was talking with my Spanish teacher in Guatemala about energy in his country, I asked about why wind and solar energy was so rare.  His answer was that these technologies are very expensive. 

Cuando yo hablaba con my maestro de español sobre energía en Guatemala, lo pregunté porque no hay mucho energía de viento y sol.  La repuesta era que estes tecnologias son muy caro. 

WindAid, the organization in Peru that I am currently working with, has come up with several models for distributing wind energy to communities without power.  WindAid has a basic volunteer program that includes training in manufacturing their wind turbines, and almost half of the volunteer fees goes to pay for a wind turbines for a home or community area without power in Peru, and the people without power get these wind turbines at no charge.  During my first week in Peru, I helped install one of these 500 W wind turbines at a beach restaurant in Sichura, Peru. 

This restaurant was in a beach area that is popular with the locals, and before the turbine was installed, this restaurant and all others in the vicinity had to rely on batteries to use lights, radios, etc.  The wind turbine will now allow the owner to keep his restaurant open later at night with music and lights. 

This type of social entrepreneurship where volunteers provide much of the funds for these technology projects has the potential to work well on a small scale.  But WindAid has also come up with other methods to get wind turbines out to communities who need power.  This beach restaurant was chosen to receive a wind turbine in part, I think, because it would be a great spot for publicity of the organization and their wind turbines.  We posted fliers explaining wind energy at the restaurant, and we did indeed get a lot of curious beach goers come by and ask questions about it.  The flyers encouraged people to contact WindAid, and I assume will lead to more purchases of wind turbines, more communities inquiring about obtaining a turbine, and hopefully more financial support into the program. 

WindAid does also sell wind turbines, so clean energy (energía limpia) can go out to more locations.  Furthermore, the organization is also working with another organization to provide the wind turbines for free, and then after the community uses it for a month or so to see how it can help improve the quality of life by enabling children to study after dark, people to charge cell phones, etc. a device will be installed to charge the users for each kW-hr they use at a very low cost.  They theory is that after enough time, the cost of the wind turbine will be paid for, and thus this becomes a sustainable distribution system of wind turbines.

Energy in Peru

I’m still in the process of analyzing all of the stove data I collected, but will have to do that in Peru since I’ve moved on to additional interesting projects. 

I got picked up by this vehicle in Piura, Peru where I will be helping install a 500 W wind turbine (turbina eólica) in communities without power.  What’s neat too is that I found out this vehicle runs on natural gas as well as gasoline.  In fact, many vehicles in Peru are natural-gas-gasoline hybrids, and in the big cities, it’s very easy to find natural gas for purchase which is much cheaper than gasoline, and the gasoline tank can still be used in the mountains.

Our first stop, after picking up a piece of wood (madera) to mount the turbine on to, was to a community where one of these 500 W turbines had already been installed.  These turbines are about the perfect size for a single multi-person household without electricity from the grid, and these turbines can generate enough electricity to power lights at night and possibly charge cell phones and sometime even a television.  Some of these houses also have solar panels that are primarily used for charging cell phones, though the solar panels have a high upkeep since they get dusty frequently, so that's why the wind energy is great to have (las panales de sol necesitan limpiar con mas frecuencia, es la razon que energía de viento es mejor).  

This particular house we visited was having problems of the turbine not reaching its full potential, most likely due to the fact that there were trees in front causing turbulence (los arboles en frente de la turbina son una problema).  We debated for a while whether the best solution would be to raise the height of the turbine since wind speed picks up with altitude, though this would create more problems with vibrations, or to move the turbine to another location.  We even began to think about what type of cheap tool we could use to measure the vibration force, maybe a smart phone app of some sort (pensamos lo que herrmienta barrata podemos usar para medir los vibraciónes, posible una aplicación de telefonos inteligentes).  Another suggestion was put out to cut down the trees (una otra opción fue cortar los arboles).  The final decision was to move the turbine and make it taller (la ultima decisión fue cambiar el lugar y hacer mas alto).  Since the sun was about to go down when we arrived, the family was planning to get this started and maybe finished, and we would return another day if needed (la familia empezará este proyecto y talvez terminará tambien, y nosotros volveremos si es necesario).

Mas a venir sobre mi primera viaje de instalación en Peru, y terminaré las estufas tambien.  (more to come about my first installation trip in Peru, and I will finish the stoves too).

Soot

A group of women came to my Spanish school earlier this week as part of the next group that will receive free or near-free stoves from the school.  Another student and I gave a talk to this group on “Las estufas y los beneficios para la salud.”  As the engineer, I explained about soot from stoves, and the other student, a medical student, explained about the health effects:  “el humo de las estufas tradicionales contiene miles de sustancias que con similares [a cigarros] y que son muy peligrosos para el cuerpo.  La peores incluyen la ceniza y hollín que se forman a causa de combustion en el fuego.  Estos cambian el calor de una olla nueva a negro.  Y la ceniza y el hollín pueden mezclar con el aire y entran nuestros cuerpos... (insert medical stuff here)... Las estufas de la escuela son mas eficientes de las estufas tradicionales.  El proceso de combustión in nuestras estufas es mas completo y las partículas de hollín cambian a gases mas limpias.  Entonces el aire es mas limpio tambien.” 

Here are some initial results of the soot measurement in the other stove project that I’ve been volunteering with.  This was from my first time lighting the stove, so this may not be the best gauge of how well the stove is performing.  It’s obvious though that even with this simple diagnostic we can tell that there’s soot forming from the flame.  Now to figure out how to reduce the amount formed. 

Before/antes (top/arriba) and after/despues (bottom/abajo)

Planning experiments

Understanding the theory of combustion and heat transfer in a stove can only help so much with the design.  To understand the performance of the current rocket stove design more, experiments need to be performed (experimentos son necesario para entender como es la functión de la estufa de cohete).  Unfortunately, we don’t have the funds for laser absorption diagnostics in Xela.  So what tools can we use for experimentation?  (No tenemos herrmientas por absorbción de lasers en Xela.  ¿Entonces, que herrmientas pedemos usar medir cosas en experimentos?) 

The company I’m working with has a few tools for experimentation.  I have two thermocouples, one with a limit near the boiling temperature of water, and one with a limit of roughly 773 Kelvin.  I can also use an IR temperature sensor to measure surface temperatures on non-reflective surfaces.  Furthermore, I have access to a scale to measure weight.  What would really be useful would be if I could monitor the air flow velocity, and that could give me a sense of the air-fuel ratio.  Additionally, a method to monitor soot would be helpful to determine how complete the combustion process is.  We started up the stove and played with the tools we had, and also several other methods of monitoring things.  The temperature measurements seem fine.  I explored a poor man’s soot diagnostic by putting a piece of clean pumice stone in the gas flow chamber (la idea gracias a Adela) – after a few minutes, the pumice stone will begin to darken from the soot, and using this monitoring technique I may be able to determine whether more or less soot is formed in different stove configurations.  To make more quantitative soot measurements, a particle counting device can be purchased for about $200, though this won’t happen in the time that I’m here.  We explored the air flow velocity by lighting another starter stick of wood and placing it near the air inlet of the stove, and by watching the flame enter the air inlet we could tell that there was substantial airflow.  I doubt this would yield a very good quantitative measurement of air flow velocity, but maybe by measuring the angle of the flame entering the air inlet I might be able to determine whether changing the flow geometry inside the stove has a significant effect on the air flow velocity. 

My planned experiments include time-to-boil tests.  In these tests, I will make lots of temperature measurements and ad hoc soot and velocity measurements.  And maybe a tortilla cooking test will occur as well. (Voy a medir la temperatura en muchos lugares y voy a tratar de medir hollín y velocidad de aire.  Haré un experimento de cocinar tortillas también).

Results to come.  Experimental suggestions welcome.

Rocket stoves

What is a rocket stove and how does it function?  (¿Que es y cómo función una estufa de cohete?)  The basic design of a rocket stove was introduced by Dr. Larry Winiarski.  A rocket stove consists of a fuel magazine for wood or other combustible fuels, supported above the entrained air into the flame by a grate or other supporting structure.  A rocket stove also has an internal chimney where the heated flue gases can further react. 

Rocket stoves are one of the primary types of fuel-efficient wood burning stoves in current programs that build and distribute cheap wood burning stoves to developing countries.   Why is a rocket stove more efficient than a normal stove?  (¿Porque es la estufa de cohete mas eficiente de una estufa normal?)

When wood is heated in a basic burning process, organic compounds in the wood gasify and combust with the surrounding air.  This behaves similar to a diffusion flame where the oxygen required for combustion diffuses into the flame from the outside.  If there is not enough oxygen to react with the gasified compounds, then unburned gases will result and appear as soot.  This leads to a loss in flame temperature, and thus lower energy conversion efficiency in the combustion process.  The rocket stove addresses these issues in several ways.  First, because the air enters the combustion process from under the flame, more mixing of the air and the fuel occurs before the flame (primero, la aire entra la proceso de combustion abajo de el fuego, la aire y los combustibles mezclan mas antes de el fuego).  Thus, the flame more closely resembles a premixed flame, which has the potential for a higher combustion temperature and less unburned gases than a diffusion flame if the air/fuel ratio is optimized.  Second, even if unburned gases remain, they can further react in the internal chimney in the rocket stove before heating the pot (segundo, si hay gases que no quemar en el fuego, los gases pueden quemar en la chimenea adentro antes de cambia calor con la olla).  Therefore, a properly designed rocket stove can be very efficient at converting energy to heat with clean combustion (entonces, una estufa de cohete con una deseño inteligente puede cambiar energía y calor muy eficiente y tiene combustion mas limpio).

To improve the cooking ability of the stove, the heat transfer efficiency must also be examined (necesitamos examinar la teoría de cambio de calor para mejorar cómo buen function la estufa).  Both convection and radiation heat transfer are important for a pot directly above the fire (Hay does tipos de cambio de calor que es muy importante por una olla arriba del fuego).  For two or three pot stoves, with a plancha/cooking surface over the internal chimney, the rear burners receive less radiation, and thus convective heat transfer is the predominant energy transfer mechanism (por estufas con dos o thres ollas como una plancha arriba de la chiminea adentro, las ollas segundaria no reciben calor para radiación y entonces conveción es mas importante).  To improve the convective heat transfer coefficient, the flue gas channels under the rear pots can be reduced, or turbulence can be induced, both strategies which have the potential to restrict the airflow and cause there to not be enough air and lead to soot formation.  These are the tradeoffs for stove design (estes es los intercambios para deseño de estufas).  Most of the literature on heat transfer in cook stoves are on single pot stoves, so many improvements are likely possible for plancha-topped multipot burners.

Types of stoves in Xela

The stove in my host family’s kitchen is a normal box stove where the combustion chamber is filled with wood and air enters through a small opening in the door (la estufa in la cocina de mi familia en Guatemala es un pollo y las leñas llenan la caja de combustión y la aire entra la caja por un hoyo en la puerta).  I’ve eaten lots of delicious rice, beans, eggs, tortillas, tamalitos and meat cooked by this stove (comí muchos arroz y frijoles y huevos y tortillas y tamalitos y carnes deliciosos que mi madre cocinó con esta estufa).  This stove looks like it’s made mostly of concrete and bricks, similar to the stoves my Spanish school installed for many families, and therefore, cannot be moved.  

In addition to these permanently fixed stoves, various different types of portable stoves can be purchased in Xela.  I saw a few different types at several hardware and appliance stores, including a portable enclosed box type stove (se llama un pollo) and portable gas stoves.  The wood stove shown below is about $125 (la estufa de leña es un mil quetzals) and the portable gas stove is about $200 and comes with one free cylinder of propane (la estufa de propano es un mil seiscientos quetzales y incluye un cilindro gratis). 

The portable gas stove costs no more than 10% more than the efficient rocket stove (la estufa de propano cuesta no mas de dies por ciento mas de la estufa se llama rocket).  This may beg the question why would Guatemalan women buy the wood-burning rocket stove over a gas stove.  I’m not sure what the cost of propane is in Guatemala, but I’ve been told that gas cooking is considered a more expensive affair, therefore, it’s likely that an efficient wood-burning stove that costs the same as the gas stove will be much cheaper in the long run.  Furthermore, I’ve also been told that Guatemalans prefer their beans to be cooked over a wood fire, and that beans cooked over a gas flame or beans cooked in a pressure cooker “do not taste as good.”  Therefore, many Guatemalan women who own gas stoves also have a wood burning stove in their kitchen if they can afford it.

Stove building

My teacher, several students, and I went to a small community about 8 km from Xela to finish the last step in completing the stoves that the school provided them (mi maestro y cuatro estudiantes y yo fuimos a comunidad peqeño mas o menos ocho kilometers lejos de Xela y nosotros terminados paso cuatro y final para construir las estufas de la escuela).  To install the door, we marked where the holes to attach the doors needed to be, then we used a hammer and chisel to make two holes in the bricks, and then we put the door in place and filled the holes with a mixture of cement and sand (marcamos donde necesitamos los hoyos para la puerta y entonces usandos un madrillo y cincel para tajar dos hoyos y entonces ponimos la puerta en sitio y llenandos los hoyos con una mezcla de cemento y arena). 

It was neat to see the completed stoves, which each had a combustion chamber much smaller than I originally envisioned when I saw the stove design.  One of the stoves we worked on was being used, and it was clear that there the small space for the combustion chamber was filled mostly with burning wood, and therefore there was not a lot of excess space with gas to be heated, and this part of the design is probably what makes the stove fairly efficient.

There weren’t really any streets or addresses in this rural community so we spent a lot of time looking for the houses that had the stoves from the school.  It would be interesting to learn more about how these types of communities get food, water, electricity, etc.

Intro to stove building

There are primarily two different types of cook stoves that burn solid biomass in developing countries.  One is a normal cook stove where the firewood is completely contained inside the stove and all of it can burn, and air can enter the combustion chamber through various locations, including openings in the stove top and through the fire door if it is open.  The other type of cook stove is called a “rocket stove” where the firewood is inserted into an opening in the combustion chamber, and only the tip of the firewood burns and the air required for combustion enters the chamber from primarily below the burning firewood for best efficiency.  These are the two types of stove for the two stove projects I will be helping with in Xela.  Both are more efficient that the traditional cooking method of creating a “three-stone stove” (using three stones to support a pot over an open fire), and in addition to the improvements in efficiency, these two types of cook stoves can direct the smoke resulting from the fire to outside of the house, improving the health of the Guatemalan women and children who typically spend lots of time in the kitchen.

The cook stove with only the firebox is very easy to build (la estufa con solo la caja de fuego es muy facil para construir).  It costs only about $100 and can be build in a four mornings in four steps by student volunteers (la estufa cuesta solo mas o menos ochenta quetzales y es posible construir en cuatro mañanas en cuatro pasos con estudiantes voluntarios).  The materials and tools that are required for the stove are also very simple (Las materiales y las herrmientas es necesario para construer la estufa son muy simple).  The materials include cement blocks, bricks, white sand, cement mixture, mud, and sugar for the base and the firebox (las materiales necesario es blocks de cemento y ladrillos u sacos de arena blanca y sacos de barro molido, y tapas de panela).  Also needed is the stove top, the fire door and the chimney (la plancha y la puerta y la chimenea tambien es necesario).  The first step is to build the base which has three layers of bricks and cement blocks (el primero paso es contruir la base; hay tres hiladas de ladrillos y blocks de cemento en la base).  The second step is to lay out another three layers of bricks to build the firebox with holes for the door and the exhaust (en el segundo paso los estudiantes volantarios ponen tres hilados de ladrillos con dos hoyo, uno para la puerta y uno para la humo sala).  The third step involves building a ramp inside the firebox for the hot gasses to heat up the burner in the rear of the stove (el tercero paso es construer una rampa adentro la caja de fuego para la gases calientes ir a la humo sala).  The third step also involves installing the chimney and the cover to keep out rain (el tercero paso tambien necesita la instalación de la chiminea y la sombrero de la chininea).  In the fourth step, the firebox door is put in place (en el paso cuatro los estudiantes voluntarios poner la puerta).  In each step, the spaces between the bricks are filled with a mixture of mud, and after the each step, it is necessary to wait for the cement and mud mixtures to dry and this is why the stove cannot be finished in a single day (en cada paso necesario llenar las espacios con una mezcla de barro y despues de terminar cado  paso, es necesario esperar, y es la razón los estudiantes nececitan quatro dias para construer la estufa). 

I’m still learning about the “rocket stove.”  From what I currently know, in a rocket stove only the tip of the firewood is in the combustion chamber, allowing for more complete and cleaner burning which leads to the potential of a higher efficiency stove.  Furthermore, if the air enters below the coals, the combustion process is also expected to be better than in the enclosed firebox stove (si la aire entrar la caja de fuego abajo de la leña la proceso de combustion es mas eficiante de la estufa normal).  Commercial stoves with the rocket design can be 50 to 100% more expensive, but the trade off for the extra cost in the stove can be recovered by the savings in firewood costs.  In many engineering projects tradeoffs exist, and different stove designs may be better for different families (en muchos proyectos de ingenieria hay intercambios y deseños diferentes para las estufas pueden mas bien para familias diferentes).

Energy in Guatemala

I am in Quetaltenango, Guatemala (Xela) for the next two weeks learning Spanish and volunteering with two different cook stove projects.  My Spanish teacher is also an engineer (mi maestro también es un ingeniero) and finished his PhD in agricultural engineering (doctorado de ingeniera agricultura).  From him, I learned a lot about the different types of energy resources in Guatemala, most of them are from renewable resources (más energías en Guatemala es renovable).  

Most electricity comes from hydropower (más electricidad es de hydroelectrica), but some solar, wind, geyser, diesel, and natural gas are also used.  Solar and wind power (electricidad de sol y viento) are primarily found in smaller residential neighborhoods.  There is a local project nearby Xela for a electricity from geysers (Hay una proyecto circa de Xela por electricidad de geisers).  Electricity from propane and methane (electricidad de propane y methano) is considered very expensive (es muy caro).  Some diesel is also used for electricity generation, but the diesel is not biodisel (pero no es biodiesel).

We also talked about what supplied energy to cars in Guatemala.  I was disappointed to find out that pretty much all cars are run on petroleum fuel, a non-renewable fuel (todos los automóviles usan petróleo, un combustible no renovable).  There is no methanol or ethanol biofuel (no hay methano o ethano biocombustibles).  There is some use of biodiesel in Guatemala (I think it’s used in cars), and the biodiesel in Guatemala is made from a plant or vegetable oil (pinón o aceite vegetal).  Other technologies are clearly too expensive for Guatemalans for powering their automobiles, such as electric cars and hydrogen fuel cells (automóviles electrico y celdas de combustíon de hidrogeno).

My teacher also taught me a lot about different agricultural things in Guatemala (agricultura organica, vermicultura, plantes medicinales, y lentrinas secas).  He even suggested a farm (una finca) where I could visit to see all of these projects, though I don’t know if I’ll have time.  The biggest problem in Guatemala are water, trash, and CO2 (hay problemas de agua, basura, y CO2), and these are additional areas where more research and/or development could be helpful.

Lastly, I learned about cook stoves in Guatemala.  My teacher designed the improved cook stove (mi maestro deseña esta estufa mejorada) that the Spanish school builds for select local Guatemalan families.  The intelligent design is very simple (el deseño intelegente es muy facil): easy to build, easy to understand, and functional, and compared to an open fire, the improved stove uses 55% less firewood (la estufa mejorada usa 55% menos leña).  The stoves consist of a base, a firebox (una casa de fuego), and cook top (una plancha).  The main disadvantage of these stoves is that the metal cook top is very expensive (una desventaje es la plancha de metal es muy caro).

After my morning Spanish lesson, I went to visit a company in Xela that builds and sells improved cook stoves (visito una compania en Xela construyen y venden estufas mejoradas).  In contrast to the stoves built at my Spanish school which are donated at low to no cost to select Guatemalan families, this company operates with a business model where all their stoves are sold at cost, but all families can buy them.  The stoves built by this company are designed to be much more efficient than both a three-stone fire and a normal enclosed cook stove.  I will be volunteering with this company for the next two weeks, working on questions including the design of the entrance for the firewood, the optimal geometry for combustion chamber and internal chimney, and additional heat transfer issues.

I started to do a literature search on cook stove research, and successful designs are (a) backed up by sound principles of heat transfer, (b) targeted to a particular region, (c) require no substantial behavioral modification from users, and (d) provided with follow-up support [Ahuja 1990].  Unfortunately, most of the research in the literature seems to be for cook stoves in rural Africa and India, where single pot stoves are sufficient.  In Guatemala (and other Latin American countries I presume) where tortillas need a plancha to be cooked on and multi-pot stoves are common, the stove designs need to differ from the successful stoves distributed in Africa and India.  One challenge is to figure out how to most efficiently get heat to the rear burners (since the main flame is under the primary burner only), which do not exist in the single-pot stove designs.  Other challenges include lowering the cost, making the stove more easily transportable and deliverable, and designing the stove such that it can burn all day if desired (apparently this is desired by Guatemalan women).