Water For San Genaro -- part 4

We finally jumped through the last two hoops of the bureaucratic procedures for establishing a public water access in San Genaro. The water utility required that we obtain written permission from the municipality to block the road for the period of time necessary to make the connection. The municipality chose to approve it for the period December 18 to 22, so unfortunately I won´t be around for the inauguration and celebration. But Freddy invited me and some of the neighbors to his house for dinner a few days ago, and they presented me with a little gift for my efforts -- a retablo (a Nativity scene in three parts, enclosed in a wooden box).

The dinner was pachamanca, a meal traditionally prepared in the ground over heated stones, with the food wrapped in banana leaves to protect it from the dirt and retain the juices. It usually consists of three kinds of marinated meat, potatoes, sweet potatoes, corn and fava beans.

Your Contributions Are Needed

The longer I work here, the more firmly I become convinced that donating things to people (whether food, housing, or whatever) is the wrong way to help the poor. In fact, it´s counter-productive because it simply maintains a cycle of dependency. People become accustomed to receiving things and begin to feel that because they´re poor they have a right to handouts. Worse, they begin to believe that the solution to their problems is not within their own power, that they must depend on others to ¨fix¨ the situation in which they find themselves.

I think that those of us who are lucky enough to have been born into a country with great wealth have a moral duty to share our wealth with others who are less fortunate, but we should do it not by sharing our cash, but by sharing our knowledge: teaching them to create their own wealth -- teaching them to fish, rather than giving them fish.

Energy-saving technologies are money-saving technologies. They have the potential to create wealth, and quickly. Not a lot of wealth, but enough to make a significant difference in the lives of the poorest. For someone who lives from day to day without stable employment (about a quarter of the population of Lima) and sometimes has to decide between buying food or paying the electric bill on time, it can mean having enough money to do both. But it will take time and dedicated effort to teach people how to use these technologies, to overcome their resistance and to convince them that a small investment that is within their means will produce a savings many times greater, which they can use to improve the nutrition of their family or buy the materials that their children need for school.

My friend Martin (an anthropologist) and I have formed a team to continue disseminating the ¨retained heat cooking¨ technology that we have found to be successful in significantly reducing the use of gas in the preparation of meals at the women´s club in Pamplona. We are going to adopt two more women´s clubs in Chorrillos (closer to where I live) and perform more rigorous studies of the benefits and the problems with acceptance of the technology. Ultimately the use of these retained heat cookers can be self'-financing since the energy savings quickly pays for the initial cost of the device, and there is virtually no maintenance cost. But during this start-up phase we need to buy materials to construct various prototypes, buy gas and other combustibles to conduct our experiments, and pay the bus fare of some of the volunteers.

So far I´ve been financing this work out of my own pocket, but I know that some of you are interested in helping out, and since we´re approaching the end of the year I suspect that some of you are planning charitable contributions to reduce your tax burden. You can send your contribution by check to Una Familia, whose temporary address is 6440 Harbridge Road, Indianapolis, Indiana 46220. We are a 501(c)(3) non-profit organization, so all contributions are tax deductible. I can promise you that your donation will not be used to pay salaries (all of us are volunteers). It will provide us with the materials we need to do our work, and reimburse the cost of transportation for those volunteers who could not afford to help us if they had to pay it themselves. And of course I´ll continue to keep you updated on the things that we accomplish together.

Day Trip To Chincha

Yesterday Sonia and I took a bus to Chincha, a town about three hours south of Lima in a fertile valley where there are many vineyards, some nice beaches, an archeological site, and a very large and interesting market. We had time to visit everything except the vineyards. In the market we found huge freshly caught shrimp selling for less than $3 per pound. But since I didn´t have any way to keep it cold for the rest of the trip, I didn´t buy any. Next time I´ll come prepared!

The typical food of this area is sopa seca (literally ¨dried soup¨), which consists of a mixture of dried potatoes and fresh potatoes cooked in a peppery sauce, and a helping of spaghetti coated with ground basil.

Class On Solar Water Heaters

The second class of the technology workshop took place on Thursday. We talked about the principles of heat transfer underlying the operation of a solar water heater, and some possible uses such as water for bathing, cooking and cleaning, as well as purification of water. Then we divided up the six students into two teams and each team built their own solar water heater.

Inauguration of Technology Workshop

I decided a few weeks ago to set up a small research and development workshop so that volunteers could carry on developing the energy- and money- saving technologies that I´ve been working on. Miguel, my landlord, graciously agreed to let me use part of the big room below my apartment that was being used for storage. I´ve been outfitting it with tools and equipment for working with wood, metal, styrofoam, etc., and instruments for conducting experiments, like a gas flowmeter, balance and thermometer. Yesterday we had the formal opening of the workshop with a half-day class. Only about half of the people who said they were interested in attending actually showed up, but there were at least two, Lucy and Olivia, who are planning to volunteer in the workshop. And the fact that they are women makes them more valuable in the role of disseminating information, since most of our potential users are women, and men are regarded as knowing nothing about cooking.

Several other friends are donating their labor to help build workbenches, shelves, etc. The mission of the workshop, which we´ve named Centro de Investigaciones en Tecnología Ahorradora -- Research Center for Saving Technology -- is to develop, implement, test and disseminate low-cost technologies that conserve energy (hence money) and are applicable to the needs of the poorest members of society.

Women´s Club in Pamplona -- part 2

I´ve spent the past several weeks designing a couple versions of a retained heat cooker (RHC) -- an inexpensive device that cooks food by retaining the heat that has been stored in the food after boiling it for a very short period of time. Essentially it´s just an insulated and sealed box or bag or basket. It takes up to twice as long to cook some foods, like beans or whole potatoes, but no fuel is consumed during the cooking process, the food can´t be burned by an inattentive cook, the kids can´t burn their hands on the pot or the fire, and the cook can leave the kitchen and go do something productive while the food is cooking.

The first RHC that I designed was for the women´s club, where they cook for 120 people every day. It´s a big plywood box in two parts, with 4 inches of styrofoam walls and a reflective plastic lining. It had to be rugged to survive daily use with pots of food weighing more than 100 pounds. Last week I installed it and trained them to use it. They´re now using it daily to cook about 40 pounds of rice. After bringing the rice to a boil for 5 minutes, they lift the pot into the RHC (luckily, it's a pot with four handles, because it takes more than two people to lift it!) They leave it for two hours, and the rice is done. At that time it´s still at 199 degrees F, so it stays nice and hot even if the rest of the meal isn´t ready for another hour or more. The women say that the rice is more evenly cooked than when they cook it over the gas stove. They proudly show off their new tool to all of the customers who come to buy their meals.

Several of the women and some of my neighbors asked me to design a smaller version for use in their homes, so I´ve built a much cheaper version from just styrofoam slabs and a plastic liner. The cost of materials is about $8, so someone could earn a living making a couple of them each day and selling them for $12 each.

Water for San Genaro -- part 3

I had another meeting with the neighbors on Wednesday and told them that SEDAPAL had approved the installation of the pilón. I brought a long two notebooks, one for recording meeting minutes and decisions and another for accounting, and told them the time had come for them to take ownership of the project and form a committee to administer it. They elected a president, treasurer, secretary and a vocal (whose only responsibility apparently is to call together the neighbors when they need to have a meeting).

They quickly put together an estimate of about $100 in materials that would be needed to bury a pipe from Fredi´s house to the control point where SEDAPAL will install the connection, about 100 meters away. Each family agreed to contribute their share for materials and to help dig the trenches on Sunday morning at 6:00 am. I arrived around 7:30 to take some pictures. By 11:00 they had finished everything except the installation of the faucet and a brick enclosure to protect it. They decided to hire an albañil (professional craftsman) to do that work. We expect that sometime this week SEDAPAL will turn on the water, and we´ll inaugurate the pilón by breaking a bottle of champagne over it.

My First Publication In Peru

I´ve been taking photos and writing design documents in Spanish for all of the various devices that I´ve created (most of them adapted from other people´s inventions) so that anyone can build them. And after Sonia corrects my grammatical errors, I´m planning to publish them in a couple of places on the internet where ¨stove geeks¨ like me hang out.

Recently I noticed that one of the newspapers in Lima frequently publishes designs for wood-burning ovens and ideas for starting businesses or saving money. They even published a design for a biogas generator using guinea pig poop! So I emailed them the design for my solar water heater about a month ago. Since they never responded, I figured they weren´t interested. Then today my landlord showed me the front page of the newspaper, and there was my picture of the solar water heater on my roof! On page seven they published the steps for building it. The rest of the article (list of materials, principle of operation, suggestions for adapting the design) will be published tomorrow.

Birthday Parties

I got to celebrate my birthday twice this year! Once on Saturday with the kids at Lucy´s project, and again on Sunday with Sonia and our friends. Sonia and her friend Malena cooked pollo al sillao(chicken with soy sauce, ginger and garlic), rice with raisins and nuts, and potatoes. And the birthday cake had fillings of manjar blanco (caramel paste) and guanabana (a fruit). In Peru they always sing Happy Birthday in English, with a very bad accent (¨hoppy beerthday ...¨), then they sing Feliz Cumpleaños.

Water For San Genaro -- part 2

After gathering all of the necessary documents to present our proposal to the water utility, SEDAPAL, we held a meeting for all of the neighbors who will be able to use the new water source, to explain what we´re planning to do and to gather their signatures. All of the people who showed up signed the proposal, and Fredi will continue to collect the remaining signatures so that we can deliver it on Wednesday. Supposedly we should get a response from SEDAPAL within just a few days, telling us what the cost will be.



The municipal elections are coming up in just a couple of weeks, and the walls of most of the houses on the hills of San Genaro have been transformed into campaign billboards. Almost all of them display the name of the incumbent mayor, Miyashiro, who is probably spending city funds and using city workers to paint the ads.

The Language of the Incas

It´s a shame that none of the pre-Incan civilizations nor the Incas themselves had a written language. The Incas did succeed in imposing a common spoken language, Quechua, on most of their empire, which stretched from Argentina to Colombia. But many of the advanced techniques of construction, metallurgy and agriculture that they and their predecessors developed have been lost. The little that we know with any certainty about the Incas comes from oral histories which were captured in Spanish by the conquistadors.
Because Quechua is spoken only in countries where Spanish has become the predominant language, almost all of the resources for learning the language are written in Spanish. So to learn Quechua well you must first learn Spanish. I´ve been sitting in on an introductory Quechua course at San Marcos University, and it´s a fascinating language. It has an alphabet of only 16 consonants and 3 vowels -- depending on how you count them, and who´s version of written Quechua you use. There´s no b, c, d, e, f, g, o, v, x or z. The various Spanish linguists who developed written forms of the language use slightly different notations, but all add the Spanish letters ch and ñ. Five of the consonants, ch, k, p, q and t, have three variations each. One variation has an extra puff of air when it is voiced, and another has a brief stoppage of air following the consonant. One of the big challenges is tuning your ear to hear the differences between these variations.
Verbs take different endings to distinguish person and plurality, as in Spanish, but there are fewer tenses and all verbs are regular -- no exceptions to remember! Nouns have conjugations as in Latin. The biggest difference between Quechua and other languages (at least the ones I´ve been exposed to) is the extensive use of word endings to add information content that is independent of the meaning being conveyed. For example, there are endings that mean ¨I know this to be true¨, ¨I´m referring to something that you just said¨, ¨and also¨, etc. In all there are eleven different endings, with as many as five strung together at the end of a word. But the stress (with very few exceptions) is always on the second-last syllable. So the most difficult part for me in listening to Quechua has been separating the base word from the endings. If you´re interested in knowing what the language looks like or sounds like, here´s a site that has a lot of information: www.andes.org.

Women´s Club in Pamplona - part 1

One of the best organized forces for helping to alleviate poverty in Peru are the Clubes de Madres, tens of thousands of small groups of women who get together every weekday to cook a big meal and distribute it to their neighbors at cost. Those who work in the kitchen receive free meals for their families, and certain other people who are disabled or have recently given birth are also exempted from payment. The clubs are partially supported by the government with free rice, and occasionally some beans or canned fish. But they have to pay for their own rent and other expenses. One of the biggest expenses is fuel for cooking.
A friend of mine, Martín, who recently graduated from San Marcos University, is serving as a teaching assistant for an anthropology class that decided to do a project investigating a women´s club in Pamplona, a community in southern Lima that sits high above the rest of the city. Martín knew of my interest in building energy-saving devices and asked if I could help them come up with ways to conserve fuel. They currently spend almost $20 per week on gas for cooking, which represents a large percentage of their variable costs. If they could achieve substantial savings on gas, they could afford to cook more nutritious meals, containing more meat and green vegetables. Or they could afford to buy the materials to build an oven, which would allow them to expand their offerings to generate more income.
A few days ago I spent a morning with six women at their comedor watching everything they do to prepare the meal, to get some ideas about what interventions help them to reduce gas consumption. They started out with these ingredients:

33 pounds of potatoes
44 pounds of olluco (similar to potatoes)
33 pounds of rice
7 pounds of pumpkin
7 pounds of onions
7 pounds of sémola (wheat-based thickener)
3 pounds of carrots
2 pounds of tomatoes
2 pounds of garlic
9 pounds of chicken feet
1 whole chicken (7 pounds)

They spent most of the four hours peeling and chopping the olluco and potatoes, and one woman spent more than an hour picking through the rice to remove impurities. They cooked in three huge pots. In one they made a soup of the chicken feet, pumpkin, carrots, and spinach. In another they cooked the rice after sauteing some garlic. In the last they cooked the chicken with onions and spices, and then added the olluco and potatoes. It was delicious, but not very nutritious, consisting almost entirely of carbohydrates and fat. Imagine serving more than 100 people with a main dish made from one chicken!

Based on what I observed, I think that placing a ¨pot skirt¨ of galvanized steel around the pots while they cook would help to conserve heat and reduce gas use, and using a ¨retained heat cooker¨ (essentially a box lined with styrofoam) after bringing the rice to a boil would allow the rice to finish cooking without consuming gas. I´ll start to build these next week after the students finish their initial interviews with the women.

We´re Eating WHAT???

Peruvian food varies greatly from one region to another. This isn´t surprising since Peru has more biodiversity than any other country in the world. Of the 104 different types of ¨life zones¨ that exist on Earth, 84 are found in Peru. Generally, on the coast you encounter more food containing fish, in the mountains more potatoes, lamb and pork, and in the jungle more fruit and vegetables. Very little of the food is spicy, but a hot pepper sauce is often offered ¨on the side¨.

One of the striking things about Peruvian food is the extensive use of organ meats. They don´t let anything go to waste here! So far I´ve tasted the following body parts in one or more forms: beef heart, lung and stomach, lamb testicle, chicken gizzard and fish head. I´ve also seen sheep heads and chicken feet for sale in the market, but haven´t yet had the pleasure of tasting any preparations that use them.

I really like the heart, which is served shish kebab style and called anticucho. I´d have to say the lung was my least favorite. It´s really hard to chew, so you pretty much have to swallow it as it is. (Fortunately they cut it in tiny pieces). The testicle wasn´t bad -- until they told me what it was!

So what is that stuff in the picture above that vaguely resembles meat? It´s a dish that you can find being prepared over a grill on just about any street corner on a weekend night, called combinado - a combination of chicken gizzards and cow stomachs, with lots of seasoning, served over boiled potatoes. The stomach is really quite tasty and tender!

Water For San Genaro II - Part 1

This is how a family typically stores water in San Genaro II (the upper part of the hill that forms the ¨human settlement¨ known as San Genaro) - using an odd collection of tubs and garbage cans with some sort of cover to keep the dirt out. This community was organized as a legal entity more than eight years ago, but there are still only a handful of houses that have connections to the public water supply, and just one ¨public¨ connection shared by 20 families who occupy one block.

When the Canadian teachers left after their reconstruction project here, some of them were interested in donating money to help with the other problems, besides housing, that face the people here. They were particularly moved by the fact that most of the people in San Genaro II had to pay more the double the usual cost of water because the only way to obtain it was to pay a downhill neighbor, who had a connection to the water supply, to let them fill their containers using a hose. The typical charge is more than $3 per hour of use (just about enough time to fill all of the containers in their house), and a family usually needs to fill their containers a couple of times each week. A private connection to the city water supply costs more than $300.

I told the Canadians that I had been interested in doing a ¨microcredit¨ project where a group of families would finance the installation of a shared water access point using the savings that they would realize on the cost of the water. They agreed to donate the money for the installation. A group of friends from Lilly who participated in a Spanish class that I taught are providing the funding for the paperwork and other miscellaneous expenses. So lately I´ve been spending a lot of time visiting with Freddy (one of the residents in San Genaro II who´s going to represent the group of neighbors), SEDAPAL (the water utility) and SUNARP (the public documents registry) trying to understand and compile all of the documents that we need to present just to perform the first step: a feasibility study that will determine the cost of the installation. Tomorrow we should have everything we need except for a cover letter from the directiva of San Genaro II authorizing the project.

The plan is to get each of the 24 neighbors on Freddy´s block to agree to buy their water from an access point that we will install, and to pay 1/12 of the water bill each month. In this way we will collect twice the amount of the water bill each month, and put the excess into a fund that will pay off the cost of the installation and generate money for another installation on another block. When the second installation has been financed, the neighbors can stop subsidizing the installations and just split the water bill each month. But even during the period of subsidization, we estimate that they will see at least a 30% reduction in their expenditures for water. Over time we should be able to provide cheaper water to everyone in San Genaro II. There are still a few details to work out, like buying and replacing hoses, and what to do in the case of nonpayment, but we´re optimistic that we can work through those.

Wood-Burning Oven

I´ve really missed being able to bake my own bread since I got here. The LPG gas stove that I borrowed from friends doesn´t have an oven, and anyway a gas oven would be very expensive to operate. So I´ve been working on building a wood-burning oven using some recycled barrels. The design is from Aprovecho Research Institute, a group that also designed the wood-burning stoves that I used to build in Central America.

The oven consists of one barrel within another, with holes in the bottom and top of the outer barrel for the smoke to enter and exit, and some baffles made of fiberglass insulation covered with aluminum foil that form a pathway for the smoke so that it makes contact with most of the surface of the barrel. That little white gadget on the door of the oven is a fancy digital thermometer that I brought with me from the U.S. I´m still looking for a cheap, simple dial-type thermometer to reduce the cost.

The oven still isn´t quite finished (it needs a layer of fiberglass insulation on the outside, covered by another barrel that is split on the side), but it´s far enough along for a test. Last weekend I baked a couple loaves of banana bread and served it to the neighbors.


This is the man from whom I rent my apartment, Miguel, who always lends me a hand with my experiments. Here he´s chopping wood to feed the fire.

Unfettered Capitalism

Ever wonder what capitalism would look like if you took away the worker protections imposed by governments like minimum wages, hours worked, age discrimination, and things like that? It would probably look a lot like what you find here in Peru, because none of those protections are enforced. The minimum wage is officially about US $140 per month, but people commonly earn as little as $80 a month working six days a week. And if they complain about it, they simply lose their job to someone else who is eager to have any job at all. If they miss a day of work for whatever reason, they´re often charged two days of pay. In other words, not only do they not get paid for that day, but they pay their employer a day´s wages for the inconvenience that he suffered.

There´s officially a work limit of 40 hours per week with extra compensation for overtime, but in practice you work for as many hours as your employer tells you to. And forget about overtime. You´re lucky if you get paid for all the hours that you work. My friend Freddy has quit his job twice because his employer kept delaying payment of what he was owed. But each time he has eventually gone back, without receiving all the pay he was entitled to, because it´s the only job he can find that he knows will provide some income every week.

If you´re over 30 years old and don´t hold a ¨permanent¨ job in the profession that you studied for, forget about ever finding one. There are plenty of younger unemployed people who don´t yet have families, willing to work for lower wages. I´ve had lots of interesting conversations with taxi drivers who used to work in industry or taught in the universities, but can´t find anyone who wants to hire them because of their age.

In Peru (like most other Latin American countries), capital rules. If you don´t have an excess of money, it´s almost impossible to join the small club of people who do. The rich families continue to get richer, and the poor continue to increase in numbers. According to the measures that capitalists like to use, Peru has one of the ¨healthiest¨ economies in the world, with a growth rate exceeding 5% for five years in a row. But during those five years the poverty rate has barely changed, and still hovers at around 50%.

The other day I heard a woman say that she would like to have a small business selling tamales, but didn´t have the capital to do it. She wasn´t talking about the money necessary to rent a space or to buy equipment. She meant that she couldn´t gather together the $20 or so that she would need to buy a large pot and enough ingredients to make a big batch of tamales in her home, so that she could go and sell them on the street.

Tómbola in Esquivel

My girlfriend Sonia belongs to a group of lay people associated with an order of nuns based in Canada that has three convents in Lima, one of which is just a couple of blocks from where I live. The asociados get together every couple of weeks to organize small projects to help people in need. Last weekend some of us went to a tómbola that was organized by a group at another convent in Esquivel, north of Lima, to raise money for maintenance of the school that they operate there. A tómbola is sort of a random sale of donated items. People donate things ranging from sacks of sugar or rice to clothing to toys. Each item is assigned a number. Then they hire a band, cook a bunch of good food, organize games for the kids (like ¨fishing¨ for prizes, above), and entice people to come and buy the things that have been donated. For 30 cents you can draw a number and receive the prize associated with that number.

They were serving pachamanca, a dish that is baked underground in banana leaves and usually consists of pork, chicken, lamb, potatoes, sweet potatoes, fava beans and corn. Unfortunately this particular pachamanca included only pork and sweet potatoes, but is was pretty tasty.

This is Sister Gladys, the coordinator of our group of asociados, stirring a big pot of carapulcra, a dish that is made from dried potatoes, fresh potatoes, onions, pork, and a bunch of other good stuff. I think the sisters are going to be eating the leftovers for several weeks!

A Quick Trip To Ecuador

Last week I made a quick run to the border to renew my visa. You have to leave the country for at least 24 hours every 90 days in order to remain ´legal´. From Lima it´s about the same distance to either Chile or Ecuador (about 19 hours) and Chile charges US citizens a $100 fee for an entry visa while Ecuador charges nothing. So I headed north hoping to escape from the winter for a few days. The tourist buses are very modern and comfortable. For $24 you get the best service, with food and drinks, movies, air conditioning. For ten dollars less you get the same comfortable seat, without the food and movies and air conditioning, but the bus stops in a lot more places en route, and even picks up or drops off people along the highway (including people who want to sell you tamales or tell you the sad story of their life and ask for money), so it takes a couple of hours longer and it´s a lot harder to sleep.
The northern coast of Peru is dotted with beach resorts but dominated by plantations of rice and bananas. Although it´s all desert and rains very little, the ground water in some places is just a few feet from the surface, so it´s economical to scrape off some sand and plant rice.
Most things are more expensive in Ecuador (about 50% more, from what I could tell in the short time I was there) but wages are also much higher, drawing many Peruvians to try to find work there, legally or not. Any citizen of an Andean nation can enter any other Andean nation with just a passport, but getting a work permit is difficult.
One of the few things that is much cheaper in Ecuador is gasoline, and people often try to bring it across the border, which is illegal (other than the gasoline in your gas tank). As we approached a customs check point on the way back, we saw agents board the bus in front of us and unload dozens of containers through the windows. When we pulled up for our inspection, we saw that they contained gasoline. I had to take these pictures from the window of our bus, because government workers are very camera-shy, especially with all the recent hidden camera videos that have been published showing officials in prisons and other institutions accepting bribes.

Feast of Santa Rosa

August 30 is the feast of Saint Rose, the patron saint of Lima. It´s a holiday for anyone lucky enough to have a ¨real¨ job in the formal sector of the economy. There are hundreds of processions and festivals all over the city. This is a procession that passed down my street.

The most popular activity seems to be the one that takes place at the ¨wishing well¨ at the church of Santa Rosa near the center of town. It used to be a regular water well, but is now a dry hole where people come to write their petitions on a card and drop them into the well, hoping that Santa Rosa will answer their prayers.

It´s a very busy (and I suppose profitable) day for people selling the cards, pens, and all sorts of food to the hungry crowds. People had to stand in line for several hours to get to the well. (I didn´t, which is why I only have pictures of the crowds, and not the well.)

Three Homes In Three Days

The Canadian teachers went home yesterday after spending three days with us helping to renovate a couple of houses. We divided them into two teams, and Sonia interpreted for one team and I for the other. It was Sonia´s first experience serving as an interpreter, and she did very well.
The teams worked very hard, and accomplished more than I expected, so that we were able to begin roofing a third house, which my friend Freddy and I finished the next day.
On the last day, we all went back to my neighborhood to eat lunch at a benefit for the family who lost their house to the fire.
And the team decided to donate a gas stove to one of the families that has eight children and was cooking its meals over a wooden fire.

Cómo Hacer Un Termo Solar

(This is for my Spanish-speaking friends who want to know how to make a solar shower.)

Se puede hacer facilmente y baratamente un aparato que caliente agua por medio de la radiación solar, con suficiente capacidad para ducharse. Funciona bien aún en regiones constantamente nubladas como donde vive yo (Lima, Perú). El modelo ilustrado aquí me costó aproximadamente $30. Con materiales usados sale mucho más barato. Los materiales que usé son los siguientes, pero se puede adaptar el diseño a los materiales que se tiene a mano. Lo importante es que la superficie del termo sea grando en relación a la cantidad del agua, y que la capa sea de vidrio y no de plastico. (El vidrio refleja los rayos infrarojos generado en la caja, mientras que la mayoría de los plasticos no tienen esta propiedad.)

• Una tabla delgada de madera, de un metro cuadrado
• 2 listones de 2 cm x 4 cm x 2 m
• 1 liston de 2 cm x 3,5 cm x 1 m
• 28 metros manguera de plastico de 3/4 pulgada
• 2 mangueras de largo suficiente para conectar el termo al chorro y a un recipiente
• 2 codos con el diametro de la manguera
• 4 abrazadores
• uno o más pedazos de vidrio con área total de 96 cm
• 1 lata de pintura negra mate (spray)
• pernos

Las fotos abajo enseñan el proceso.

Haz la base con la tabla y los dos listones de 2 x 4.

Forma un espiral de la manguera y asegurarlo con cinta y adjunta los codos a sus fines con abrazadores.

Mete la manguera en la caja de madera de tal manera que el fin del tubo más lejos del centro esté centrado en un lado de la caja. Corta un agujero de tamaño suficiente que el codo pase por el fondo de la caja. Corta el listón de 2 x 3,5 cm en pedazos y ubícalos en los lados de la caja para apoyar el vidrio.

Usa los pernos para asegurar la borde del espiral.

Pinta todo el interior de la caja con la pintura negra mate.

Conecta un chorro de agua al codo en el interior del espiral y asegúralo con abrazador. Conecta el otro codo a una manguera para sacar el agua caliente. (Puede ir a una cabeza de ducha, un balde o cualquiera. Pon el vidrio encima de la caja y asegúralo con pedados de madera. Instálalo en un techo o otro lugar expueso al sol, con la salida del agua más arriba de la entrada.

Una vez conectado, abre la llave hasta que el agua fría salga del aparato. Cierra la llave y esperar hasta que el agua caliente. Luego abre la llave otra vez para sacar el agua caliente.

Con manguera de 3/4 pulgada, cada metro tiene capacidad de aproximadamente 0,25 litro, así que este modelo tiene capacidad de 7 litros. En un día de bastante sol, este modelo levanta la temperatura del agua de 20 grados a 40 grados en una hora. En un día muy nublado con una temperatura ambiental de 19 grados (lo más común acá en Lima), la temperatura del agua en el termo alcanza 31 grados -- no muy caliente pero adecuada para ducharse cómodamente.

Cualquier mejoramiento que descubras, por favor comunícate conmigo a jimwilmes@hotmail.com.