This restaurant required seven thousand of these bricks and after about an hour and a half we had moved just over one-hundred. As I shuttled the bricks from one pile to another, sweat pouring off me and my hands feeling quite raw, I couldn’t help but feel a sense of awe for the women who built that first centre. Adobe construction is one of the most physically demanding building projects, and The Solar Women of Totogalpa, small in stature but giants in determination, had worked to achieve a vision that even caught the attention of the United Nations, who declared the partnership with Groupo Fenix and their joint achievement as one of the most inspirational in the world.

Read the rest of Robert’s blog entry here: http://blog3p.wordpress.com/2010/05/07/the-solar-women-of-totogalpa-pt-2/

Two main types of solar power plants dominate the utility industry today, Photo voltaic power plants (PV) are large arrays of solar panels grouped together to produce electricity. These solar panels, very similar to panels you can put on your house, use light photons that react with a thin layer of silicon to excite electrons and produce electricity. Unfortunately, this technology is still rather expensive.

The technology many utility companies are now using is concentrated solar fields. This is a simpler, more cost effective option for solar power, and can even be more easily utilized in developing countries. Parabolic shaped solar concentrators are U shaped to catch, and reflect the sun into a single focal point. When these concentrators are aligned in a row, thousands of focal points create a line of concentrated solar energy. Placed exactly along this focal line is a tube receptor filled with fluid that is then heated to extremely high temperatures. This fluid can then be used by the power plant to create steam, and turn a turbine to produce electricity. A picture of a solar parabolic concentrator can be seen below.

Image 1: Parabolic Solar Concentrator (Photo from Greenterrafirma.com)

Recently there has been a new development in solar concentrating power using Fresnel lens technology. The Fresnel lens, first developed for light houses to cast a brighter beam of light, is now being used in place of parabolic concentrating troughs. By angling flat mirrors towards a single focal point, a similar focal line can be achieved. And, similar to the parabolic mirror, a receiver filled with fluid can then be heated and used to create steam. This steam then goes through the same turbine generator process to create electricity.

Image 2: Concentrated Solar Fresnel Array (Photo from csposi.org)

There are many benefits to this Solar Fresnel array over the traditional parabolic concentrator. Fresnel lens concentrated solar is much less expensive to build. They do not use the more expensive, curved mirrors to concentrate light. This is a very important aspect for Salud del Sol as a company because it is one of our main goals to promote projects that can be made in the regions that we serve. Parabolic reflectors drive up the cost of a concentrated solar project and they are not as prevalent in developing countries such as Nicaragua. Flat reflectors can be manufactured more easily and cost significantly less.

Another benefit to Fresnel technology over parabolic technology is the wind factor. Parabolic reflectors are larger and tend to catch the wind more easily. These wind gusts cause the focal point to shift, dropping the effectiveness of the solar concentration. A Fresnel array utilizes smaller mirrors which are typically closer to the ground and in turn catch less wind. Also, since the Fresnel mirrors are closer to the ground, they cast less of a shadow. With fewer shadows, concentrators can be put closer together and thus save space. If solar power concentrators interest you, there are many different resources online that can tell you more.

Some of my favorite sites are:
1. www.nrel.gov
2. www.solarbuzz.com
3. www.ases.org

Resources:
1. http://www.nrel.gov/learning/re_csp.html
2. http://greenterrafirma.com/
3. www.csposi.com
4. www.solarbuzz.com

Come to Nicaragua and engage your head, heart, and hands in the real work of developing countries. Our hands-on courses allow you to be immersed in the daily life of rural Nicaraguans by living with host families and working alongside local community members to create their vision of a model community through renewable energy and sustainable practices.

Discuss the theory behind solar energy and the challenges of development with your instructors and other course participants. Spend your days learning how to construct solar cookers, photovoltaic panels, and installing photovoltaic systems. Laugh along with your host family as you try to recall your high school Spanish, balance water on your head or make tortillas. Most activities and classes are held in the new adobe Solar Center. Housing will be simple, like that of a typical rural Nicaraguan family.

Explore a beautiful country and its culture while learning about renewable energy and sustainable development in the field. Our courses provide a unique travel experience that is educational, rewarding, and fun!

This 11-day course, offered twice a year, has been held by Grupo Fenix since 1999. It is a great introduction to the science and use of appropriate renewable energy technologies such as solar cookers, dryers and photo-voltaic systems. Dr. Richard Komp, an expert from the United States with over 40 years experience working with solar technologies, teaches the technical classes for the January version of this course and the July version is based on his methodology for fabrication of PV panels in developing countries. During this 11 day course participants will:

• Visit Suni Solar, a renewable energy business in Managua started by Grupo Fenix
• Build a solar oven with the local women’s group, the Solar Women of Totogalpa
• Listen to talks on Solar Dryers and Medicinal Plants
• Learn about solar cooking and eat the final product of your class!
• Install a PV system with local solar experts
• Make a solar powered battery charger

Also, the course includes various tourist activities such as a visit to nearby beautiful spots in the mountains of northern Nicaragua. If weather permits, we will spend a day exploring the Somoto Canyon and swimming in its natural pools. Also, at the end of the course we will spend a night at a rustic ecolodge in the Tisey Nature Reserve, which has hiking trails, fields of organic vegetables, a farming community that produces its own specialty cheeses and one of the best panoramic views in the country.

The course fee of $995 includes all food and lodging, with a $50 deposit to be sent to the nonprofit Skyheat Associates at PO Box 184, Harrington ME 04643 before December 15th to insure a place in the course, which has a limit of 15 participants and is often completely full. For more information, please contact thegrupofenix@gmail.com or look on-line at www.grupofenix.org for details of all of our programs.

Lori Hanna was interviewed by Nancy Scola of WorldChanging.com to describe the solar autoclave and the application to rural clinics in undeserved areas. The article highlights the solar autoclave for Nicaragua and FrontlineSMS:Medic of Malawi, Africa as two examples of social innovations that are closing the gaps in healthcare delivery.

Two projects led by US students and their international allies are helping to fill gaps in health care gaps in the Global South. Though one project involves cell phone text messaging and the other equipment sterilizers powered by the sun, they have the same inspiration: using simple technology to build on the value of existing social capital.

These innovations are developing in Malawi and Nicaragua, both counted amongst the all-too-many places on the globe where the holes in the net of public health are so gaping that many people slip right through. Numbers tell that story. Of the fifty thousand Malawians who contracted tuberculousis last year, for example, an estimated 70% of them are also carry HIV. And that’s just a small portion those with HIV; nearly one million of Malawi’s 14 million people are infected. Yet in all of the country, there are just 250 or so doctors. Nicaragua is somewhat better off, yet nearly half of all of births happen there with no medical professional in attendance. Into those breaches have, in many cases, stepped community health workers (CHWs), local laypeople who work with the local health care system, often as volunteers. The two projects profiled here are equipping those CHWs with simple, appropriate ways to shrink the holes in their country’s health care nets.

You can read more of the article at the Worldchanging website, http://www.worldchanging.com/archives//010007.html

WorldChanging.com is a nonprofit media organization headquartered in Seattle, WA, that comprises a global network of independent journalists, designers and thinkers. We cover the world’s most innovative solutions to the planet’s problems, and inspire readers around the world with stories of new tools, models and ideas for building a bright green future. We have brought awareness to issues like refugee aid, renewable energy and innovative solutions for improving building, transportation, communication and quality of life. Our readers are ready to change the world, and Worldchanging connects them with the latest ideas on how to do that.

Monday I got right back into testing. However, the first real rainstorm of the season occurred over the night, and the rest of the day was very cloudy and overcast, on the verge of raining, through the day. While one test was performed, it was less than desirable. Instead, I spent the morning repairing the DaqPRO that has been broken for awhile. In the end I got most of the thermocouples working (which are used to measure temperatures in a very specific area), which is good news because I can then use them in future testing, whereas previously I had only been using one. With this I can gain more temperature readings, which will help me to see if the autoclave is reaching the temperatures we need.

I spent Monday afternoon talking with David Smith, the new Grupo Fenix Volunteer Coordinator (aka the new Amanda). He is in charge of keeping track of all the volunteers and making them aware of what needs to be done. I roped him into a meeting with Nathan to find out what it is that we could do in our down time, such as on overcast days where testing is useless or even during testing whereby I can leave the system running while I go do something else productive. In the end, after about 2 hours of discussion, the three of us came up with a working list of things that need to be done, and what it is that Nathan and I could each do. I even made a short list of ideas of what Erin and Maria could do when they come.

With this in mind, we went home that night to digest what we learned and to come up with a plan of attack for the next month. That evening I also beat my niece, Skarleth in Scottish Speed three times (a card game; a Scottish-version of Speed that we learned from Roberto last summer). Then she taught me a game that was like Rummy but that I did not understand, and she beat me three times. What goes around comes around, eh?

Tuesday I ran some tests on the autoclave, but it was proving difficult because the daq needed to be charged. This was unfortunate because it was a good, sunny day. However, this allowed me to share my plan of attack with Nathan, then get started. Actually, Tuesday was a productive day: I built/repaired fan blades for a windmill that had broken a few weeks ago. Apparently one of the blades flew off, and so we took it down and I rebuilt the fan portion. Repairing it was somewhat easy, but balancing it was very difficult and time-consuming. Balancing helps to prevent that the blades spin evenly, reducing vibration and thus reducing wear by bounds. In the end, I did this by using squares to situate a screwdriver in a vice straight up, then try to balance the fan-blade system on the tip of the screwdriver. Whenever necessary, I would make adjustments to the blades to redistribute weight. Several hours later, I attached the blades to the generator and windmill stand, then we stood it up. I watched with pride as it was generating electricity as soon as we put it up!

That was before lunch. After lunch I charged the daq a bit more (it could not be charged during lunch because they shut the solar generator off to preserve power), and so I got to work on the hut meant to be a snack stand by the road. The idea of this hut is to propel the Solar Restaurant forward and help get things moving (while it is being built and money being generated for it) by having a place to sell solar-cooked food by the road and a place for customers to sit. When we arrived they had a small structure built out of large sticks (built by Mitch, another volunteer who has been here for several months that we saw for the first week; he now works with Suni Solar in Managua). Now they just need a new driving force to keep that project going. Well, that driving force is me. So, I ordered the palms necessary to build the roof and I am going to buy rope here in Ocotal. Other than that, all that really needs to be done is prep the area (such as cut the grass) and get the people motivated to start cooking. I asked Nathan to go up to the cooks and seriously plan out the agenda for the restaurant, such as who is going to cook what and when, as well as to help work out pricing for the foods. I hope to have this built by the end of next week, and so two weeks from now they could be selling!

Today, Wednesday the 20^th, has been an excellent day for testing. It has been sunny and nearly cloudless all day. I worked on the daq and autoclave first thing this morning, and then have since just let the test run. I have meanwhile been making technical notes left and right, as well as excitedly watching the results of testing. I have also organized and reviewed the data from the last few days of testing.

Today marks one week until Tim and Jim arrive, who will be working with Suni Solar in Managua. We are excited for their arrival and plan to either go see them in Managua or have them come up here for next weekend. Meanwhile, this weekend we thing we may go up to Honduras! Honduras is only about half an hour from where we are now, and it is so easy to get there. So, I would like to take this opportunity to include Honduras on my list of place to have traveled. We think we may stay in Tegucigalpa for a night, but we are debating whether we want to travel further up north to the nicer, prettier areas instead. Somewhere up north, near Guatemala, is a city that is an incredibly ancient Mayan city and it is supposed to be gorgeous. Traveling through Guatemala, I would also be on the lookout for any Salud del Sol potentials, but I don’t necessarily consider this a business trip.

The idea of going up to Honduras for two days also makes me want to go down to Costa Rica for a few days as well, which is in the other direction but also very close and easy to get to. It is funny, traveling out-of-country is something that didn’t really occur to me last summer, but I have already seen much of the in-country stuff, so I think changing it up this year is a great idea. Once again, this would help me expand my list of countries that I know.

Anyway, that brings you up to speed on what I have been doing! Things are going great and we are having a lot of fun of course. Nevertheless, we are very excited for when other volunteers will be coming; Mary is a volunteer from New York who has been here before and supposedly comes to Sabana Grande on the 1^st of June. Having people come in always keeps things happening and makes the trip fun and interesting.

So, if you want to come visit, you should!

Oh, and to sum up the title of the blog, it has finally started raining. However, in the traditional tropical sense: it rains really, really hard, every day, but only for a few hours at a time, if that. Truly, I like it. It is refreshing and fun, so long as you are not caught in it and ruin your camera (ahem, Matteo).

-Daniel

Pressure Release Valve
The team wanted to build the pressure release valve of easily-found materials, however each of their designs proved to be too insensitive.  In the end, the team decided to use the release valve off of a commercial pressure cooker.  Fortunately, these are available to purchase without requiring the purchase of a whole pressure cooker.  Its precisely machined weight and aperture is necessary.

Sterilization Indicator
For much of the semester, the team worked to improve a cylinder/washer design, in which a small plastic cylinder would be filled with a phase-change material, Polywax2000 and a washer. The idea is that the washer starts on top of the solid wax, but as the autoclave heats up and the wax melts, the washer moves to the bottom. There is a calculated amount of wax inside such that when the washer lies on the bottom (i.e. all of the wax has melted), at least 15 minutes have passed, the minimum for sterilizing surgical instruments at 121 degrees Celsius and 15 psig.  Ultimately, this design was abandoned because too much pressure built up inside the cylinder. 

The final design is a two-compartment cylinder, with one compartment filled with Polywax2000.  It functions as does an hourglass, and is manufactured such that when all of the wax melts and flows into the bottom compartment, the solar autoclave operator can rest assured that sterilization is complete.  It has a hole in both ends, for ventilation, and a cap that blocks the whole at the bottom.

This design requires further testing, so the team also offered a contingency plan-an electronic timer, using a thermistor and powered by a small solar cell. Currently, the price of one sterilization indicator stands at $2.00, which complies with the team’s goal of under $10 if reusable and about $0.01 if non-reusable.

Pressure Vessel
For the solar autoclave pressure vessel, the team has replaced one of the wooden end caps with an aluminum end cap, used a silicone pie pan as the seal, and used hex bolts with wing nuts to hold it all together. Upon testing with hydraulic oil, they successfully brought the pressure up to 32psig – well above the 15psig required for sterilization – before it started to leak at the seal again. The stresses were well below the yield strength for the can.  It is currently thought that the leaking seal, once validation testing is complete, could provide the emergency safety release, because it always fails well above the operating pressure, but fails before rupture of the vessel.

Testing with air revealed that the prototype does not consistently maintain pressure-so, tests run in an oven were not able to achieve 15psi because the system is not completely air tight.  Further development is necessary to ensure a good seal.  The oven testing also revealed that the time to heat up is very lengthy, but that steps can be taken to decrease this time, such as adding already-boiling water in the autoclave instead of cold water.

K(A)BEBS – Sean Drennan, Katlyn Lopus, Emily Getter, and Becky Herrman
Redirecting the Sun

During the second semester of the first year at the University of Dayton, the Engineering Innovations class was presented the challenge of building a prototype of a device that could be used in developing countries to track the sun throughout the day. This device would be used to maximize the amount of sunlight directed onto a solar panel to capitalize on the efficiency of the energy. The class was divided into groups and each group had a $50 budget to work with.

The design team decided on a design that was much different from the rest of the groups in the class. A device that would remain stationary and be constructed using reflective newspaper tin would be built around the solar panel and redirect the sun onto the panel. The sunlight would enter through the top of the device and would reflect off the panels, which would be at carefully calculated angles. The design team tried to design the device so that no matter where the sun would be in the sky, its’ rays would be directed onto the solar panel after being reflected off the newspaper tin. The team had reasonable results and found that the idea did work but more calculations and testing would need to be done in order to correctly position the reflective panels for use throughout the day. Overall, the design team was happy with their final project and excited to see what could become of their idea on a bigger scale.

Solar Tracking Device Project – Alex Jules, James Lab, Jim Razzante, Alex Reed

In the class Engineering Innovations this semester at the University of Dayton, our team was presented with the project of designing an automated (hands free) and sustainable(reusable) solar tracking device. What the device needed to do was move a solar panel throughout the day so it faced the sun at all times. This would result in increasing the efficiency of the solar panel by forty percent.

When the day came to actually test our design, our team saw great success. Our simple design worked well, although we did encounter some problems. Interference with the weather caused some issues as clouds blocked the sun and a strong wind moved our rotating piece of wood. Our group was able to come up with propositions to create a better device in the future.

Overall, this project was a great introduction to the design process and gave us hope for our futures in engineering.

Again, as their student teacher who is heavily involved in projects like this, I was impressed with the results and proud of the work they had done. Our only hope now is that they will take away what they have learned about appropriate technologies and solar trackers and spread the word. They have a great opportunity to see some change in the world. Once again, comments and suggestions are always appreciated!

Many thanks and peace always,

Daniel J. Hensel
Director of Product Research