Global investments in green energy up nearly a third to $211 billion

Wind farms in China and small-scale solar panels on rooftops in Europe were largely responsible for last year’s 32% rise in green energy investments worldwide according to the latest annual report on renewable energy investment trends issued by the UN Environment Programme (UNEP).

Last year, investors pumped a record $211 billion into renewables — about one-third more than the $160 billion invested in 2009, and a 540% rise since 2004.
For the first time, developing economies overtook developed ones in terms of “financial new investment”–spending on utility-scale renewable energy projects and provision of equity capital for renewable energy companies.
On this measure, $72 billion was invested in developing countries vs. $70 billion in developed economies, which contrasts with 2004, when financial new investments in developing countries were about one quarter of those in developed countries.
The report, Global Trends in Renewable Energy Investment 2011, has been prepared for UNEP by London-based Bloomberg New Energy Finance.
It was launched July 7 by UN Under-Secretary-General and UNEP Executive Director Achim Steiner and Udo Steffens, President and CEO of the Frankfurt School of Finance & Management as it was also announced that a new UNEP Collaborating Centre for Climate & Sustainable Energy Finance is being inaugurated at the Frankfurt School.
China, with $48.9 billion in financial new investment in renewables (up 28%), was the world leader in 2010.
However, other parts of the emerging world also showed strong growth:
South and Central America: up 39% to $13.1 billion; Middle East and Africa: up 104% to $5 billion; India: up 25% to $3.8 billion, and Asian developing countries excluding China and India: up 31% to $4 billion.
Another positive development, highlighted in the report with implications for long-term clean energy developments, was government research and development. That category of investment climbed over 120 per cent to well over $5 billion.
Mr. Steiner said: “The continuing growth in this core segment of the Green Economy is not happening by chance. The combination of government target-setting, policy support and stimulus funds is underpinning the renewable industry’s rise and bringing the much needed transformation of our global energy system within reach.”
“The UN climate convention meeting in Durban later in the year, followed by the Rio+20 summit in Brazil in 2012, offer key opportunities to accelerate and scale-up this positive transition to a low carbon, resource efficient Green Economy in the context of sustainable development and poverty eradication,” he added.
“The finance industry is still recovering from the recent financial crisis,” adds Udo Steffens, President of the Frankfurt School of Finance and Management. “The fact that the industry remains heavily committed to renewables demonstrates its strong belief in the prospects of sustainable energy investments. ”
“The investment activity in the developing world is not only leading to innovations in renewable energy technologies. Further more, it will open up new markets as first mover investors are facilitating a range of new business models and support entrepreneurship in the developing world,” explains Udo Steffens.
The report points out that not all areas enjoyed positive growth in 2010: there was a decline of 22% to $35.2 billion in new financial investment in large-scale renewable energy in Europe in 2010. But this was more than made up for by a surge in small-scale project installation, predominantly rooftop solar.
Michael Liebreich, chief executive of Bloomberg New Energy Finance, said: “Europe’s small-scale solar energy boom owed much to feed-in tariffs, particularly in Germany, combined with a sharp fall in the cost of photovoltaic (PV) modules.”
Investments in Germany in “small distributed capacity” rose 132% to $34 billion, in Italy they rose 59% to $5.5 billion, France up 150% to $2.7 billion, and the Czech Republic up 163% to $2.3 billion.
The price of PV modules per megawatt has fallen 60% since mid-2008, making solar power far more competitive in a number of sunny countries.
By the end of 2010, many countries were rushing to make their PV tariffs less generous. Indeed, Spain and the Czech Republic both moving to make retroactive cuts in feed-in tariff levels for already-operating projects “damaged investor confidence,” the report says. “Other governments, such as those of Germany and Italy, announced reductions in tariffs for new projects — logical steps to reflect sharp falls in technology costs.”
Nevertheless the small-scale solar market is likely to stay strong in 2011, the report suggests.
Further drops in costs for solar, wind and other technologies lie ahead, the report says, posing a growing threat to the dominance of fossil-fuel generation sources in the next few years.
Throughout the last decade, wind was the most mature renewable energy technology and enjoyed an apparently unassailable lead over its rival power sources.
Wind turbine prices have fallen 18% per megawatt in the last two years, reflecting, as with solar, fierce competition in the supply chain.
In 2010, wind continued to dominate in terms of financial new investment in large scale renewables, with $94.7 billion (up 30% from 2009). However, when investments in small scale projects are added in solar is catching up, with $86 billion in 2010, up 52% on the previous year. With $11 billion invested, biomass and waste-to-energy come in third in front of biofuels, which boomed at $20.4 billion in 2006, but fell off dramatically — to $5.5 billion last year.
The sharpest percentage jumps in overall investment were seen in small-scale projects — up 91% year-on-year at $60 billion, and in government-funded research and development, up 121% at $5.3 billion, as more of the “green stimulus” funds promised after the financial crisis arrived in the sector.
Two areas of investment showed a fall in 2010 compared to 2009: corporate research, development and deployment (down 12% at $3.3 billion, as companies retrenched in the face of economic hard times) and provision of expansion capital for renewable energy companies by private equity funds (down 1% to $3.1 billion).
Clean energy share prices fell in 2010, with the WilderHill New Energy Global Innovation Index (NEX) down 14.6%, under-performing wider stock market indices by more than 20%. This showing reflected investor concerns about industry over-capacity, cutbacks in subsidy programs and competition from power stations burning cheap natural gas.
Acquisition activity in renewable energy, representing money changing hands rather than new investment, fell from $66 billion in 2009 to $58 billion in 2010. The two largest categories of M&A — corporate takeovers and acquisitions of wind farms and other assets — both fell by around 10%.
The low price of natural gas — which was between $3 and $5 per million BTU for almost all of 2010– hurt the growth of renewables, the report says. The price of natural gas was far less than it was in much of the mid-2000s, before it peaked at $13 in 2008.
“This gave generators in the US, but also in Europe and elsewhere, an incentive to build more gas-fired power stations and depressed the terms of power purchasing agreements available to renewable energy projects,” says the report.

Read the full article here:
Global investments in green energy up nearly a third to $211 billion

Solar panels keep buildings cool

Latest news was that, Solar Panels Keep Buildings Cool. They are cooling your house, or your workplace. Its create a stronger cooling efffect than panels flush with the roof. Solar panels, increasing number of residential and commercial roofs and it becomes more important to consider their impact on buildings’ total energy costs. The benefit are greater there is an open gap where air can circulate between the building and the solar panel.

Read the full article here:
Solar panels keep buildings cool


Adobe | Energiaelectrica | Piscina

Calentando la Piscina (Alberca) con el Sol

  • Las cubiertas para albercas representan la solución más económica para reducir las pérdidas de calor, la evaporación excesiva del agua y el uso de los productos químicos para su mantenimiento.
  • La superficie requerida para el colector solar varía entre el 50 y el 100% de la superficie de la piscina (alberca). Las variables que determinan su tamaño son: eficiencia del colector, ubicación del mismo (orientación, viento) y las preferencias del dueño
  • Lo ideal es que el colector mire al sur (norte) y tenga una inclinación respecto de la horizontal de unos 20 a 32 grados.
  • Piscinas (albercas) instaladas dentro de la casa, para uso durante todo el año, necesitan colectores cerrados planos, con cubierta de vidrio y deben tener una inclinación entre 35 y 45 grados.
  • Caños de ventilación que salen del techo pueden presentar problemas de instalación cuando se quieren ubicar este tipo de colectores en el techo.
  • Ya sea por una mala orientación o porque la superficie del techo no es suficiente, puede forzar la instalación de los colectores a nivel de tierra, usando una armazón de sostén que se ubica cerca de la piscina.
  • La mayoría de los colectores comerciales requieren que se los drene completamente cuando llega el invierno, para evitar problemas de congelación.
  • Toda la plomería debe diseñarse para que drene a la piscina cuando el sistema no estáen uso. A veces se requiere que exista un drenaje manual, el que se activa con el cambio de estación.
  • Pinte toda la cañería de PVC para defenderla de los rayos ultravioletas.
  • Si la bomba del sistema no resultare suficiente, puede que se necesite una bomba adicional.
  • Para evitar el uso de sistemas automáticos de alto costo es preferible la activación manual del sistema o el uso de un reloj activador (timer).
  • Aisle, mediante la instalación de válvulas divertidoras (bypass), el sistema solar cuando tenga que limpiar el filtro revirtiendo la circulación (backflush)
  • Eficiencia del Sistema

    El calentamiento de una piscina para natación es una de las aplicaciones más económicas de la energía solar. Su uso no sólo permite la extensión del período de uso de la misma, pero ayuda a un mejor control de su temperatura y, en algunos casos, no se incrementa el costo de operación con el nuevo sistema.

    Empecemos por el Comienzo- Reduciendo las Pérdidas de Energía<

    El paso más elemental y práctico para extender el período de uso de la piscina es usar una cubierta para la misma. Hasta el 70% del calor suministrado a una piscina se pierde por evaporación. Si a esta pérdida se le agregan las de radiación y convección, la idea de calentar una piscina sin usar una cubierta resulta ser similar a la de calentar una casa con todas las puertas y ventanas abiertas. Si bien es un inconveniente el poner y quitar la cubierta, ésta no sólo ayuda a extender la temporada de uso, pero la mantiene más limpia y disminuye el uso de las substancias químicas usadas en su mantenimiento.

    Si la cubierta es transparente, el sol contribuirá a su calentamiento. Las cubiertas de plásticos tienen un costo de alrededor de 30 a 40 centavos de dólar por pié cuadrado y duran entre 2 y 5 años.

    Cómo Funciona el Sistema Solar

    La plomería requerida por el sistema solar se acopla a la existente, incluyendo el filtro. Durante el día, cuando el filtro está en operación, el agua pasa por el colector antes de ser retornada a la piscina. Si se adiciona un sistema automático, se debe agregar un control central, que obedece a sensores agregados al sistema, el que actuará sobre dos válvulas en la línea, a fin de mandar el agua a los paneles o descargar los paneles a la piscina.

    Si no se adiciona el control, el dueño deberá operar las válvulas.

    Diseñando el Sistema

    Para determinar el número de colectores se necesitan tener en cuenta varios factores. El más importante es la superficie de la piscina. El diseño se comienza considerando un área de colección igual al 50% de esa área. Este valor se corrije teniendo en cuenta la velocidad del viento, el sombreado de la piscina, la temperatura y humedad del lugar y el final de temporada que se prefiere. No es desusual que se termine con un área de colección que representa el 100% de la superficie de la piscina.


    Lo ideal, como siempre, es que los colectores miren al sur y tengan una inclinación de unos 10 a 15 grados respecto de la horizontal. Si no se puede darle esa inclinación (colectores sobre el suelo) o se ve obligado a que apunten hacia el oeste, aumente la superficie un 75%. Otro tipo de orientación no es recomendable.

    Si bien lo más común es la instalación de los paneles en el techo, a veces la distancia, la orientación del mismo o razones estéticas dictan el uso de una construcción auxiliar de sostén para los mismos, “a nivel de tierra”. Si los inviernos tienen días de baja temperatura, es imprescindible vaciar el sistema para evitar la congelación del agua.


    Un sistema solar para calentamiento de piscina trabaja con un alto volumen de circulación, de manera que el agua a la salida es apenas 2 a 3°F sobre la temperatura de entrada.


    Dependiendo de cuántos colectores se necesiten y el largo y complexidad de la plomería se puede estimar un costo que oscila entre los $2.000 y los $4.000 dólares.


    El colector típico para esta aplicación está hecho de plástico, el que tiene un tubo superior de gran diámetro al que se conectan un gran número de tubos de muy pequeño diámetro, los que vuelven a juntarse en otro tubo igual al superior. Estos colectores se amarran al techo (o la estructura de sotén) tanto en la parte superior, como la inferior y la media.

    Eligiendo el Contratista

    Elija un contratista que tenga licencia de instalador para estos sistemas. En algunas ciudades se requiere obtener un permiso para instalar la parte de plomería.

  • Pida referencias sobre el contratista para hablar con otros de sus clientes.
  • Verifique que la garantía que le ofrece cubre todos las partes del sistema.
  • Si tiene seguro para su casa, verifique si cubre este tipo de instalación.
  • Fuentes de Información (en inglés)

  • Departamento de Energia de los EEUU (Department of Energy)
  • Reduzca el Gasto de Energía para su Piscina de Natación (RSPEC)
  • Ofrece programas (“software”) gratis para analizar el costo energético actual y predecir los ahorros cuando use una cubierta o incorpore sistemas de calentamiento solar.
  • Puede obtener “software” de la Internet:

  • Si contacta al Energy Efficiency and Renewable Energy Clearinghouse (EREC) necesitará dos discos de 3,5″.
  • Dentro de los EEUU puede llamar en forma gratuita discando 1-800-DOE-EREC o enviar un e-mail:
  • Hojas de información

  • EREC PO Box 3048 Merrifield VA. 22116-0121
  • Florida Solar Energy Center 1679 Clearlake Rd. Cocoa Florida 32922407/638-1000 fax: 407/638-1010
  • Panfletos informativos pueden asimismo conseguirse por correo (publication FSEC-GP-16) sobre evaluaciones de paneles colectores (Collector Thermal Performance Ratings ) o diseño (Design and Installation Manual , publicación FSEC-IN-21-82) o System Sizing (publicación FSEC GP-13)


    Adobe | Energiaelectrica | Piscina

    Notas para el Lector
    La Asociación Solar de El Paso (EPSEA) pone a su disposición, en forma gratuita, y sin reclamar derechos de autor, el Manual sobre los sistemas fotovoltaicos escrito por el ingeniero Héctor L. Gasquet, un ex miembro de la asociación, que ahora reside en Austin (TX).

    Notas de bajada (downloading)
    Todos los documentos, como se indicó en la sección BIBLIOTECA, son del tipo PDF. Lea esa página si no está familiarizado con este tipo de extensión.

    Algunos documentos son muy cortos y, por lo tanto, rápidos de bajar. Otros, sobre todo los capítulos con abundantes ilustraciones, llevan mucho más tiempo.
    El tiempo de bajada depende del tipo de servicio de internet que Ud ha contratado. Por nuestro lado hemos hecho el mayor esfuerzo para reducir el tamaño de los documentos, sin deteriorar la calidad de los mismos.
    La lectura de los mismos requiere el uso del ADOBE READER . Si no lo tiene, lo puede obtener, en forma gratuita, visitando la dirección

    Ni el autor, ni la Asociación (El Paso Solar Energy Association) asumen responsabilidad alguna por pérdidas materiales o accidentes ocacionados por individuos que instalen sistemas fotovoltaicos basados en la información proporcionada.

    Ni la Asociación ni el autor endorsan ninguno de los productos que se mencionan en este publicación, ya que sus nombres sólo sirvieron para ilustrar algunos productos típicos. El autor, así como la Asociación Solar de El Paso agradecen el apoyo brindado por todas las firmas, ya sea con fotos de productos o algún apoyo técnico.

    Introduccion (38K)

    la Organización del Manual (23K)

    Indice (4k)

    CAPITULO 1- La Radiación Solar Parte A 1 – 12 (3421K)
    Parte B 13 – 18 (3450K)
    Introduce las nociones básicas y la terminología relacionadas con la radiación de la energía solar.

    CAPITULO 2- Sistema Fotovoltaicos 19 – 24
    Presenta el diagrama en bloques de un sistema fotovoltaico para uso doméstico. (60K)

    CAPITULO 3- La Celula Fotovoltaica 25 – 32 (195K)

    CAPITULO 4- El Panel Fotovoltaico Parte A 33 – 41 (432KB)
    Parte B 42 – 45 (731KB)

    CAPITULO 5- Baterías Recargables 47 – 56 (198K)

    CAPITULO 6- Baterías Solares 57 – 66 (83K)

    CAPITULO 7- Control de Carga 67 – 78 (3120K)

    CAPITULO 8- Cables de Conección 79 – 86 (61K)

    CAPITULO 9- Componentes Auxiliares 87 – 104 (300KB)
    Describe los componentes del sistema FV no cubiertos en los capítulos precedentes.

    CAPITULO 10- RENAME Diseño de un Sistema FV (CC) 105 – 116
    Detalla los pasos de diseño de un sistema FV con cargas de CC.     (2275K)

    CAPITULO 11- Diseño de un Sistema FV (CA) 117 – 128
    Detalla los pasos de diseño de un sistema FV con cargas de CC y CA.     (3737K)

    CAPITULO 12- Instalación de Sistemas 129 – 144
    Proporciona una guía para la instalación de un sistema FV.       (586K)

    CAPITULO 13- Mantenimiento de Sistemas 145 – 156
    Proporciona una guía para el mantenimiento de un sistema FV.      (866K)

    CAPITULO 14- Bombeo de Agua Solar 157 – 174 (1020K)

    APENDICE I – (100K)
    Proporciona los conocimientos básicos para entender los circuitos de CC y de CA. Describe los diodos y se reveen los conceptos básicos sobre porcentajes y su aplicación a los errores de redondeo de cantidades.
    Circuitos Eléctricos de CC A1.1 – A1.16
    Circuitos Eléctricos de CA A1.17 – A1.21
    Porcentajes A1.22

    APENDICE II – (206K) Proporciona tablas para conversión de unidades inglesas al sistema métrico (y viceversa)
    Unidades de Medida A2.1 – A2.3

    APENDICE III – (128K) Información Complementaria A3.1
    Explica cómo puede conseguirse la información más reciente sobre fabricantes y distribuidores de componentes para estos sistemas.

    Ing. Héctor L. Gasquet
    Austin, Texas



    Adobe | Energiaelectrica | Piscina

    (Para hacer casas, no el programa para la computadora)

    Las construcciones de adobe representan las estructuras más antiguas del sud-oeste de los EEUU que an están en pié. Existen an edificiones de misiones religiosas y casas privadas. Los colonizadores de la región construyeron las casas de adobe porque el material (terreno) era abundante. No había bosques o grandes cantidades de rocas, de manera que contruyeron con lo que tenían a mano. Resulta que hoy día hemos “descubierto” que ésta es la manera de elegir los materiales de construcción Casi seguro que el material más abundante en una región es, asimismo, el que mejor se adapta al clima y al medio ambiente.

    Cuando se construyeron los ferrocarriles, se facilitó el transporte de materiales de construcción a larga distancia y las construcciones en el sud-oeste americano comenzaron a usar otros materiales, cambiando asimismo la arquitectura local. Muchos de las casas continuaron siendo de adobe, pero no porque era el material preferido, pero el más económico. El adobe se convirtió en el material “de los pobres”, cuyas familias participaban en la fabricación de la mezcla usando los pies, y volcando la misma dentro de formas de madera para fabricar los ladrillos. Lo importante es que ellos no dependían de otros para obtener los materiales de construcción. Actualmente an existen los que eligen al adobe porque no pueden construír con ningun otro material, pero han aparecido un numeroso grupo que ha elegido al adobe simplemente porque les gusta.

    Mientras que muchos consideran que el adobe es el material “de los pobres”, otros piensan que sólo los ricos pueden hacerse una casa de adobe. En lugares como Santa Fe (Nuevo México), las casas de adobe diseñadas a gusto del cliente llegan a costar más de 100.000 dólares. Lo cierto es que una casa de adobe puede ser construída en N.M. a precios más económicos. Los ladrillos de adobe son producidos en corralones de adobe, en forma industrial. Los futuros dueños de casas de adobe se dividen, casi en igual nmero, entre los que optan por convertirse en constructores y los que pagan a un constructor especializado.

    ¿Cuáles son las características de un ladrillo de adobe?

    Es un ladrillo hecho con barro que tiene, tradicionalmente, unas 10 x 14 x 4 pulgadas. La mezcla ideal contiene un 20% de arcilla y un 80% de arena. Estos materiales, mezclados con agua, adquieren una forma más fluída que permite volcarla en formas de madera con las dimensiones dadas anteriormente. Cuando parte del agua se evapora, el ladrillo es capaz de sostenerse por sí mismo. Es entonces cuando se remueve la forma, completándose su secado al sol. Despues de varios días, para acelerar el secado, los ladrillos son movidos, apoyándoselos en una de sus caras laterales. Al cabo de unos pocos días están listos para ser apilados. La cura completa toma unos 30 días. Es entonces cuando el ladrillo es tan fuerte como el cemento.

    A la paja se la considera comnmente como parte esencial del ladrillo de adobe. Esto no es cierto y los ladrillos de adobe contemporáneos no la usan. Su uso se creyó importante para dar rigidez al adobe, o evitar rajaduras al secarse. Lo cierto es que si la proporción de arcilla y arena es la correcta, no se la necesita. Si el adobe se raja al secarse es porque tiene mucha arcilla. Debe recordarse que el uso de la paja roba a muchos insectos de su alimento.

    Adobe “de alta tecnología”

    Si bien la combinación correcta de barro y arcilla permanece inalterada, en este tipo de adobe se le agrega un nuevo componente: asfalto emulsionado. Esta emulsión es un subproducto del petróleo que es comnmente usado en la construcción de caminos. Cuando se lo mezcla con agua, barro y arcilla, dependiendo de la proporción, se obtiene un ladrillo de adobe resistente al agua (semi estabilizado) o totalmente impermeabilizado (completamente estabilizado). La incorporación del asfalto emulsionado no es aceptada por todos, ya que la pared exterior de adobe va a ser cubierta con un revoque (plaster). Cuando la pared dá a un patio o jardín interior su uso es justificado. Los “puristas” no se encuentran cómodos con la idea de agregar un producto del petróleo a algo que, de por sí, ofrece una belleza natural al edificio.
    La posible gasificación del asfalto es otro motivo de preocupación. Todos los materiales usados en una construcción liberan gases que resultan ser nocivos, y, algunos de ellos, carcinogénicos. No tenemos conocimiento de que se haya investigado el tema de la gasificación de la emulsión de asfalto con algn detalle, sobre todo sus posibles efectos a largo plazo.

    ¿Porqué usar el Adobe?

    Hay ventajas y desventajas asociadas con su uso. Desde el punto de vista del que construye su casa, el adobe representa el material más fácil de manejar. Como está hecho de barro, se hace fácil cortarlo o darle un cortorno en particular. La mezcla que une los ladrillos de adobe es barro, y creo que todos tenemos una experiencia tempranera trabajando con este material.

    Si bien Ud. puede fabricarse sus propios ladrillos, el costo asociado al construír una casa de 200m2 oscila entre $ 2.000 y $ 3.000 dólares. La diferencia en costo depende de su locación y de si adquiere ladrillos tradicionales o estabilizados.

    La cantidad de energía y polución asociada con el proceso de manufactura del adobe dependen del tipo de material. Si comparamos lo que se necesita para fabricar un ladrillo horneado, los valores son mucho menores (2.000 Btu para el adobe contra 30.000 para el ladrillo de horno)

    También se ahorra energía cuando ambos son transportados, ya que el proveedor resulta ser “local”. Esto, a su vez, crea trabajo en la zona donde es consumido. Para el entusiasta de la energía solar el adobe representa la manera más sencilla de crear una masa térmica. Tal es el vínculo entre estos dos conceptos, que en el sud-oeste de los EEUU se habla del “Solaradobe”, combinando dos palabras en una.

    Construyendo con Adobe PDF File (141K)

    SEED – School Energy Project

    Sponsored By

    Public Service Company of New Mexico

    In 1996, PNM’s Good Neighbor Program funded the SEED project for school districts in Southern New Mexico. The project seeks to expand student energy education and to involve students in energy conservation in their school and community. The program involves students from K-12 and is modeled after a Texas project developed by the Energy Center at the University of Texas at El Paso.


    Watt Watchers are teams of elementary school students who patrol their schools checking for energy waste. Several times during the school day the students patrol their assigned areas, and should they find lights on in an unoccupied room, the offending responsible party i.e. teacher/administrator, is issued a ticket.

    The program begins with a presentation to the school sponsor (teacher/admin.) and students. Participants learn how the energy used in the school is produced, the relationship of fossil fuels and pollution, and the importance of conservation/efficiency. The students also learn how renewable energy can play an important role in their future.

    Watt Watcher patrols have consistently reduced school energy use and utility bills, but it doesn’t end there. Everyone in the school becomes more energy conscious and the lessons learned are taken home and implemented. Saving energy reduces pollution and improves our environment.

    New Mexico School Districts currently participating in the program include Gadsden, Silver City and Deming.

    Student Mentoring

    Click to see full photo

    The 3rd grade students at Chaparral Elementary School are not only very diligent about their Watt Watcher Patrols, they also gave up their recess time to develop an energy presentation for the kindergarten classes.


    The High School program begins much the same way except that the sponsor and students are often part of an established group such as the Student Council or Science Club. Projects for High School students include school energy audits, energy displays in school and community, auditing of utility bills, weatherization of homes in the community, and mentoring of elementary school students. The Energy Council “adopts” elementary schools and implements Watt Watcher Programs and more.


    Click to see full photo

    Gadsden High School students spent a Saturday morning weatherizing homes for senior citizens.

    Start Saving Energy In YOUR School

    Solar Food Drying

    The art of drying food using solar energy is a little more complicated than you might think. We have tried to gather some practical information and to provide links to other resources. Although dried food is popular with campers, backpackers etc. this page

    is driven by the need for solar dryers in areas where fruit is plentiful in summer months, but because there is no simple and economic method to preserve it, much of it is left to rot, while in the winter there is hunger.

    Solar food drying can be used in most areas but how quickly the food dries is affected by many variables, especially the amount of sunlight and relative humidity. There are some basic guidelines to drying food.

    Most of the resources we researched recommend pre-treatment of the food, such as blanching, (boiling/steaming). Many experienced users do not pre-treat food.

    Wash fresh fruits and ripe vegetables thoroughly.

    Effective drying is accomplished with a combination of heat and air movement.

    Remove 80 to 90% of moisture from the food.

    Typical drying times range from 1 to 3 days, again depending on sun, air movement, humidity, and type of food.

    Once the drying process has started it should not be interrupted, do not allow to freeze.

    Direct sunlight is not recommended.

    Temperature ranges of 100 to 160 degrees will effectively kill bacteria and inactivate enzymes, although temperatures around 110 degrees are recommended for solar dryers.

    Too much heat especially early in the process will prevent complete drying.

    Food should be cut into thin slices, less than 1/2″ thick and spread out on trays to allow free air movement.

    Rotate trays 180 degrees daily for uniform drying. Move dryer food to bottom racks.

    Safe tray materials include Stainless steel rack-wood slats-cheesecloth-Teflon -Teflon coated fiberglass-nylon -food grade plastics

    Allow food to cool completely before storing.

    Store food in air tight jars or plastic containers, and do not expose dried food to air, light or moisture.

    Most fruits taste great dried including apples, apricots bananas, grapes etc.

    Vegetables are best reconstituted by covering with cold water until they are near original size.
    They can be added in their dry form to soups/stews. Vegetables can also be ground into powders and used for instant soups or flavoring.

    RESOURCES good chart on preparation and drying times.


    Proceedings of Ises Solar World Congress
    Budapest 1993, Volume 8.Numerous papers on
    solar drying of various crops.

    From: Home Power Magazine

    Basic Solar Dryer

    Interior of box is insulated 

    Optional solar chimney is glazed on south side and interior is painted black.

    Solar Cookoff

    Cook Off

    Solar Cook Off ’97

    EPSEA’s Solar Cook Off coincided with Eath Day Festivities in El Paso on April 20. On a beautiful Solar Day, EPSEA not only conducted the cook off but also set up working solar displays which included; PV water pumping, solar distillation, concentrated solar energy, a stirling engine and the “Human Sundial”. Thousands of people visited our booth and left with information about the equipment displayed as well as solar design, hot water and more.

    The Human Sundial

    Once laid out the human dial holds their hands slightly apart and turns until there is no shadow on either palm.

    Lilly Ojinaga, Program Coordinator for Renewable Energy, State Government of Chihuahua, Mexico demonstrates just how easy it is to tell time.

    Here are a few photos of the entries from elementary, middle and high school students from El Paso and Juarez, Mexico. Congratulations to all who competed.


    Solar Stills

    Solar Water Purification Project

    In 1995, EPSEA received funding through the State of Texas, State Energy Conservation Office (SECO), for a solar demonstration project. EPSEA’s project demonstrated the feasibility of using solar energy to purify water. The target audience (end users) are the people who reside in colonias along the Texas/Mexico Border. A colonia is an unincorporated settlement, lacking a safe water supply and waste water treatment. EPSEA’s work in solar water purification continued in colonias in Dona Ana County, New Mexico through a collaborative effort with the Southwest Technology Development Institute (SWTDI) at New Mexico State University. In 2000, EPSEA was able to install stills in Juarez, Mexico through a grant from “Border Pact”. EPSEA has since received funding through the U.S. Environmental Protection Agency (EPA) to continue it’s work in solar water distillation.

    EPSEA has presented papers and hosted workshops at the American Solar Energy Society’s (ASES) national conferences and the Mexico National Solar Energy Conferences.

    The problems faced by many colonia residents include contaminated water, as well as water with very high salt content. The sources of contamination include septic systems, industrial pollution, and run off of fertilizers and pesticides. These problems are seen on both sides of the border and like the resulting sickness and diseases, know no borders. These problems are not confined to only colonias, but it is the conditions that exist in colonias which allows for the proliferation of sickness and disease. The causes of these problems can be traced to pollution, poverty, ignorance and greed.

    The Marcos family, Juarez, Mexico
    Solar Solutions

    EPSEA’s demonstration project is only a small example of the potential role for solar energy in water treatment, and disease prevention. Solar distillation is a proven technology for water disinfection. Systems can be sized for one person, up to community sized systems. They have no moving parts, relying only on the sun for energy, and should last 20 years or more. Larger disinfecting systems which generate chlorine and other gases can be operated in remote locations, using solar energy. It is hoped that through the success of our local project, these technologies will be replicated in other regions currently facing similar conditions.

    The heart of EPSEA’s project is a basin solar still. EPSEA’s research resulted in a basin still, with emphasis on ease of replication and readily available materials. The still utilizes standard patio replacement glass (34″X76″), and during the summer months produces over 3 gallons/day. Winter production is about 1/2 that amount. The still has no moving parts, uses only solar energy to operate, and is self cleaning.

    Project Update

    The El Paso Solar Energy Association’s (EPSEA) solar water distiller projects (under an EPA grant for TX & NM, and Borderpact/Conahec for Mexico are progressing successfully. Only two more stills need to ben installed in the colonia areas of Ciudad Juarez, Mexico to complete the Borderpact project. The EPA project is just beginning Phase II which includes public community meetings and further education via energy fairs, etc., and a hands-on stills construction workshop that will be taught by Mike Cormier at the Water Festival in Columbus, NM in March. Applications are already being accepted by EPSEA from potential still recipients in the Luna, Dona Ana, and El Paso Counties of southern NM and west TX.

    A selection process will be used to decide who will receive a still. A cost-share amount of $50-$100 per still (small or large, respectively) will be paid by the recipients who are chosen. A sponsorship and payment plan program is available for individuals who cannot afford the cost-share amount. A recent fundraising breakfast was held at St. Pius Church by the St. Pius Colonia Ministry to aid in achieving funds for such sponsorships.

    Border Pact Presentation – PDF Document (327k)

    For more information about these projects contact us at 915-772-SOLR email:

    Final Update

    Having completed this project, we presented a final paper to the Solar World Summit for the International Solar Energy Society in Orlando, Florida in 2005.


    Solar energy is allowed into the collector to heat the water. The water evaporates only to condense on the underside of the glass. When water evaporates, only the water vapor rises, leaving contaminants behind. The gentle slope of the glass directs the condensate to a collection trough, which in turn delivers the water to the collection bottle.

    EPSEA Still Cutaway (39k)

    The still is filled each day with twice as much water as was produced. The still is fitted with overflow outlets, which allows the excess water to flush the still every day. A major advantage of the basin still is that it does not require a pressurized water supply. Colonia residents often have their drinking water delivered by truck and it is then stored in 55 gallon drums. Still recipients report that the water tastes very good and their children now drink more water than before.

    Construction Cost

    EPSEA material costs, with bulk purchasing, are approximately $200 per still. The cost of materials to build a single still should be less than $300. Only basic tools are required.

    Construction Plans Available

    Solar Hot Water

    Most everyone has experience with passive solar water heating. How many times have you turned on the hose in the yard and nearly burnt yourself with hot water? While you weren’t looking, old Sol was quietly working to give you hot water, even if you didn’t want it. Well if it’s that easy, imagine what you can do if you’re actually trying to make hot water. Passive solar hot water systems are probably the oldest commercially available solar systems. At the turn of the century there were large numbers of solar water heating systems on roof tops, especially in Los Angeles and Florida. Very little has changed from the original concept. Put a water holding tank in a box, with glass on the side facing south and fill it with water. No moving parts, nothing to break down, free fuel and no pollution.

    The passive solar water heater is known today by many names; PSWH, Batch Heater and Bread Box are the most common and then there is the very technical; Integrated Collector and Storage System (ICS).

    The PSWH of today usually starts with a 40 gallon, glass lined tank. These tanks come disguised as ordinary electric water heaters, which are stripped of their appliance shell and insulation. Painted flat black, with high temperature engine or barbecue paint and they’re ready for solar.


    The box should be well insulated to prevent energy loss and the amount of insulation should reflect your local climate. The typical box is constructed with 2X4s or 2X6s, using fiberglass batt insulation. The exterior siding may match that of your home, or some other material suitable for your area. The interior sheathing is often ridged insulation, preferably with a foil face facing in which works to reflect more energy onto the tank. Ridged insulation comes in various thicknesses which can help increase your insulation R-value.

    The size of the box must be big enough for the tank, but also large enough to allow adequate solar gain. Typical glass sizing is 1 sq. ft. of glass for every 2 to 2 1/2 gallons of water. A standard size, double glazed, patio door replacement glass (34″X76″) is ideal for a 40 gal. water heater. Of course if you already have a piece of glass…….

    A water heater has an inlet and outlet and how you attach your plumbing does make a difference. The cold water inlet has a dip tube which extends down nearly to the bottom of the tank, to deliver the cold water to the right place. The hot water outlet takes the hottest water from the top of the tank. If your design calls for the tank to lie on its side be sure that the cold inlet is at the bottom.

    Be aware that the 40 gallon tank when filled with water will weigh over 350 lbs. Add to that the weight of the box/glass and it’s time to reconsider putting this monster on your mobile home. Ground mounted PSWH are very common. As always be sure the system will receive full sunshine from 9 am to 4 pm. Remember, if your installing a solar system and you’re working in the shade, there’s something wrong.

    If the collector will be installed on a frame roof it’s best to attach in such a way as to spread the weight over a few rafters, and if possible, provide additional support with braces extending up to the rafters from interior walls. The ideal location is as close to the existing water heater as possible.

    Shorter plumbing runs are not only more efficient, they decrease the winter freezing potential. The chances of freezing 40 gallons of water are minimal but frozen pipes are a reality. With the tank installed close to the water heater the freezing potential is minimized but not eliminated. All plumbing between the existing water heater and the PSWH is insulated, with more insulation on any pipes exposed to the outside. Also be sure to carefully insulate all plumbing in attic areas.

    Plumb the system by first supplying cold water to the solar tank. From there, the hot water outlet is plumbed to the cold water inlet on your existing water heater. As long as the solar water entering your water heater is above the thermostat setting, your water heater does nothing. When the temperature of the solar water entering the water heater is less than the thermostat setting, your water heater makes up the difference.

    The temperature of the water from a PSWH depends on many variables. The amount of sunshine, ambient air temperature, the amount of insulation used, the temperature of the supply water as well as the hot water demand all effect outlet temperature. Under ideal weather conditions, and no hot water used since morning, the water temperature at 5 pm can exceed 180 degrees F. You may consider installing a tempering valve which allows you to set the temperature for the water before it reaches the faucet.

    How much of your hot water demand will be met by your PSWH varies depending on a number of factors. Have you installed low-flow shower heads and aerators? Have you installed a water heater blanket and set the thermostat to 120 degrees F? When do you use the most hot water? If you normally wash clothes/shower etc. in the evening, there probably won’t be any solar water in the morning. If someone is normally home during the day and clothes washing is scheduled for around solar noon, you can stretch your solar water. After normal water use in the am, the sun heats the water all morning and then that water is used for the laundry (if necessary). This schedule allows time for the water to heat up again during the afternoon.

    Be sure your installation meets all local plumbing codes etc.

    Solar Distillation
    Solar Water Purification for the

    Plumbing Diagram

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