Tag Archives: energía solar térmica en latinoamérica

Guatemala Solar Thermal

In Guatemala, talking about solar radiation use for electric and thermal energy generation in homes seems a myth. And in the case of thermal, even more.

So far, according to Ministry of Energy and Mines (MEM) data, approximately two thirds of energy is produced with fossil fuels, which translates into high costs and environmental pollution.

A good part of that electricity is used in order to heat water for human consumption, especially for the shower.

During approximately 350 days a year there is sufficient solar radiation to meet 95% of hot water needs in Guatemala.

As in many countries of Central America, thermal energy generation from solar radiation is an industry almost unknown and often confused with electric energy generation.

The few households that have incorporated solar thermal energy experienced a minimum decrease of approximately 40% in their electric bill amount and will pay off the investment made in less than 3 years.

Resultado de imagen de solar térmica guatemala

Currently it is possible to find two types of solar heater systems technologies in the country: non-pressurized and pressurized.

The first is generally used for residential use because it is of little pressure and simple installation, and the second one is more used in industry and services sectors.

Experts and leaders from Latin America and the Caribbean gathered in Costa Rica to promote quality assurance mechanisms implementation in solar water heaters use, in order to increase technology confidence and stimulate its development in the region.

Issues such as standards, testing, labeling and certification, as well as the use of quality infrastructure to support regional policies on the promotion of solar thermal energy were considered.

Solar heating technology has arrived at a maturity, technological and of price, that nowadays allows developing national strategies as well as regional to promote water heating with solar energy.

Currently, less than 3% of solar thermal energy is used in Latin America and the Caribbean, so that better quality assurance mechanisms can lead to significant market growth.

Solar thermal energy can also be used to dry grains, especially coffee.

The drying system consists of solar collectors, recirculation pumps, water pipes, thermal insulation, storage tanks, precision fans and heat exchangers.

Solar collectors absorb solar energy, this is transmitted to the water that flows through the pipes. The hot liquid is stored in the central tank, from where it flows to the mechanized dryers. At this point, water-air heat exchangers dehydrate and heat the ambient air, drying the grains.

Resultado de imagen de secador solar café

In El Novillero village, Santa Lucía Utatlán, Sololá, there is the ecological park and protected area Corazón del Bosque, a project of the Artisanal Association for La Guadalupana Development.

Linking community benefit with natural resources sustainable use were concerns that originated this project, which to date generate 13 permanent and more than 800 temporary jobs.

Solar energy wherever you are with Sopelia.

Solar Layout (Thermal)

Solar Layout is the App for collectors and solar modules on site positioning.

This is the most intuitive Solar App of the market.

To use it on field is not necessary to have an Internet connection because it works from place latitude, obtained by GPS.

Today we will see solar thermal energy part.

To begin press left command shown in initial screen with the house, the solar collector and the user taking a hot shower.

If our Smartphone GPS is not enabled, the App will ask us to activate it to locate our position.

Intermittent earth planet image immediately appear with the legend “Localizing”.

When our device GPS have located our position, the following screen appears to confirm it.

By confirming our location the Solar Equipment Use Menu displays.

There are 3 applications in the Menu:

1 Hot water: represented by a shower image
2- Heating represented by a radiator image
3- Outdoor pool conditioning: represented by a pool ladder image

By selecting one of the 3 applications, Options Menu will display.

There are 3 variables in the Menu:

1- Inclination: represented by collector and angle image
2- Orientation: represented by collector and cardinal points image
3- Distance: represented by 3 collectors rows image

By pressing the Inclination option, we get recommended inclination value for location and solar application selected, accompanied by some Tips considering collector type used.

Pressing Orientation option, we obtain procedure to fix collectors orientation description and access to recommended compass App discharge, if we don´t have it.

Pressing Separation option, the Kind of Surface Menu is displayed for us to select the appropriate option (Horizontal / Non horizontal). If the surface on which the collectors will be placed is horizontal, we only must enter Collector Height in cm data.

If the surface on which the collectors will be placed is non horizontal, in addition to Collector Height in cm data, we must enter Surface Inclination Angle data. We will enter a positive value if it matches the collector inclination direction and a negative value if it is different.

In this way we obtain the Separation (distance) between collector’s rows in meters.

Pressing i button Tips related to shadows and singular locations (snow, desert and rain areas) are deployed.

Download Solar Layout and placed solar thermal collectors on site in the most intuitive way with Sopelia.

(Español) 10 Semanas Solares Térmicas

Este cronograma representa la dosificación recomendada de dedicación para una correcta asimilación de conocimientos durante el curso e-learning de Técnico – Comercial en Energía Solar Térmica impartido por Sopelia.
Puedes recibir esta formación íntegramente desde tu computadora, smartphone o dispositivo móvil.
Supone dedicar entre 1 y 2 horas diarias entre lunes y viernes de cada semana.
* Semana 1: Introducción a la Energía Solar
1.1) El futuro de la energía solar
1.2) El Sol
1.3) Nociones básicas de Física
* Semana 2: Introducción a la Energía Solar
1.4) Nociones básicas de Electricidad
1.5) Nociones básicas de Energía
1.6) Energía del sol
1.7) Tablas
– Resolución Test 1 y 2 y Ejercicio 1
* Semana 3: Energía Solar Térmica – Equipos
2.1.1) Colectores
2.1.2) Sujeción y anclaje
* Semana 4: Energía Solar Térmica – Equipos
2.1.3) Fluido caloportador
2.1.4) Protección de la instalación
* Semana 5: Energía Solar Térmica – Equipos
2.1.5) Tuberías
2.1.6) Tanques acumuladores
2.1.7) Intercambiadores
* Semana 6: Energía Solar Térmica – Equipos
2.1.8) Grupos de bombeo
2.1.9) Aislamiento
2.1.10) Otros componentes
– Resolución Test 3 y Ejercicio 2
* Semana 7: Energía Solar Térmica – Instalaciones
2.2.1) Principios básicos
2.2.2) Diseño
2.2.3) Regulación
* Semana 8: Energía Solar Térmica – Instalaciones
2.2.4) Proyecto de un sistema de ACS
2.2.5) Cálculo de la superficie colectora
2.2.6) Cálculo de los demás elementos de la instalación
* Semana 9: Energía Solar Térmica – Instalaciones
2.2.7) Presentación de un proyecto
2.2.8) Otras aplicaciones
2.2.9) Ejecución y mantenimiento de la instalación
* Semana 10: Energía Solar Térmica – Instalaciones
– Resolución Test 4 y 5 y Trabajo Práctico final
Se trata de la formación en Energía Solar con la mejor relación calidad-precio del mercado.
Puede recibirse donde quiera que estés.
Solamente se necesita una computadora, smartphone o dispositivo móvil y conexión a Internet.
Por tratarse de la 1era edición hay un 50% de descuento sobre el PVP.

Esta acción de formación brinda capacitación técnico – comercial en aplicaciones domésticas de energía solar con el objetivo de difundir la tecnología y desarrollar recursos humanos para su incorporación al mundo laboral y empresarial.
La edición 2016 comienza el día 19 de septiembre y finaliza el día 25 de noviembre.

El plazo de inscripción es hasta el día 16 de septiembre inclusive en www.energiasrenovables.lat
Ya no tienes excusas, energía solar donde quiera que estés con Sopelia.

Free Solar Tools (III)

On Internet we can find free tools for basic or low complexity solar systems dimensioning and for certain components or accessories estimation.

Sopelia research team has carried out an exhaustive search and testing from which a new corporate website section called Free Solar Tools has been created.

Selected tools were classified into 4 categories.

Today we will analyze the third of them: Solar Thermal.

In first category we have already analyzed tools to obtain data about solar resource and other variables to be considered in energy estimation solar system will provide in our location.

In the second category we have analyzed tools to calculate the “load”, ie the energy demand to be met.

Now we are going to analyze tools to solar thermal system dimensioning and others to estimate individual components of a system.

The order of the tools is not random. We have prioritized the most intuitive, the most universal and those that can be used online without download.

For this third category our selection is as follows:

1) Solar Thermal Calculator

Approximate calculation tool from which budget, production data and system performance study is automatically obtained.

A Navigation Guide and Manuals can be found at page bottom.

Resultado de imagen para calculadora solar térmica

2) Simulation for Solar Thermal System Pre-design

Online application based on the TSOL software that allows solar energy system simulating to ACS and ACS + heating contribute.

Available in German, English, Spanish and French.

Resultado de imagen para simulación solar térmica

3) Solar Fraction Calculation

Free download program developed by IDAE (Institute for Energy Diversification and Saving) and ASIT (Solar Thermal Industry Association) that allows to define a wide variety of solar systems introducing a minimum of project parameters, associated to each system configuration; and in this way, obtain solar system coverage on ACS and pool conditioning energy demand.

Resultado de imagen para fracción solar

4) Solar Expansion Vessel Calculation

Tool developed to calculate solar expansion vessel volume.

Volume values (total circuit, solar collectors, pipes), Maximum system temperature (ºC), Glycol concentration (%), Height between expansion vessel and system highest point (minimum value 1 Bar) and safety valve Pressure setting must be introduced.

Resultado de imagen para vaso de expansión solar

5) Thickness Insulation Pipes Calculation

Calculator that allows to estimate minimum and more economical water pipes insulation thickness.

Pipe Grade and Size, Insulation Material, Humidity and Temperature (Internal and Ambient) must be entered.

Resultado de imagen para aislamiento tuberías

Solar energy wherever you are with Sopelia.

Thermal Solar Collector

Thermal solar collector is responsible for capturing solar radiation and converting its energy into heat energy.

A body exposed to the sun receives an energy flow Er and heats up.

Simultaneously, thermal losses occur due to radiation, convection and conduction, which grow as the body temperature increases.

There comes a time when thermal losses Ep equals the gains due to the incident energy flow, reaching the so-called equilibrium temperature:

 Er = Ep

The equilibrium temperature of the collectors is usually between 100º and 150º C under normal conditions of use and for irradiation values in the order of 1,000 W / m2.

If it is possible to continuously extract a part of the heat produced Ee to take advantage of it as usable energy, the equilibrium conditions change:

Er = Ep + Ee

Ep is now smaller because a part of the energy received Er is tapped Ee.

The body has become a solar thermal collector.

If we want to increase Ee we have two options: reduce thermal losses Ep or increase energy flow Er.

First option involves collector design and construction improving in order to reduce losses.

For the second option is used the concentration technique, which by some optical system concentrates the solar flux on a smaller surface so that as the area decreases, the intensity increases.

In a solar collector the energy is extracted through a fluid called heat carrier.

Resultado de imagen de rendimiento colector solar térmico

The greater the difference between operating temperature and ambient temperature, the greater the thermal losses and thus the lower energy amount that heat transfer fluid will be able to extract.

The collectors must be operated at the lowest possible temperature, provided that temperature is sufficient for the specific use in each case.

This is because collector efficiency decreases as the operating temperature increases.

Improved insulation helps thermal losses reduce.

Reflection losses are due to transparent cover that usually exists in almost all collectors.

It will be necessary to properly orient the collectors so that they receive the greatest radiation amount possible during the period of use.

The question: which is the best collector ?

A priori has no answer.

It will depend on system location and energy demand that is intended to be met.

There are many types of solar collectors, but there are two large groups: unconcentrated collectors and concentrated collectors.

Solar thermal collectors according to their working temperature:

1) Low temperatura

1.1) Flate: protected and not protected

1.2) Vacuum tubes: direct flow, heat pipe and solar concentrator CPC)

2) High temperatura

2.1) Parabolic Cylinder

2.2) Central receiver system

2.3) Parabolic disks

2.4) Solar chimney

3) Other collectors

3.1) Rubber

3.2) Spherical

3.3) Conical

Resultado de imagen de colector solar térmico de baja temperatura

In next posts we will analyze in detail each collector type.

This content was extracted from the Solar Thermal Energy Technical-Commercial Manual and is part of Solar e-learning.

Solar energy wherever you are with Sopelia.

El Salvador Solar Thermal

Great was our surprise when we began to carry out the research work on El Salvador domestic solar thermal energy applications sector.

Considering that in country central region solar irradiation is high (5.3 kWh/m2/day), compared with other locations such as Germany or Tokyo (3.3 kWh/m2/day), the potential is enormous.

Given the almost non-existent information available (and official agencies lack of response), we decided to consult professionals and companies in the renewable energy sector of El Salvador.

The conclusions are:

1) There are very few companies that offer solar thermal equipment (some, including inventory they wish to liquidate due to low sales volume)

2) Unfortunately local mentality still focuses more on initial investment than on long-term savings from electricity consumption expenditure reduction

3) The use is practically limited to hotel and hospital sectors and is irrelevant in residential sector

4) There is no normative that regulates and promotes sector development.

Resultado de imagen de solar térmica el salvador

This situation, which is repeated in many Latin American countries with solar resource great potential, raises the question of why solar thermal development is so inferior in relation to photovoltaics.

To answer this question we will make a brief comparison between both solar technologies:

– Domestic solar thermal applications

+ It is a simpler technology

+ It is more efficient respect to the space used

+ Higher yields are obtained (around 40% for solar collectors compared to maximum 20% of solar modules)

+ Solar fraction can easily exceed 70% in locations with medium-high radiation level

+ It is a technology with lower level of complexity in its installation

Aspects to consider:

* System performance is much lower in winter months, when hot water needs are higher

* If there is frost risk in system site, antifreeze use in heat transfer fluid is indispensable.

Resultado de imagen de solar térmica el salvador

– Photovoltaic solar energy applications

+ Photovoltaic systems are more versatile

+ Photovoltaic modules have longer service life (30 years with a guarantee of 20 years by almost all manufacturers) than thermal solar collectors (10 years with between 1 to 5 years guarantee)

+ Frost does not affect them

Aspects to consider:

* Higher investment compared to solar thermal system of equivalent power

* Grid connected systems are subject to numerous bureaucratic procedures and taxes that lengthen its amortization time

* It is a newer technology that needs technical advances to improve its performance and efficiency.

We can conclude that the balance is slightly tilted in favor of solar thermal.

So, why photovoltaics development is bigger?

The answer is that solar thermal is developed almost exclusively in distributed energy generation way, while solar photovoltaic does it mainly from large central power plants.

Solar energy wherever you are with Sopelia.

Solar Thermal Energy

Solar thermal energy systems for domestic applications will be increasingly present in the built landscape and will be promoted by regulations such as solar ordinances or future building technology standards.

The most basic system is the compact equipment called thermosiphon, which incorporates all subsystems and where the fluid circulates naturally (difference in densities).

Resultado de imagen de termosifón solar

Solar thermal systems use the sun’s rays to get hot water or air.

Special plates, called collectors, concentrate and accumulate Sun heat and transmit it to the fluid we want to heat.

This fluid can be home’s drinking water or home’s heating or cooling hydraulic system.

Generally a thermal solar energy system is constituted by several subsystems, which in turn can be considered as interdependent systems connected to each other.

However, sometimes the same physically independent element performs several functions within the solar system.

These different subsystems are:

a) Capture system: composed of solar collectors. They are responsible for receiving the solar radiation and transmit it to the fluid that circulates inside.

Imagen relacionada

b) Accumulation system: composed of one or more deposits to accumulate the hot water generated up to the moment of its use.

Resultado de imagen de tanque solar térmico

c) Hydraulic system: composed of the pumps and pipes through which the working fluid circulates. A primary circuit transports the energy captured to the accumulator. The circulation of the fluid through the pipes is performed by a circulation pump or by natural circulation.

Resultado de imagen de circuito solar térmicod) Exchange system: exists in case the fluid flowing through the solar collectors is not the same as the one used by the user; for example when there is frost risk or user fluid can damage the solar system. The exchanger can be part of the same accumulator or located outside.

Resultado de imagen de intercambiador solar

e) Control system: in pumps forced circulation systems will be in charge to start and stop them. Different components system actuation (motorized valves, pumps, etc.) is done through control mechanisms.

Resultado de imagen de centralita solar térmico

f) Auxiliary energy system: generally solar system economic viability requires that total energy demand cannot be met with solar input at all times. The energy produced by solar system depends on climatic conditions and that is why an auxiliary energy production system is available. These support equipment complement the solar system in order to ensure at all times hot water service continuity.

Resultado de imagen de caldera gas

Solar thermal systems have a great similarity with conventional thermal systems.

In fact, they share all their components (pipes, protection mechanisms, accumulation tanks, exchangers, pumping groups, insulation) except one: solar collectors.

This content was extracted from Solar Thermal Energy Technical & Commercial Manual and is part of Solar e-learning.

Solar energy wherever you are with Sopelia.

Solar Layout (Thermal)

Solar Layout is the App for collectors and solar modules on site positioning.

This is the most intuitive Solar App of the market.

To use it on field is not necessary to have an Internet connection because it works from place latitude, obtained by GPS.

Today we will check solar thermal energy part.

To begin press left command shown in initial screen with the house, the solar collector and the user taking a hot shower.

fig-1

If our Smartphone GPS is not enabled, the App will ask us to activate it to locate our position.

Intermittent earth planet image immediately appear with the legend “Localizing”.

When our device GPS have located our position, the following screen appears to confirm it.

fig-2

By confirming our location the Solar Equipment Use Menu displays.

There are 3 applications in the Menu:

1- Hot water: represented by a shower image
2- Heating: represented by a radiator image
3- Outdoor pool conditioning: represented by a pool ladder image.

fig-3

By selecting one of the 3 applications, Options Menu will display.

There are 3 variables in the Menu:

1- Inclination: represented by collector and angle image
2- Orientation: represented by collector and cardinal points image
3- Distance: represented by 3 collectors rows image.

fig-4

By pressing the Inclination option, we get recommended inclination value for location and solar application selected, accompanied by some Tips considering collector type used.

fig-5

Pressing Orientation option, we obtain description of procedure to fix collectors orientation and access to recommended compass App discharge, if we don´t have it.

fig-6

Pressing Separation option, the Kind of Surface Menu is displayed for us to select the appropriate option (Horizontal / Non horizontal).

If the surface on which the collectors will be placed is horizontal, we only must enter Collector Height in cm data.

fig-7

If the surface on which the collectors will be placed is non horizontal, in addition to Collector Height in cm data, we must enter Surface Inclination Angle data.

We will enter a positive value if it matches the collector inclination direction and a negative value if it is different.

fig-8

In this way we obtain the Separation (distance) between collector’s rows in meters.

fig-9

Pressing i button Tips related to shadows and singular locations (snow, desert and rain areas) are deployed.

Download Solar Layout and placed solar thermal collectors on site in the most intuitive way with Sopelia.

Solar Hydraulics

Hydraulics is the physics field that studies fluid mechanics and is divided into Hydrostatic (liquids at rest) and hydrodynamics (liquid in motion).

density of a body d is called the mass m and volume V ratio:

d = m / V

specific gravity pe is the weight (= m g.) and volume ratio:

pe = m. g / V

Fluids (liquids and gases) always exert a pressure pr in all directions.

The pressure is the quotient between a force f (the exerted by the fluid) and the surface area S acted upon by this force:

pr = f / S

The pressure unit in the SI is the Newton divided by m2 (N / m2) and is called pascal.

Pressure exerted by gravity and the forces tending to compress the fluid is called static pressure.

The pressure resulting from movement of a fluid is called dynamic pressure.

Knowing the density or specific gravity of a fluid we can find the static pressure due to gravity at any depth h from either of the following two formulas:

pr = d. g. h

pr = pe. h

Resultado de imagen de presión estática en líquidos

The pressure difference is equal to the depths difference h between 2 points or vertical distance between them.

A typical static pressure, is the atmospheric pressure produced in all directions on the bodies placed on earth surface due to the large air column above them. The result of this all directions atmospheric pressure action produces no net force pushing the body to one side, tends to compress it.

In the case of a container, the atmospheric pressure acts inside and outside and therefore their actions cancel each other.

We are interested in knowing the excess pressure above atmospheric pressure that may be inside the container (tanks or pipes) through measuring devices (manometers).

If air can freely enter and leave a container through the edge of the lid, the liquid surface will only be subjected to atmospheric pressure. It is an open or non pressurized reservoir.

If we measured pressure at different heights in the tank with a manometer it will be equal to zero at the surface and maximum at the bottom.

If the container is now sealed and subjected to additional pressure p, transmitted through the pipes that communicate with distribution circuit; the measurement is equal to the previous one but increased in the value of p. Usually the small pressure difference caused by the height difference is negligible compared to the overall circuit pressure p.

Archimedes’s theorem allows us to know a body weight when it is immersed in a liquid.

This theorem can be applied to a same liquid portion.

Suppose that a liquid portion suffer a slight temperature increase relative to other liquid parts.

Bodies expand by its temperature increasing and when increasing its volume density decreases as mass remains unchanged.

Resultado de imagen de presión estática en líquidos

If d1 is the new density of the portion considered (d1 < d):

Weight of the liquid portion: p = m. g = V1. d1. g

Thrust acting on the liquid portion: E = V1. d. g

Where V1 is the volume of the liquid portion

Resultado de imagen de termosifón

These are the called fluids natural convection currents, in which hot parts tend to rise. Natural circulation or thermosyphon systems are based on this phenomenon for supplying hot water by solar collectors.

This content is part of “Solar Energy Introduction” eBook and solar e-learning of Sopelia.

Ecuador Solar Thermal

In most of the Ecuadorian territory, for domestic hot water applications, the type of collector recommended is the flat collector.

The solar radiation levels and atmospheric conditions allow this type of collector to provide optimal yields and to minimize installation overheating risk.

Only in mountain areas, where environmental conditions are more stringent, it is advisable to use vacuum evacuated tube, U-pipe or heat pipe collectors.

Resultado de imagen de energía solar térmica en Ecuador

The country has atlas of solar and wind resources developed by CONELEC and MEER respectively. However both are based on satellite images, they have not been validated with field measurements and its resolution is not good.

Following this the INER developed a project that involved the installation of 17 weather stations in Cuenca canton and 10 weather stations in Chimborazo province, in addition to the placement of sensors for repowering existing meteorological stations in Chimborazo province.

With the data obtained methods of estimating solar radiation were applied to complete historical data series. So far preliminary solar resources maps have been drawn.

This project seeks to validate information about solar resource in the country and the proper use of the sun as energy supply resource.

An Alliance for Energy and Environment in the Andean region with the Inter-American Institute for Cooperation on Agriculture Program led hot solar water to Ecuadorian Páramo region.

The Ecuadorian Páramo includes the communities of Cotopaxi, Chimborazo and Bolivar, located more than 3,800 m above sea level.

The project initially focused on solar hot water use in schools and community centers and then extended to all the inhabitants.

Training workshops related to installation, use and maintenance of solar thermal systems were performed by the Fondo Ecuatoriano Populorum Progressio (FEPP).

Program also sought to generate money income for participants from installation, repair and maintenance of equipment. It was possible to train 54 people, including 19 women.

44 systems were installed in 42 schools, directly benefiting 2,186 boys and 2,206 girls, plus an old people center attended by 32 people. In a community agroindustrial plant where medicinal plants are processed consumption of liquefied petroleum gas (LPG) could be reduced.

Resultado de imagen de energía solar térmica en Ecuador

In another initiative, MEER and MIDUVI delivered solar collectors to population.

Nationally are 2,632 households beneficiary with the installation of these collectors granted to fund housing bond through the MIDUVI.

The delivery was made after a family’s selection process with suitable houses for solar collector’s installation, which had to have water connection and roof slab.

If there is no solar radiation to cover the water tank demand, there is an auxiliary system based on electricity.

The solar thermal collectors cost is still very high in Ecuador compared to fossil fuels operating systems.

Given country radiation levels, besides these isolated initiatives would be wise to develop policies for solar thermal systems mass use.

Solar energy with Sopelia.