Solar Ovens & Cookers (2017)

Apunte Inglés
Universidad Universidad Politécnica de Valencia (UPV)
Grado Ingeniería de la Energía - 5º curso
Asignatura Tecnologías Avanzadas de Energía Solar Térmica
Año del apunte 2017
Páginas 2
Fecha de subida 10/06/2017
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Temas 5a y 5b

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Pau Carnero MUTEDS Si necesitas más apuntes puedes encontrarlos en buscando el usuario "pcarnero" Other Applications of Solar Thermal Power Solar Ovens A solar furnace is a structure that produces high temperatures by means of concentrated solar power onto a focal point, through the use of mirrors.
Applications Depending on the configuration of the installation, a wide range of temperatures can be reached, and, hence, different applications can be found: • • • • Around 1.000ºC. Used to produce hot air.
Around 1.400ºC. Used to crack CH4 molecules and produce H2.
Up to 2.500ºC. Used for material testing related to nuclear reactors or even space vehicles.
Up to 3.500ºC. Used to produce nanomaterials.
The temperatures can be in the order of 3.500ºC, and the uses are mostly industrial applications such as melting steel, production of hydrogen, etc.
Large-Scale Installations Odeillo The biggest solar furnace installation in the world is at Odeillo, in the French Pyrenees. It consist on 63 adjustable heliostats facing South, which redirect the radiation to a huge parabolic mirror, facing North, that then concentrates all the energy into a focal point, of 40 cm diameter. It has around 300 clear day skies each year.
This installation is able to reach temperatures above 3.500ºC, and with this thermal level many applications are carried out like investigation for aerospace industries, production of hydrocarbons, purify materials, etc. It has around 270 clear day skies each year.
Uzbekistan The second largest solar furnace in the globe is at Uzbekistan, Russia. It has a large, 54mx54m with around 10.700 mirror tiles, parabolic mirror that focuses the energy onto a 1m diameter focal area.
This installation is able to reach temperatures 800-3.000ºC.
Almería SF-40 In the Plataforma Solar de Almería (PSA) there are 28 flat mirrors, with 92% reflectivity, making a total surface of 120 m2. They are able to concentrate the radiation onto a focal point of 26 cm diameter, 7,45m away coupled with 3-axis positioning system.
The system has an horizontal attenuator, which is able to reduce the incident sunlight on the focus of the concentrator. This plant is able to achieve a peak flux of 3 MW/m2, with an incident radiation of 1 MW/m2, generating a total power of around 69 kW in the focal point.
Almería SF-60 In PSA there is another installation, this one with 12 curved fiberglass petals, making a total surface of 100 m2, which concentrates the energy onto a focal point 4,5m away, with 3-axis positioning system.
Pau Carnero MUTEDS Si necesitas más apuntes puedes encontrarlos en buscando el usuario "pcarnero" Like the SF-40, this one has a louvered shutter as well, so as to attenuate the incoming radiation.
The plant is able to reach a maximum thermal power of 40 kW in the focal point.
Small-Scale Devices Much lower temperatures may be reached with smaller scale devices, among them are: • • • Solar cookers.
Solar water pasteurization.
Solar crematorium.
Solar Cookers Introduction In developing countries the highest energy consumption is linked to cooking, and the means used, based on firewood, are very rudimentary, inefficient (around 7%) and, even, dangerous.
Basing the ability to cook on this resource produces many deaths by the inhalation of fumes, inside the dwellings, but also force people to walk long distances in order to get the firewood facing may hazards, along with the existing risk of the deforestation and the atmospheric pollution.
Some solutions have been implemented, linked to the improvement of the cook stoves’ efficiency and the generation of smoke. More sophisticated devices have failed to be generalized among the population, due to the lack of cleaner fuels and the cost barrier. This fact has opened the path to the introduction of solar cookers.
Characteristics The main advantages of solar cookers is that they can be constructed with local materials, and that the sun is a resource available almost anywhere in the globe. However, there are also some drawbacks, like the slowness of the process, the need to cook outdoors, and, mainly, that there’s a total dependence on the presence of the sun.
The aim in the configuration of the device is to take profit of the accumulation of heat in the form of local greenhouse effect, and the concentration to reduce the size of the system.
Types There are several ways of classifying the solar cookers, depending whether they make use of direct or indirect radiation; or if they can be portable or they are stationary; also they can be divided by the existence of heat storage or not.