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Receiver design for Solar parabolic dish concentrator

  1. Nov 13, 2009 #1
    Hi All,
    Am Madan Mohan Reddy, Interior accessory design graduate (finished this year) from National Institute of Fashion Technology, Hyderabad, India. Am so much interested in designing green solutions, so now am working on making a Solar Parabolic Dish Concentrator for all heat required applications now for home like cooking, hot water and so...

    Basically the construction is similar to Satellite dish construction, the only difference is that am applying/sticking reflective film onto the plastic sheet (in the place of mesh in satellite dish). This dish has both elevation-azimuthal tracking which is been controlled by solar tracker.

    Now coming to the receiver part, I have some ideas to share with you all (to know your suggestions)

    1. Pyramidal Cavity receiver
    The whole receiver is made of Borosilicate/Pyrex glass which has high thermal shock stability as well a good insulator. All the inner side faces except the bottom one which is facing the dish are coated with highly reflective radiant barrier. Inside the cavity, we are keeping Copper coils (preferably spiral in shape) which are coated with high solar absorptivity and low emissivity substance. We are using heat transfer fluid inside the copper coils to transport the heat energy from the receiver to the well insulated heat storage tank. This demands Glass-Metal seal. then we are evacuating the cavity thereby creating vacuum inside the cavity which reduces the conductive and convective heat transfer. Anyways we have highly reflective radiant barrier coating on the inside faces which reflects the radiation inside.

    2. Secondary Concave lens concentrator
    This is just the same as the earlier, the only difference is that am keeping a concave lens (material (glass) of high optical transmission over wide range of wavelength of sunlight) in place of flat bottom lens in the earlier pyramidal cavity. When light rays upon reflection from the dish hits this concave lens and this lens make them parallel upon refraction into the cavity. The advantage with this compared to earlier design is that :
    Inside the cavity, the radiation is emitted from the high temperate solar absorptive coated copper coils. The inner faces except the bottom one has radiative barrier. So the only way for the radiation to escape is that from the bottom one. In earlier design, the distance
    between the bottom and the coils is very less but whereas in this concave lens set-up, as the rays are turning to parallel, this gives an advantage to raise the distance between. This seems something like a black body kind of set-up (not completely sure). Even this cavity
    should also be evacuated like in the earlier.

    Am not a mechanical/technical engineering background student (had Sciences in high school, am applying those I learnt there and Internet and discussing with wonderful people like you all). The climate change and the global warming are the factors which are driving me to work this way though it is not my cup of tea.

    Thanks a lot in advance for spending your valuable time in going through this long post and giving your priceless suggestions on it....

    Madan Mohan Reddy
    Ph : 91-9030236021
  2. jcsd
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