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Whats the real difference between evac solar tube and flat panel.

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  • 24-04-2008 1:59am
    #1
    SillyMonkey
    Registered Users Posts: 54 ✭✭


    Am getting a geothermal system with UFH. Also getting 300ltr tank heated by the geo.

    Just this week decided to go for solar panels evac tube preferably. So went in to see my geo supplier but they only do flat panel.

    Now flat panel appeals to me because of looks but evac are meant to be better.

    How exactly are they better, is my water at a higher temp before the geo kicks in therefore saving me electricty or what?


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    #2
    Mothman
    Closed Accounts Posts: 6,498 ✭✭✭Mothman


    Start with this current thread
    http://www.boards.ie/vbulletin/showthread.php?t=2055263582

    There are also other recent threads that may help.


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    #3
    boardwalk
    Closed Accounts Posts: 3 ✭boardwalk


    SillyMonkey wrote: »
    Am getting a geothermal system with UFH. Also getting 300ltr tank heated by the geo.

    Just this week decided to go for solar panels evac tube preferably. So went in to see my geo supplier but they only do flat panel.

    Now flat panel appeals to me because of looks but evac are meant to be better.

    How exactly are they better, is my water at a higher temp before the geo kicks in therefore saving me electricty or what?
    Evac collectors are about 30% more effectiv per annum than flat collectors. They collect more energie at low themperatures and cloudy skys. Flat collectors work best the more vertical the sun shines while evac collect energie from the sides and low sun aswell.


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    #4
    AckwelFoley
    Registered Users Posts: 12,556 ✭✭✭✭AckwelFoley


    One of the biggest reasons for their higher efficiency is how they collect the heat and transfer it.

    With panels there is insulation between the pipework where the fluid flows, the insulation is never really high enough to stop the geatloss from the panel, if it was to be high enough the panels would be much too thick looking.

    With evac tubes, there is a copper rod and sealed within is a refridgerant liquid. The liquid firstly heats up alot quicker than the solar liquid that goes through the panels, but also, because the sealed copper rod is within a twin vaccum wall of glass there is no significant heat loss, do all the heat that is generated is exchanged into the manifold at the top of the tubes that carries the solar solution.

    There are within solar tubes as described diferent efficencies, and ive seen the price of the more efficent ones and they are about 15% more costly, but probably worth it.


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