Evacuated tubes vs plate




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  1. #1
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    Default Evacuated tubes vs plate

    Does anybody know what the efficiency gains in heating water are when replacing a collector plate system(??) with a evacuated tube system?

    I have a solar system in place that increases water temp by max 20C on a hot day and I am considering replacing the collector with evacuated tubes.

  2. #2
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    Default Re: Evacuated tubes vs plate

    Evacuated tube collector is very efficient in situations where wind is a factor ( big heat loss from
    plate collector because no insulation on front) . Generally will outperform flat plate except in very hot
    ares with a lot of sunshine (such as inland N Cape or Namibia) . Only downside is , it is prone to overheating the water in the geyser if it is not used.
    I have been totally offgrid for 2 years now in Longbeach Namibia using, for hot water, a 20 tube collector and 150L tank and only have about 2 or 3 days a year when the water is below 40C .
    I have installed over 600 evacuated tube systems ( large and small) at the Namibian coast over the past 10 years and they are by far the the most used system here.

  3. #3
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    Default Re: Evacuated tubes vs plate

    Quote Originally Posted by kingchris View Post
    Evacuated tube collector is very efficient in situations where wind is a factor ( big heat loss from
    plate collector because no insulation on front) . Generally will outperform flat plate except in very hot
    ares with a lot of sunshine (such as inland N Cape or Namibia) . Only downside is , it is prone to overheating the water in the geyser if it is not used.
    I have been totally offgrid for 2 years now in Longbeach Namibia using, for hot water, a 20 tube collector and 150L tank and only have about 2 or 3 days a year when the water is below 40C .
    I have installed over 600 evacuated tube systems ( large and small) at the Namibian coast over the past 10 years and they are by far the the most used system here.
    I have a twenty five year old flat plate on my roof. How long do those tubes last.?

  4. #4
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    Default Re: Evacuated tubes vs plate

    Tubes are effective until they start degrading in SA's UV then you try and replace them ...

    If your plate collector is not installed in the correct orientation and correct angle to the ground level, it cannot absorb the maximum isolation possible.

    Also I quite commonly find that the plumbing make no provision for auto removal of air locks formed by steam generation. The result is severely restricted flow through the system.

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