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Thread: Solar gain / optimisation

  1. #1
    Automated Home Legend paulockenden's Avatar
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    Default Solar gain / optimisation

    I don't know whether others will find this interesting, but I certainly did.

    Look at this graph:

    graph.jpg

    See how from mid morning until mid afternoon the temperature rises, even though the heating is off (as we're way above set-point). This is solar gain, in a south facing room.

    You can also clearly see optimisation at work here. The schedule has 19 degrees from 5:30, but as you can see the set-point was sent at around 4:30. Similarly, the drop to 13 degrees (daytime holding temp) is scheduled for 8am, but the setpoint was sent about 20 minutes before that.

    The afternoon jump to 20 degrees is scheduled for 16:00, and that happened on dot. optimisation didn't kick in because solar gain had already raised the room temp to above set point.

    The other odd thing eagle eyed readers will notice is that when the heating goes off at 22:30, the temp continues to rise for a while. Obviously THAT isn't solar gain! It's because this is one (relatively unused) end of an open-plan area, and during the evening the other end is heated to a slightly higher temperature. This is that temperature spreading across the open area.

    I find stuff like this fascinating! Hope I haven't bored you.

  2. #2
    Automated Home Legend paulockenden's Avatar
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    The other thing to note here is that because I'm using an HGI80 rather than the API, I'm getting temperatures to the nearest 0.1 degree, rather than 0.5. And without the in-built bias towards the set point.

    P.

  3. #3
    Site Sponsor The EVOHOME Shop's Avatar
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    Default

    Quote Originally Posted by paulockenden View Post
    I don't know whether others will find this interesting, but I certainly did.

    Look at this graph:

    graph.jpg

    See how from mid morning until mid afternoon the temperature rises, even though the heating is off (as we're way above set-point). This is solar gain, in a south facing room.

    You can also clearly see optimisation at work here. The schedule has 19 degrees from 5:30, but as you can see the set-point was sent at around 4:30. Similarly, the drop to 13 degrees (daytime holding temp) is scheduled for 8am, but the setpoint was sent about 20 minutes before that.

    The afternoon jump to 20 degrees is scheduled for 16:00, and that happened on dot. optimisation didn't kick in because solar gain had already raised the room temp to above set point.

    The other odd thing eagle eyed readers will notice is that when the heating goes off at 22:30, the temp continues to rise for a while. Obviously THAT isn't solar gain! It's because this is one (relatively unused) end of an open-plan area, and during the evening the other end is heated to a slightly higher temperature. This is that temperature spreading across the open area.

    I find stuff like this fascinating! Hope I haven't bored you.
    Solar gain is incredible and unaccountable by evohome. We have 'anti-sun' glass in our Sunroom (part of our open plan) to prevent the house becoming too hot!

    Nothing boring about these graphs Paul - I have similar graphs myself and great for fault diagnosis.

  4. #4
    Automated Home Legend top brake's Avatar
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    thanks for sharing ;-)
    I work for Resideo, posts are personal and my own views.

  5. #5
    Automated Home Guru
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    It's a fun new nerd obsession -- looking at my graphs and trying to figure out what is going on.

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