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we got the elevation angle wrong

ecletrical Member Posts: 22
We were headed for 60 degrees because we're heating a slab and want to reduce output during the summer.

We ordered the wrong tilt up which gives us only 49 degrees. We could modify things by

extending the legs. Is it worth it? How much gain would we get during the winter?


  • hot_rod
    hot_rod Member Posts: 19,289
    where are you located?

    how many collectors? You could use a solar simulation software and get a comparison for your exact system. Here is one modeled for the Wisconsin/ Minnesota area.

    As expected winter months like the steeper angle, if that is the primary focus of your array the steeper adds a small %.

    I increased mine from 48 to about 65 degree this fall, but I also added some collector area so I can't make a fair comparison. I have been starting at 8:15 and running until 4:30 ish.


    credit: Solar Skies for this graph
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Karl_Northwind
    Karl_Northwind Member Posts: 139

    extend those legs.  of course as HR said, it all depends on where you are. 

    keep in mind if you have a pressurized system it'll be less stress on everything in the summer if you can reduce that heat gain.  that's a nice graph, and the important thing to recognize is that the in addition to the heat output being a little higher in the winter months, the heat output in the summer months is substantially lower, which of course in a space heating system is when you don't need the extra, and still have plenty of capacity for DHW heating

  • hot_rod
    hot_rod Member Posts: 19,289
    Also on that graph

    notice the output difference, regardless of angle, from summer to winter.

    When customers ask about solar for DHW and heating, be realistic on how much energy is to be expected in the winter months.

    Two or 3 collectors may cover the DHW in winter month, but there will not be much, if any, left to contribute to the heating loads. I don't know that is is a good idea to spend $$ building a combined system unless you have the hp available to help with the load.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Tilting collector

    Over the course of the year the average collection may be similar, but notice how in the winter you get almost 50% more collection with the steep tilt, that's significant. Most people say forget about solar space heating because they have 45% angle collectors that don't shed snow very well, and are tilted away from the low winter sun. My collectors are fixed at almost 70 degrees, they shed snow very well and collect a lot of solar energy for heating. I wish I could tilt them to about 45 degrees for the fall and spring.

    Thanks, Bob Gagnon
    To learn more about this professional, click here to visit their ad in Find A Contractor.
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