Solar kiln location off slightly

[Stevenjohn21]

A friend of mine offered to help frame my solar kiln this past weekend since he had some time off work but unfortunately that weekend I had to work. We had gone over the plans and even printed the plans out. He's done a fantastic job of the framing however, when I stood inline with the kiln and checked the compass, it is a degree or 2 off being exactly south facing. It is more south than it is south east. How much is this going to affect the kiln? 

[btulloh]

You'll be ok. To be exact with a magnetic compass you need to correct for deviation at your location anyway.  Being off a few degrees won't be a huge deal. It's always nice to be exactly on your mark, but not something to stress over. A bigger impact will come from trees or obstacles blocking early morning or late evening sun because it shortens the exposure time. It's almist impossible to achieve perfect positioning that catches sun from sunup to sundown. The kilns still work well with the compromises we all have to live with. If you decide to reposition the kiln (if that's even possible) use true south instead of magnetic south.  But you'll be fine as is.

[btulloh]

Also to reduce the stress level over this - the orientation of the kiln is only perfect for a couple minutes around midday. As the sun moves across the sky it is constantly changing anyway.  The perfect angle for the collector also changes with the seasons as well.  To achieve absolute maximum efficiency the collector (kiln) would need to rotate to  track the sun all day.  And then the angle of the collector would need to would have to be adjusted as the seasons changed.  AND you would need no obstructions on the horizon (about 12 miles should do it) from due east, around to the south, all the way to due west.  So it's virtually impossible to be perfect.  And unnecessary. 

Far more important is the vent placement, baffling, and getting the airflow consistent through the stack.  If you're using the VA tech plan, just pay attention to the details and don't worry about a couple degrees. 

I'm sure your kiln will turn out well.

[Ianab]

I'm going with, not enough to matter. The due South idea is that in theory that should give the most solar energy collection over the day, and maximises the collection during the brightest time of day. But it's not a critical design factor, same as the roof pitch alters the time of year that it's most efficient. 

I wonder if canting the kiln slightly East might actually improve it's operation, as it would tend to collect the morning sun a little better, and so come up to temp a bit quicker. It would loose a bit later in the afternoon, but at that point the kiln and all the wood inside is warmed up and only needs enough heat to keep it warm.  Would it make enough difference to notice?
 Dunno ???

[Don P]

In one of the solar home books from my memory they advised being within ~10 degrees of south was going to perform well for that use, I doubt it is much different for this.

[Southside]

I can't recall whose hypothesis it is but the idea that the solar system is planar has been disputed and the orientation of the sun to the equator moves with time, so true south isn't always in the same spot in all likely hood, and over the course of the lifetime of a solar kiln really won't matter one photon.   ;D

[Sod saw]

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Our passive house engineer, who is helping design my daughters home, agrees with Dons memory.

10 degrees off of due south is perfectly acceptable, east or west.  More importantly  (for a home) is view and trees etc. causing shade.

The other suggestions here are also valid with air movement and vents etc.

Pay special attention to painting black inside and out with lots and lots of insulation (floor too) and calk or spray foam all joints.  Calking the roof panels for preventing air infiltration is one of the most important points to pay attention to.

have fun


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