Solar Kiln Build

[Delawhere Jack]

An FYI for anyone looking at corrugated poly-carbonate panels. HD and Lowes carry panels that appear to be identical, and (as of last fall), they were selling at the exact same price. The panels HD had were actually 40% thinner.....

[Deese]

Good info Doc. See you Saturday.

[nativewolf]

The cover for a solar kiln was discussed in Sawmill & Woodlot magazine recently.  There is no question that two layers are essential.  Also, the further that the black absorber is away from the collector, the better. 

Glass is a perfect cover, but often is too breakable...hail, rocks, etc.  The stronger glass, like a patio door, is no longer as effective as a solar cover.  Glass with a seal between the two layers (thermo-pane) will get cloudy quickly due to kiln heat.  Glass that has a green edge is not so good.  Glass is heavy, so the frame must be stronger. 

Plastic film is ok if it is U-V stabilized.  Sometimes the material made off-shore says it is stabilized, but it is not really that good.  Plastic fIlm also gets brittle and then will tear, especially due to flexing from wind and fans. Five year maximum life, but often much shorter.   

Polycarbonate (single or double) is strong and durable, but somewhat expensive.  It is Very easy to install.  The two layer stuff seems to be close to perfect.

Corrugated fiberglass will last for 20 plus years and is low cost and durable.  It is not 100% clear, but other benefits make this covering very practical.

Might have something of value to add (doubtful but here goes).

In the greenhouse hobby world  a recent trend has been to use bubble wrap meant for pool covering.  It is UV stabilized, it has a great R factor compared to the other materials, cost per sq ft is very very low.  Now this is in the greenhouse world where they need to cover large areas.  However, it is holding up well, early adopters from a few years ago report no problems and it is dead simple to install.  Anyhow, something from another industry.  Hope it worthy of consideration

[WLC]

Nativewolf, I had not heard of using the pool cover bubble wrap, but there is a product called solawrap which is made for the greenhouse industry that sounds very similar.  Supposed to be very durable with very good longevity.  Greenhouses in the UK have been covered with it for over 20 years with little to no degradation.  I've not priced it here in AK, although we do have a dealer for it in the state, I've thought it would make a good solar cover for a kiln.

[nativewolf]

Interesting.  The thing with pool covers is that there are maybe a million pools, many have covers.  That means that industry has scale and prices are lower.

Just an fyi for you since R values might matter more in AK, folks are double layering it, then putting in blower fans to push an air blower between the layers (this is for the greenhouse world).  With the air layer R value goes up dramatically.  Pretty simple and very cost effective in greenhouses, maybe in your neck of the woods too?