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effect of sunlight on window installation

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effect of sunlight on window installation

Postby mary_louise_white » Sat Jul 23, 2016 11:59 am

My project proposes to install five kiln carved panels each 19" x 36" x 6mm (with variation in the kiln carved areas into a recessed window space, between the regular window and the room, placing the panels one above the other (landscape orientation) with small stops between each panel and wooden side stops (frames). The building is above the 49th parallel, the window is west facing and has a substantial overhang, so no panel would get direct sunlight even in the summer, until past mid day. The window is in the shadow of the roof overhang until it begins to climb the wall about 2pm, and by 6pm, all 5 panels would receive direct light. The shift from shade to sun is moderate, and each panel would have a moving patterrn of both shade and sunlight for less than an hour, at the moderate angle that the latitude delivers.
I would like an opinion about whether or not this exposure pattern would cause stress within any one panel.
Mary Louise White
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Re: effect of sunlight on window installation

Postby marykaynitchie » Mon Jul 25, 2016 8:24 am

Hi Mary Louise,

Can you tell us more about the design, and what kinds of glasses you are using? Are they all transparent, or are some opalescent? How thick are the panels? Can we assume that the interior of the building will always be above 60 degrees F?

Mary Kay
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Re: effect of sunlight on window installation

Postby Ted » Tue Jul 26, 2016 9:26 am

Hi Mary Louise,

There are people who routinely succeed in making work like what you have described, laregly without much testing. I offer the following by way of describing some of the possible issues and how you might work on addressing them.

It is certainly possible that the low angle of the sun could cause the work to absorb a fair amount of IR energy from the sun. If it heats unevenly, which is possible if the glass is not of uniform thickness, it may develop some strain. Whether it develops enough strain to cause failure is not something that we have adequate expertise to evaluate on a speculative basis. Some things that you can do to help mitigate the effect of the IR:

1. Design the blank that you will ultimately kilncarve to have continuous layers clear as both the top and bottom layers. This encasing with clear helps unify any strain in the piece.

2. Avoid kilncarving the piece to have extremely sharp edges. If kilncarved on the cooler side, you will not have sharp/90° transitions from thinner to thicker areas, but instead have transitions with a slight radius. A radius transition will more uniformly distribute strain than will a right angle.

Ultimately the only way to know with any certainty if you are going to have success is to create a test panel and either test it directly in the location where it will be installed, or send it to a solar calorimetry lab for testing. This is obviously the more expensive route, but it will give you a fairly clear picture of whether this work, if you intend to do much of it, it suitable for your specifc location, or any other location that you want to have simulated. There are labs around the world. We have worked with the Fraunhofer Institute in Germay: https://www.ise.fraunhofer.de/en/front-page

I hope that this is helpful.

Thanks,

Ted
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