Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Hi, I am looking for a kind of glass 2

Status
Not open for further replies.

Mabrouk92

Civil/Environmental
Aug 30, 2019
8
0
0
US
Hi, I am looking for a kind of glass that has a high transparency (as high as possible to transfer heat) and at the same time I need it to be capable of affording a vehicle load. I have no experience in this field. I just think that as the thickness of the sheet goes bigger, its transparency will go down. Thus, I need something that could be as transparent as possible and could afford vehicle loads at the same time. The dimensions of the glass sheet could be 0.5 * 0.5 m but if it could be wider, that's better.
 
Replies continue below

Recommended for you

Mabrouk92,

Glass loses most energy at its surfaces. If the glass is anti-reflection coated and it is kept clean, your transmissability should be good.

When you say it must afford a vehicle load, do you mean the glass is structural?

--
JHG
 
drawoh,

Could you clarify what you mean by that the glass is structural? I need the for the glass to be capable of carrying a vehicle load without getting damaged because it will be subjected to traffic and I need a transparent material (as transparent as possible) even if it is not glass but I think that the glass is the most transparent material that I can use.
 
Sorry, but conventional window glass is an insulator, and does not transmit beyond about 2 um, so it does not "transfer heat"

You've used the term "vehicle load" twice, but you've not explained what this means, because it appears you are saying it needs to support the weight of a vehicle. A glass roadway surface would need to be extremely thick and laminated to prevent breakage, which reduces transmission.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
Mabrouk92,
Are you trying to transfer heat through the glass or are you trying to transfer light through the glass to heat something on the underside? If you are trying to transfer heat through the surface, glass is a poor choice for the reasons stated above and likely more, but your insistence on its transparency makes me think you are actually trying to allow light through for solar heating. Is that the case?

Andrew H.
 
BrianPetersen said:
If by "vehicle load" you mean "traffic", glass which is smooth enough to be "transparent" (to light) will be extremely slippery and dangerous.

Easy fix... we have already transitioned to the realm of magical materials that don't exist. Just add "good traction" to the specification requirements:

-Transparent to light
-Transparent to heat
-Supports several tons across a 0.5m span
-Good traction



 
I am sorry if my post was not clear enough. Yes, I need it to be transparent to light and I will use this light to heat something, and yes it will be subjected to traffic but there is no big fear of the skid resistance so don't count for this.
 
More information = better answers.

You need to define your loading conditions, for one thing. "Vehicle" could be anything between a shopping cart and an armored personnel carrier. Perhaps you know where you are going to be on that spectrum, but the rest of us don't.
 
Gooood luck.

If there is regular traffic going across it then you SHOULD be concerned with the friction coefficient. Vehicles lose control and crash into each other when there isn't enough grip, even if there is no hill, even if they are not turning a corner. Happens in winter on icy roads often enough; there's no need to make it happen in summer as well!

What happens when a vehicle drives across it which has a piece of stone embedded in its tire treads? Add to the above selection criteria for this magical material:
- Impact resistant
- Abrasion resistant
 
New York used to have glass blocks in some sidewalks, so something similar would be required; but, city traffic is pretty brutal on pavement; so small blocks with multilayer laminations would seem to be the starting point. I don't hold out much hope that you'll get any sort of decent heating; you're looking, at best, getting a couple hundred watt-hours, which seems hardly worth the expense and maintenance of a glass pavement.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
Again, the glass will be limited only to a 0.5*0.5m area. Thus it is not a glass pavement. Can we then get a material name??
 
Perhaps a safety laminated glass for the stated dimensions. Saflex as a lamination material developed by Monsanto comes to mind. Obviously a lot of tests will be required to determined types of glass such as the tempered type perhaps, thicknesses for the intended loads and light transmission. I have no idea if laminated tempered glass has ever been made.
 
A nice coating of dirt will knock back transmissibility and any transferred road tar will finish the job. At 100% in the middle of the day that size is worth about 250W. Factor in losses from dirt and passing vehicles and off-peak values; maybe 50 watts for 40% of daylight hours, trailing off if it's away from tall buildings. After a year or so of surface damage from grit scratched by vehicle tires if it peaks above 10 watts it would be amazing.

Setting up a solar panel in a safe location and running some wires is a better bet.

(There are panels where the outer layers are tempered. The reason for tempering the glass is to prevent surface cracks from penetrating to the core. In lamination this is a natural outcome - surface cracks cannot propagate directly to the inner layers so there's no reason to use tempered glass in center layers. However, for safety, tempered glass prevents shards from injuring people who might have contact with it.)

As far as I know most glasses are terrible for letting IR through. Sapphire is fairly good and is harder than most glasses. I'm not sure if anyone would make it in a piece large enough and thick enough for this case.
 
"I will use this light to heat something."

Asphalt gets pretty hot in the sun. Maybe a few heat pipes like the inverse of radiant heating, run thru a larger area area between (or as others mentioned, well above) traffic lanes, could circulate enough coolant to meet your needs.
 
Status
Not open for further replies.
Back
Top