Anyone concerned about the sunlight and heat build up under the large windshield surface?

[anionic1]

it, plus the glass roof, does seem to make for a rather large solar collection in the cabin

though unclear how much more significant that will be compared to the panoramic roofs in other models, which also have sloping rear windows

Those panoramic roofs have been one reason I’ve not been not attracted to other vehicles

but I tend to be of the view that the CT roof may have switchable electrochromic glass

in any event, as with all my vehicles, I plan to tint the everyloving hell out of it

and with the slope of the CT windshield, a whole lot of it is probably subject to tinting

There is an Israeli company making a switchable electrochromatic tint for glass.

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[anionic1]

I’m worried about as much as I was worried before and after purchasing a Model 3, aka not worried at all.

I’m more concerned about the body of the CT getting super hot to the touch during sun exposure. Because of this, I’m glad it’ll have the auto-presenting doors.

So I had to research this one. Your welcome. Below is a brief description of thermal conductivity of various metals. This basically represents their ability to transfer heat, which means how much it can burn you. so basically if you sit on an aluminum park bench it will gladly transfer its heat enegy into your thighs rather quickly. Stainless will still be hot but it will be a more dragged out transfer of heat. How hot it can get really depends a lot on its color, specific heat and thickness and I am not going to to go into comparing that, but generally based on the below, usually the paint is so think that its thermal resistance is incredibly low and it is considered negligeable conpared to its base materail. Obviously a white paint is going to reflect a lot of light and keep its base material cooler anyway and thus transfer less heat. The thickness of the stainless is going to hold more heat, but upon a touch it should transfer about 3x less heat and thus be cooler than a steel body truck and much cooler than an aluminum body truck to an immediate touch. Interestingly, depending on the overall layers and assembly of the shell compared to a steel or an aluminum truck, the stainless truck should also insulate the cab better. If the design was like for like.

Conductivity in Aluminum
Pure aluminum has a thermal conductivity of about 235 watts per kelvin per meter. Aluminum alloys tend to have much lower conductivity. However, this is rarely as low as iron and steel. Aluminum is often used in electronic heat sinks due to the metal’s good thermal conductivity.

Conductivity in Carbon Steel
The thermal conductivity of carbon steel is much lower than that of aluminum. Its thermal conductivity is around 45 watts per kelvin per meter. This material is a good and economical choice for building structural components.

Conductivity in Stainless Steel
Stainless steel has an even lower conductivity than carbon steel at about 15 watts per kelvin per meter. Stainless steel is an ideal material for structures in corrosive environments or for Architecturally Exposed Structural Steel (AESS) applications.

 

[Bathbunny]

Is anyone else concerned about the sunlight and heat build up under the large windshield surface area under it? Besides a huge sun reflecting blocker when parked. is there a legal limit on the amount of mirrored reflection a windshield can have built into it?

The law does not allow you to tinker with the windshield -- you can tint, mirror-coat, or polka dot the side windows and the back window, but not the windshield.
Honestly, though, this is no larger proportionally than the windshield on Model X and Model X drivers report no issue. All Tesla models have very large windshields (that on the X was the largest ever in a production car) and glass on at least part of the cabin roof, and it works just fine. Yes, the windshield sunscreen is going to be a corker (I hope Tesla offers one from the start on its store), but modern turn-and-flip mylar-like screens are lightweight and fold small. No problem.

 

[Bathbunny]

Good points, but it also means that stainless could build hotspots -- although a back-of-the-envelope calculation suggests it would take the kind of radiation you'd get at 20'000ft, not at normal altitudes.

So I had to research this one. Your welcome. Below is a brief description of thermal conductivity of various metals. This basically represents their ability to transfer heat, which means how much it can burn you. so basically if you sit on an aluminum park bench it will gladly transfer its heat enegy into your thighs rather quickly. Stainless will still be hot but it will be a more dragged out transfer of heat. How hot it can get really depends a lot on its color, specific heat and thickness and I am not going to to go into comparing that, but generally based on the below, usually the paint is so think that its thermal resistance is incredibly low and it is considered negligeable conpared to its base materail. Obviously a white paint is going to reflect a lot of light and keep its base material cooler anyway and thus transfer less heat. The thickness of the stainless is going to hold more heat, but upon a touch it should transfer about 3x less heat and thus be cooler than a steel body truck and much cooler than an aluminum body truck to an immediate touch. Interestingly, depending on the overall layers and assembly of the shell compared to a steel or an aluminum truck, the stainless truck should also insulate the cab better. If the design was like for like.

Conductivity in Aluminum
Pure aluminum has a thermal conductivity of about 235 watts per kelvin per meter. Aluminum alloys tend to have much lower conductivity. However, this is rarely as low as iron and steel. Aluminum is often used in electronic heat sinks due to the metal’s good thermal conductivity.

Conductivity in Carbon Steel
The thermal conductivity of carbon steel is much lower than that of aluminum. Its thermal conductivity is around 45 watts per kelvin per meter. This material is a good and economical choice for building structural components.

Conductivity in Stainless Steel
Stainless steel has an even lower conductivity than carbon steel at about 15 watts per kelvin per meter. Stainless steel is an ideal material for structures in corrosive environments or for Architecturally Exposed Structural Steel (AESS) applications.

 

[cvalue13]

The law does not allow you to tinker with the windshield -- you can tint, mirror-coat, or polka dot the side windows and the back window, but not the windshield.

not sure where your laws are from, but there are other places with other laws

then there’s those of us who test the edges of the law

(or have a dermatologist spouse, who can write scripts for tint law exceptions)

 

[cvalue13]

How hot it can get really depends a lot on its color, specific heat and thickness and I am not going to to go into comparing that

but isn’t comparing the combination of those things… a lot of the point?

and I’m not sure I’m completely following all of your maths/conclusions around the effects of conductivity

isn’t conduction only one corner of the thermal triangle? The other two are: convection, which in this case involves a cooling of air flowing over a heated object; and radiation, which involves the emission of heat in the form of electromagnetic energy.

don’t your conclusions suggest that, even if the conductivity of bare stainless is lower, that the convection cooling of it will be far slower, and the radiation from it far longer?

and conversely, that cold steel (eg in winter) will remain colder longer?

which would all be especially true if accounting for the increases thickness/thermal mass of CT panels vs conventional panels?

I’m not really pressing to disagree, just explore. I think this use of materials in the CT will have various interesting differences from what we’re used to, and my interest picks up thinking about these quirks

 

[shaneaus]

I had a 97 Trans-Am and it had a long shopping front windshield, a long sloping rear window, and glass T-tops. Everyone claimed it would have heart retention issues. But, I never had an issue. Of course, I had all except the front windshield tinted with reflective tint. And, the Tesla's all have treatment. So, I can't imagine it being an issue. I live in Austin and we have lots of triple digit days most summers.

 

[Old Pro]

Is anyone else concerned about the sunlight and heat build up under the large windshield surface area under it? Besides a huge sun reflecting blocker when parked. is there a legal limit on the amount of mirrored reflection a windshield can have built into it?

Yes, it may be a huge issue. I will be more than happy to take your reservation over.

 

[Old Pro]

I thought the view above in our Model 3 and Model Y were awesome and then on our Denver road trip a grater on the side of the road threw a road that cracked our moon roof and the crack spread across the entire moon roof and it had to be replaced. Not warranty so it cost me $1,200. As a result, I am concerned about the ability of the armor glass to withstand this kind of abuse much more than I am concerned about how much heat enters the cabin.

Get Glass Breakage deductible waiver from your Insurance Carrier

 

[anionic1]

but isn’t comparing the combination of those things… a lot of the point?

and I’m not sure I’m completely following all of your maths/conclusions around the effects of conductivity

isn’t conduction only one corner of the thermal triangle? The other two are: convection, which in this case involves a cooling of air flowing over a heated object; and radiation, which involves the emission of heat in the form of electromagnetic energy.

don’t your conclusions suggest that, even if the conductivity of bare stainless is lower, that the convection cooling of it will be far slower, and the radiation from it far longer?

and conversely, that cold steel (eg in winter) will remain colder longer?

which would all be especially true if accounting for the increases thickness/thermal mass of CT panels vs conventional panels?

I’m not really pressing to disagree, just explore. I think this use of materials in the CT will have various interesting differences from what we’re used to, and my interest picks up thinking about these quirks

The question was based on a quick touch of the metal. If you laid out the three metals in the sun and they all absorbed energy and maxed out their heat capacity, which would all be very hot. Theoretically the aluminum would transfer more heat to your skin the fastest and thus be “hotter”. Of coarse if there is a breeze aluminum will cool faster, but assuming a constant energy input such as a summer sun the aluminum would feel hotter instantly, just like aluminum feels colder in the opposite condition.

 

[Jhodgesatmb]

Get Glass Breakage deductible waiver from your Insurance Carrier

Does Tesla have that? They certainly never offered it, before or after this incident. I’ll ask them. Thanks!

 

[cvalue13]

The question was based on a quick touch of the metal.

Yes and the touch/conductivity bit is interesting, thank you.

caused me to read up a bit and find that generally speaking paint increases conductivity and heat dissipation generally. unclear if automotive body paints are specially formulated otherwise.

but that paint helps dissipate heat is apparently one reason engine components were once painted, or that radiators would be painted, etc.

 

[Diehard]

Absolutely. The question is would you pay $5K extra to the solar option and would you be OK paying more for repairs?

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