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  (Source: CBS)
National Association of Home Builders has promised an investigation into heat-glare from window treatments

Heather Patron of Studio City (Los Angeles, Calif.) accuses her neighbors of a dastardly crime -- melting her Toyota Motor Comp. (TYO:7203Prius.  No, really.  This was no Hawaiian Baby Woodrose-induced optical illusion, her neighbors’ energy-efficient window treatment had melted the plastic molding of her Prius' mirror housings.

Los Angeles is a seasonable southern city on the west coast.  Its average monthly maximum temperatures are historically confined to the 64-77 ºF range year round [source].  Unsurprisingly, the big concern for residents in terms of energy efficiency is the cost of air conditioning.  One of the major sources of heat entering the house is through window light.  So southern Californians, like residents of other longitudinally southern U.S. states, have taken to applying reflective windows treatments, both as a cost-saving measure and as a "green" energy saver.

But in this case the approach backfired, as the neighbors' energy efficient reflective gloss created a brilliant beam during daytime hours that directed itself directly at the car port.

"The side view mirrors were melting.  Anything that was plastic on the car was melting," the Prius-owner recalls.

Melting Prius owner
Ms. Patron shows offer her damaged Prius.  She claims her neighbor's energy-efficient window treatment did the damage.  [Image Source: CBS]

And Ms. Patron says her Prius wasn't the only ones damaged -- a neighboring vehicle saw similar melting.  She comments, "I'm positive that this window is what is causing the damage to my car.  I just don't feel like it’s fair.  I feel like it needs to be known that this is happening. And a lot of people probably have damage out there, that they aren't aware that it’s the windows that are causing this."

She claims to have measured the temperature in the car port when it's exposed to the beam and found it to be 120 ºF.

Studio City
The damage occurred in Studio City, a suburb of southern California's biggest city, Los Angeles. [Image Source: Google Maps]

Similar claims of reflective windows burning people or plastics were leveled in Sept. 2010 by a lawyer staying at the Vdara hotel in Las Vegas, Nevada.  Reportedly in that case the situation was even more severe as the reflective windows were acting as a hyperbolic solar dish, focusing sunlight into a "death ray", which swept across the pool deck.

Reportedly other homeowners have also complained about plastic-melting reflective beams coming off windows with certain energy-efficient treatments.  The National Association of Home Builders has promised a thorough investigation into this problem.

What makes Ms. Patron's story more curious is that automotive mirror housings are usually primarily composed of ABS (acrylonitrile butadiene styrene) [source] -- the same type of plastic found in LEGO blocks and plastic pipes.  Pure ABS has a melting point of 221 ºF [source], so it's unclear how the beam was able to melt the plastic, even if the air temperature was 120 ºF.  

One possibility was that the black mirror plastic absorbed the light, and heated up to a temperature far hotter than the surrounding air (think of an Easy-Bake oven).

Prius
The Prius is the best-selling hybrid electric vehicle in the U.S. (and in the world). 
[Image Source: Jason Mick/DailyTech]

The Prius is the best-selling hybrid electric vehicle in the world.  As of March 2011, 3 million Prius vehicles had been sold worldwide, with 1 million sold in the U.S. alone by April 2011. 

Source: CBS



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Umm
By borismkv on 1/26/2012 12:01:33 PM , Rating: 4
Maybe she should be blaiming Toyota for using crappy plastic in their mirror casings instead of complaining about the windows?




RE: Umm
By quiksilvr on 1/26/12, Rating: -1
RE: Umm
By JasonMick (blog) on 1/26/2012 12:53:38 PM , Rating: 5
quote:
Was just about to say that. In Phoenix, it would get to 120F. Generally at that point we just cover the cars but cars left out don't usually have this issue. It's the plastic, not the windows.
True, but that's 120F AIR TEMPERATURE. Thus your heat transfer problem is a matter of convective heating.

By contrast here you have semi-direct solar radiation .

I'm guessing if the owners aren't faking this, then any black plastic ABS car mirror would see similar melting. Toyota's mirrors aren't exactly special to my knowledge.

I would say the video (see the source link) tends to support their claims as it shows small dimples as melting first. Typically molded plastics have pockets of poorly set plastic -- structural weak points. If exposed to a large amount of heat, theses would go first, hence the dimpled look.

Would it help if Toyota applied a glossier finish? Say silver? Sure. But the victim's car (and its mirrors) were black.

At the end of the day, the key problem here IS the windows, if the results are confirmed. After all, do you really want your neighbors melting your kids' sandbox and toy trucks? Are you going to blame Tonka for "poor quality" in that they didn't protect their plastics against an intense solar beam?

And you can be sure that if you have a lawn and/or backyard garden/landscaping, a 120 F beam will do a pretty good job cooking them. Is it the plants fault for not being designed well enough?

The current incident showcases the problem nicely as its the worst case scenario -- a black plastic. This makes it the perfect color to absorb the majority of the visible and near-visible spectrum. Anyone who's run outside on a sunny day in a black T-shirt knows this. Basic physics.

From what I understand there are alternative gloss treatments that reflect a more diffuse, scattered light.


RE: Umm
By tastyratz on 1/26/2012 1:13:10 PM , Rating: 2
Precisely on point
To the original OP... abs plastic has been used to cast a majority of automotive plastics from bumpers to mirrors to window trims or antenna flashing for 20+ years. The same abs plastic mirror having the "issue" is likely no different in composition than cars nearing antique status. This does present a quite unique situation though. Maybe it would be wise in hotter regions to enact ordinances on special reflective treatments that have a scatter pattern (diffusing the light). Otherwise yea, it's like lining your house with mirrors.


RE: Umm
By bupkus on 1/26/2012 2:50:59 PM , Rating: 1
quote:
Maybe it would be wise in hotter regions to enact ordinances on special reflective treatments that have a scatter pattern (diffusing the light).
What?! No resentful opines about more government interference? Where's the damning references to liberals, Democrats, socialists, Obama controlling all facets of our lives?... <Inaudible sigh>


RE: Umm
By Reclaimer77 on 1/26/2012 2:53:49 PM , Rating: 1
Are you serious or just trolling?

A state or neighborhood ordinance for something like this is entirely acceptable and, frankly, preferred. States rights, look it up. What in the hell does that have to do with Obama or the "government"?


RE: Umm
By The Raven on 1/30/2012 1:07:51 PM , Rating: 2
You forgot Republicans.

Actually this would preferably be kept between the parties involved and keep even the local gov't out if possible. It should be my right to reflex light wherever I want and for whatever reason if it doesn't hurt anyone else. What if there was a solar panel where the car was? That would be a good reason to do it.

Do we need an ordinance for excessive <insert problem here>? No. You can call the cops to help with your neighbors even if there isn't a law. And if it elevates higher than that we have a court system.

And if that fails, set up a mirror to reflect the same light at their car ;-)


RE: Umm
By mlmiller1 on 1/26/2012 1:22:39 PM , Rating: 2
The open carport receives enough radiant heat to raise the air from 77 to 120 degrees? Peak solar about 1kw per meter sq. So 1KW direct from sun and assume 1kw for reflection. With 120 degree ambient. So at what point does the black body mirror housing obtain convective heat balance with the incident radiation of 2kw/meter? Yep about 200C, good melting point for most PVC's
http://www.engineeringtoolbox.com/convective-heat-...


RE: Umm
By AnnihilatorX on 1/26/2012 5:02:38 PM , Rating: 1
Your figure is way too lax.

The black body mirror cannot have 1kw per sq. meter surface area, that's a huge mirror housing.
More like 250cm^2= 0.025m^2.

Reflection is not 100% efficient either, I'd say 90% since you are assuming a 1sq. meter window project all it's reflection on the mirror with no missed beam.

So the radiation input is 0.925kW


RE: Umm
By mlmiller1 on 1/26/2012 5:53:37 PM , Rating: 2
Yep the 2KW / meter sq. is general, but is the rate that a surface receives heat, regardless of the surface area (assuming no lens or focusing effect). This basically cancels area out of this, "back of the envelope" type "is it possible," calculation. Area cancels because convective heat transfer (cooling) very proportional to surface area, as is heating (the area exposed to the radiation (light)).

To be more accurate looks like 85% of infrared ration is reflected for the below film:
http://apex-window-film-store.com/store/product.ph...
PVC melts from 100-260C

So 1.85KW/meter sq. is still enough to melt some PVC. (1kw from sun, .85 from reflection)

Solar Absorption for black paint is 0.98 (white is like 0.25)

From this we can see that if painted white it wouldn't hit over 100C...at least on the back of the envelope.

From the pic, looks like the convective currents (at the more vertical parts) get cooled enough. Its just the top has a slower moving air currents and then heats up, then melts.


RE: Umm
By drycrust3 on 1/26/2012 2:14:41 PM , Rating: 2
The interesting thing here is that the damage is outside of the car. There doesn't appear to be any internal damage too, which is what one would expect.
Looking at the video, it appears another car which also uses the same car port also has the same damage; and it also appears the light is focused and not an even spread, which would point to either a manufacturing defect in the window concerned or the way the reflective coating was applied caused the window to become slightly concave.
As a thought, if the thermal expansion and contraction of the reflective coating was significantly different from that of glass, then it could cause the window to focus light under the right conditions. E.g. if the coating was internally applied and the thermal expansion of the coating was greater, then when the window and the coating are warmer than when the coating was originally applied then the reflective coating would actually "suck" on the window causing it to focus sunlight.


RE: Umm
By Iketh on 1/27/2012 12:35:55 AM , Rating: 2
I think interiors are built to withstand a significant amount of heat already.


RE: Umm
By JediJeb on 1/27/2012 3:54:39 PM , Rating: 2
quote:
The interesting thing here is that the damage is outside of the car. There doesn't appear to be any internal damage too, which is what one would expect.


I was thinking about this. Conclusion is that glass transmits UV radiation very well but transmits IR radiation poorly. In direct sun your interior heats up because the UV heats the components inside the vehicle which then radiate off IR radiation as heat which does not get transmitted back through the glass and causes the interior temperature of a vehicle to rise far above the outside air temperature. If the coating on the building is reflecting more IR than UV then it is going to heat up the outside of the vehicle more than the inside since the glass on the vehicle will not transmit it.


RE: Umm
By Trisped on 1/26/2012 5:35:17 PM , Rating: 2
I don't believe it is 100% the window. In fact, I would be surprised if the window was at fault at all.

You can tell from the video that the reflected light is rather dispersed by the time it hits the ground, and since the window is not concave the light would not have passed its focal point so the mirror would have received even less light.
There is no other direct light hitting the car because the car port is covered, so the only source of light is from the relatively small window.
The window is transparent, so not all of the suns light is being reflected as some will continue through the glass.
The melting on the other car was at a strange angle compared to the window (which is located on a wall above it). I would have expected the melt to have covered the whole area exposed to the glass, not just a small stretch of it.

While I do agree that the mirror damage looks heat related, the window does not look like the source.


RE: Umm
By geddarkstorm on 1/26/2012 1:02:15 PM , Rating: 2
You just contradicted yourself. If in Phoenix it gets to 120F and cars don't have a problem even when uncovered (I'm sure people in Phoenix have Priuses) then that supports the idea the glare from the windows was the cause, by focusing reflected heat on the black plastic casing and greatly heating it above air temperature. Also notice, her car was in a car port, and thus "covered".

Additionally, this also happened to another neighbor's car, but I didn't see where that type of car is listed. Still, that increases our sample size. And we have previous reports of similar things.

It really isn't a surprise: heat has to go somewhere, and if you aren't letting it in, but reflecting it tightly, it's going to go right where you're directing it. Remember, you can't destroy energy.

The real danger is a fire starting; especially in the dryer summer months if one of these reflected heat beams gets focused on dry grass. How would they fix this? Just make the reflective coating of these heat mirror windows simply disburse the light rather than gather and reflect.


RE: Umm
By JediJeb on 1/26/2012 1:50:06 PM , Rating: 2
Problem comes in the shape of the window/windows. If they total surface reflecting is concave then it will focus the sunlight, if it was convex then it would disperse it. If you have a four window set on that side of the building say in a two by two arrangement and it happens that the corners of those windows which are nearest the center of the grid all are recessed into the building slightly then you have a concave mirror which would focus the light reflecting from them, if those same corners are protruding from the building slightly then you would have a convex mirror and the sunlight would not be concentrated into a smaller area.

Seems here there is just the right combination of window shapes, direction the house is oriented and relative position of the neighboring carport to cause some serious problems.


RE: Umm
By spread on 1/26/2012 2:33:31 PM , Rating: 2
quote:
Problem comes in the shape of the window/windows.


Not an easy fix. Probably double pane windows sealed with argon or nitrogen in between. How much they flex and what shape they take depends on atmospheric pressure and temperature of the gas (and how much it expands or contracts relative to outside air). They are sealed TIGHT to prevent moisture from getting inside as well.

I agree that this is not Toyota's fault. If they made high temperature plastics you know what happens? They become brittle when temperatures are low. And if you put softer plastics that are more flexible in lower temperatures without shattering, they melt in the Phoneix sun.


RE: Umm
By MrTeal on 1/26/2012 3:50:39 PM , Rating: 3
Here's a fun fact that applies more for a circular piece of glass but should be similar for a square: if a 48" glass flat is ground to a saggita (depth of arc) of 1/8", it would have a focal point about 100' away. It wouldn't be a perfect focus for a couple reasons, but you could get a lot of light concentrated into a very small area even with a fairly small curvature. The plate glass would probably never distort by 1/8", but I could a lot of energy being dumped into a black mirror.


RE: Umm
By Reclaimer77 on 1/26/2012 2:38:14 PM , Rating: 1
There's is no such thing as "crappy" automotive plastic. They use the same plastic that EVERY single other car maker uses. You're an idiot and didn't even THINK before you posted.


RE: Umm
By bh192012 on 1/26/2012 4:13:18 PM , Rating: 3
Shouldn't we be angry with whoever designed the carport? Apparently none of the black Prii outside in direct (not reflected) light had melted mirrors, therefore it can't be only the reflected light that did it. Plenty of cars get direct sunlight + bonus reflected light and don't melt. It's the carport that's preventing the heat from dissipating.

I'm assuming the reflected light isn't from an array of concave windows all focused on the Prius.


RE: Umm
By bh192012 on 1/26/2012 4:18:18 PM , Rating: 2
I guess there could be a neighborhood full of windows all dumping into that same carport, that would suck.


RE: Umm
By sigmatau on 1/26/2012 5:58:56 PM , Rating: 2
These windows have been melting siding on houses for several years. There have been many reports.

A piece of dark plastic gets much warmer than 120 degrees F if that is the air temperature measured. She needs an infrared temp measurer that can measure on a surface temperature. I bet it got over 200 dgrees F.


RE: Umm
By Natch on 1/27/2012 9:50:30 AM , Rating: 2
She should have bought the James Bond Prius, with the pop-up laser beam deflecting mirror. That way, she could have turned the death beam around, and melted the neighbor's house!! ;)


Myth Busted
By iamezza on 1/26/2012 2:46:59 PM , Rating: 2
Mythbusters have investigated 'death rays' from various sources numerous times now and each time have found them rather useless as a 'weapon' that could burn/melt something.




RE: Myth Busted
By BugblatterIII on 1/26/2012 3:28:37 PM , Rating: 2
There are ants that might disagree if they weren't now crispy...and had opinions...


RE: Myth Busted
By JediJeb on 1/26/2012 5:09:38 PM , Rating: 2
But they did manage to start a fire on a wooden ship with a wall of mirrors didn't they?

I believe it was with the help of CalTech and they ended up moving each mirror slightly so that they began to focus the light into a tighter spot.


RE: Myth Busted
By Fritzr on 1/27/2012 12:37:04 AM , Rating: 2
As a weapon, focused light is not much good as the targets tend to move out of the focus.

Magnifying lense+sunlight focused on a spider makes a nice low explosive firecracker.

Matte black in sunlight easily reaches temps of 200F on a sunny day. People are severely burned by sunlit black objects every year.

Car windows are famous for destroying things on a sunny day. If the outside temp is 72F, the inside temp of a car parked in the sun can easily go above 140F ... this kills a few pets and children every summer.

This sounds like a simple case of sunlight being aimed at a piece of black plastic for a long period of time. To see the effect, put a CD on the top of your dashboard and park the car in the sun on a warm day. CDs treated this way are very decorative, though not overly useful for anything else.

Just for fun, put a dark vinyl sofa out on your sunlit porch, let it warm up for a few hours & then take a seat. You would be wise to check the temp of the plastic before taking a seat...just a suggestion that :P


RE: Myth Busted
By JediJeb on 1/27/2012 4:00:08 PM , Rating: 2
I had black vinyl seats in a 79 Mustang with a glass sunroof. Never wear shorts when driving such in the summer :)


walt disney concert hall
By kattanna on 1/26/2012 12:21:43 PM , Rating: 3
when they first built the disney concert hall in downtown los angeles it was doing similar things to its neighbors. they ended up have to sand the outside of the building to reduce the glare.




RE: walt disney concert hall
By really on 1/26/2012 12:28:53 PM , Rating: 2
Actually, it was the glare from the concert hall that was the problem. It wasn't frying neighbors cars just merely blinding the neighbors. There was similar concern for air traffic being blinded.


RE: walt disney concert hall
By kattanna on 1/26/2012 3:45:30 PM , Rating: 2
blinding was a big issue but it was also heating up neighboring office buildings as the sun would poor in through their windows.


Re: Scattering the reflection
By dgt224 on 1/26/2012 2:29:45 PM , Rating: 2
The problem with the suggestions above that reflective windows should scatter the reflected light, rather than producing a specular reflection, is that the windows are intended to provide the normal functions of windows, including the ability to look out through them to observe the world outside. Does anyone know how to make a partially reflective surface that produces a diffuse reflection without also diffusing the transmitted light? (For extra credit, make it manufacturable at a cost not drastically greater than current reflective windows.)




RE: Re: Scattering the reflection
By JediJeb on 1/26/2012 5:13:57 PM , Rating: 2
Could it be done with some type of double Fresnel lens on the inner and outer pane of glass where the lenses are anti to each other and the inner one corrects the distortion of the outer one?


RE: Re: Scattering the reflection
By Nanobaud on 1/26/2012 5:36:07 PM , Rating: 2
Etch a pattern on one surface of the window, apply the refelctive coating to that side, then cover the etched pattern with more glass so the pane has uniform thickness. The reflected light would be diffuse while the transmitted light would be relatively undistorted. You could do something similar with a plastic film and apply it to one of the inner surfaces of a double-pane window.

nBd.


RE: Re: Scattering the reflection
By rich876 on 1/27/2012 9:16:40 AM , Rating: 1
Buy an American car and you won't have that problem.


An eye for an eye
By Spookster on 1/26/2012 1:22:31 PM , Rating: 3
Set up a big reflective mirror outside the garage and reflect the heat back at the offenders house and melt their reflective windows. :)




RE: An eye for an eye
By mmatis on 1/26/2012 1:53:50 PM , Rating: 2
And their windows will reflect it back at the sun!

You fool! You're going to fry us all by starting Anthropogenic Solar Warming!


Rather not
By rrburton on 1/26/2012 12:19:38 PM , Rating: 2
Mick, since when is 64-77 rather hot? Thats rather comfortable to me.




RE: Rather not
By IsDanReally on 1/26/12, Rating: -1
RE: Rather not
By tng on 1/26/2012 12:41:25 PM , Rating: 1
Temps climb rapidly once you leave the metro LA area which is right on the coast. I have seen temps inland there climb to 100+ on Summer days.

Granted, I really don't know if this is the case for where she is located, but in some areas it could easily be 110+ in the garage with the reflections shining on something black and hollow like the mirror. Imagine what the temp has to be inside the mirror assembly to do that.


RE: Rather not
By twhittet on 1/26/2012 7:13:31 PM , Rating: 2
My town's yearly average temperature is 40. Yay me......


How is reflected light concentrated?
By dgt224 on 1/26/2012 2:14:30 PM , Rating: 2
I don't think I've seen a condominium with windows that appear concave from the outside, so presumably the reflected light would be no more intense than direct sunlight. In fact, it would ordinarily be less intense, as energy-efficient windows are designed to pass a fraction of the light, at least in the visible spectrum, and reflect the rest - otherwise a sheet of plywood would work equally well and be a lot cheaper. So it seems likely that the reflected light from the window strikes the car at a time when the car is also exposed to direct sunlight; doubling the effect of solar heating might well be enough to cause ABS melting.

If that is the source of the problem, I would also expect to see some damage to plants on the ground that are exposed to light reflected from the window and to direct sunlight at the same time - any light source capable of melting ABS should also do detectable damage to most living plants. No indication that anyone has looked for that sort of damage, though.




By JediJeb on 1/26/2012 5:16:02 PM , Rating: 2
Only a very slight curvature is needed to focus the light that is reflected, or multiple windows with slightly different angles could also act to focus the light.

It also looks like the doubling effect would not come into play since the carport is shading the mirror from overhead sunlight.


Wouldn't it be great if....
By Philippine Mango on 1/27/2012 7:39:52 AM , Rating: 2
the windows have absolutely NOTHING to do with the melting mirrors and in fact this was caused entirely by an act of vandalism? The reflective coatings on windows do not shine the light in any particular direction but instead diffuse the light in all directions so I fail to see how the window can act as a parabolic mirror to which it actually melts plastic. Even if this window was actually a mirror and it was angled just so with the sun, because it's a flat window, it just isn't going to reflect enough light to cause melting of the side mirror.

This make a good episode of mythbusters.




RE: Wouldn't it be great if....
By JediJeb on 1/27/2012 4:04:03 PM , Rating: 2
One thing to note, panes of glass used in windows are rarely completely optically flat, plus they flex when installed so they can curve into a concave shape easily. Also you don't need but a very small amount of curvature to focus at long distances.


By puckalicious on 1/26/2012 12:28:53 PM , Rating: 3
I think I need more photos to fully answer this very important question.




Toyota
By rich876 on 1/27/2012 9:14:53 AM , Rating: 3
Another case of Toyota cheap crap. If were happening to GM, the whole world would know about now. GM can not even get praise for the Volt, the most technologically advance car in the world.




Plausible
By GreenEnvt on 1/26/2012 12:22:29 PM , Rating: 2
I was vacationing in South America last month, and the air temp was over 110F. I put my (black) digital watch out in the sun for 5 minutes, and it was reporting well over 140F. I'm sure if I left it there longer, it would have gotten much hotter. I took it in to due fear of damaging it before I saw how hot it got though.

And yes, did try the egg frying thing, which partially worked.




WooHoo!
By mmatis on 1/26/2012 1:16:03 PM , Rating: 2
Greens being burned by Greens! Life just doesn't get any better than this!




Windows melt siding
By Terminator64 on 1/26/2012 2:13:38 PM , Rating: 2
In Wisconsin, there is 1 road where houses were laid out in just the right manner where one house windows would melt the siding on the next house. There was 6 house that were in perfect order to make this happen. Builder had to come in and replace the windows facing south and replace the melted siding. Problem went away after that.




By toyotabedzrock on 1/27/2012 1:14:17 AM , Rating: 2
You took the headline of a CBS story and changed it to suite an idealogical preference.

Fox does the same thing with AP stories.




It is true
By bkrharold on 1/27/2012 6:24:59 PM , Rating: 2
My neighbor has similar treatment on their windows. I live in Southern California, where the weather can be quite hot, even in winter. One day last summer, as I was in my driveway, I was rather startled to feel a searing blast of heat. Looking around for an explanation, I noticed that the heat was focused around a small area, directly in line with one of my neighbors treated windows. I experimented by moving a short distance one way then the other, and I confirmed that it was indeed coming from that source.




Longitudinally?
By CharonPDX on 1/27/2012 8:06:46 PM , Rating: 2
quote:
So southern Californians, like residents of other longitudinally southern U.S. states...


Uh, you mean latitudinally...




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