[viggienomad]

Having been lived for most part in Madurai, Tamilnadu, I can very well feel the heat as it was shown on the meter! There is no escape from experiencing this hot oven effect when we go anywhere & have to park in open.

Those days, pre-cooling was not an option in cars. Here is what I do!

1. Open driver side door.
2. Half-enter! Ensure hand-brake on & gear is in neutral!
3. Switch on the car with one foot in clutch
4. AC full blast & mostly focused downwards
5. Get out & from driver door, open all windows half-down
6. Run back to a shade!

1. Come back after 2-3 minutes with family.
2. It will still be uncomfortable,but not the hot oven as it was.

[dkaile]

Originally Posted by dkaile

I have seen people here packing their Sunroof gaps with thermacole sheets (kindly refer to the Skoda Kodiaq thread - a car with a panaromic sunroof), just to be able to drive in these months and have a effective AC.

The Post in that I was quoting - https://www.team-bhp.com/forum/offic...ml#post5566763 (2022 Skoda Kodiaq Facelift Review | 2.0L Petrol DSG)



Cheers...

[navinmra]

Originally Posted by electric_eel

The additional safety feature of sunroof in Nexon --- when you lock it the sunroof closes -- means that you cannot lock the car and leave the sunroof in tilt mode .

I do not know how it is for other cars.

That is so true! But in a way I like it because I am so paranoid of leaving a gaping hole for rodents, lizards and other Ugggh things getting into my car aka my space

Another related feature is that it auto closes when it rains! Tata wants you to be be clean and dry at all times

[electric_eel]

Originally Posted by navinmra

That is so true! But in a way I like it because I am so paranoid of leaving a gaping hole for rodents, lizards and other Ugggh things getting into my car aka my space

Another related feature is that it auto closes when it rains! Tata wants you to be be clean and dry at all times

Coming to think of it yes the autoclose is the natural correct operation but then the recent heat wave made most of us desperate and probably me a little bit wonky as well --- It is not pretty to see efficiencies of 150+ Wh/km; hurts the ego quite a bit you know .

[navinmra]

Attachment 2606141

Originally Posted by Jeroen

Great experiment! Thanks! Surprised to see so much effect of the cover!



Sunroof is in tilted mode and has a cover. So you don’t get the sun inside. Hot air will rise, so opening the roof in tilt mode is the most effective. Most likely recommended in the owner manual as well.


Jeroen

That’s right. There is no sun coming into the car in this mode. The sun roof tilts forward. And the cover beneath remains drawn and vents in the cover let the hot air out…

[navinmra]

Originally Posted by dkaile

The Post in that I was quoting - https://www.team-bhp.com/forum/offic...ml#post5566763 (2022 Skoda Kodiaq Facelift Review | 2.0L Petrol DSG)

Attachment 2606140

Cheers...

My fullest sympathies for the poor soul! When it’s blazing 46 degrees, a panoramic sunroof is the last thing on your mind!

[dkaile]

Originally Posted by navinmra

My fullest sympathies for the poor soul! When it’s blazing 46 degrees, a panoramic sunroof is the last thing on your mind!

On the contrary, it was the 1st thing on his mind if he has to drive his car as that's the new normal in Delhi NCR and perhaps in most of India. Such high temperatures will prevail for a few months now and it's getting worse by the day. Hence adaptability is the order of the day, whether from the manufacturers or the end users.

Cheers...

[GeeTee TSI]

Fabulous exercise and outcomes which corroborated my own hunch. I am always suspicious of leaving electronics in a parked car (phones/tablets) as the inside temperature is way beyond ambient, thanks to the sealed chamber soaking in the heat.
For the same reason, if approaching a car parked in the sun, it pays to open all the doors for a little while before starting as the trapped hot air just escapes. Opening the hatch greatly aids this circulation and sometimes in a parked car with people inside I have done this (subject to it being safe).

Lastly, I hope the short sighted rule about banning sun films is revisited as our geography does not have the luxury of mild sun and mild summers

[EV Fan]

Originally Posted by BhayanaV

More than the experiment and the product, I'm more amazed with the temperature in your city.

It's 35 deg Celsius here but with 70% humidity, so it can be almost same as 43deg of North India where humidity might be as low as 20%.


Source: ResearchGate

Combine this with exposure to direct solar radiation and it can be quite surprising. Something that requires specialized thermometers like "Wet Bulb Globe Temperature (WBGT)"
Source: WBGT Thermometer

Originally Posted by navinmra

1. Will it fit the Nexon? One of the Amazon reviews says it doesn’t, hence curious.

They modify if necessary. You have to mention which car it is if you are using Amazon. I had directly contacted them using the phone number on their website(7827726841).
They did same for me, while i can't say it was a tailor fit but mine is a bit of a rare car (Hyundai Kona electric). So i had to send dimensions, pics etc.

For widely available/mass cars they have it readily available.

Originally Posted by navinmra

2. Does it tend to scratch the paint from your experience?

They have a second layer of soft/smooth fabric underneath which did not seem to scratch. Atleast i did not notice anything on mine uptill now. But again like any other car it is not going to be as safe as a microfiber cloth

Originally Posted by navinmra

As a side note, I find the Nexon EV Max cabin cools faster than my earlier Civic after being in the sun.

I think it is more due to the extra powerful AC that EV's have. EV's need to cool the batteries and can't skimp out on AC.

[BhayanaV]

Originally Posted by navinmra

Attachment 2606141

That’s right. There is no sun coming into the car in this mode. The sun roof tilts forward. And the cover beneath remains drawn and vents in the cover let the hot air out…

Not possible when the cover is electric and not manual. Honestly, I have pano sunroof and haven't find it to be an issue yet, though this is first summer for my car. Not used remote start yet, though that can be another way of pre-cooling the car. AC on full blast and sunroof slightly opened does the job.

[navinmra]

Originally Posted by BhayanaV

Not possible when the cover is electric and not manual. Honestly, I have pano sunroof and haven't find it to be an issue yet, though this is first summer for my car. Not used remote start yet, though that can be another way of pre-cooling the car. AC on full blast and sunroof slightly opened does the job.

I thought as much. So it appears, some things in life have to be manual

[navinmra]

Originally Posted by EV Fan

I think it is more due to the extra powerful AC that EV's have. EV's need to cool the batteries and can't skimp out on AC.

I agree. I think it also has to do with no engine heat radiating into the cabin. Sure there is a firewall, but eliminating the heat source is always better than insulation… I can feel it when you turn of the a/c in both cars. The Civic will almost immediately start becoming uncomfortable while the EV will stay cool a little longer.

Also, and I need someone to verify this - The operating temperature of the a/c condenser of an EV is much lower than the same in an ICE car, which is housed very close to the engine radiator which operates at a much higher temperature. Therefore the EV a/c has to work on a lower temp differential and therefore cools better with lesser power. Let me dig around a little more on this.

[EV Fan]

Originally Posted by dkaile

That is why I am a strong opponent of this Sky Roofs and Full length Sunroofs etc. especially in North India.

Can't agree more. If they atleast could have provided good insulated glasses and covers, it could have been tolerable.
I tried driving the MG ZS Exclusive (Panaromic sunroof with the stock curtain), in the pleasant weather of Bangalore, and the heat from over head was noticeably high. God knows if that car will be even drive-able if the AC fails.

Originally Posted by navinmra

On the contrary, opening the sunroof in tilt mode, without sliding the cover below, creates a chimney effect that sucks out hot air from the cabin in a jiffy.

Originally Posted by Jeroen

Sunroof is in tilted mode and has a cover. So you don’t get the sun inside. Hot air will rise, so opening the roof in tilt mode is the most effective. Most likely recommended in the owner manual as well.

Originally Posted by antz.bin

Never owned a car with a sunroof but wouldn't opening the sunroof slightly aid in cooling the cabin faster, with hot air rising up and all?
This strategy could help cool a superheated car.
Step 3: Wait for the car to reach the required temperature.

Completely agree, i used to resort to all these earlier. These were more of "CURE" like solutions, "what is to be done after it gets hot". Hence, i started looking for preventive solutions.
And more importantly we are forgetting about the glasses & interior surfaces - seats, armrests, steering wheel etc. These surfaces were at 60 deg Celsius or higher. The AC can cool all the air in the cabin in the first few minutes but the surfaces take quite some time to cool down, a good 15 minutes or higher.

Till then, these surfaces could still be quite hot, and with the the cabin air which is cold, it causes quite a strange inconvenience and atleast in our case, my mother starts feeling unwell with headache & fatigue which could ruin her entire day. For some people (especially old folks), i have noticed - they can separately handle heat or cold conditions easily but not mixed/temperature gradients, it make them feel ill - like cold air and hot sun/surface.

Originally Posted by antz.bin

Step 0: Install 99% IR Rejection VKOOL film on the Sunroof glass. (less heat enters through the sunroof)

During this experiment the car had 70% Transmittance sunfilms (clarest/highest visibility) & sunshades. The 60 deg C you saw, are with all of those.
Once the glass gets hot, all of these addons are useless. The glass crosses 60 deg Celsius within 15 mins if vehicle is not running or AC is not running in a parked car.
What we dont realize is that the air flow outside & AC inside keeps the glass temperature to a manageable 50 deg Celsius while driving.
Simple glass based solar cookers with black painted box are known to boil water. I would need a higher range thermometer to prove that our car glasses could be reaching temperatures far higher than 60 deg C.

Originally Posted by antz.bin

With EVs, the extra energy required can be measured easily.

That's what this experiment was. A car parked under sun for 30 mins at 35 deg Celsius needs 1 KWh to cool the car interiors back down.
Feel free to calculate on the macro level.

Originally Posted by antz.bin

It is also time OEMs mandate IR cut glass to boost efficiency with aircon.

That would have been a godsend. But for now it is the privilege of the government and the elites.

Originally Posted by antz.bin

Maybe someone has done this kind of research in the developed world. Need to figure that one out.

Been done a lot for building facades and although the same IR data is applicable for car's (actually worse). But somehow industry seems to be unusually silent on it.

Till then solutions like this might be a possibility
AIS IR Cut glasses

Originally Posted by NomadSK

Regarding cooling, it's always better to tilt the roof during initial drive, due to the pressure differential and venturi effect, the air inside the cabin will be sucked out immediately, add AC to circulation mode and the temperature would be lowered fast.

Originally Posted by electric_eel

The additional safety feature of sunroof in Nexon --- when you lock it the sunroof closes -- means that you cannot lock the car and leave the sunroof in tilt mode .

I do not know how it is for other cars.

Hyundai Kona allows us to leave it open even while locking but personal experience dust, debris and insects. Done once, but never again not even if i have to cool a car parked full day under the sun.

[BhayanaV]

Originally Posted by EV Fan

It's 35 deg Celsius here but with 70% humidity, so it can be almost same as 43deg of North India where humidity might be as low as 20%.

True. That's why IMD started showing temperature as Actual and "Feels Like", which goes way above actual when it rains here in North India.

[AVIS]

Car colour makes a big difference as well -

https://www.youtube.com/watch?v=lcaiwad2M-U

https://phys.org/news/2011-10-silver...rs-cooler.html


Using a windshield sunshade is very effective -