Mod HVAC fans to run on solar power while car is parked?

[mmntech]

What if it rains?

I know a lot of meteorologists who can tell me before it does. True story.

 

[BUTCH1]

Try one of these, simple to put on, reasonable price, keeps interior cool..

http://www.capoptop.com/

 

[PottedMeat]

Try one of these, simple to put on, reasonable price, keeps interior cool..

http://http://www.capoptop.com/

These vehicles were fitted with a PopTop at 10 AM and were left to bake in the 105 degree heat for 3 hours. While the vehicle bodies reached temperatures of 147 degrees (black vehicle), the roof temperature only ranged between 65 and 80 degrees.

...er if the ambient is 105, isn't that the lowest the roof can be?

 

[Gillbot]

I want to see an internal temp, those look like the top is merely reflecting energy and not being properly seen by the camera.

Similar to my glasses in this pic, but we know my eyes are the same temp as the rest of my head +/- a few degrees.

 

[Throckmorton]

I know a lot of meteorologists who can tell me before it does. True story.

Obviously you don't live in Texas or Hawaii

 

[BUTCH1]

...er if the ambient is 105, isn't that the lowest the roof can be?

Possibly cooler because it can't get the sun's ray's or little air circulation under the cover. Anyway, these have to be a big improvement over the windshield reflector types and less expensive than a full cover. If you've got a nice leather interior I could see the $69-79 as a worthwhile investment.

 

[Throckmorton]

Possibly cooler because it can't get the sun's ray's or little air circulation under the cover. Anyway, these have to be a big improvement over the windshield reflector types and less expensive than a full cover. If you've got a nice leather interior I could see the $69-79 as a worthwhile investment.

But no matter what the car can't be cooler than ambient temperature, unless there is some kind of evaporative cooling

 

[BUTCH1]

But no matter what the car can't be cooler than ambient temperature, unless there is some kind of evaporative cooling

But the car started the day at a much lower temp and the cover is acting like an insulator..OK, I'm guessing LOL..

 

[jlee]

..

 

[jlee]

But no matter what the car can't be cooler than ambient temperature, unless there is some kind of evaporative cooling

My oil temp is lower than ambient temp in the morning.

Seriously though, it could be - garaged vehicle going outside, AC running inside, kept out of direct sunlight while ambient temp increases...it'll equalize eventually (likely pretty quickly) but it could be different for a little while.

I'm not sure about 3 hours though.

 

[Throckmorton]

My oil temp is lower than ambient temp in the morning.

Seriously though, it could be - garaged vehicle going outside, AC running inside, kept out of direct sunlight while ambient temp increases...it'll equalize eventually (likely pretty quickly) but it could be different for a little while.

I'm not sure about 3 hours though.

Well yeah, if you put a block of ice out in the sun it will be 0 degrees. They're misleading people with their claims though

 

[Murloc]

getting a car cover is probably the fastest, cheapest and most effective thing you can do.
Windshield shade is the minimum, it only helps so much with the air temp, but it's very useful to avoid burning yourself when you touch the wheel, the seat and the stick since they don't get direct sun.

 

[Throckmorton]

getting a car cover is probably the fastest, cheapest and most effective thing you can do.
Windshield shade is the minimum, it only helps so much with the air temp, but it's very useful to avoid burning yourself when you touch the wheel, the seat and the stick since they don't get direct sun.

You can't really put a car cover on when you're parked at work or at a park & ride station. And if you do it at your apartments, you look like that dbag obsessed with his car. Not to mention the time it takes. You aren't going to put a cover on so you can go in a shop for an hour.

A fan works and is simple-- at most you'd just have to flip a switch. I think all cars need to just come with a system like what the Prius has, except it doesn't need to be so complex.

 

[AustinInDallas]

Im interested to see if circulating the amount of air a solor panel can push will lower the temp much?

 

[exdeath]

Insulated mylar shade in the windshield, darkest tint on the sides and rear, and leave the windows cracked 1/4".

If it works in Arizona, it will work for you.

 

[heymrdj]

You can't really put a car cover on when you're parked at work or at a park & ride station. And if you do it at your apartments, you look like that dbag obsessed with his car. Not to mention the time it takes. You aren't going to put a cover on so you can go in a shop for an hour.

A fan works and is simple-- at most you'd just have to flip a switch. I think all cars need to just come with a system like what the Prius has, except it doesn't need to be so complex.

Well you don't look like it atm, but you're sounding like it. The physics of it have already been explained to you, hot air doesn't just disappear if you don't have something cool to exchange it with. You're just simply blowing hot air around.

I've done this experiment, and it's probably good for you to do it too. Turn your vehicle fan on low with no A/C turned on, just fan only. Now leave your basic cooking thermometer in there for 30 minutes and go do something else. Come back and I guarantee you the temp on the thermometer won't have changed. Now crack your windows open 1/4" and come back in 30. Boom you're a few degrees above ambient.

For the record I use a windshield reflector and vent shades on my truck. To me, the vent shades actually help the look.

 

[Mandres]

^ That's what I was going to say. Running the blower motor by itself, which I seriously doubt you can do on solar (that thing pulls a lot of amps) isn't going to do anything to cool your car unless you have an open window or some other way to exhaust the hot air.

Hell, why not figure out a way to run the AC compressor on solar power while you're at it?

 

[Throckmorton]

Well you don't look like it atm, but you're sounding like it. The physics of it have already been explained to you, hot air doesn't just disappear if you don't have something cool to exchange it with. You're just simply blowing hot air around.

I've done this experiment, and it's probably good for you to do it too. Turn your vehicle fan on low with no A/C turned on, just fan only. Now leave your basic cooking thermometer in there for 30 minutes and go do something else. Come back and I guarantee you the temp on the thermometer won't have changed. Now crack your windows open 1/4" and come back in 30. Boom you're a few degrees above ambient.

For the record I use a windshield reflector and vent shades on my truck. To me, the vent shades actually help the look.

You know a car isn't sealed right? Where do you think air goes when you set your HVAC to fresh air mode? As long as air is coming out of the vents, air is also exiting somewhere else.

 

[heymrdj]

You know a car isn't sealed right? Where do you think air goes when you set your HVAC to fresh air mode? As long as air is coming out of the vents, air is also exiting somewhere else.

Right, cars breath, with movement. If your remove some body work you'll find various vent flaps. Problem is that a fan on low does not create enough pressure to cause this movement. Open your door when the car is really hot inside, and you'll most likely be greeted by a rush of hot air (air that should have forced its way out). Try to shut a huge hatch with occupants inside, and you'll find everyone's ears popping as the air can't get out fast enough.

Again I'm not saying a car is sealed. I'm saying that with a blower on low (the max speed you could obtain from a solar panel) you won't have any appreciable affect if you don't at least roll down the windows. Like I said though, you can go do the experiment. Make sure to make an unbroken video to show us all how right you are. The experiment is free other than a little of your time.

 

[jagec]

I have pretty much no knowledge when it comes to solar power. But it seems awfully wasteful to have no way to store energy. It may kind of work without a battery, but with one, it will work a whole hell of a lot better.

If you want to draw a fixed amount of power whenever you feel like it, then yes, you need a battery. If you just want a motor to run whenever the sun is out, a bit faster in direct sunlight and a bit slower in indirect sunlight or when a cloud passes by, then you can wire the panel directly to the motor.

Lots of off-the-grid people do this with water pumps...assuming that the pump+panel are big enough to supply your needs and the water reservoir is big enough to hold a few days' supply, you actually get a cheaper, simpler, AND more efficient system with direct wiring.

For the car, you would still need to exhaust the hot air somewhere to have any appreciable effect on the interior temperature. A 12VDC computer fan hooked up to a cracked-open window is probably the best way, and eliminates the need to splice into your blower fan wiring. If you do a good enough job with the vent design it might not even look terrible...no guarantees, though.

 

[JCH13]

Obviously solar panels are for sissy Prius owners. The real solution is to use thermoelectric generators.

In all seriousness, a thermoelectric generator allows you to power a small fan or two without needing a solar cell on the outside of your car or in the window, or require you to remember to setup something.

If I were going to do this I would install fans/vents inside the door cards, possibly blowing through the speaker covers if that was possible. One would draw air in through the door drain vents, the other would expel it out the other side of the car through the door drain vents also. A control relay connected to the power window system would turn it off when the vehicle's electrical system was on. I wouldn't bother with a battery at all. Maybe a biggish capacitor, but that's a big maybe. I like thermoelectric generators for this because they are powered directly off of what you're trying to avoid: a temperature difference between outside and inside the car.

That's what I would do, as an engineer.

 

[phucheneh]

You really don't need an exhaust. Or you don't need an intake...take your pick. But it's easier to build pressure and let it get expelled on its own.

Modern cars should be sealed well enough that the air seeking an area of lower pressure will gradually flow toward the vents in the trunk.

 

[olds]

http://www.amazon.com/Autocool-Solar...owered+car+fan

 

[JCH13]

You really don't need an exhaust. Or you don't need an intake...take your pick. But it's easier to build pressure and let it get expelled on its own.

Modern cars should be sealed well enough that the air seeking an area of lower pressure will gradually flow toward the vents in the trunk.

Please explain the logic or natural law behind this.

 

[phucheneh]

Please explain the logic or natural law behind this.

Laziness.

Quit thinking like an engineer, and think like a lazy person. I didn't say it was better, I said it was easier.

If you blow from door to door, you're not going to circulate air throughout the entire car. With a single intake fan in the fresh air duct, you will.

edit: And if I want to be a dick...

I dunno which law says 'high pressure to low pressure.' I was thinking that was in that ideal gas law kajigger. ;P