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Solar roof kit-fan

Discussion in 'Gen 3 Prius Accessories and Modifications' started by GG707, May 22, 2020.

  1. GG707

    GG707 Member

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    Hey,
    A
    I was wondering when we leave our cars under the sun in a hot day... And the fan kicks in... It gets fresh air inside no matter if before turn off the car the recirculation was choosen... Although when we start the car it goes back to what the driver had choose before turn off the car...
    But my question is...

    When fresh air comes in ... There must be some airways to allow the air out again... Otherwise it needs to escape through some crack spots (rubber door seals or smt) in order to achieve circulation of the air ... Every time I let the back windows a bit open while it is in the secure parking I have seen that the car is a lot cooller than when I park it with closed windows... So that makes me wonder... Are escape airways for the cabin's air which might got stack closed or smt? Or should I let the windows slightly open ? Which is not my preferred solution especially when i park outside-to keep it cooller?

    Posted via the PriusChat mobile app.
     
  2. ChapmanF

    ChapmanF Senior Member

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    There are large air exit openings at each side of the car, concealed by the rear bumper cover.

    The easiest way to find images of them is probably to search in the "Prius mouseproofing" threads.
     
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  3. Ed Beaty

    Ed Beaty Active Member

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    My solution:
    I have WellVisor wind deflectors installed:

    WellVisors2.jpg

    These allow you to crack all four windows (if you wish) and remain pretty secure.

    I also have a very close-fitting windscreen reflector (from PC shop). Fitting that reflector and cracking the windows keeps the car much cooler even in direct sunlight here in Utah. Since most of the heat is located UP in the car, the heat can easily dissipate thru the cracked windows.
     
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  4. ChapmanF

    ChapmanF Senior Member

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    One advantage to the way Toyota designed it is that as the air is passing toward the designed-in air exits at the rear of the car, it passes through the traction battery, and keeps it cool too.
     
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  5. 2012 Prius v wagon 3

    2012 Prius v wagon 3 Active Member

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    Since heat rises, both inside and outside the car, I would have thought that if you have a fan blowing air to cool a parked car, you'd want to blow it out from the top of the car (tops of windows or sunroof), and suck in fresh cool air from low points, such as the Prius has in the rear at bumper level. Seems better in every way, also considering turbulence and mixing.

    But I also believe the Toyota engineers who designed the system know what they're doing, so can anyone help me understand how the system works and why it's done by blowing in the air up top? (vs. blowing it out up top)
     
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  6. ASRDogman

    ASRDogman Senior Member

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    The air inside a car with closed windows will be hotter than the outside air.
    In the summer that is.
    Passing the outside air through the car keeps it cooler and makes it easier and faster
    for the a/c to cool the car down.
     
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  7. GG707

    GG707 Member

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    Way too cool e.g. parked at open garage direct sunlight all day long with fan operating at 45c elsius degrees env temp the car have 50... Without, I think the car goes past 65... One day I had prepare to travel so put my stuff in the car to be ready for afternoon to go... There was a pla 3dprinted battery mount for my ebike that had lost its shape... It melt! By gravity the pla needs more than 60 to 65... to do so... :D :D :D

    Posted via the PriusChat mobile app.
     
  8. Grit

    Grit Senior Member

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    Never heard of that feature on the car, not even in the manual but i heard of intelligent parking assist.

    Stick a thermometer in the car with different type of window rolled down variations, then take a look at it after the work day.
     
  9. GG707

    GG707 Member

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    Oh no, I mean really a secure parking area where I leave the car while I am at work... With security guys and cameras... Not a mode of the car... I just mention that because I can let it there with fully open windows without being afraid someone to steal the car or anything.. but I can not park it with open windows on road side... so that is where I checked the fan... Especially during summer it was too hot outside and even more inside the car... And despite the fan was operating it was really hot in the car when I was going to take it... So some times I let the rear windows a bit open 5 to 10mm and the difference was huge...
    Posted via the PriusChat mobile app.
     
  10. Grit

    Grit Senior Member

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    If it happened to be windy that day with windows slightly down then that would be it. There’s also other factors that can affect temp obviously like altitude, humidity & etc. I diy’d my own door windows and both front back windshield reflective sun shade/ blockers also, helps a little during summer

    I always leave all windows closed, there’s bees near my work parking, they like to go for rides also. They have to pay for gas if they want to go cruising.
     
    #10 Grit, May 22, 2020
    Last edited: May 22, 2020
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  11. Solar Blue

    Solar Blue Member

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    I got my solar package Prius last January.
    Now that the weather is warming up, I m really digging it.
    I'm hoping to try an experiment this summer. A friend has a non solar Prius. I want to compare interior temps in a controlled way. I'll post results. But don't expect anything until July or August. I'm in the PNW, after all.
     
  12. ASRDogman

    ASRDogman Senior Member

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    Are they both the same color? Very interested in the results.


     
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  13. Solar Blue

    Solar Blue Member

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    Sadly, no. I really wish they were so that I could eleminate that variable.
    The solar car is dark blue. The non solar car is white. Bummer, but it's all I have to work with.
     
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  14. Grit

    Grit Senior Member

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    Experiment like what kind of stuff?
     
  15. Solar Blue

    Solar Blue Member

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    Not clear on your question, but I'll park both cars next to each other on a warm day. Then I'll track and log outdoor temp and the interior temps of each car. I'll do this with the solar fan on and off (to help understand the effect of color). I'll also compare the solar Fan's effectiveness as compared to having the windows cracked.
    Stuff like that.
     
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  16. ice9

    ice9 Active Member

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    Correct me if I'm wrong, but I am pretty sure that those rear vents are for venting over-pressure and are designed to vent out, not in. Although they probably can let air in, I believe they use a plastic flapper (mainly to keep water out) that would impede airflow coming in somewhat.

    Technically, you are correct, but only IF the rear vents were two-way. It would be more efficient to exhaust hot air out of the top of the car, but the gain in efficiency would still be very small.
     
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  17. ASRDogman

    ASRDogman Senior Member

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    That's a bummer, but, you'll certainly get a ball park figure. A place to start.....

     
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  18. ChapmanF

    ChapmanF Senior Member

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    Exactly. The design airflow through the car is always in through the HVAC system in front, through the cabin, through the vent into the battery ductwork, through the battery into the space below the rear decking, and out the rear exits.
     
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  19. Grit

    Grit Senior Member

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    Oh just temp comparison. I was thinking something was going to be rigged or mad scientist related.
     
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  20. Vinylrobot

    Vinylrobot Junior Member

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    I just watched Consumer Reports do a test, cracking the window does nothing.