Solar hood?

Discussion in 'General' started by lyekka, Apr 11, 2008.

  1. lyekka

    lyekka Well-Known Member

    Perhaps a totally nutty idea, but I thought I would mention it... Part of my job is new ideas and once in a while I hit on something that works out. Just have to keep trying. I am told Ted Turner has a 90% failure rate....

    I recently saw a story on solar cookers on the TV and was wondering if something like that could be adapted to keep the engine warm.

    The premise is to take a hood, cut openings into it, inset clear plastic into the cutouts, then color the top of the insulator black (or replace it?) to see if it would keep the engine compartment warmer than say a painted black hood. The hood on a Prius appears to have an air space of about 1.5 inches or so.

    If it would work, all sorts of interesting custom designs could be used.

    If anyone thinks it is feasible, let me know I can can work on a prototype. We have a fiberglass division in our company and they have built carbon fiber hoods before. I do a fair amount of designing for laser burnounts and I could come up with something for a metal version.
  2. ATL

    ATL Well-Known Member

    I don't follow your description of the hood, but by all means, if you have the resources and idea why not try it?

    However, with a solar cooker the sun's rays are reflected from many angles to one common point to heat the food. This would prove to be very difficult if you were trying to heat an engine I would imagine, not to mention you would have to park with the hood facing the sun for it to work.

    PS, I'm sure that the people that are trying to keep their engines warm for MPG purposes wouldn't mind that their hood was lighter (CF or glass) as opposed to metal
  3. bomber991

    bomber991 Well-Known Member

    I'm not too sure what the point of this is, just to minimize warmup time? I guess this sounds kinda like that solar heater thing I built over the winter, but inside an engine bay instead.

    Anyways seems like you might have issues with the clear plastic getting too hot while the car's running.
  4. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    What about a black hood, with copper pipe running back and forth, also painted black (maybe on the underside?). Feed the loop of piping through the cooling system. It'll preheat the coolant.
  5. shifty35

    shifty35 Well-Known Member

    Sounds like an idea that could work Andrew...

    Problem is, shiny parts reflect sunlight. You'd have to go like dull flat black for maximum effect.

    Don't think that would be a popular look. :)

    It seems like on sunny days it's hot under the hood even when the engine hasn't been running!
  6. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Not a popular look? It's just like all the ricers do with their "carbon fiber" hoods - except not so shiny. ;)

    What about just making the underside of the hood shiny, to keep the heat in better?
  7. Shiba3420

    Shiba3420 Well-Known Member

    Don't forget...that extra weight will hurt economy. The easiest thing would be just to keep your hood in the sun and have it painted a dark color. A step up would be to add insulation around the sides of the engine compartment to keep that heat in.
  8. vtec-e

    vtec-e Celtic MPG Warrior

    Apart from the extra weight, i love this idea! To advance this idea, what do you think about this: Remove the radiator and re-plumb the coolant pipes to the new under/in-bonnet solar collector and it becomes a super aerodynamic radiator!:Banane01:
    Then you can grill block to your hearts content, ie: block completely, go as aero as possible.
    With good design, the heat loss through the bonnet panel would be enough to stabilise engine temps and would heat the engine a little when parked in the sun. I've thought of this before but it seemed a little odd so i said nothing.:eek:

  9. dobsont

    dobsont "How's your mileage?"

    Definitely wouldn't want to be looking out over score of tiny discoball mirrors on your hood while trying to drive. The flat black idea is good though. This time of year I deliberately park so the hood is in the sun, and it sits like that all day. I don't know if it makes any difference or not but the afternoon warmup hit is minimal compared to the morning.
  10. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    I'm talking about foil or discoball mirrors on the underside of a black hood. The heat gets in, but then it can't get back out.
  11. lyekka

    lyekka Well-Known Member

    Thanks for the feedback! I use a block heater at home, but was trying to find a cost effective way to preheat coolant at work and on the go. I ruled out solar panels to run the block heater due to panel cost and battery/inverter issues among other things.
  12. lyekka

    lyekka Well-Known Member

    Andrew, I like the idea! I'm sitting here looking at a flexible heating pad with loops embedded in it and wonder if something similar could be made to carry coolant:

    A roll up black mat with insulation on the underside to protect the car (perhaps also it could cover the windshield / roof to keep the interior cool?), liquid tube loops with quick disconnects to the engine's coolant system, and a flexible solar panel attached to drive a pump. A quick search found a 12v pump rated at 600 LPH that only uses 18 watts.


    Not much weight involved except for the coolant?

    Justin, any comments as you are familiar with solar water heating? I have no idea of what quantity of coolant in the loops would need to be, or the velocity of the coolant to give it time to pick up the heat.

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