Anti-stealth Prius camping - going large...

Discussion in 'Gen 3 Prius Main Forum' started by geedub, Apr 30, 2020.

  1. geedub

    geedub Member

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    I don't get the appeal of stealth camping. I don't want to be anywhere that I'm not welcomed.

    I'm sure glamping means different things to different people, but what I'm doing is far from roughing it. Of course my Pruis supplies the power, but little room. Space is a luxury and I want it.

    My approach is influenced by the fact that I'm in central Florida, and will probably spend the summer camping here. I sold my house at the beginning of April and I don't want to buy or lease anything until the market settles down. I would travel but I want to stay near family until the virus issue is settled more or less.

    The Florida wetland where I'm staying beautiful, and rich with biting insects and torrential rains. To solve both issues I bought a 10 X 20 foot (3 X 6 meter) screen room canopy. It seems a bit fragile but I reinforced it somewhat and it has survived a few pretty strong storms already.

    Since it's inconvenient to have the car outside of the living area I bought some screen and installed it on one end of the canopy. Both smaller sides of the canopy have zippered access and are held in place with velcro. I put the new screen on the inside and roll it up out of the way when the car isn't there. The new piece does a decent job of sealing out the bugs but I found that partially connecting the original screen works even better. It's been stopping at least 95% of the bugs so far.

    The kitchen and dining area is behind the car so I attached a few sections of gutter downspout to the exhaust pipe and ran it under the screen. From there I attached a foil lined pvc vent to direct the the fumes up. This has worked very well but I'm curious if anyone thinks this could cause problems with the engine. The pipe is about 3X the diameter of the exhaust pipe, but the length concerns me a little. I've been doing this for a few days now and haven't noticed any issues.

    I'll share more of my set up if anyone is interested.

    chimney outside.jpg chimney inside.jpg
     
  2. ChapmanF

    ChapmanF Senior Member

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    Idea is probably ok. I'm pretty sure it won't hurt the engine. Let's make sure it doesn't hurt you.

    If you used round tubing rather than downspout, and could find a short silicone rubber tube of the right diameter, you could probably join your tubing to the exhaust with the silicone tube and have it gas-tight. You might not be limited to metal for the tube material; I don't think the car will be doing anything but idling while in this configuration, and if you've got access to a temperature probe, you might measure what's arriving at the tailpipe and find out it might be cool enough to give you more material options.

    I think you want a way for condensed water to drain out separately so that it does not accumulate in the low bend there and gradually increase the back pressure. You can do that with a reducing tee out there, where the exhaust leg points up (full diameter), and the reducing leg points down, with a U bend for a trap, and then a bit beyond the trap to direct the escaping water away from your mattress.

    When setting up, pour some water in the trap so it is already sealed; you don't want it being a ground-level exhaust gas outlet for as long as it takes to condense enough water to fill it.

    I might also add a couple feet to the top above the roof of the tent.
     
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  3. bisco

    bisco cookie crumbler

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    that is so cool, well done!(y)
     
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  4. geedub

    geedub Member

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    Thanks. I did spring for CO alarm just to be safe.
     
  5. Johnny Cakes

    Johnny Cakes Senior Member

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    I love it -- your setup is like a Prius Habitent, but on steroids: habitent.jpg
    I can't see any engine issues. If you wanted to insure a positive flow, you could add a 12v fan somewhere in the exhaust path. I've used this one for something different, but it works well: fan.jpg
    Stealth is more about not making anyone uncomfortable. Think of all the places you'd like to visit or sporting events you'd like to see in person. One of the biggest expenses is hotel cost. I can park just a few blocks from the sold-out stadium the night before the game for free and roll out of bed while others fight traffic for hours. I can visit places and friends all over the country without hotel cost. It's all legal, but by being stealth, you don't make the people who actually live there uncomfortable.

    Definitely!
     
    #5 Johnny Cakes, Apr 30, 2020
    Last edited: Apr 30, 2020
  6. geedub

    geedub Member

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    In practice I was getting too much leakage with this system so I took your advice and considered round ducting. I checked the temp of the tailpipe and was surprised that during the brief cycling of the ICE it only registered in the mid 90's Fahrenheit, 35ºC+/-.

    For this version I settled on a 3" to 1.5" PVC reducer coupling and the same duct I was using as the chimney. I needed to remove a small amount of material on the inside of the small end of the coupling to give a nice snug fit on the tailpipe. I put a tiny bit of grease on the tailpipe and friction is all that's needed. The outside of the 3" end of the coupling is just right for the inside diameter of the duct.

    I put a CO monitor at the end of the exhaust duct for a ICE cycle and it peaked quickly at 674 ppm, and then steadily declined during the cycle to end up at 118 ppm when the engine cycled off.

    exhaust run.jpg

    exhaust connection.jpg
     
    #6 geedub, May 2, 2020
    Last edited: May 2, 2020
  7. ChapmanF

    ChapmanF Senior Member

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    Hehe. You've got the exhaust-to-coolant heat exchanger in there doing its thing, plus several feet of cold stainless steel to pass through, and not really idling long enough to take the chill off.

    Were you measuring the temp of the metal tailpipe itself, or of the gas exiting the tailpipe?
     
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  8. geedub

    geedub Member

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    I was using an infrared thermometer on the metal. And because I'm old, I also held it with my hand during the cycle...
     
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  9. ChapmanF

    ChapmanF Senior Member

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    The gas might be warmer than the metal gets.

    You've reminded me of a youtube video I saw once of a guy who thought he was showing how to test a catalytic converter. He had an IR thermometer, and it was a classic case of having a fancy tool and not reading the manual:

    2102.jpg

    Guy thought that because it projects a laser spot at the center of its measuring cone, he's somehow actually plucking the temperature off a sliver of exhaust pipe showing between a heat shield and a flange.

    If he had taken a look at the diagram in his manual:

    spot.png

    ... he'd have known that 210.2 °F was the average of a tiny sliver of exhaust pipe, a bunch of heat shield, part of a joint flange, and some air. :)
     
  10. Johnny Cakes

    Johnny Cakes Senior Member

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    I think you raise a good point. A catalytic converter won't even function under 400 degrees; stainless tips at end of an exhaust pipe get discolored over time from the heat of the exhaust gas, so it must be pretty darn hot. A quick Google search indicates that a foil-lined pvc vent has max temp of 230.

    But the flip side is a very short idle time so my guess is that its a non-issue.
     
  11. geedub

    geedub Member

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    You guys forgot the part where I held it with my hand. I'm a chef, so I'm used to judging temps with my flesh...:cool:
     
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  12. geedub

    geedub Member

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    I only lately realized that my Prius has an eyeglass holder in the bedroom! :cool::cool::cool:

    Prius bedroom eyeglass holder.jpg
     
  13. geedub

    geedub Member

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    I figured out a hack for easily opening the hatch from inside with or without power on.

     
  14. ChapmanF

    ChapmanF Senior Member

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    I believed you, but I wondered whether measuring the surface of the stainless steel tailpipe might show a lower temperature than the actual gas coming out. (The steel temperature is going to be a balance of how much heat is transferring to it from the exhaust gas and how much is radiating and convecting away.)

    So I went out and compared mine, using an IR reading of the tailpipe itself, together with a thermocouple probe stuck a few inches into the tailpipe in the middle of the flow.

    Still, it wasn't that bad. At idle, the thermocouple in the exhaust gas flow was seeing about 43 °C. The IR reading of the tailpipe was initially 20-something before I realized I had the emissivity set for 0.97 which is about right for water. Metals can have really low emissivity depending on how shiny they are—I could get the reading to look more like 60 °C if I lowered the emissivity setting to somewhere in the fifties. That's probably too low because the tailpipe is anything but shiny. The value given here for "Stainless steel, weathered" is 0.85, which probably would have made the reading around 40-ish and a pretty good match for the thermocouple reading.

    What emissivity was yours set for?
     
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  15. geedub

    geedub Member

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    It's a $15 little unit. I believe it has 2 ranges programmed but the battery crapped out so I can't check for now.
     
  16. ChapmanF

    ChapmanF Senior Member

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    An IR thermometer without an adjustment for the emissivity of the material it's pointed at can give readings quite wide of the mark depending on the material.

    The good news is there are lots of materials (like good black electrical tape) that have emissivity in the high 0.90s, so if that's what the thermometer is adjusted for, you can just slap a layer of one of those on whatever you're trying to measure, and then point the IR thermometer at that. :)
     
  17. Minima Domum

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    Nice work! I have a similar gazebo but only half the size that I use behind the car when camping (we don't have so many bugs here) and have been thinking about an exhaust "chimney" since purchasing my Prius, glad to hear that it is possible and works well
     
  18. geedub

    geedub Member

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    It turns out that the canopy top radiates a lot of heat when the sun hits it which negates the shade it provides. I had components left over from a mini sprinkler system I had used for landscaping, so I installed a few sprinkler heads on top. This canopy has two peaks and I put one circular pattern head on each. The canopy is 10 X 20 feet and the sprinklers cover a circle of 10-12 feet. This site has a well water hook up, so, easy life!

    It's only bringing temps down a little, but better than nothing. I'm working on a swamp cooler design now...

    canopy shower.jpg

    shower detail.jpg
     
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  19. geedub

    geedub Member

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    I finished the swamp (evaporative) cooler. These work best in lower humidity conditions so not ideal for an actual swamp, but I'm enjoying a temperature reduction of 8-10ºF or +/-5ºC. We have relatively low humidity for Florida today so that probably helps.

    I realize that this isn't something most people will need or want, so, here ya go anyway!

    20200513_112348.jpg
    20200513_112022.jpg
    20200513_110305.jpg
    20200513_112633.jpg
    20200508_100513.jpg
     
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  20. ChapmanF

    ChapmanF Senior Member

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