Vehicle heat storing device-use for camping?

[greenalien8]

I am building a device that can store my vehicle's waste heat (at ~300F). I am thinking it could be useful for outdoor use like warm showers, boiling water or heating tents. Also on a day to day basis, I plan to use it to offset my home water heating needs.

If you have some ideas or if you have tried something like this, let me know. I'd love to hear back.

[Happy Joe]

Re: Vehicle heat storing device-use for camping?

The problem with storing heat is that there are basically two systems (phase change like turning ice to water or water to steam and mass storage; heat a ton (or more) of rocks or water above ambient in an insulated environment and then extract the heat later); neither system lends itself to portability.
I did make a heat exchanger, using copper pipes that used engine waste heat to heat shower water but it was really more trouble than it was worth, needed a pump and enough hose to reach to a stream pond etc.

Solar showers, or water in an inner tube/black bag, heated by the sun work for limited washing.

I currently use a cheap garden sprayer panted black (heated by the sun) for a quick rinse of in the field, most folks use a kitchen sink sprayer as a showerhead.

Propane point of use heaters with a pump appear to be the best near conventional way to heat shower water. I considered one of these for a while;
https://www.eccotemp.com/re-conditio...-water-heater/



I do see coils of tubing, on the market, that are heated by flame/fire/stove that some folks apparently use to heat water.

I heat water for the morning shave (and morning & evening wash up) using an alcohol burner.

Btw, the water (or antifreeze) in water cooled engines typically run from 180 degrees to over 212 degrees (the system is pressurized to prevent boil over) unless you are tying to capture heat from the exhaust or catalytic converter which can get even more dangerously hot (can glow cherry red/melt aluminum or some brass/bronze alloys in the right conditions).
Naturally, at ambient pressures, water in contact with anything over 212 degrees F. (less at altitudes above sea level) will boil and turn to steam.



Please don't become discouraged some of my best Ideas were done in the face of skeptics...

Enjoy!

[MacGyver]

Re: Vehicle heat storing device-use for camping?

I've been trying to figure out how to make a simple heat exchanger to heat a tent using a campfire for years. In my head, I have it based on the concept the Zodi heaters use. Heat the metal in a heavy gauge tube that's connected to ducts with air forced through it with a 12 volt fan. Unfortunately, the cost of materials to even make a prototype is way too high for my wallet.

[Happy Joe]

Re: Vehicle heat storing device-use for camping?

I worked out a tent heater similar to the zodi (flame outside the tent) using a cheap propane burner (like the early zodi heaters) a stainless tubing heat exchanger, a medium flow pump and a vehicle heater core (used to use them for water cooling computer processors) with a computer fan (12 volt) blowing through the core.
When I totaled up the hassle (propane + water + electricity) I concluded that a good sleeping bag, and temporarily heating the tent to enter and leave it with propane was the better idea, at least for me...


Enjoy!


EDIT; any one experimenting with steam or hot water heating needs to be sure that they include provision for water/steam expansion and pressure relief: a steam explosion could be deadly and would likely ruin your whole day...

[greenalien8]

Re: Vehicle heat storing device-use for camping?

Joe, Mac, Thanks for your your comments.
Portability and safety are issues. But water is not the storage medium here. nor is it stones . And is from over the exhaust pipe after the catalyst. So not red hot but more manageable.
There are many commonly available (solid) materials that store energy in phase change that melt around 150-200C.
I am still trying to address the portability issue. I agree, propane options seem to be the most portable. But if you park your car close to the camp site, it will be useful additional energy that would otherwise be lost. Hopefully the cost/ hassle is not too high to shelve it. Ill keep you posted.

[toedtoes]

Re: Vehicle heat storing device-use for camping?

I would assume that trying to store heat from a stationary heat source (like a campfire) would be much easier than trying to store heat from a moving vehicle. Realistically, the vehicle is only going to be creating that heat while it is out on the road. That means you have to be able to collect and store it while driving and then transfer it when you get home.

[MacGyver]

Re: Vehicle heat storing device-use for camping?

This is what I've kicked around to make my Zodi-like heater from a campfire:
3 or 4 inch diameter stainless tube to match 3 or 4 inch flexible duct. The heavier the wall thickness the better. Unfortunately, I don't have the means to weld stainless, the U bend in stainless was hard to find and very expensive as was the high cost of thick walled stainless tubing to begin with. Can't see dropping that much cash on something that may or may not work.

[Irate Mormon]

Re: Vehicle heat storing device-use for camping?

Storing heat from a vehicle - an expanded radiator reservoir would do it. You would need a means of keeping the extra coolant circulating through the radiator, but that's a fairly trivial task. If the reservoir were, say, detachable, you could place it into your cold tent at night. You could do it with a few Jerry cans (I'm thinking a modular system). Interesting idea. Not too difficult to do either.

[MacGyver]

Re: Vehicle heat storing device-use for camping?

Storing heat from a vehicle - an expanded radiator reservoir would do it.

Wouldn't you need a huge reservoir to maintain enough heat to last more than an hour or two, maybe a bit more? I can't picture 5 gallon cans retaining enough radiant heat to last all that long. From my experience with Winter camping, I know even a big block V8 engine cools down in a couple of hours, and that's a huge chunk of metal to cool down!

[toedtoes]

Re: Vehicle heat storing device-use for camping?

Wouldn't you need a huge reservoir to maintain enough heat to last more than an hour or two, maybe a bit more? I can't picture 5 gallon cans retaining enough radiant heat to last all that long. From my experience with Winter camping, I know even a big block V8 engine cools down in a couple of hours, and that's a huge chunk of metal to cool down!

That's my thinking. Most vehicles are good at creating heat, but once the engine is turned off, that heat dissipates pretty quickly. You'd need to find a way to insulate the container so the heat can't escape. You would also need to maintain that heat in a location that won't create a problem with the engine - it's important for the engine to cool down quickly. Moving the heat storage away from the engine is going to reduce the heat retention of the container.

[tplife]

Re: Vehicle heat storing device-use for camping?

It's not a heat storage device, but another way of heating that my relatives use. A small version of a home heater could work. The house version has a large outhouse-sized shed that is in essence a big wood-burning stove. Insulated pipes containing water run through this "big stove" then go underground. The water is pumped to and from the house and heat is exchanged out of radiators on each floor of the home. The wood-burner runs over a day before it needs wood again.

[MacGyver]

Re: Vehicle heat storing device-use for camping?

It's not a heat storage device, but another way of heating that my relatives use. A small version of a home heater could work. The house version has a large outhouse-sized shed that is in essence a big wood-burning stove. Insulated pipes containing water run through this "big stove" then go underground. The water is pumped to and from the house and heat is exchanged out of radiators on each floor of the home. The wood-burner runs over a day before it needs wood again.

An excellent bit o' engineering - but hardly a portable solution for camping.

[Irate Mormon]

Re: Vehicle heat storing device-use for camping?

I missed the part about the exhaust pipe. You could use Peltier junctions to charge a battery - something like that.

[JoeN]

Re: Vehicle heat storing device-use for camping?

I haven't pursued this idea, but I have considered it. A heater core out of an old vehicle could be the radiator in the tent, lengths of radiator hose from the radiator to a coil of copper tubing in a bucket of water heated by a camp fire or a small DIY wood burner boiler system. I don't know if natural convection flow of the water through the coils would be enough to keep the water flowing through the system or if a small pump would be needed. Also I don't know if the radiator in the tent would radiate enough heat without a small fan to circulate the air.

The biggest problem is developing a system that is small enough to be portable and simple to set up yet able to yield enough heat to warm a tent. Another option is one of the small wood burning stoves designed for tents but you would have to be willing to installing a stove jack in the tent if one is not already there. Like someone else stated, a good sleeping bag is really all you need with maybe a small propane heater to take the chill off just before bedtime and when you first wake up.

[tplife]

Re: Vehicle heat storing device-use for camping?

I was thinking along the line of a SS heating coil inside a firepit, with insulated lines and a 12V recirculating pump running a loop through a tent-mounted radiator. The systems work so well for homes where I hail from, so possibly a portable variation would provide wood-fired heat without the CO dangers of suffocation.