Anybody make a stovetop water heater coil?

[DirtBean]

Wife has requested some easy to use hot water.

I tried to do this over the weekend, but didn't get enough heat.

The zodi firepit kit looks like 2-3 loops of copper tubing that is placed in fire and water gravity feeds through it. The stovetop model is some coils in a box (how many?) and is pumped through by a 6V pump. I thought about buying it, but figured I'd skip buying a pump, since I could run it off of my camper water pump anyway.

Here is what I did:
Put a dishwasher quick-connect fitting on the faucet and ran a SS hose from that to a 1/2" check valve, then SS hose to some 3/8" copper tubing that I had shaped into about 3 1/2 loop circular coil (looking like the zodi firepit model) and ran last of tubing back to sink. I put this on the stovetop, turned on water, fired up stove. I played with flow rate and had flame on max, no hot water. I put a little ad-hoc deflector plate over the coils and started to get some little bit of warmth, but not enough to call it success. I was starting to get frustrated and decided fire and angry don't mix well.

Has anybody tried this type of thing, or can anybody comment on number of coils in the zodi stove top heater box?

 

[ntsqd]

You can go at this one of two ways, dig out your Heat & Mass Transfer text book (everyone has one of those in their light reading library, right?) or you can do it cut and try.

Right, so some suggestions for the latter. The more surface area exposed to the high temp source the more thermal transfer you'll get. With only one side of the coil exposed directly to the flame the area being heated isn't quite what you might expect. Try putting the coil in a pan of water, then heat it on the stove. Increase the number of coils and close down the spacing between them.
Flow rate plays a part in this. To a point slower is better, but don't get too hung up on it.

BTW, this is a std. text book chapter question, to calculate how much surface area is needed at a given flow rate to get X degree temperature differential. Usually the text book question is dealing with a liquid to liquid heat exchanger, but not always.

 

[Overland Hadley]

I was going to suggest using the Zodi stove top unit.



.... dig out your Heat & Mass Transfer text book (everyone has one of those in their light reading library, right?) ....

No. But I bet you have it.

 

[brp]

The JetBoil is a very slick water heater and overall system/package. I bought one for "real" camping and I always bring it in my camper now. You can go from packed to about 12 oz. of boiling water in 2 minutes or so. You can carry a JetBoil around while it is lit and there are no matches needed. The heat exchanger is so efficient that the gas seems to never run out.

You can also make a cup of soup or a freeze dried meal with it.

I like the McGyver, homemade type stuff, but the JetBoil is such a great package that I had to go for it. For me, it has performed fine in cold and at altitude as well.

 

[Hittheroad]

My theory is that water that comes out of a tap is likely to be wasted. Much better to pour it from a container. In the evening we boil up a pot on the stove and then fill a thermos. The thermos usually lasts us through til breakfast. For the same reason we have a hand pump water tap rather than a electric pump.

I apply none of this logic to showers. They need to be hot, powerful and long lasting.

 

[Overland Hadley]

I apply none of this logic to showers. They need to be hot, powerful and long lasting.

 

[DirtBean]

Can anybody comment on the number of loops and deflector plate design in the zodi stove top?

During my experiment, I was using city water, I might have had much better success from on-board water at ambiant temp.

 

[pods8]

Another consideration I was thinking I'd use is get a pump up solar shower: http://www.duckworksbbs.com/gear/shower/index.htm which can obviously be used for solar heating. Or when in the camper just heat up a pot of water and mix it with your regular water to get a temp suitable to your desire. Then you've got a batch shower ready to rock w/o messing around with heating coils in a camper...

 

[imix]

Take a plastic bottle, paint half of it black. Fill with water and place in sun. This gives you hot water. This works best in summer. Keep hot water in thermos as above poster stated, or place in "cooler" that you have also painted interior black and placed in sun. This gives you 24 hrs/day of hot water.

In winter, heat hot water on stove. Place in thermos type device, pour out as needed. This also gives you hot water. Am I missing something? Other than the strange western compulsion to turn a tap and have hot water pour out?

 

[MarkBC]

Take a plastic bottle, paint half of it black. Fill with water and place in sun. This gives you hot water. This works best in summer. Keep hot water in thermos as above poster stated, or place in "cooler" that you have also painted interior black and placed in sun. This gives you 24 hrs/day of hot water.

In winter, heat hot water on stove. Place in thermos type device, pour out as needed. This also gives you hot water. Am I missing something? Other than the strange western compulsion to turn a tap and have hot water pour out?

Yes, missing something.... Is this how you generate hot water at home? If not, then you must be subject to that same "western compulsion".

 

[DirtBean]

Yes, missing something.... Is this how you generate hot water at home? If not, then you must be subject to that same "western compulsion".


Exactly. Back to original post... my WIFE WANTS HOT WATER: proposing that I should tell her to sit a water bottle on a rock in the sun and wait is potentially dangerous advise.

Sitting water bags out in the sun is probably great for people that basecamp in warm areas. My typical trip is lots of driving in non-sweltering Canada weather and late night stops, usually 1-2 night per site.

The thermous idea is pretty good, I'll probably give that a try this weekend.

I'll probably also add another couple loops and a deflector plate to my 'on-demand water heater' contraption, you never know, it might actually work.

 

[ski3pin]

... my WIFE WANTS HOT WATER: proposing that I should tell her to sit a water bottle on a rock in the sun and wait is potentially dangerous advise.
<snip>


Well said.

 

[joez3]

Not sure if this will work for you, but I have a battery powered zodi shower. I extended the hose going to the shower head. When I get to camp I pop the hood and wrap the extra hose around the radiator hose, fill the bucket with water and put the shower head in the bucket and start the pump. After a few minutes warm water.

 

[pods8]

Did you catch my early post about the pump up style solar shower and just dumping some hot water off the stove into it? Pressurized hot water with just a few pumps... Simple compared to heating coils.

 

[4llamas]

Did you catch my early post about the pump up style solar shower and just dumping some hot water off the stove into it? Pressurized hot water with just a few pumps... Simple compared to heating coils.


I was thinking about this very unit (without knowing it existed) last week while standing under my failing battery powered shower pump. Time for an upgrade. How would you rate the flow: A- you can dodge the drops, B- ok, but keep pumping, C- Aaahhh, D- I'm out of water over here and haven't finished rinsing.

 

[HIKEMT]

I was thinking about this very unit (without knowing it existed) last week while standing under my failing battery powered shower pump. Time for an upgrade. How would you rate the flow: A- you can dodge the drops, B- ok, but keep pumping, C- Aaahhh, D- I'm out of water over here and haven't finished rinsing.


Really depends on how you use water. I was impressed with the water pressure and duration of a fully pressurized tank. We can usually take two "military-type" showers with ours although i still haven't figured out a great way to mount the shower head for a more sustained washing. Easy to pump the pressure back up if needed. No batteries to replace. Typically we boil a pot of water and add a pot of cold because we didn't get the unit in the sun early enough or weather is too cold. Easy enough to have an extra pot ready and refill. Does dual duty sitting outside the camper during the day for vegetable or hand washing, etc. Works great and no extra heater units to worry about. Not everyone will find this shower sufficient but when my wife found out this would let her shampoo her hair with hot water it gained me an extra night or two in the camper before having to check into a hotel mid-trip. Recommended.