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denimlabels
06-24-2015, 23:27
Does anyone have experience with using an Olicamp XTS Pot with a lightweight alcohol stove? The heat exchange fins on the pot bottom raise the weight a bit but require less fuel and quicker boil times than a traditional straight Ti pot and alcohol is this correct?

Lyle
06-25-2015, 07:41
I have the combination, but have not used it yet. I will be interested to read any responses you get.

Odd Man Out
06-25-2015, 13:03
Yes I use this combination. You can buy the exact same pot without the heat exchanger. I have sometimes thought about getting one just so I could test how effective they are. Otherwise, it is difficult to say how much of a difference they make.

However, it makes a big difference what kind of stove you use. With the Olicamp XTS pot, you must use a center-burning alcohol stove (flame in the middle) rather than a side burning stove (such as a Super Cat). I tried using the XTS with a super cat stove and it was a disaster. I think what happened was that unburned alcohol fumes condensed on the heat exchanger and then ignited so the whole bottom of the pot was on fire. I think this is because the heat exchanger extends down below the bottom of the pot and the jets on the side of the can to too close to the heat exchangers. With out enough space and air for the fumes to ignite they condense.

On the other hand, a stove with the flames in the center (using a pot stand to hold the pot an inch above the stove) works great. I use a home made Easy Capillary Hoop Stove. With that I can boil two cups of room temperature water wuth about 13 mL of methanol in about 3 minutes. Note that you must also use wind screen. I have a cylindrical screen made from aluminum flashing that is about 1/2" larger diameter than the pot and extends an couple of inches above the bottom of the pot. The system is efficient enough that the wind screen does not get very hot, indicating that very little heat is being lost.

Is the extra weight of the heat exchanger worth it? Hard to say. I think that would depend on what kind of stove you are using. If you are using a low power stove (such as a Zelph Starlyte) then you can probably get pretty good efficiency without a heat exchanger. If the pot can transfer heat at the same rate the stove is making heat then the heat exchanger won't add much. But if your stove is producing heat faster than it can be transferred to the pot, then the heat exchanger will help. the eCHS stove I use is a real blow torch of an alcohol stove so in my case the heat exchanger might help, but I haven't done the tests to measure its effect. I should also add that the air flow around the pot due to the wind screen also affects the rate of heat transfer into the pot. I know you can similar results without the heat exchanger using a cone shaped wind screen.

If I had to guess, I would say that you would be unlikely to recoup the excess weight of the heat exchanger by fuel savings unless you are very good at rationing your fuel usage. But I do like this pot for many reasons. It is a great size and shape. I really like a 1 L pot with a 1:1 height to diameter ratio. Not too tall and skinny and not to wide and shallow. This proportion maximizes volume to surface ratio and helps keep your food hot. Those are hard to find. Also, I can swap the handles for lighter ones (DIY from a clothes hanger). I like the anodized aluminum finish. Easy to clean. I can boil my food in my pot rather than just FBC, if I like. The lid fits tight (albeit a bit heavy). It has volume marking on the side.

zelph
06-25-2015, 16:31
I use the cobalt Blue Soloist under my Jetboil "sol" Companion cup that has the heat exchanger fins. The StarLyte stove should work well also.

http://www.woodgaz-stove.com/cobalt-blue-soloist-1.php

http://www.woodgaz-stove.com/starlyte-stove.php

Odd Man Out
06-25-2015, 21:38
OK, so I did some testing this PM. Tests were done in my kitchen. I know these are not field conditions but for testing we want consistent conditions. I used 20 mL of denatured alcohol (50/50 mix of ethanol and methanol) and 16 oz of room temp water. My thermometer battery died so I don't have water temp but I took the water samples from the same pot so they would be the same.

First I repeated the boil test with my standard system which is an eCHS stove, olicamp XTS pot, 3 1/18" tall pot stand, aluminum flashing wind screen that comes about 3/4" above the bottom of the pot with 1/4" air gap all around. The bottom of the pot about 2" above the top of the stove (1/2" higher than the pot stand because of the 1/2" tall heat exchanger.

For the other test I used a Kmart Grease Pot. It is a lightweight, thin aluminum pot with a flat bottom. It is slightly larger in diameter than the XTS (5 3/8" vs 4 1/2"). Because there was to heat exchanger, the bottom of the pot was 1/2" closer to the top of the stove (1 1/2" vs 2"). I have a larger wind screen to give about the same air gap and coverage up the side.

So for the results:

The Olicamp XTS test boiled in 3 min, 45 sec (in my last post I meant to say about 4 min, sorry). The fuel burned out in 6 min, 0 sec. Assuming a linear rate of fuel consumption (which I know to be reasonable from previous testing), it used 12.5 mL of fuel to boil the 2 cups of water (20 x 3.75/6.00).

The Grease pot test boiled in 4 min, 15 sec with the same burn time. Thus it took 14.2 mL of fuel to boil 2 cups or about 14% more fuel than the XTS.

So does the heat exchanger work? From this test, I would say yes, a little. Is it worth the extra weight and cost? That would be up to you. But keep in mind, in this test, the XTS pot used about 2 mL less fuel which is about 1.6 g or 0.056 oz of fuel savings. On my scale (which is crappy) the XTS pot with DIY handles is 6.25 oz plus 1 oz for the lid. The grease pot is 2.5 oz (no handle) plus 1 1/8 oz for the lid.

denimlabels
06-26-2015, 01:13
I am amazed that the eCHS stove boiled 2 cups in under 4 minutes. That stove must be a great fit for that pot. Thank you for running the test. How are the heat fins attached to the pot? Is it tig welded or just attached by force against the pot base? They need to come up with a Ti model.

Odd Man Out
06-26-2015, 10:22
I am amazed that the eCHS stove boiled 2 cups in under 4 minutes. That stove must be a great fit for that pot. Thank you for running the test. How are the heat fins attached to the pot? Is it tig welded or just attached by force against the pot base? They need to come up with a Ti model.

I don't know anything about welding so I can't say so I attached pics. The heat exchanger fins are underneath a cowling that extends 1/2" up the side of the pot and 1/2" below the pot covering the heat exchanging fins. The cowling also cover the bottom of the heat exchangers to provide a flat surface underneath.

The outer diameter of the base of the cowling is 4 1/2". The inner diameter of the cowling opening is 2 7/8". You need to make sure your pot stand is either small enough to fit inside the cowling (2 3/4" diameter) or large enough to fit on the cowling (3 3/4" diameter would be centered). Some of canister stoves have rather short pot support arms that may not be quite long enough to fit securely on the base of the cowling but also not short enough to fit inside the cowling on the base of the pot.

The cowling seems to be made of the same anodized Al that the rest of the pot is made from. It really is pretty bomb proof. You can see a matrix of 12 dots on side of the cowling which I assume are the welds holding it in place to the side of the pot. The zig zag heat exchanger is a thinner metal that seems to be attached to the bottom of the pot (as expected) but not the base of the cowling. Although thin, it is still very stiff.

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