The Jetboil Joule cooking system is a liquid-feed canister, high-volume cooking system.
Liquid feed canister systems take advantage of the canister in an inverted configuration to deliver liquid fuel to the burner, in contrast to upright canister systems, which deliver fuel as vaporized gas to the burner.
The primary advantage of a liquid feed canister system is that it offers better cold weather performance, since the vapor pressure in the canister isn't changing while the stove is operating.
In upright canister systems, as the vapor pressure in the canister decreases, the canister temperature decreases, and the rate of fuel delivery to the burner decreases.
Thus, upright canister systems don't work so well in the cold, or for boiling large volumes of water at cooler ambient temperatures.
The Jetboil Joule attempts to solve this problem not only by inverting the canister, but also by preheating the liquid fuel before it hits the burner, which allows it to maintain power in cold temperatures.
In addition to the inverted canister configuration and the preheated liquid fuel delivery tube, the Jetboil Joule pot has an integrated heat exchanger, which allows for more efficient heating of the pot, and greater fuel efficiency.
The other unique feature of the Jetboil Joule is that it's an integrated system that consists only of two parts - the stove base and the pot - which connect to each other to make one solid unit during operation.
There are no separate parts such as windscreens, fuel pumps, or external heat exchangers, and the entire stove unit - with an attached fuel canister, nests neatly into the pot for space efficient storage.
ARTICLE OUTLINE
- Overview
- Features & Specifications
- Table 1. System Specifications (Comparison of Jetboil Joule & MSR Reactor 2.5L System)
- Using the Stove
- Baseline Fuel Efficiency
- Table 2. Baseline Comparison of the Jetboil Joule and MSR Reactor: Boil Time & Fuel Efficiency
- Observations
- Preliminary Assessment
# WORDS: 1270
# PHOTOS: 6
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Discussion
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Companion forum thread to:
Jetboil Joule Review – Part 1, Overview
I don't think I will be getting one antime soon. 27oz+ is way too heavy.
^^^^
But not to bad if you're with 5 others doing group cooking.
It's the right tool for that job.
But that's not My job.
and in the winter when the inverted canister would be very useful
Ya know, I usually only go with myself and sometimes one other person I call me.
Wow. It's a bit expensive too. $200 at http://www.rei.com/product/868190/jetboil-joule-group-cooking-system
Meh.
Roger Caffin's inverted canister stove cost me $144.00, and I still need to supply my own pot (such as the Primus ETA 1.8L pot for $55.00)
The MSR Reactor is also a $200.00 stove.
An MSR Dragonfly white gas stove would cost $140.00. A Primus 1.8L ETA heat exchanger pot would cost an additional $55.00
I'd say this is right in line with similar products on the market designed for winter use.
How does its fuel efficiency compare to other canister stoves?
THAT'S the real question for longer group trips.
9.5g of gas for a liter of water seems pretty good. My cheapo gas stove uses 7g for half a liter.
From Roger's article http://www.backpackinglight.com/cgi-bin/backpackinglight/canister_stove_efficiency_p3.html
average upright canister stove was 11.6 g/L, four Jetboil models were between 8.5 and 9.5 g/L, Reactor was 10.5 g/L
From this (Ryan's) article Jetboil and Reactor were 9.5 g/L
So Roger and Ryan are pretty consistent on the Jetboil (although Roger didn't measure the inverted Jetboil). Roger measured Reactor 10% higher than Ryan.
In Roger's article, the Jetboils used about 20% less fuel than average upright.
You got to read the article – has a bunch of different stoves…
I think this measurement is tricky. Hard to compare two different experimenters – any difference might just be the way they measured it. Roger's measurement where he uses same test set-up to measure different stoves is more valid.
There are a lot of variables that can effect the efficiency numbers. Oxygen content of the air will effect the efficiency of the burns. Humidity. Ambient temperature. Surface you put the stove on. Height of the burner/pot. Etc… 10% is within tolerance. I usually give these numbers a spread, min, max and average. I call 15% a significant deviation to account for the crudity of most tests. For example, depending on weather you have a burner on high, medium or low, but there is no set definition for these terms. People eyeball the medium setting. High is the maximum for a stove, but this can vary between 4500BTU and 11000BTU. Low can sit there forever without boiling a liter of water, yeilding inconclusive results. Some stoves will not run evenly on lower settings (Simmerlite for example.) And, how low is low? Too low will drive *up* fuel consumption.
I usually try for a 10-12 minute burn for a half liter. This usually produces the best fuel efficiency. Longer means more heat is radiated out. A 20 minute burn for one liter is barely tolerable, though. If you want a 10 minute burn, you will use more fuel. This is assuming all else remains the same: pot, lid, distance, heat screen, etc. For 2 Liters, the numbers can get worse. At least with the Joule, it will make a good cold weather stove(<20F) for a larger group(>4 people.) I think this is where Ryan is headed with this. For me, myself and I, well, we have no use for it. But it is interesting to read about these little toys.
Yeah
Roger's stove is probably better for really cold temps. If you don't want to fiddle with putting canister in a bath of water or … It weighs less and you'll never make up for the added weight with improved efficiency on the Jetboil
For 1/2 liter or 1 pint, I figure 3 minutes on fairly high, or turn to medium and it takes 5 minutes but saves 10% of the fuel
"For me, myself and I, well, we have no use for it."
Interesting how many solo hikers there are on BPL. Reaction to working in "the Dilbert world"?
I will be very interested in seeing how the Joule actually performs in cold weather. It could well be the ultimate snow melting machine! The time difference with the Reactor shown here is astounding.
The other feature that seems promising for winter use is that the burner is high above the ground, so you could hopefully use a less heat resistant stove base as well as having less melting of the snow under the stove.
It also looks like it could work well as a hanging stove.
The big question for me when looking at the design is how well the flame control works in cold weather, since it is on the liquid fuel line, not on the vaporized part at the top.
However, for winter use I don't do a lot of simmering or fine cooking, so as long as it can be turned down far enough to prevent the snow from scorching, it's acceptable to me.
There's an alpinist hanging kit for $20 that includes a windscreen. Would also be interesting to see if the wind screen afects CO2 performance.
http://www.jetboil.com/Products/Joule-Alpinist-Kit/
How useful is a regulator on a liquid feed stove like this? Could a significant amount weight and $$$ be saved by eliminating it?
Thanks for the review, looking forward to the cold weather assessment.
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