Cold Tumbler Trouble ...

Jeepster47 · July 2015

Did a preliminary test today on the Yeti 20oz tumbler to dry run a cold fluid efficiency test. Not the best test location for a real world assessment ... my basement is at 69 degrees during the summer months. But, it's only a dry run ... right? Hmm ... got another "duh' result, that I should have, but didn't expect.

Left the lid off. Filled the tumbler with cold water and ice ... gave the fluid/tumbler time to fully stabilize slightly below 33 degrees. Set up the test equipment and removed the ice. Used my Flameboss 200 to record the data ... damn good thing 'cuz it took SIX hours for the fluid to warm up from 35 degrees to 45 degrees. Wow ... if you're drinking that slowly ... well, nobody drinks that slowly.

Image: https://us.v-cdn.net/5017260/uploads/editor/l2/ym6p2ey4rapb.jpg

After three hours, with the temperature up only 5 degrees, I started to question the equipment set up. Checked the fluid temp with a Thermopen and found a interesting result. The fluid was 45 degrees at the surface, 40 degrees a couple of inches down at the tip of the FB probe, and 35 degrees at 4.5 inches below the surface. With the tumbler and fluid motionless for three hours, the fluid had formed a smooth transition from warm at the top to cool at the bottom of the tumbler. Kind of a thermal black-and-tan.

Not sure how to measure and compare efficiency with cold fluids now. Not sure it really matters ... with cold fluids, it looks like any of the tumblers are more efficient than they need to be.

Your thoughts?

DoubleEgger · July 2015

It all sounds logical in a stationary test. Maybe a test where you remove some liquid on a fixed interval (taking a sip)? That's as close to real world as you'll get.

I would think the other one you tested would be off the charts due to it's size characteristics.

Thanks as this has been an interesting test you've been performing.

RRP · July 2015

Tom, I'm an accountant - not an engineer like you. Now, given that disclaimer should you question your hot results as well? Does the same layering principle apply? BTW how much longer before we see a listing in some Illinois university undergrad class of:

E 207 - Testing thermo insulated vessels - 2 semester hours - Professor Jeepster

Jeepster47 · July 2015

RRP said:

... Now, given that disclaimer should you question your hot results as well? Does the same layering principle apply? ...

@RRP ... The majority of the heat energy escapes out the top of the tumblers ... feel the stainless near the top and it'll be warmer than the bottom. Once the top layer gives up the energy and cools a little, it heads for the bottom. Thus, there is a constant thermal churning of the fluid when it's warmer than ambient temp.

When the fluid is cooler than the ambient temp, then the top layer, in a reverse manner, absorbs heat energy via the top of the tumbler. The warmed fluid simply stays at the top of tumbler ... thus, no thermal churning. If the tumbler isn't moved, nudged, or vibrated then you get the thermal layering that occurred today.

The missus went the professor route ... wasn't for me ...

Ozzie_Isaac · July 2015

Try a margahrita over ice. The nature of the floating ice cubes should keep the thermal gradient at a minimum.

wbradking · July 2015

I like the sound of a black and tan.

Jeepster47 · July 2015

Ozzie_Isaac said:

Try a margahrita over ice. The nature of the floating ice cubes should keep the thermal gradient at a minimum.

The test parameters have to be repeatable ... too many margaritas and test protocols tend to go out the door.

I'm thinking that a simple two point test might be okay. Start with the fluid cooled to a repeatable point (34 degrees for example), then let it set for a six hours, shake to equalize the fluid temperature, and measure the temp. Nothing fancy. Kind of like filling coolers with ice and peeking after 7 days to see how much ice is left.

Ozzie_Isaac · July 2015

Jeepster47 said:

Ozzie_Isaac said:

Try a margahrita over ice. The nature of the floating ice cubes should keep the thermal gradient at a minimum.

The test parameters have to be repeatable ... too many margaritas and test protocols tend to go out the door.

I'm thinking that a simple two point test might be okay. Start with the fluid cooled to a repeatable point (34 degrees for example), then let it set for a six hours, shake to equalize the fluid temperature, and measure the temp. Nothing fancy. Kind of like filling coolers with ice and peeking after 7 days to see how much ice is left.

Shaking introduces heat. Make sure you shake the same amount.

You also need to use the same volume of water in each test case.

Jeepster47 · July 2015

Ozzie_Isaac said:

Shaking introduces heat. Make sure you shake the same amount.

You also need to use the same volume of water in each test case.

I'm shaking right now ... with chuckles. This is a shade tree test, not an ISO referenced test.

I disagree on the volume of water ... the tumbler needs to be full for a viable comparison.

nolaegghead · July 2015

I think your test is fine (for a relative comparison) as long as the probe is at the same place - bottom. That's the most insulated part of the vessel.

Ozzie_Isaac · July 2015

Jeepster47 said:

Ozzie_Isaac said:

Shaking introduces heat. Make sure you shake the same amount.

You also need to use the same volume of water in each test case.

I'm shaking right now ... with chuckles. This is a shade tree test, not an ISO referenced test.

I disagree on the volume of water ... the tumbler needs to be full for a viable comparison.

If volumes are different then we need to compare joules instead of degrees. Otherwise largest volume has a considerable advantage.

It takes 4190 joules to raise 1 liter of water 1 deg.

nolaegghead · July 2015

@Ozzie_Isaac - The goal is to measure the insulation effectiveness on cold beverages - if I'm drinking out of a X oz mug, I'm putting X oz of adult beverage in it. There are many variables we're ignoring - the surface area to volume ratio if full, the diameter, length, etc. Obviously the perfect container to hold a volume with the least amount of insulation is a sphere, but as a real world test, lets use them with the volume they're designed to hold. We're leaving out the top since one is insulated and the other isn't. Plus I think most of us don't like to sip our beers through a slit.

grege345 · July 2015

id still like to see how it holds up against the others.

YukonRon · July 2015

Great evaluation, with interesting results, and the ensuing conversation was truly riveting.

My test: Does it hold a lot of beverage? Does it keep that beverage hot/cold for a really long time? Is it durable? Is it capable of withstanding poor judgement of inebriated souls? Does it limit waste by spillage due to previously mentioned inebriated soul? Does it fit ergonomically?

If the answers to these qualifiers are "yes," I buy and use. To keep ice in a tumbler for over 24 hours in the heat of this summer ( high 90s, low 100's everyday in July) impressed the heck out of me. I have spent more on vacuum bottles that did not perform as well.

Are there better tumblers to be had? Likely, I suppose, but I am not aware of that product. If so, I will send the Franklins flying when I become aware. (because I am just that OCD, and uncontrollable impulse spending is the only way I roll.)

lousubcap · July 2015

Nice test and assessment. Follow-on discussion enjoyable, likely aided by the fact that it is Friday AM. Regardless, thanks for the info.

Cold Tumbler Trouble ...

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