Quote from JedRothwell

AND, I expect this is the temperature of the inside wall of the calorimeter box. Not very hot. So maybe you should not worry about the insulation temperature? On the other hand, if the bubble foil falls off the wall onto the reactor (which is at 363°C), that might be a problem. I suggest you heat some metal up to ~363°C and hold a piece of bubble insulation up against it to see what happens. I expect the plastic will melt, but maybe nothing bad other than that. The stuff is probably engineered to avoid fire hazards.

Mostly worried about the insulation falling off the inside of the lid and onto the calibration cylinder. I may drill some tiny holes and string wire across the top to hold insulation in place. A fan failure could also cause dangerous problems, so I will install a thermal fuse in the box somewhere to cut power to the heater if it gets too hot where it shouldn’t be.

Quote from JedRothwell

Blower power (W)	3.84	From 1:40 to 5:00
St dev	0.0063
Blower (m/s)	4.25

That fixes the calculations up quite nicely.

Inserting the new velocity, at 32.1 C and 60 % humidity (a guess), the new recovery calculated is 77.635 %, which is reasonably close to what Mizuno reported (79 %).

Assuming dry air instead, the result is 78.135 % recovery.

Quote from Paradigmnoia

Using the outlet air temperature and 60 % humidity to determine air density, 1.448 kg/m3, the recovery result is 72.0189 %.

Mizuno computed Air weight (kg/s): 0.0171 from 1:40 to 5:00, including all kinds of factors. That's weight, not volume.

As I said, the recovery rate during that time was 78%. I wouldn't quibble over the difference between 72% and 78%. Call me nonchalant, but I just don't sweat the details. More or less is good enough for hand grenades and horseshoes!

Quote from Paradigmnoia

the new recovery calculated is 77.635 %, which is reasonably close to what Mizuno reported (79 %).

REASONABLY close?!? That's miraculously close. Suspiciously close. I'd check that again, it's so close.

(Since this is the Internet, and nobody knows you are a dog, I should explain that I think that's hilarious. Not a problem. https://knowyourmeme.com/memes…-nobody-knows-youre-a-dog)

Quote from JedRothwell

Mizuno computed Air weight (kg/s): 0.0171 from 1:40 to 5:00, including all kinds of factors. That's weight, not volume.

As I said, the recovery rate during that time was 78%. I wouldn't quibble over the difference between 72% and 78%. Call me nonchalant, but I just don't sweat the details. More or less is good enough for hand grenades and horseshoes!

REASONABLY close?!? That's miraculously close. Suspiciously close. I'd check that again, it's so close.

(Since this is the Internet, and nobody knows you are a dog, I should explain that I think that's hilarious. Not a problem. https://knowyourmeme.com/memes…-nobody-knows-youre-a-dog)

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The calculations should be miraculously close.

I am calculating Mizuno’s answers from Mizuno’s data.

Quote from Paradigmnoia

The calculations should be miraculously close.

I am calculating Mizuno’s answers from Mizuno’s data.

Yes. I was kidding.

So to summarize, it looks like Mizuno is calculating the air heat properly in this example, while I don’t like the example given in the 2018 power point where the mass of air and the air volume/s values seem quite wrong.

Fully outside insulated and recovery is now just barely 0.86, which is a definite improvement.

The insulation is noticeably warm to the touch near the top of the box, so improvements can be made.

The bubble foil package claims 96 % of radiant heat reflected, but nothing on conduction. There is a photo of the stuff lining the inside of a cooler, however,

(in case someone beams heavy IR at your cooler?)...

Still refining the velocity traverse methods..

.

From some interweb research, it seems that the bubble foil only has an R value of 1, or 2 if combined with an air space, even though it reflects 96-97 % of radiant heat.

So I will line the calorimeter box interior with 1” inch thick aluminum-faced PolyISO insulation board. That will add real insulation to the box.

Quote from Paradigmnoia

From some interweb research, it seems that the bubble foil only has an R value of 1, or 2 if combined with an air space,

Is that R-value in U.S. units or SI? In U.S. units it is 6 to 12. Perhaps it degrades over time, but it is not 1 or 2 according to the manufacturers. See, for example: U.S. Energy Products bubble insulation described at HomeDepot.com and:

https://www.reflectixinc.com/w…-6-Submittal-Rev-0618.pdf

Quote from JedRothwell

Is that R-value in U.S. units or SI? In U.S. units it is 6 to 12. Perhaps it degrades over time, but it is not 1 or 2 according to the manufacturers. See, for example: U.S. Energy Products bubble insulation described at HomeDepot.com and:

https://www.reflectixinc.com/w…-6-Submittal-Rev-0618.pdf

That stuff is an inch thick, and should show an R of 3 per inch. The manufacturer manual claims that to achieve R 6, this wrap must be installed with a 3/4” air gap between the wrap and the duct. (I believe that it is actually illegal to advertise R values of a material that require an assembly to achieve a specific R rating. The material only rating is allowed.)

As the information I received is in R units, rather than RSI, I assume that the ratings are Imperial.

See page 14 here: https://www.reflectixinc.com/w…-for-the-Pro-Rev-0210.pdf

Note that the manufacturer claims that doubling the wrap to two layers, without an air gap between them, only adds another 1.1 to the R rating. If there was real insulating ability, doubling the thickness would double the R value.

Quote from Paradigmnoia

That stuff is an inch thick, and should show an R of 3 per inch.

I looked up the R-rating of material very similar to what Mizuno uses at HomeDepot.com, and I asked the Japanese distributor. They said it was 11.

Quote from JedRothwell

I looked up the R-rating of material very similar to what Mizuno uses at HomeDepot.com, and I asked the Japanese distributor. They said it was 11.

RSI of 11 maybe. Divide by 5.68826 to convert to R (basically 2). Unless those bubbles are filled with low conductivity gas, there is only weak insulation value from any bubble wrap. The reflectivity only works on radiated heat, although it will prevent radiation of the heat conducted into it.

See the Home Depot website. I do not think these products would be advertised with a much higher R-value than they really have. Regulators would frown on that.

Reflectix

16 in. x 100 ft. Double Reflective Insulation Roll with Staple Tab Edge

https://www.homedepot.com/p/Re…ab-Edge-ST16100/202851859

• R-values range from R-3.7 to R-21 depending on application

Everbilt

48 in. x 25 ft. Double Reflective Insulation

Insulation R-value 21

https://www.homedepot.com/p/Ev…-ADD04-1220x7-5/307281317

Quote from JedRothwell

See the Home Depot website. I do not think these products would be advertised with a much higher R-value than they really have. Regulators would frown on that.

Reflectix

16 in. x 100 ft. Double Reflective Insulation Roll with Staple Tab Edge

https://www.homedepot.com/p/Re…ab-Edge-ST16100/202851859

• R-values range from R-3.7 to R-21 depending on application

Everbilt

48 in. x 25 ft. Double Reflective Insulation

Insulation R-value 21

https://www.homedepot.com/p/Ev…-ADD04-1220x7-5/307281317

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Regulators do frown on it, but they have limited funds to do any enforcement and require a complaint to act on, if they were to act at all. And these ads probably cross the line of insulation value regulations, if not walk a tightrope down it. Look at the directions for R-21. The R-21 system is an assembly value, with two layers and two large air spaces, as well as extensive air sealing.

Notice that on your second link, the product claims to be 0.25 inch thick, with an R21 rating, which is clearly bullshit. Every house would use it if that were true.

Well, anyway, the R-value is measured with a calorimeter. It is the ideal system to measure it. So you will find out whatever the R-value is for whatever insulation you use.

It does not actually matter. As long as you know how much heat is being lost, and as long as it is consistent and reasonably linear, it can be accounted for. Less is somewhat better, but not crucial.

Quote from JedRothwell

Well, anyway, the R-value is measured with a calorimeter. It is the ideal system to measure it. So you will find out whatever the R-value is for whatever insulation you use.

It does not actually matter. As long as you know how much heat is being lost, and as long as it is consistent and reasonably linear, it can be accounted for. Less is somewhat better, but not crucial.

The main thing is that the rigid insulation, besides being real insulation, is rigid so it can be installed inside the box without much fuss about keeping it from falling onto the heater. It will also keep the acrylic cooler, which is increasingly important as the heater power is increased.

Quote from RobertBryant

The insulation value of the aluminium foil under my hot steel garage roof is due to its low emissivity rather than its reflectivity.

Perhaps you mean reflectance..

Thank you for your pedantic and yet imprecise comment.