Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-01-2025, 16:31   #1
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Insulation

While I'm no where near needing it as my current frig/ freezer is still working well - knock on wood - it is an old system. My boat is 40 years old, I'm not sure how old my Adler-Barbor system is, but may be 20 years old or might even be original to the boat. So I can foresee I may well have to deal with changing it out in the foreseeable future. Hopefully not but....

In all the threads on refrigeration, one thing everyone always agrees on is how well insulated the box is, the better.

But no one talks about types of insulation. It seems spray foam and similar products are what are recommended.

It's always perplexed me as to why no one has ever explored the types of insulations used in cryogenics. There are three fundamental types used, the one that could be done by an individual fairly simply is called MLi (Multi-Layer Insulation).

MLI can achieve R values of about 1440 per inch. OK - that's not a typo. That's about the equivalent of roughly 200 inches of closed cell foam insulation.

Given the space constraints on especially small boats, and the energy requirements needed to run refrigeration I'm surprised no manufacturer has explored using this type of insulation. Neither do I hear of folks building their own boxes using it.

Is there a good reason for this? I find it very perplexing but figure maybe there is some obvious reason I'm missing. Anybody know?

dj
dlj is offline   Reply With Quote
Old 12-01-2025, 18:22   #2
Registered User

Join Date: Nov 2015
Boat: R&C Leopard 40
Posts: 1,030
Re: Insulation

First information I came across said it works best in a vacuum, like space, not like on your boat. Find a price for something that works on Earth. I couldn't locate pricing.

The best is typically Aerogel/Cryogel-Z.

I suspect anything that could be used would be prohibitively expensive, or it would be in use already.
__________________
-Chris
FlyingScot is offline   Reply With Quote
Old 12-01-2025, 18:46   #3
Registered User

Join Date: Aug 2021
Location: PNW
Boat: 35 Ft. cutter, custom
Posts: 2,934
Re: Insulation

Quote:
Originally Posted by dlj View Post
Given the space constraints on especially small boats, and the energy requirements needed to run refrigeration I'm surprised no manufacturer has explored using this type of insulation. Neither do I hear of folks building their own boxes using it.
In a word, money.
An outfit I worked for was playing around with Aerogel/Cryogel/vacuum panel stuff for boat refrigeration 40 years ago.
Actually, in some ways it made more sense than now, as the cost of both the production and storage of energy was relatively higher than now.
Before boats had high output alternators, Lithium batteries, and an acre of solar panels, anything to reduce refrigeration energy use would be more than welcome.
A well-made reefer box using foam and with a good sealing top is still a pretty cost-effective way to go and is low-tech enough for DIY.
With the proliferation of better devices for energy production and storage a few extra amp-hours for daily refrigeration needs isn't such a big deal as it once was.
__________________
Beginning to Prepare to Commence
Bowdrie is offline   Reply With Quote
Old 12-01-2025, 19:07   #4
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by FlyingScot View Post
First information I came across said it works best in a vacuum, like space, not like on your boat. Find a price for something that works on Earth. I couldn't locate pricing.

The best is typically Aerogel/Cryogel-Z.

I suspect anything that could be used would be prohibitively expensive, or it would be in use already.
It works on earth - it's used all the time on dewars and pipelines etc. What has lead me to think about it is that I use a dewar almost every day. It sits next to one of my microscopes.

What's the R factor of Aerogel/Cryogel-Z?

dj
dlj is offline   Reply With Quote
Old 12-01-2025, 19:22   #5
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by Bowdrie View Post
In a word, money.
An outfit I worked for was playing around with Aerogel/Cryogel/vacuum panel stuff for boat refrigeration 40 years ago.
Actually, in some ways it made more sense than now, as the cost of both the production and storage of energy was relatively higher than now.
Before boats had high output alternators, Lithium batteries, and an acre of solar panels, anything to reduce refrigeration energy use would be more than welcome.
A well-made reefer box using foam and with a good sealing top is still a pretty cost-effective way to go and is low-tech enough for DIY.
With the proliferation of better devices for energy production and storage a few extra amp-hours for daily refrigeration needs isn't such a big deal as it once was.
Yeah, I understand money could be an issue for commercial applications - but that's because it's labor intensive to build. Without a large commercial market it would be difficult to ramp up a commercial production line. But DIY, if you don't consider your time, would be quite inexpensive to build. The materials are not expensive.

Thinking about my current box, I have about 4" of insulation. No idea if good bad or indifferent quality as it's 40 years old. Just reducing that to 1" thick insulation with a substantial increase in R value would give me some very nice options I don't currently have.

So besides cost, and I'd build it myself, what downsides are there?

dj
dlj is offline   Reply With Quote
Old 12-01-2025, 20:28   #6
Registered User

Join Date: Aug 2021
Location: PNW
Boat: 35 Ft. cutter, custom
Posts: 2,934
Re: Insulation

Quote:
Originally Posted by dlj View Post
So besides cost, and I'd build it myself, what downsides are there?
dj
Ok, you've got a factory produced boat, it probably has a molded fiberglass ice box that foam was sprayed onto.
Now you want to destroy the factory countertop and cabinetry and tear out the box and get rid of the foam so you can reduce from 4" to 1" of insulation?
And then have to rebuild the whole works and hopefully it will end up looking like a factory job. Why? to satisfy yourself? If so, go for it.
Here's one of the sneaky details:
The fiberglass box will condense the water out of any air that comes into contact with its outside surface.
The factory spray job, (or you pouring liquid foam directly on its surface,) closes-off all air contact from the surface.
You can't get that hermetic seal with just wrapping or glueing some miracle insulation product to the box with all its radii and slopes/corners.
You still need to have a good spray foam or poured foam "sub-surface" that's thick enough to stop condensation that you can add your miracle product onto.
No free lunch even with "free" time.
__________________
Beginning to Prepare to Commence
Bowdrie is offline   Reply With Quote
Old 12-01-2025, 21:54   #7
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by Bowdrie View Post
Ok, you've got a factory produced boat, it probably has a molded fiberglass ice box that foam was sprayed onto.
Now you want to destroy the factory countertop and cabinetry and tear out the box and get rid of the foam so you can reduce from 4" to 1" of insulation?
And then have to rebuild the whole works and hopefully it will end up looking like a factory job. Why? to satisfy yourself? If so, go for it.
Here's one of the sneaky details:
The fiberglass box will condense the water out of any air that comes into contact with its outside surface.
The factory spray job, (or you pouring liquid foam directly on its surface,) closes-off all air contact from the surface.
You can't get that hermetic seal with just wrapping or glueing some miracle insulation product to the box with all its radii and slopes/corners.
You still need to have a good spray foam or poured foam "sub-surface" that's thick enough to stop condensation that you can add your miracle product onto.
No free lunch even with "free" time.
I don't think my boat would be considered a "factory made" boat. But no matter, the various considerations of condensation, finish and such are noted.

It's also obvious your knowledge of MLI cryogenic insulation is pretty limited. That's also fine, I'm am looking for feedback and I'm getting it.

I'll also note, for reasons i don't understand, it seems discussions within the refrigeration subject seem to illicit rather hostile responses. No idea why that is...

dj
dlj is offline   Reply With Quote
Old 13-01-2025, 03:33   #8
Senior Cruiser
 
GordMay's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 51,780
Images: 241
Re: Insulation

Multi-Layer Insulation reduces heat loss by thermal radiation, but it does not appreciably insulate against heat conduction or convection. It is therefore commonly used on satellites, and cryogenic applications, in a vacuum, where radiation dominates.

“Multilayer Insulation Material Guidelines” ~ by M.M. Finckenor, NASA’s Marshall Space Flight Center
https://ntrs.nasa.gov/api/citations/...9990047691.pdf
Quote:
Originally Posted by NASA
“... MLI requires an atmospheric pressure of <10 -5 torr to prevent convection and gas conduction between radiation barriers. At pressures > 10 -5 torr, the conductivity of the MLI quickly reverts to approximately the conductivity of air, thus degrading the MLI blanket's protection. ...”
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is online now   Reply With Quote
Old 13-01-2025, 05:03   #9
Registered User

Join Date: May 2020
Posts: 108
Re: Insulation

I think there are two aspects: Space and Energy


If you primary concern is energy, consider adding a solar panel
If you primary concern is space (maximize usable space), then thinner and better insulation will help you.


In the end you get a cool fridge by removing more heat than what gets in (via insulation, lid opening, adding warm things). Heat ingress is minimized by good insulation and a good seal on the lid. Removing heat is simply a function of how much energy you use to run your compressor (assuming the system is kept in good order).


Improving you insulation is a question of where you start from. If your current one is not working at all, then adding a cheap foam panel will be a big improvement already. If you already have 2 inches of perfectly sealing foam, then another inch will be less of an improvement.



On our boat we went the simple route: Add foam between box and cabinetry. We used a mix of panels and spray foam for the last gaps. This ensured we could remove the if we ever needed to. I did investigate vacuum panels, but dropped that idea because of cost and simplicity of just using foam.



On the energy side a simple improvement is to make sure the compressor gets enough air to cool the compressor itself and the heat exchanger. If they work in a closed hot compartment, they cannot be efficient.
barnab is offline   Reply With Quote
Old 13-01-2025, 09:28   #10
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by GordMay View Post
Multi-Layer Insulation reduces heat loss by thermal radiation, but it does not appreciably insulate against heat conduction or convection. It is therefore commonly used on satellites, and cryogenic applications, in a vacuum, where radiation dominates.

“Multilayer Insulation Material Guidelines” ~ by M.M. Finckenor, NASA’s Marshall Space Flight Center
https://ntrs.nasa.gov/api/citations/...9990047691.pdf
Essentially all insulation that has extremely high R values requires vacuum. I have a report from NASA ranking the various insulations that talks to this. They do list the material that provides the highest R values without using vacuum which I may investigate but it's likely quite expensive. The materials to manufacture MLi are very inexpensive. I own the equipment to create the vacuum so while that would be a stumbling block for many, not so much for me.

There are three forms of heat transfer: conduction, convection, and radiation. In order to attain these very high R values, all three must be controlled.

I have dissected liquid nitrogen dewars. The ones I've looked at use MLI. They obviously have an extremely high R value in the environment we live in - they don't require space to function.

dj
dlj is offline   Reply With Quote
Old 13-01-2025, 10:04   #11
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by barnab View Post
I think there are two aspects: Space and Energy


If you primary concern is energy, consider adding a solar panel
If you primary concern is space (maximize usable space), then thinner and better insulation will help you.


In the end you get a cool fridge by removing more heat than what gets in (via insulation, lid opening, adding warm things). Heat ingress is minimized by good insulation and a good seal on the lid. Removing heat is simply a function of how much energy you use to run your compressor (assuming the system is kept in good order).


Improving you insulation is a question of where you start from. If your current one is not working at all, then adding a cheap foam panel will be a big improvement already. If you already have 2 inches of perfectly sealing foam, then another inch will be less of an improvement.



On our boat we went the simple route: Add foam between box and cabinetry. We used a mix of panels and spray foam for the last gaps. This ensured we could remove the if we ever needed to. I did investigate vacuum panels, but dropped that idea because of cost and simplicity of just using foam.



On the energy side a simple improvement is to make sure the compressor gets enough air to cool the compressor itself and the heat exchanger. If they work in a closed hot compartment, they cannot be efficient.
All good points.

As far as space and energy - I'm looking to maximize space and minimize energy use. I already have a solar panel and wind generator. If I do an energy source upgrade I'll likely add in Watts and Sea as currently my biggest energy concern is during passage making and running all my electronics. At anchor, I can go sometimes up to a month, sometimes only a week depending upon solar and wind availability. I'd love to make that an unlimited time period.

Additionally, the less a unit cycles, the longer it should live, seems to me anyway but that could be wrong.

As I stated in my original post, my current system is somewhere between 20 and 40 years old and while it's currently running well, in fact really well, I'm looking towards the future when that may no longer be the case. Hopefully this is merely an academic conversation. I'd love to never have to rebuild my refrigerator/freezer. But let's be realistic ...

If I have to change out my current Adler Barbour system, it's going to be pretty invasive given how it was built. Additionally, the galley in my boat is quite small - something I'm looking at redesigning. In short - this discussion is simply one small component of s much larger overall part of my long term plan for this boat.

I wonder is there is a limit to how much insulation is really needed. Let me explain. Let's say you have a freezer that is opened once a week. When it's opened, there is an amount of energy needed to reestablish temperature simply from that act. The amount of insulation that would be optimal, would be such that at that one week time frame, you'd have to run your compressor anyway. Having more insulation is a waste since given the heat loading through the door being opened will require the compressor to run anyway. Do you see what I mean?

Our current level of insulation is such that the compressor needs to cycle just sitting there to compensate for thermal losses. Hmmm....

Now 1 inch of MLI has an R1440 - maybe all I need is to build 1/2 inch panels attaining an R700 approximately. That is still substantially better insulation than currently being used. Recall, most current refers are running with insulation levels of R40 or R50 on the high side...

dj
dlj is offline   Reply With Quote
Old 13-01-2025, 11:26   #12
Registered User

Join Date: Nov 2015
Boat: R&C Leopard 40
Posts: 1,030
Re: Insulation

Quick web search on dewar storage devices show they use "vacuum" between the stainless steel layers. Think Yeti mugs, or many other popular brands.
https://demaco-cryogenics.com/blog/c...storage-dewar/

People seem to be confusing made to work in the vacuum of space (or other locations where a deep vacuum is created) and the use of vacuum (think Yeti mugs or Vacuum Insulated Panels). People do use VIPs in boats, but I'm told many find they to fail prematurely.

So what type of insulation does your dewar container have?

If this is a roll of material you can just place 10mm of and have incredibly high R values that work at normal freezer temperatures and atmospheric pressures at sea level, something tells me this would have already taken over every insulation use case in the world. But that hasn’t happened and I’m sure there is a very good reason for that.
__________________
-Chris
FlyingScot is offline   Reply With Quote
Old 13-01-2025, 11:33   #13
Registered User

Join Date: Apr 2022
Posts: 12
Re: Insulation

As Gord pointed out, MLI is only useful for reducing heat loss due to thermal radiation. This is why it's used within vacuum spaces as insulation. Yes, you can 'wrap' your refrigerator in MLI, IF you are confident that you can create a vacuum space around it. You'd want to qualify the leak rate to ~ 10-9 torr, which isn't really practical on a DIY setup.
Let's say that you do have access to the equipment that will allow you to build a box like this, it's probably going to be out of fiberglass and epoxy. The smallest of the most minor of leaks (think a 10-8 torr leak and easy to do in fiberglass) will spoil the vacuum. I.E. allow water, mold, bacteria to enter the vacuum space. At which point the MLI acts as a giant sponge and/or growing medium and ANY/all insulating probertites disappear.
To make the vacuum space effective, you'd have to build it out of stainless steel or aluminum, which have their own issues in a salt-water environment.

-silverlark
Silverlark is offline   Reply With Quote
Old 13-01-2025, 12:07   #14
dlj
Registered User
 
dlj's Avatar

Join Date: May 2020
Location: Warwick NY
Boat: Belliure 41
Posts: 869
Re: Insulation

Quote:
Originally Posted by FlyingScot View Post
Quick web search on dewar storage devices show they use "vacuum" between the stainless steel layers. Think Yeti mugs, or many other popular brands.
https://demaco-cryogenics.com/blog/c...storage-dewar/

People seem to be confusing made to work in the vacuum of space (or other locations where a deep vacuum is created) and the use of vacuum (think Yeti mugs or Vacuum Insulated Panels). People do use VIPs in boats, but I'm told many find they to fail prematurely.

So what type of insulation does your dewar container have?

If this is a roll of material you can just place 10mm of and have incredibly high R values that work at normal freezer temperatures and atmospheric pressures at sea level, something tells me this would have already taken over every insulation use case in the world. But that hasn’t happened and I’m sure there is a very good reason for that.
The "fail prematurely" is a concern. The dewars I've worked with over numerous decades have never failed, but I do know of cases where they have. But manufactured properly, there should not be a failure rate of any notable level. I would not be surprised if the problem faced you mention may more likely be due to attempted lower cost manufacturing short cuts to keep costs down. I am not concerned with costs at this point - I'm not selling them nor plan to. They are strictly for my personal use.

No it's not a roll of material you can just lay out it's complicated to build properly - it will never take over as a commercial product - that is not my focus.

My focus is a one off custom made insulation system.

My fundamental question is if achieving this kind of high R value insulation is actually worth the effort. Threads on refrigeration consistently say more insulation is better. So this would be at an insulation level well beyond the current state of the art on boats.

dj
dlj is offline   Reply With Quote
Old 13-01-2025, 12:17   #15
Registered User

Join Date: Nov 2015
Boat: R&C Leopard 40
Posts: 1,030
Re: Insulation

Quote:
Originally Posted by dlj View Post
The "fail prematurely" is a concern. The dewars I've worked with over numerous decades have never failed, but I do know of cases where they have. But manufactured properly, there should not be a failure rate of any notable level. I would not be surprised if the problem faced you mention may more likely be due to attempted lower cost manufacturing short cuts to keep costs down. I am not concerned with costs at this point - I'm not selling them nor plan to. They are strictly for my personal use.

No it's not a roll of material you can just lay out it's complicated to build properly - it will never take over as a commercial product - that is not my focus.

My focus is a one off custom made insulation system.

My fundamental question is if achieving this kind of high R value insulation is actually worth the effort. Threads on refrigeration consistently say more insulation is better. So this would be at an insulation level well beyond the current state of the art on boats.

dj

The potential failure of the vacuum is what has likely stopped everyone up until now.

People don't say the more R value the better, at least the ones I've read. 30-50 range seems to be the top. Diminishing returns.

Building an entire cabinet structure that can live in the salty marine boat environment seems a challenge and maintain it's vacuum over decades seems to be a challenge. I hope you try it and succeed.
__________________
-Chris
FlyingScot is offline   Reply With Quote
Reply

Tags
insulation

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Engine Room Insulation (Long Question) Zach Engines and Propulsion Systems 21 06-08-2010 19:03
Hull Insulation SkiprJohn Construction, Maintenance & Refit 12 21-10-2009 13:00
icebox insulation Connemara Plumbing Systems and Fixtures 6 28-09-2007 06:58
Engine room insulation? Strygaldwir Engines and Propulsion Systems 22 26-11-2006 10:34
Engine Compartment Insulation Longhair Engines and Propulsion Systems 8 29-03-2006 06:46

Advertise Here


All times are GMT -7. The time now is 05:45.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2025, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.