Vacuum Insulated Composite Panels

[DzlToy]

Doing some research for a potential client a few months back and came across an article detailing Panasonic's "U-Vacua" panels. I saved the link and forgot about it. Last night, while going back through my notes looking for something else, I came across it again. So, off on a tangent I go and quickly found that these things are pretty damn impressive and they aren't nearly as expensive as one might think. Depending on what you are comparing them to, they could be a bargain, especially when performance is factoured in.

I found a list of manufacturers in a trade journal and set to calling sales departments. The first company was Nano Pore out of Albuquerque NM. I spoke with their Regional Sales Director Rodney who kindly answered all of my questions and even offered to send me a free sample of their material.

Now for the good stuff:

Panels can be made upto 1.5" thick and cost in the $10-$20 per square foot range depending on the type of panel you order. Everything is built to your application by size. The panels are not structural so they will need a "backing" on both sides, no different than a residential style SIP (Structural Insulated Panel) which is commonly made using OSB and EPS foam.

The R value (thermal resistance) is approximately 40 PER INCH. That's right, R-40 for a one inch thick panel. Rodney suggestion for an RV, Trailer or Expo application was to bond the VIPs to a sheetmetal, offering some abrasion resistance from tree branches, road debris and the like, but almost any thin composite or metal sheeting could be used. The same would be done on the inside with an eye towards interior finish, thereby eliminating the need to finish the wall seperately. It could be stainless, copper, Luan plywood or book matched fiddleback Walnut for all I care.

Their site is http://www.nanopore.com/vip.html and he was very interested in my inquiry. He mentioned several meetings with people in the RV industry and they cant seem to get their head around a one inch thick panel with an R value of 40. For an expedition truck or trailer where weight, space and insulation are at a premium, this could be a game changer. There are many marine and space tech composite derivatives that cost several times what these panels cost without offering the R value and K value thereof.

Discuss.

EDIT: some other sites are http://www.microthermgroup.com/low/EXEN/site/vip-intro.aspx – 20mm panel = R40 and http://www.panasonic.com/industrial/appliances-hvac-devices/vacuum-insulation/panel.aspx

 

[gait]

nice find.

I built my very efficient compressor fridge using 25mm vacuum insulated panels about 5-6 years ago. At the time there was really only one company in US making small quantities of custom size panels at economic price. Air freight was as much as the panels. Given the price of solar panels at the time it was cost effective. Their target market was the marine industry. They stopped a couple of years ago. Also somewhere along the line I think Dow stopped making the foam.

Electrolux at the time had a prototype / near production fridge that relied on a small vacuum pump to maintain the vacuum. I can't find reference to it now. Panasonic had reached production stage but fridge was top end of the market and only available in Japan. Nice to see they have made another step.

As well as the foam panels there's aerogels. Fascinating stuff, I believe its now made into panels and blankets.

The EU has a lot of work behind the scenes in their energy star system but have struggled to motivate fridge manufacturers to use VIPs. I believe Germany in buildings have a combination of VIPs and phase change materials to insulate and store energy to maintain relatively constant temperature. Getting there slowly.

I didn't get to the second part of my fridge efficiency which would be a phase change material around the evaporator. Ethylene glycol and water weren't good enough for me. Melts over a temperature range not a single temperature like ice. At the time a sample size from China would be one tonne. Phase change materials have since become more available.

VIPs and PCMs are used extensively in vaccine distribution cold chains in Africa and other developing places where there's a lack of electricity.

My panels have worked in rough conditions (middle of Aus and Malaysia to Europe and back via all sorts of nasty bumpy twisty places) without apparently leaking. There are some tricks in building the carcass as in a normal carcass the foam insulation is part of the strength which is not available with VIP (for the diy). There's also the corners to consider. And of course abrasion of the panels.

Bottom line - I have a 150 litre compressor fridge freezer that's been running for 5+ years with the energy consumption of about a commercially available 50 litre RV fridge. Energy requirement is a function of surface area (not volume). Apart from a sphere the most efficient is a cube. My fridge reaches the back of my bench so I have drawers to make access easier. Which of course helps prevent movement of air and a further loss of efficiency.

I don't talk about it too much these days. As DzlToy says there's a bit of incredulity among RV industry and owners. Even with the data its an uphill struggle against dominant design (that term is worth a google also).

And so on.

 

[dlh62c]

...mentioned several meetings with people in the RV industry and they can't seem to get their head around a one inch thick panel with an R value of 40.

I can see the product being a hard sell to the RV industry since it lacks a backing on both sides to make it useable as a structural component. When I first read your post, my first thought was; How can I build a structure out of it? Once I saw that you couldn't, in its standard form, my interest wavered.

 

[DzlToy]

It would not be difficult IMO to build a composite panel out of the VIP's and use them essentially the same way that one would use a foam core, which is not structural either.

On the exterior of the box, you would have something like a 14-16 gauge aluminum, then the VIP, then on the inside you would have a Luan plywood, plyboo, stainless or whatever you wanted the inside of your box to be. Glue it all together with some Sikaflex and you have a composite panel that is about an inch thick with an R value of 40 or more. Not a five minute $500 RV box for sure, but we are talking about custom fab here or motivated/talented DIYer. I have seen plenty of "drop on" boxes for sale in the low six figure range (new) and they dont have half the sound attenuation and R/K value these panels have. I have seen custom builds on this site that took years of time and tons of money and while they are very nice when completed, they are typically not an inexpensive endeavour.

Judging from the poor construction quality that I saw at an RV show a few weeks ago, even in coaches costing 250- 350 thousand dollars, I would not expect anyone but the highest end builders to be interested in these products. Depending on your location, 350 grand buys a nice to decent house. A 40 foot x 8 foot box (320 square feet) that costs 350 grand should be top quality construction not camping world windows and home depot cabinets. JMO

EDIT: I did research the aerogels and nano gels as well. I found a 10mm thick blanket in a 60 foot roll that was about $5 per square foot. It had an R-value of 10 per inch. You are now at least $10 per foot (price of vacuum panels) but only half the R value (25.4 mm in an inch, so you need at least two layers of blanket).

 

[gait]

I used 2mm food grade polypropylene sheet for inside. I had a commercial hand plastic welder from making water tanks. Outside is 3mm Dibond (polyethylene with very thin Al faces with baked enamel finish). PP sheet and Dibond can be bent after making groove with flat bottomed 45deg router bit. PP shallow groove and heat to assist bend. A bit of practice to achieve engineering tolerances. My panels had a raised 50mm dia bit on one side. A few mm of polyurethane foam each side of panels and to fill corners. Panels wrapped in foam wrap to limit abrasion. Built outer carcass, install panels, slide in inner carcass, pop rivets, feed refrigerant pipes and wiring (for light and thermostat) through space left by vip, add self adhesive magnetic strip to where door seal meets polypropylene. Plan how to attach evaporator, shelves/drawers, door hinges, and door catch so as not to puncture panels.

The good fit in the bench provided additional rigidity. If I did it again for the outer carcass I'd probably use the same fibreglass/foam panel used for the house and make it explicitly part of the bench structure.

Other reason for diy fridge was space efficiency. Couldn't find a commercial fridge with reasonable capacity that would fit under diesel cooker or sink, let alone reach the back of the bench. The drawers increase the food packing density while improving accessibility. I haven't measured it but there's a desirable temperature gradient top to bottom.

Probably not wise to use metal for the interior carcass, we're only talking about 30w of compressor power, the metal could conduct it away.

 

[DzlToy]

Thanks, now I have to make my own fridge and freezer in addition to building the camper box ;-)

 

[mhiscox]

I appreciate the information in this thread. Somehow, the idea that I can buy extremely sophisticated computers and cars and electronics, while there's no obvious place to buy a high-quality camper cabin seems odd, so all of the information you care to share is welcome.

 

[gait]

pleased to help

its just a box!

a couple of other memories -
separate compressor from carcass, easier to build, increases volume for small surface area increase, easier to get good air flow over compressor/condenser - most efficient is low condenser temperature,
consider seperate fridge and freezer,
add a switch with resistors into the secop/danfoss compressor thermostat circuit to change speed (lowest speed most efficient but may not keep up in really hot conditions), the marine guys have controllers that do that automatically,
check it fits through the door
also, since I built my fridge household fridges have improved while RV fridges have been fairly static.

here's the numbers - one of the problems is that there's no (that I can ever find) similar data for commercial fridges and everyone who ever installed a fridge reckons their's is best. I was once a wannabe combustion engineer with industrial oil fired metallurgical furnaces to play with - all the same principles.

 

[DzlToy]

Mike, I was thinking of your jeep build and all of the hard work that Paul put in sealing and staining and fiberglassing the interior. I have seen boxes built that way as well. Certainly a composite vacuum panel box would be simpler and less labour intensive. You can be the guinea pig

I spoke with a mate of mine who runs a metal fab shop and he had some ideas for the box and the fridge. We may do some experimenting when he gets caught up.

 

[mhiscox]

We may do some experimenting when he gets caught up.

I hope you do, and that you share the results.

I look back and realize that between the XV-JP and my two Safari Vehicle Manufacturing shells:

,

I've had three very nice, and very strong, molded fiberglass cabins . . . and each of the three was so expensive to build that it was apparently impractical to keep making them. And none of the composite panel cabins I've watched being built seem cost-effective once the builders count their time investment realistically. And for a while there, Unicat's Terracross group was selling really nice empty cabins at some probably justifiable, but truly staggering, prices.

My Unimog's homebuilt cabin was built thirty years ago and I've been hoping for a modern version of it for two decades. I just have a feeling that I should be able to send in an order form along with a reasonable (though sizable) payment and have a big truck bring a strong, well insulated cabin for me to outfit. Unfortunately, I've been waiting a long time for some entrepreneur to decide there's money to be made at this, so apparently there isn't. But I'll always be around to encourage anyone with even a whiff of a better idea.

 

[whatcharterboat]

And none of the composite panel cabins I've watched being built seem cost-effective once the builders count their time investment realistically. And for a while there, Unicat's Terracross group was selling really nice empty cabins at some probably justifiable, but truly staggering, prices.

Hi Mike,

Hope you and yours are all well .

Do you remember how much the Unicat Terracross cabins were? They used composite angles and sections on composite panel to ensure similar expansion rates and to reduce thermal bridging, right? Just interested. I know how much a bare Global Warrior shell costs us to make and I'd be very interested to know how this would compare with the Terracross should we sell our shells separately in Australia.

Take care mate. Regards john.

 

[mhiscox]

Do you remember how much the Unicat Terracross cabins were?

Well, John, it's pretty sad, but I just last year threw away the silly-big collection of expedition camper fodder I'd collected over the years, and my Terracross cabin stuff got pitched.

I'm reluctant to test my memory (hey, I'm old), because it's likely Charlie or Haven or Victorian or one of the other experienced hands will remember more precisely. That said, I remember them, as you do, as being full-on composite cabins, very well constructed, just the same quality as the Unicat cabins, but in standard sizes and without available custom features like sloped rears, lifting roofs, etc. And my understanding is that "Terracross" lives on as several existing semi-standard Unicat models that have fixed lengths and floorplans. But the first thing Unicat did with Terracross (I'm thinking middle of last decade) was to make the cabins available with independent pricing.

My vague memory was that even the short ones were into the six figures USD; my strong memory is that they seemed to cost all the money in the world. Even then, I knew enough to understand that they were very well built and would be the right starting point for an extremely high end vehicle, but I still remember thinking, "It's a box, a door, and three windows. How the heck can it cost THAT much?"

Can't think why you'd have to limit your cabin sales to Australia. There can't be too many things that big easier to ship to Portland than an indestructible empty camper box. Keep me posted. :sombrero:

 

[DzlToy]

"empty indestructible camper box" my ********....

you better fill that thing up with "cool Australian stuff that we dont get in the states" - same amount of space in the container, so its much more efficient

 

[SkiFreak]

you better fill that thing up with "cool Australian stuff that we dont get in the states"

You mean like kangaroos and koalas?

 

[mhiscox]

You mean like kangaroos and koalas?

Nah, that'd be a waste. There's lots more examples of kangaroos and koalas around North America than of the aforementioned "cool Australian stuff that we don't get in the states."

You know, that point about the empty cabin needing filled is the basis for a fantastic entrepreneurial setup. It'd be perfect for someone who was bilingual in 'Strine and 'Murcun.