HPC v Aerogel Thermal Insulation
Boris, SPI Coatings
Aerogels are not “new”. They have been in the market for 16 years. I had some shipped to me from NASA research in 1998 that cost $200 per ounce. They were good but not the best to use at the time.
Over the years, I have received samples to try out and have one sample that is promising but had to find the correct surfactant to make it blend with the water-based formulas.
In other words, I have aerogels and have tested with them for the pass 16 years. I can easily induce the one aerogel that does impress me into the formula at any time, but I know that using a “single” aerogel or bead will not work consistently over time. The aerogels or beads deteriorated over time and collapse or the surfactant used to water proof the surface, so that they can be initially induced into a water-based formula or into a blanket and resist moisture, is ony temporary for only a matter of years and then absorbs moisture.
This is why I use 7 different ceramic compounds to insulate. 5 of the 7 are inert and will not deteriorate nor absorb moisture over time.
There is a lot of chemistry and ceramic understanding to develop a “long term” product.
Blankets are not the best because they will eventually absorb moisture and deteriorate.
The problem here, as I can see it, is not a chart of HPC’ real thermal conductivity on the same page with aerogel conductivity, so customer can visually compare them…we can do it, but as I told you before they are very close, with aerogel having a little advantage at the lowest temperatures…By seeing both conductivities on the same page customer can say: okay, they are the same we’ll use the aerogel, especially if they already used it before or have a company representative pushing it for use…
The problem is that if we concentrate on the conductivity values comparison of aerogel and HPC we can put ourselves in disadvantage… It will be very difficult (next to impossible) to vin any project for HPC if we allow conversation come back to comparing conductivity values only of perspective products…
Overall, thermal conductivity values of most conventional insulation products are almost the same in the range of 0.035-0.045W/m K at the best favorable conditions.
Aerogel boasts that it has the lowest conductivity of all and shows between 0.02W/m K at 0C to 0.089W/m K at 600C, which is somewhat a little suspicious and have to be taken critically, because the air (the best known insulator!) have also 0.02W/m K conductivity!
It is the fact, that the HPC conductivity numbers you have (based on some European laboratory tests done almost ten years ago…) are not as good looking as the Aspen aerogel’, but all our field experience of HPC applications and field tests (Belgium, Russia, Germany…) shows that these values at all temperature levels have to be adjusted to at least 30%.
But it is not all…Our own tests (supported by Belgium and Russia field experience) shows that HSC/HPC real conductivity values in the range of temperatures from 93C(200F) to 177C(350F) are from 0.031W/m K to 0.038W/m K which better than conventional insulation…
So, we can definitely state that HPC insulation thermal conductivity values are the same or very close to aerogel, but contrary to aerogel HPC not only slowed down heat transfer from hot pipe to outside environment but block heat inside the pipe! This is the main point we need to drive to their heads…
Not everything depends on conductivity, but there is invaluable ability of HPC (due to its propriety formula) to block heat inside the pipe, and that is from where most energy savings come from.
You bring a very important point that is confusing when you read the testing and read all the marking materials of the competitors.
How can we be that much better if the W/mK is the same for their product versus HPC?
HPC® Coating – used to coat over pipes or surfaces that load up to 650°C. The coating is not a reflective coating, but works to block the loading of higher heats and to resist the transfer of heat through the coating to the cooler side. Single component water based. Holds heat in the surface in which it covers. Once coated, the surface will be equal to the interior temperature which could be 200°-300°F higher than what is registering on the exterior.
Understand how marketing works –
The aerogel that the others are talking about – in dry state and alone does test to be the same as HPC , except – they are not using the aerogel in it’s powder form, alone. They are taking this powder and now making a blanket with it, which requires other materials to form the blanket. Now, the blanket is not just aerogels, but is now a rigid piece of material that does not have the same W/mK as aerogels alone. At the same time, this material must be wrapped and secured causing the wrap to be compressed which eliminates some of the W/mK result that was assigned to the aerogels powder itself. Next, the wrap is not totally bonded to the surface of the pipe or tank, which allows air to be trapped with humidity to cause deterioration and CUI over time.
Whereas, HPC is sprayed directly to the surface, bonds to 100% of the surface, covers over valve and elbow configurations (wraps cannot do this), can be easily removed for repair and replaced in minutes with minimum down time and loss of materials (wraps must be removed and total new replaced taking days and new full expense).
Given that the wrap is not 100% bonded, leaving air and moisture pockets, the wrap is not 100% aerogel but only a combination of aerogel and binding material, and must be protected with some over coat that must flex with the wrap and be tough to withstand weathering without cracking — versus — HPC that covers 100% without air/moisture pockets and seals down with a combination of coatings proven in the field.
The most important thing in this entire comparison is that HPC as a coating applied is the W/mK as presented and not reduced as is the wrap (finished product).
This marketing of the aerogel is over blown as the latest technology which it is not, Nanogel is the latest technology, which is what I am working with as a finished part of HPC.
As a side note, I had asked the Chinese for a bag of nano materials. They sent me a .3 metre x .3 metre bag 3.5 cm thick weighing over 2.2 kilos and a white powder.
Nano materials cannot be seen and would weigh approximately 56 grams. There is no way to have packed nanos in a pouch. They have only some idea of what this technology is and to believe their advertisements is dangerous.
Okay, we decided to move away from discussing for a long time just thermal conductivity values (K-values) of HSC/HPC and standard insulation because it will bring us to nowhere as HSC/HPC have the same conductivity or lower as all standard insulation materials and the difference in thickness will give us a disadvantage as our thickness is much less than standard insulation if customer’ measurement of success in thermal insulation depends on the K-value only and thickness of insulation…
Now comes the most difficult part of how to explain it to customer, and it will not be an easy task if customer didn’t have any negative experience with the existing standard insulation, which is just material wrapped around the pipe or vessel with metal jacket and works by slowing heat transfer from hot surface to ambient environment by the means of K-value (thermal conductivity) and the thickness…
So, I think, here we need to make a few points:
1. All conventional insulation materials including Aspen aerogel by their design (insulation wrapped around the pipe with metal jacket) leave empty space between insulation and metal pipe, is not sealed by metal jacket from outdoor environment, are prone to air and moisture penetration and thus corrosion under insulation (CUI) and insulation values deterioration in the very short period of time, especially at the outdoor application…
2. This process is inevitable and happened sometimes even at the time of installation (insulation compression, moisture penetration), but customer don’t see it because of the metal jacket…
3. Insulation deterioration and energy lost is gradual and customer don’t see it for a long time…
4. Corrosion under insulation is happening from the very first moment insulation and metal jacket is applied, but not visible until some visual signs on the jacket or when jacket and insulation removed for maintenance purpose…
5. All current tests and values (K-value, R-value) are designed for standard insulation materials when K-value and thickness of insulation determines insulation effect (all these tests are in the laboratory settings and values derived not always hold in the real life)…
6. Insulation effect determined only by thermal conductivity (K-value) and the thickness of insulation, so the less K-value and more thickness of insulation is the better…
7. Traditional insulation doesn’t eliminate radiation and convection heat transfer from the metal pipe…
8. HSC/HPC insulation is a completely new “animal” on the insulation market and this we have to drive in the potential customer’ head!
9. HSC/HPC applied directly to the pipe or vessel, eliminate radiation and convection heat transfer from the metal pipe…
10. Eliminate corrosion under insulation (CUI);
11. Insulation effect of HSC/HPC is twofold:
- It depends, as all other conventional insulation materials, on the thermal conductivity and thickness of HSC/HPC;
- But, in the most part, also on the inherent ability of HSC/HPC due to the proprietary chemical formula, which include, beside other things, a combination of selected ceramic compounds and the blend of specific acrylic resins to build a strong and very low density matrix to provide a non-conductive block against heat transfer!
- It is a physical phenomenon (in our opinion this block is happening on the molecular or atomic level of heat transfer vibrations…) which still needs to be researched and explained, but this is not our field of study…
- The inventor invent a product with the certain thermal heat resistance characteristics, which exceeds the overall reduction in heat, based on the thermal conductivity and thickness and practically showed on the field applications that it is working as stated…
- Now, the only field application of the end user will prove it or not!
SUMMARY:
Other insulation materials do not have a “direct” adhesion to the hot surface. There is air that was accepted as the best method of insulation due to the radiating heat off the surface will slowly heat the air pockets and release to the exterior side of the material or atmosphere. This is a constant movement of the heat loss through the material. This is why standard insulation materials must have thickness to try and retain heat longer before releasing to the atmosphere.
HPC becomes a direct adhesion to the surface. What this provides is that the “initial” heat release off the surface is resisted immediately because air is not used as the insulation. The ceramic compounds used are extremely light density which resist the “absorption” of heat. Because this is an initial resistance directly on the hot surface to block heat release off the surface, this action is faster and more immediate to holding heat in the unit and resisting the loss off the surface. HPC does not use air to “absorb” heat and allow it to immediately release off the surface. Therefore, has a more instant resistance to blocking heat loss.
Standard insulation testing as for ASTM C177 is testing “only” for conduction of heat. Because the ceramic compounds block out radiation and controls convection, which helps with the slowing of heat transfer from the initial heat load, HPC uses all three methods of heat transfer and not just conduction. The standard materials were not designed to have any effect on radiation nor convection and therefore the C177 conductivity test can not accurately show how well HPC is working and performs against these other products. In real world testing, standard insulation products cannot perform to the level of HPC because the effects of radiation and convection are in play on the insulation materials and these materials have no performance ability in regard to radiation and convection. Simply because the standard materials have no ability to control radiation nor convection, does not change the insulation rules for heat absorption and transfer which involves Radiation, Convection and Conduction. Not only Conduction. The ASTM C177 testing was designed to test for heat transfer by conduction only which is only 1/3 of the heat transfer standards.
