Thermal Tutorial

This tutorial is simply intended to give some of the basics of Thermodynamics and how it relates to insulation and ceramic coatings. It is not intended to be comprehensive.

Do we really understand heat? To understand insulation and how a unique product like ceramic coatings work, we must understand the basics of heat energy transfer, such as: heat always seeks and moves to cold and more. Read this tutorial to increase your knowledge.

How does heat move?

Where does heat move?

What is R-value?

How does air trapper type insulation work?

The downside of R-value testing.

How is SUPERTHERM® different?

How can ceramic coatings help you?

How to choose insulation?

 

How does heat move?:

There are three basic types of thermal transfer: radiation, convection and conduction.

Radiation

Convection

Conduction

SUPERTHERM® works against all three forms of heat transfer however it is most effective against radiation. It deflects and repels over 95% of the energy from the sun and over 90% of interior sources of radiated heat.

SUPERTHERM® deflects 100% convection because it allows no air movement through the coating while avoiding taking up any heat from the air itself.

SUPERTHERM® resists heat transfer through conduction as well, due to the unique ceramics used to resist the movement of heat through the coating itself. However HPC® Coating Multi ~ Ceramic Insulation Coating is specifically Engineered to Block Heat and stop thermal transfer via conduction.

Also note that energy is constantly being converted from one heat transfer method to another. Using an uninsulated roof can demonstrate this quite nicely in a "cooling environment":

  1. Energy comes down from the sun in the form of radiation.
  2. A small amount of heat is absorbed by the air, transforming it into convective heat.
  3. When the radiation from the sun and the convective heat from the air come in contact with a roof, they heat the surface converting this energy into conductive heat transfer, which heats the roof. SuperTherm® coated on a roof prevents this from happening by deflecting and repelling the suns energy before it reaches the roof underneath.
  4. As the roof gains heat it is conducted through the roof and radiated to the inside. Have you ever stood a few feet away from an uninsulated metal door and felt the radiated heat? It then heats the air inside the building, forming air convection currents. When SuperTherm® is used, the roof doesn't have a chance to heat up and thus the building remains cool.

The reverse occurs in a "heating environment".

  1. Energy comes from interior sources in the form of radiation.
  2. A small amount of heat is absorbed by the air, transforming it into convective heat.
  3. When the radiation and the convective heat from the air come in contact with a ceiling, they heat the surface converting this energy into conductive heat transfer which heats the surface. SuperTherm® coated on a ceiling prevents this from happening, by deflecting and repelling the energy before it reaches the ceiling underneath.
  4. As the ceiling gains heat it is conducted through the ceiling and radiated to the outside. When SuperTherm® is used, the ceiling doesn't have a chance to heat up and thus the building remains warm.

Where does heat move?:

A simple rule for the direction of transfer of heat is this: HEAT MOVES TO COLD.

What is R-value?

R-values are rating thermal resistance related to thickness and not necessarily thermal and insulative efficiency. An R rating means the insulation loads and unloads with heat. This is why when the outside ambient temperature cools down at night the building is still hot inside (requiring extra work by the HVAC equipment). An R rating only measures conduction and doesn't account for convection and radiation, the other two methods of thermal transfer. The greater the thickness, the greater the ability of the insulation to absorb conductive heat until it reaches saturation point at which time the bulk insulation becomes a "heat pump", pumping the heat into or out of a structure. An R rating is merely the "Flow Through Rate".

A little bit of history:

How does "air trapper" type insulation work?:

The downside of R-value testing:

The R-value system only accounts for the abilities of insulation against conduction. Against the other two forms of heat transfer (convection and radiation) the effectiveness varies greatly depending on the type of insulation.

For fiberglass, the results of these tests change dramatically under even slightly different conditions:

R-value testing methods do not reflect real world conditions, which can vary greatly with regard to all of these factors: material humidity, temperature differences and air movement.

Unfortunately these same tests are still used today, despite the fact that new insulations have been introduced into the market. Solid insulations are even more effective than their R-value would suggest, as they are completely unaffected by humidity, temperature and air movement, as well as having long-term thermal resistance. SuperTherm® performance is not affected by temperature differences, moisture or air movement.

Another downfall is radiation is not accounted for in R-value testing. If stopping radiation was included in R-value testing, SuperTherm® R-value equivalence would go up 'significantly' because radiation heat transfer increases by the 4-th power of temperature difference. SuperTherm® would outperform all other insulations.

As noted by PhD Inn Choi " When 95% of heat input into a substrate is blocked and only less than 5% of heat is allowed to enter into a substrate, the overall benefits from different material insulation properties for this 5% are trivial ".

How is SUPERTHERM® different?:

SuperTherm® works against all three forms of heat transfer. It is most effective against radiation, as it repels over 95% when applied to the exterior and over 90% when applied to the interior of building envelopes.

SuperTherm® fights convection because it allows no air movement through the coating, while avoiding taking up any heat from the air itself.

SuperTherm® resists heat transfer through conduction as well, due to the unique ceramics used to resist the movement of heat through the coating itself. However HPC® Coating Multi ~ Ceramic Insulation Coating is specifically Engineered to Block Heat and stop thermal transfer via conduction.

This simply means that heat never builds up. Bulk insulations resist and store heat, thus preventing it from passing through the bulk. SuperTherm® stops heat movement so effectively that heat hardly builds up at all. It strongly resists any energy movement through radiation, conduction and convection, through its unique blend of ceramics.

How can SUPERTHERM® ceramic insulation coating help you?:

How to choose an insulation application?:

Basically, the energy costs must be examined. If heating costs in the winter are considerably less than the cooling costs in the summer, SuperTherm® should be applied to the exterior of equipment or the building envelope (and qualify for "LEED" points). This is especially true where heating is not an issue: in coolers, freezers, and arenas where the sole objective is to maintain a low temperature.

If energy costs involved with heating are higher, then SuperTherm® should be applied to the interior side of the equipment or building envelope (and qualify for "LEED" points). See COLD CLIMATE CONTAINER INSULATION.

Of course the optimum application would be to coat both sides, so that neither side could absorb heat, in which case the substrate itself would become part of the insulation package as documented in ASTM C-236 (C236-89(1993)e1) - Standard Test Method for Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box. This test shows thermal conductance of 0.31. when SuperTherm® is coated on the interior and thermal conductance of 0.21 when SuperTherm® is coated on both sides of the substrate. To the extent possible it is desirable to have the ceramics facing the heat source. If one side of the substrate is uncoated and allowed to absorb heat, the heat will still be repelled once it reaches the ceramics. This was demonstrated by the use of infrared technology where the SuperTherm® was applied to the exterior of a roof only and then Infrared scans were taken in the middle of winter to document the heat retention.

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