How good is the thermal insulation?

“Thermal insulation” is defined as that which prevents heat transfer between substances. While there are differences in heat transfer properties between all materials, thermal insulation materials with the specific characteristic of inhibiting the transfer of heat are used in houses, buildings, electronic equipment, automobiles, and a variety of other applications.

A foam with good thermal insulation

A foam with good thermal insulation

There are three mechanisms of heat transfer: Conduction, convection, and radiation.

All materials are static, and heat is transferred from high-temperature to low-temperature materials.
The material flows, thus transferring heat.
Heat energy itself moves as electromagnetic waves.

SunForce is a foam, and therefore requires only a small amount of plastic. Conduction through the plastic component is therefore minimal, and since the independent bubbles of the foam contain air, convection by gas flow is prevented. The diameter of the bubbles is very small, with many foam membranes, thus minimizing radiation. The superior insulation properties of SunForce are obtained by this suppression of all three mechanisms of heat transfer.

On the other hand, metals readily transfer heat by conduction, water readily transfers heat by convection, and clear air readily transfers heat by radiation. Insulation brings many advantages by reducing the effects of high-temperature components, heat sources, and low temperature environments, and by reducing convection, maintains a constant temperature, raises thermal efficiency, and eliminates temperature differences between inside and outside, thus preventing condensation.

Thermal conductivity (W/m·K) is often used as an index of thermal insulation (conduction) for comparison of a range of materials as shown below.

Material Thermal conductivity
Material Thermal conductivity
Material Thermal conductivity
Carbon nanotubes 5500 LCP (Liquid Crystal Polymer) 0.56 SunForce (x5) 0.041
Diamond 2000 FRP (Fiber Reinforced Plastic) 0.26 Cellulose fiber 0.040
Copper 370 PPS (Polyphenylene Sulfide) 0.26 Rockwool 0.038
Aluminum 200 Polycarbonate 0.19 SunForce (x7) 0.038
Graphite 120 ABS 0.19 Glass wool 32K 0.036
Iron 80 Polyvinylchloride (PVC) 0.17 Melamine foam 0.035
Carbon-copper 41 Plywood 0.16 SunForce (x10) 0.034
Alumina 32 Particle board 0.15 Extruded polystyrene foam (Type 3) 0.028
Stainless steel 16 Modified PPE 0.15 Hard urethane foam (Type 1 #1) 0.024
Carbon fiber-reinforced plastic 4.7 Polystyrene 0.15 Air 0.022
Zirconia 3.0 Cypress wood 0.095 Silica aerogel 0.017
Concrete 1.6 Cedar wood 0.087 Carbon dioxide 0.015
Glass 1.0 Cork 0.043 Vacuum insulation material 0.002
Water 0.58

<Room temperature reference values>

Foam has a very low thermal conductivity in comparison to metals and plastics. It can be seen as having excellent thermal insulation with low thermal conductivity.

The thermal conductivity of SunForce foam is equal to that of general insulation material, and by combining it with ease of shaping and flame-retardant characteristics not found in other thermal insulation materials, it is possible to use it in new applications such as flame-retardant and thermal insulating chassis of complex shapes.

Many thermal insulation materials are affected by the following:

  • Variations in performance due to moisture (water absorption, hydrolysis)
  • Diffusion of thermal insulation gasses over time
  • Changes in shape when used at high temperatures
  • Insufficient strength

SunForce, with its superior water resistance and high-temperature characteristics, is able to provide stable thermal insulation performance free from most of the above issues.