Construction example

4.Insulation performance

(Unit: W/m•K)

4-1. Thermal

Product-specific Average of both surface temperatures (°C) 0 10 20 30 40 50

Micro Duct 64K-25mm 0.031 0.033 0.035 0.036 0.037 0.040

Glass wool 24 K-25 mm 0.034 0.036 0.038 0.041 0.042 0.044

4-2. Thermal transmittance

Micro Duct 64K-25mm Thermal

transmittance(W/㎡・ K)

1.10

Heat insulation of glass wool 24K-25mm in metal duct 1.19

The temperature inside and outside the duct was set at 12°C and 32°C, and the wind velocity inside the duct was set at 10m/s. We considered the glass wool for heat insulation of steel plate ducts to be an aluminum kraft paper laminate. The heat transfer coefficient of the outer surface of the Micro Duct and the surface of the aluminum kraft paper side of the iron plate duct heat insulating material was treated as 7W/m · K considering the change of the emissivity of the aluminum foil with time.

5. Durability

The table below shows the corrosion resistance of the Micro Duct to various materials.

Water vapor Micro Duct

Inner surface of the duct

(Glass wool surface) Outer surface of the duct

(Aluminum foil surface) Iron plate duct

A A B

NOTE) A is good B is roughly good C is somewhat inferior D is inferior

When using a Micro Duct, Note the presence of alkali and halogen groups.

Water B A C

Sea Water B C D

CO2 gas A A A

Carbon monoxide A A A

Sulfurous acid gas B B

Halogen group (chlorine, etc.) B D D

C

6. Performance of the reinforcement

Item Stiffener

Cross-sectional shape 50×25×5×3×0.5tmm or more

HeavyAmount 0.41kg/m

Second moment of section 0.40cm4

Modulus of section

Z1=0.30㎝3 Z2=0.52㎝3

NOTE) When a material other than the above is used as a reinforcement material, carefully check its cross-sectional performance.

Design calculations for Micro Ducts

1. Acoustic design calculation

For acoustic design calculations in the case of adopting a Micro Duct, The following formula is used for the general duct system as shown in the figure below.

1. Noise generated by

PWL=10×ℓog10Q+20×ℓog10P+C+Bri-12.6..............................................................(1)

Q : Air flow rate (m3/min) P: Static pressure (mmAq) of the blower

C : Constant determined by the type and frequency of the blower Bri: Increase due to the sound passing through the blade

2. Sound attenuation

ΔL=10×ℓog10(A/Se)....................................................................................................................(2) Se: Outlet area of the chamber (㎡)

A: Total sound absorbing power of the chamber (α × Sw) α : Sound absorption coefficient of inner paste Sw: Interior pasted area (㎡)