Absorption coefficient of solar radiation

The absorption coefficient of solar radiation for the cable surface is used to calculate the temperature rise due to solar radiation.

The coefficient is material-dependant. Typical values are given in standard IEC 60287-1-1 for different cable jacket materials and in standard IEC 60287-2-1 for different duct materials.

No reference values were found for Polypropylene (PP), Silicone rubber (SiR) and Chlorosulphonated polyethylene (CSM) and they are assumed to be similar to PVC.

Symbol

$\sigma_{sun}$

Used in

$\Delta \theta_{sun}$

Temperature rise by solar radiation [K]

$W_{sun}$

Solar radiation heat transfer to surface [W/m]

Choices

Material	Cables	Ducts
PE	0.4	0.4
HDPE	0.4	0.4
PVC	0.6	0.6
PP	0.6	0.6
POC	0.6	n.a.
SiR	0.6	n.a.
CR	0.8	n.a.
CSM	0.6	n.a.
CJ	0.8	n.a.
RSP	0.8	n.a.
BIT	0.8	0.8
Metal	n.a.	0.3
Fibre	n.a.	0.6
Cem	n.a.	0.75
Earth	n.a.	0.75