Diffuse radiation formula (Heat Overlay): Difference between revisions
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| τ<sub>a</sub> >=0.7 | | τ<sub>a</sub> >=0.7 | ||
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Revision as of 14:50, 11 September 2019
The diffuse radiation is an input parameter for the PET-formula
The diffuse radation Qd at time t is calculated using the following formula:
Qd,t = Qgl,t * ftransmission,t
where,
- Qgl,t is the amount of sun radiation at time t, measured at a weather station.
- ftransmission,t is the Atmospheric transmission factor at time t.
Atmospheric transmission factor
The atmospheric transmission factor is calculated as followed:
| Factor | Condition |
|---|---|
| 1 | τa <= 0.3 |
| 1.6-2* τa | 0.3 < τa < 0.7 |
| 0.2 | τa >=0.7 |