pvperfsolar performance modeling

Reference

API field

ASHRAE b₀

Coefficient of the ASHRAE angular-response formula

Unit –

What it is

The single coefficient of the ASHRAE angular-response formula. A larger value means the glass rejects oblique light sooner.

Typical values and how to get it

0.05 for plain glass. Datasheets of textured or coated glass sometimes give 0.03 or 0.04. If not given: 0.05.

How it is applied

IAM(θ)=max⁡ ⁣(0, 1−b0(1cos⁡θ−1))\mathrm{IAM}(\theta) = \max\!\left(0,\ 1 - b_0\left(\frac{1}{\cos\theta} - 1\right)\right)

where

Symbol Meaning Unit
IAM(θ)\mathrm{IAM}(\theta) the share of the light accepted at incidence angle θ\theta, relative to normal incidence —
θ\theta the angle of incidence °
b0b_0 this input —

References

  1. ASHRAE Standard 93-2010, Methods of testing to determine the thermal performance of solar collectors (incidence-angle modifier)

API

iam.b0

Symbols follow the symbol registry.