LE PRESS · DIGITAL CLIMATE STUDY

Follow the sun. Test a roof intervention.

Actual Le Press geometry, Lucknow solar positions and regional typical-year weather. Preliminary design analysis: orientation and construction details still require verification.

1 · Solar path and surface beam radiation

21 May 2026 — 12:00 IST
Le Press model with calculated sun path and incident direct solar radiation

Hourly snapshots, 07:00–17:00 IST. Colours show direct beam W/m² at triangle centres, with self-shading and opaque canopy. They do not show temperature. Azimuth is clockwise from true north; the model-to-north rotation is provisional. This viewer displays calculated frames; it does not run a new ray trace when changing roof properties.

2 · Roof heat-gain sensitivity

Compare two hypothetical unshaded horizontal roof assemblies using identical May weather. Change Case B to understand the effect of insulation and reflectivity.

Case B U-value: W/m²K
Case B solar absorptance:

Orange: Case A, U 2.5 W/m²K, absorptance 0.7. Teal: adjustable Case B. Positive heat flux is inward. Formula: q = U [Tout − 26 + α GHI / 15]. Indoor reference 26°C; external film coefficient 15 W/m²K.

Design scenario, not measured Le Press savings. No long-wave correction, thermal storage, zone heat balance or annual HVAC load is calculated. The reference roof curve is separate from the surface-radiation model.

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