# Le Press Green Story — Evidence and Methods

10 October 2026. Five-minute landscape documentary.

## Film provenance

The first ten seconds use an AI representation of Gaurav Vatsa based on his supplied profile. Narration is synthetic, not his recorded or cloned voice. The following 290 seconds pair excerpts from https://www.youtube.com/watch?v=DiQrkUy7vXY with calculated model views and explanatory graphics. No embedded photo attribution was removed. Music is generated.

## What was calculated

Solar positions use the NOAA equation-of-time and declination method at 26.849769° N, 80.944080° E, UTC+5:30. North remains provisionally aligned at 13° and needs survey confirmation. The model is not a verified as-built survey.

The study compares 21 May, 21 July and 21 December 2026 at hourly samples from 06:00 to 18:00 IST. A 0.75 m receiver grid and 1,400-pixel sun-depth raster classify direct sunlight at a fixed model elevation of 1.35 m. This is a horizontal study plane, not an accurate pedestrian-height surface over all terrain. A 0.22 m depth tolerance handles raster precision. Building-covered points above 1.8 m are masked. The rectangular domain includes areas beyond the property, so its aggregate values are not site-wide performance claims.

Direct solar exposure sums hourly direct-normal irradiance multiplied by sine of solar altitude and the model's sunlight mask. Irradiance is the corresponding month's mean hourly profile from the Lucknow airport TMYx 2011–2025 weather file. Values describe this sampled 06:00–18:00 period, not complete annual radiation. Diffuse sky and reflected radiation are omitted. Tree geometry is opaque: its shading effect is an upper-bound scenario rather than measured leaf transmission. It is not an air-temperature map.

Weather source: [Climate.OneBuilding Lucknow–Amausi airport TMYx 2011–2025](https://climate.onebuilding.org/WMO_Region_2_Asia/IND_India/UP_Uttar_Pradesh/IND_UP_Lucknow-Amausi-Singh.Intl.AP.423690_TMYx.2011-2025.zip). The airport is approximately 11 km away. A typical meteorological year is a regional design input, not a forecast or a courtyard measurement.

Numerical checks: adding opaque canopy never increased the calculated receiver exposure; 100 random noon receiver points matched independent ray-triangle intersection checks. These checks validate implementation samples, not physical site calibration. Results are in `science-check.json`. Selected figures and numerical summaries are in `figures/`.

## Stack effect and materials

### Added surface-radiation and heat-gain study

The model animation includes the 21 May sun path with true solar altitude and azimuth. Solar positions follow [NOAA's published equations](https://www.gml.noaa.gov/grad/solcalc/solareqns.PDF). The path is a projected solar hemisphere, not an arbitrary decorative arc. Its radius is a display convention.

Surface colours represent DNI × |normal · sun vector| × visibility, in W/m², using the mesh's two-sided convention. Occlusion is sampled at each triangle centre against a 1,400-pixel sun-depth buffer with 0.12 m tolerance. Large triangles may miss partial shade, and mesh face orientation has not been independently audited. No building-wide absorbed energy total is inferred. Diffuse sky and reflected radiation are excluded from this surface map. Trees are opaque.

The separate roof comparison uses an unshaded horizontal reference roof and the May monthly mean hourly dry-bulb and global-horizontal radiation series. It evaluates q = U × [Tout − 26 + α × GHI / 15], with q in W/m². Case A assumes U = 2.5 W/m²K and solar absorptance α = 0.7; Case B assumes U = 0.5 and α = 0.3. Neither assembly is asserted to be the existing Le Press roof. The calculated profile peaks are approximately 135.3 and 14.8 W/m² respectively. These compare hypothetical assemblies, not measured savings.

This is a simplified steady sol-air sensitivity. It omits long-wave sky exchange, thermal storage, transient conduction, zone heat balance and HVAC response. It is not an EnergyPlus simulation. The [EnergyPlus engineering reference](https://energyplus.net/assets/nrel_custom/pdfs/pdfs_v24.2.0/EngineeringReference.pdf) explains the fuller outside-surface heat balance that a calibrated dynamic study would require. The mapped surface beam radiation and reference-roof calculation are separate studies; the roof comparison does not integrate all model surfaces.

The interactive explorer allows review of hourly model frames and adjustment of hypothetical roof U-value and absorptance. It is a preliminary design-analysis tool. A claim of state-of-the-art validated project performance would require verified geometry and constructions, orientation, boundary conditions, schedules, solver convergence and comparison with monitored data.

The airflow diagram uses Q = Cd × Aeff × sqrt(2gHΔT/T). Assumptions: Cd 0.6; two unobstructed 1 m² openings; effective area 1/√2 m²; vertical opening separation 3.5 m; absolute temperature 303 K. At ΔT = 5 K, Q is approximately 0.45 m³/s. For an illustrative 50 m² room with 16 ft (4.8768 m) height this is approximately 6.7 air changes per hour. This assumes a connected path and favourable buoyancy. Wind, opening resistance and actual temperature differences can change the result. It is not CFD or measured ventilation. The courtyard chimney is not assumed to extract room air.

Three-brick masonry is interpreted as nominally 690 mm, subject to measured brick and mortar dimensions. Thermal mass can delay heat transfer; it does not establish an insulation rating or guarantee cooling. Tall ceilings require useful air paths and high-level outlets. Shading and evapotranspiration can improve comfort, but no universal temperature reduction is claimed. Humid monsoon conditions limit evaporative potential.

## Carbon: report a baseline, not an offset certificate

[Gaurav Vatsa's Sustainability Next article, 17 April 2025](https://sustainabilitynext.in/le-press-galleria-reviving-the-past-sustaining-the-future/) provides the cultural and adaptive-reuse context. The film identifies its approximately 1,500 t CO2 replacement-mall estimate as an author-reported hypothetical baseline. It is not independently verified net reuse savings. A credible comparison must deduct refurbishment, repairs and new services, use consistent areas and service life, and account for demolition and operation. The article's larger carbon and tree-equivalence totals are not adopted as verified outcomes.

Avoided one-off embodied emissions must be kept separate from recurring annual operational changes. Conserved trees are not newly planted trees. No certified offsets, measured total carbon savings, or tree-planting total is claimed.

## Supplementary water sensitivity (not shown in the revised film)

| Item | Assumption / result |
|---|---|
| Connected roof | 1,000 m² |
| Annual rainfall | 0.9901 m, report assumption |
| Runoff × usable capture | 0.8 × 0.75 |
| Useful rainwater | 594.06 m³/year |
| Wastewater | 10 m³/day × 365 days |
| Reuse fraction | 80%, giving 2,920 m³/year |
| Combined freshwater displacement | 3,514.06 m³/year if adequate reuse demand exists |
| Avoided supply energy − reuse pumping | 0.6 − 0.2 = 0.4 kWh/m³ |
| Illustrative electricity factor | 0.7 kg CO2/kWh |
| Favourable electricity saving | 983.94 kg CO2/year |
| Additional treatment sensitivity | 3,650 m³ × 0.4 kWh/m³ × 0.7 = 1,022 kg CO2/year |
| Net if treatment is wholly additional | −38.06 kg CO2/year avoided: a small increase |

These are illustrative inputs, not Le Press meter readings. The favourable case assumes treatment is common to both baseline and project. Methane, nitrous oxide, chemicals, sludge and infrastructure are excluded. This is not a complete greenhouse-gas inventory. Rainwater and recycled water cannot both displace the same litre of demand.

## Next evidence needed

Confirm survey north, geometry and vegetation porosity; meter water capture, STP flows and electricity; monitor outdoor and indoor temperature, humidity and air movement; inventory retained material quantities and refurbishment inputs. With these, the digital model can support calibrated comfort and whole-life carbon studies. CFCPD means Culture, Finance, Community, Planet and Digital.


## Figures attributed in the revised film

Sustainability Next, 17 April 2025: https://sustainabilitynext.in/le-press-galleria-reviving-the-past-sustaining-the-future/

The revised film attributes 5,150 t CO2 offset, 22 million litres annual rainwater, 75% wastewater reuse and a potential 30–40% cooling-energy reduction to this article. They are not independently verified model outputs. The approximately 1,500 t CO2 replacement-construction figure is a separate hypothetical baseline; it must not be added to 5,150 t. The rainwater figure needs catchment/rainfall reconciliation. Actual net reuse savings need refurbishment impacts and a consistent counterfactual. No tree-planting equivalence or certified carbon-credit claim is made.


## Updated voice and thermal comparison

All narration now uses the same Indian-English preset voice, including the opening. Spoken reverification comments have been removed; published figures remain attributed to Sustainability Next. The roof and wall chapters now compare the requested thicknesses. The older roof-sensitivity explorer remains a separate scenario.

U = 1/[Rsi + sum(d/k) + Rse]. k: brick masonry 0.81, lime plaster 0.70 and dense concrete proxy for RCC 2.10 W/mK. All cases include 20 mm lime plaster each face. Wall films total 0.17 m²K/W; summer downward roof films total 0.21. Wall U-values: 690 mm = 0.9268; 230 mm = 1.9566 W/m²K. Vault U-values: 450 mm = 1.2155; 600 mm = 0.9922. RCC 175 mm = 2.8533. Thus the thick wall passes about 53% less steady conductive heat, and the vault about 57–65% less, under equal temperature difference and equal actual surface area. No added insulation. These percentages are not annual HVAC savings.

The vault is a local one-dimensional section approximation. Actual curvature, fill, moisture, finishes and thermal bridges can change performance. Limestone plaster is interpreted as lime-based plaster. A modern insulated assembly can outperform these uninsulated cases. Reflective paint changes solar absorption, not material k or assembly U. Illustrative albedos 0.80 and 0.30 imply absorptances 0.20 and 0.70: 71% lower absorbed short-wave radiation, not 71% lower room heat gain.

Sources: Knauf W62 technical conductivity data (brick masonry 1800 kg/m³ and dense concrete 2400 kg/m³); Historic Environment Scotland Technical Paper 15, Table 13, p167 (lime plaster); US DOE Guidelines for Selecting Cool Roofs. Direct source links and calculation assumptions are on the Green Story page.