Idea Bank — Request for Climate Startups
Passive Wind Cooling Systems
Design and install passive ventilation and wind-catcher systems that cool buildings without electricity.
The ask
Build a design-and-install business in Bangladesh that applies passive wind-catcher and cross-ventilation principles — proven over millennia in Iran, Egypt, and South Asia — to new construction and retrofit projects, delivering measurable indoor temperature reduction with zero operating energy.
Why now
Bangladesh's peak electricity demand is increasingly driven by air conditioning; Dhaka's urban heat island now pushes summer heat indices above 45°C. The government's energy subsidy bill for cooling is politically unsustainable. Meanwhile, CFD (computational fluid dynamics) software has made it practical to engineer a passive cooling system for any building geometry in days, not months — turning what was artisan craft into a repeatable engineering service. Green building certifications (LEED, EDGE) now explicitly reward passive cooling strategies.
Why Bangladesh
Bangladesh has a strong prevailing southwest monsoon breeze from May to September — exactly when cooling demand peaks — that wind-catcher geometry can harvest efficiently. Traditional Bengali vernacular architecture already used stack-effect ventilation in courtyard houses; this is a revival with engineering rigour. The government's National Building Code revisions underway include passive cooling provisions, which will create demand for qualified designers. Factory workers in RMG sheds are a high-priority segment: passive cooling cuts absenteeism and meets ACCORD/ILO thermal comfort standards without adding to energy bills.
As a business
Revenue is design fees (৳1–5 lakh per project) plus materials and installation margin on terracotta wind-catchers, louvred stacks, and evaporative clay panels fabricated locally. RMG factories are the anchor B2B market — they must meet international audit standards and have capital budgets. Residential and institutional clients (hospitals, schools) are a secondary pipeline. A carbon-audit add-on — quantifying kWh offset versus a baseline AC installation — supports access to green finance and ESG reporting.
Economics
Move the sliders to model your own passive cooling design firm. Defaults are order-of-magnitude estimates — pressure-testing them is part of what a founder pitches us.
Model a passive wind-cooling design firm
Clears its setup cost after ~5 months, then profit (volt) from there. Hover or tap the chart for any month.
Illustrative model — defaults are order-of-magnitude estimates from public data, not a forecast. Pressure-test every number before you build.
What ZEPH would back
A founder pairing an architect or civil engineer with a business developer who has already completed at least two passive-cooling installations with measured temperature data. We want demonstrated reduction numbers, not theoretical CFD renders. Experience with RMG compliance audits is a major plus.
Impact
A single well-designed passive wind-catcher retrofit can reduce a building's mechanical cooling load by 40–70%, avoiding 3–8 tCO₂e per building per year where AC units would otherwise run on Bangladesh's coal-heavy grid. At 24 projects per year across RMG factories, offices, and residences, the firm avoids ~120–190 tCO₂e annually — and eliminates entirely the imported refrigerants (HFCs) those AC units would require. Bangladesh's southwest monsoon breeze, combined with a growing green-building certification market, means the addressable base runs to hundreds of thousands of commercial and industrial buildings.
Also being built elsewhere
Companies proving the model in other markets.
7,000 passive windcatcher units installed in UK public buildings 1979–1994 — proves institutional demand for zero-energy cooling.
Modern computerized wind tower in Abu Dhabi drops indoor temps by 10°C with zero AC — proof of concept in a hotter, more humid climate than Bangladesh.
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