Idea Bank — Request for Climate Startups
Underground Data Center Waste Heat Recovery
Site data centres underground and pipe their waste heat into district heating or industrial processes.
The ask
Develop a co-location data centre designed for underground or semi-subterranean installation, capturing 90%+ of server waste heat via a heat-exchange loop and selling it to an adjacent industrial or commercial heat user — turning compute infrastructure into a net-positive energy contributor.
Why now
Data centre power use is growing at 25–30% per year globally on AI workloads; European operators are under regulatory pressure to demonstrate waste-heat utilisation. Thermal energy networks for industrial processes (pharmaceutical, food processing, textile finishing) represent a $50B+ annual market that has historically relied entirely on fossil boilers. Heat-recovery systems now achieve coefficient-of-performance (COP) ratios of 4–6, meaning 1 kWh of electricity extracts 4–6 kWh of usable heat — making the economics compelling at almost any heat tariff above ৳1/kWh.
Why Bangladesh
The Bangladesh government is investing heavily in digital infrastructure — data centre parks in Kaliakair and Comilla are under development. Textile mills and pharmaceutical manufacturers in the same industrial belts use steam at 80–120°C continuously; a co-located data centre that supplies this heat as a byproduct can displace gas boilers at zero additional cost to the data centre operator. Underground siting reduces cooling load significantly in Bangladesh's hot-humid climate, improving PUE from a typical 1.6–1.8 to under 1.3. The heat-buyer absorbs the cooling problem; the data centre operator earns a heat credit.
As a business
The data centre earns on standard co-location fees (rack-space, power, bandwidth) and a heat-supply contract with the adjacent industrial user (priced at 20–30% below fossil-fuel equivalent). The underground construction premium (estimated 15–25% over above-ground) is recovered through lower cooling costs and the heat-credit revenue stream over a 10-year contract horizon. The industrial partner provides long-term revenue visibility that improves the data centre's financing terms.
Economics
Move the sliders to model your own data centre waste-heat recovery project. Defaults are order-of-magnitude estimates — pressure-testing them is part of what a founder pitches us.
Model an underground data centre with heat recovery
Clears its setup cost after ~21 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
This is a capital-intensive project best suited to a real-estate and infrastructure developer with existing industrial-estate relationships rather than a pure tech play. ZEPH would participate as part of a consortium alongside a DFI, with our value-add being the industrial heat-offtake origination — matching the data centre to a pharmaceutical or textile anchor tenant in the same zone.
Impact
A 200-rack co-location facility with 70% heat recovery at 5 kW/rack supplies roughly 500 kW of continuous heat to an adjacent textile or pharmaceutical plant, displacing ~4,400 MWh/year of gas-boiler energy and avoiding approximately 900 tCO₂e annually. Underground siting cuts the data centre's own cooling power consumption by 30–40%, further reducing grid draw — important in Bangladesh where grid power is predominantly coal and gas. Displacing imported natural gas or furnace oil for industrial heat saves ~$320,000/year in foreign exchange at a 200-rack scale, making this a genuine FX and carbon double-win.
Also being built elsewhere
Companies proving the model in other markets.
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