Pre-heat dryer make-up air with recovered exhaust heat. Enter exhaust conditions and operating hours to see annual energy, cost and CO₂ savings — plus payback if you add equipment cost.
m³/h
°C (dryer outlet)
°C
% (plate 60–75, wheel 70–85)
h/yr
$ / kWh (gas≈0.04–0.10, elec 0.12+)
$ for payback
Recovered heat
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Annual energy
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Annual cost saving
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CO₂ reduction
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Simple payback period
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Assumptions: air density 1.2 kg/m³, cp 1.005 kJ/kg·K, grid factor 0.55 kg CO₂/kWh. Sensible-only (latent moisture in exhaust is not recovered here unless you use an enthalpy wheel — add ~10–20% for that). Subtract added fan power (typically 5–15% of recovered energy).
Why drying is the best heat-recovery case
Exhaust is hot (80–180°C) and continuous — large ΔT means big recoverable power.
Make-up air must be heated anyway, so recovered heat has a direct fuel offset.
Plate or heat-pipe cores tolerate the high temperature and any particulate carry-over; washable designs handle fouling.
Frequently asked questions
Plate or heat-pipe for an oven?
Both work. Heat-pipe has no moving parts and self-drains condensate; plate is cheaper per kW and easier to size large. Avoid rotary wheels near flammable vapours.
What about the moisture in exhaust?
Sensible exchangers ignore it. If exhaust is also humid and you want that energy back, an enthalpy wheel recovers part of the latent load — but only where the airstreams are safe to contact.
Is payback realistic?
Drying lines running 5,000+ h/yr at >80°C exhaust commonly see 1–2 year payback. The calculator gives a first-order figure; a site audit refines it.
Preliminary estimate only. Zibo Qiyu designs plate, heat-pipe and wheel recovery for industrial dryers — request a quote.