Hot Air Generator (HAG) — Cashew Shell / Biomass Fired

Detailed specifications for this machine are still being finalized on our end. Contact us directly for current pricing and capacity options.

A hot air generator (HAG) is a biomass furnace plus heat-exchanger unit that burns cashew shells — the processor’s own waste — to produce clean, controllable hot air. The dependency is the story, not a footnote: there is no hot air without the burner. The shell/biomass burner makes the heat and the HAG delivers it, so this is supplied as a burner + HAG combination (and listed as a standalone HAG in the machine range).

Its first job is drying wet raw cashew nuts in the rainy/monsoon season, when incoming RCN is too moist to store or process and would otherwise mould and lose outturn. Its second job is clean process hot air year-round, replacing diesel or electric heaters. Throughout, the hot air is indirect — delivered through a heat exchanger — so combustion smoke and soot never touch the nuts. (Heat belongs on biomass, not solar — see should you go solar? for why.)

Why it needs the shell/biomass burner

The HAG is the delivery half of a two-part system: the shell burner generates the heat by burning shells, and the HAG’s heat exchanger turns that into a clean stream of hot air. Buy them together, or add a HAG to an existing burner — but there is no hot air without a heat source.

Direct vs indirect hot air — why indirect matters

In a direct system the combustion gases mix with the product air; in an indirect system a heat exchanger keeps flue gas and clean air apart. For food-grade cashew drying, indirect is the right choice — it keeps soot, smoke and combustion odours off the nuts.

Use 1: drying wet RCN in the rainy season

Freshly harvested cashew nuts carry 17–20% moisture and must be brought down to a safe storage level of about 8–10%; above that, RCN moulds within days and outturn falls. In the monsoon there is no sun to do it, so a shell-fired HAG dries the crop reliably — see cashew season for why the timing bites and cashew shell for the fuel itself.

Use 2: year-round clean process hot air

Outside the rains, the same unit supplies process hot air for drying and conditioning duties that would otherwise burn diesel or draw electric heat — cutting energy cost with a fuel you already have.

Fuel: your own cashew shells

The shell left after cutting is a disposal problem for many plants; here it becomes free drying energy. Burning it in a HAG closes the loop — a circular-economy solution that pairs naturally with the biomass boiler and steam boiler for the rest of the plant’s heat.

Integrating with dryers and the plant

The HAG feeds hot air to a borma or RCN dryer and slots into the wider line — see the manufacturing process for where drying sits, and the turnkey plant for a complete build. Capacity (kcal/hr), air temperature and volume are specified per plant and confirmed per order — no figures are invented here.