Cooperative mango dryer — Senegal design scenario
Technology sized honestly to a cooperative.
A mango drying line for a women’s cooperative in Senegal, sized to member production rather than to ambition. A mid-range burner feeds chambers at 1,500 kg per standard tunnel, with a control interface designed to be operated across a range of literacy levels and capacity added in phases.
A women’s cooperative facing distinct barriers: inability to meet formal market quality requirements, a fresh selling season of only three to four months, minimal prior experience with processing technology, limited capital, and the structural barriers restricting women’s access to agricultural technology.
The configuration
- Mid-range biomass burner sized honestly to cooperative volumes rather than to aspiration.
- Multi-tunnel configuration matched to member production.
- Simplified control interface — designed for operation across a range of literacy levels. This is a genuine engineering requirement, not a concession.
- Phased implementation — capacity added as the market grows, avoiding the debt burden of buying ahead of demand.
- Combined technical and business training.
Projected outcomes (modelled design targets)
- Meaningful income increase for participating members.
- Extended earning season through stored-product sales.
- Diversification into multiple mango product formats.
- Full transfer of operational management to the cooperative.
- Renewed engagement from younger women members.
Principles we design around
Interface design is not cosmetic — it determines who can actually operate the equipment. Cooperative structure supports technology adoption in ways individual ownership does not. Securing buyers before expanding production avoids the classic overcapacity trap. And technical support without business development produces a well-run facility with nowhere to sell.
What this scenario is
A costed design we are ready to build, not a delivered project. GreenMach has one commissioned installation — a cashew shell burner firing a steam boiler at PCCL in The Gambia — and no drying line has been built yet.
The volume assumption here is deliberately conservative, and it is an assumption. It would be replaced by the cooperative’s own recorded intake before manufacture.
The line, item by item
| Item | Specification |
|---|---|
| Burner | Mid-range within 200,000–900,000 kcal/h, sized to recorded member production |
| Hot air generator | Double chamber, three-pass, indirect exchange |
| Chambers | Standard tunnel chambers at 1,500 kg fresh per batch |
| Control interface | Simplified HMI — icon-led, few decisions, no free-text entry |
| Product contact | SS 304 trays, wagons and wearing decks |
| Phasing | Chambers and burner capacity added as contracted volume grows |
| Training | Technical and business, delivered together |
How the line would be sized
The method is the one set out for Banfora, run against member production as recorded rather than as hoped. Peak-day intake gives the water to remove, the cycle gives the rate, and the efficiency chain turns that into a fuel input.
The chain is combustion 0.85 × hot air generator 0.78 × ducting 0.95 × envelope 0.97 × exhaust 0.68 — 0.415 multiplied out, carried at 0.40. It is published because a cooperative comparing quotations should be able to tell an honest system figure from a combustion figure dressed up as one.
Phasing is what makes an honest size affordable. Buying the burner for the volume you expect in year five and the chambers for the volume you have in year one is the cheaper mistake; buying both for year five puts a debt on the cooperative before the market exists to service it.
What we would need to confirm on site
The volume question dominates, and it is answered from records rather than from a meeting.
- Recorded member production. What members actually delivered last season, by week, rather than what the cooperative aims to handle.
- Who operates the line. The interface is designed around the answer. So is the training, and so is the number of decisions the PLC asks an operator to make.
- The selling season. Fresh sales run three to four months. What the stored product is worth in month eight decides whether the phasing plan makes sense.
- Fuel access. Whether shell can be collected reliably, or whether the line should be specified for a residue mix from the outset.
Modelled design targets, not measured results
These are modelled design targets for this configuration, not measured results — we have not yet built this line.
Frequently asked questions
Why size to current production rather than to the target?
Because an oversized line is a fixed cost against a variable income. A burner bought for a volume that arrives in year 5 runs at part load for 4 years and carries debt the whole time. Adding a chamber later costs more per chamber and far less in total, and a burner at 60 % of rating leaves room for two.
What does a simplified interface actually change?
The number of decisions. A recipe is selected by icon, the setpoints come with it, and there is no free-text entry to get wrong. The line still holds 65 to 70 °C for mango on a 16 to 20 hour cycle — the simplification is in what the operator is asked, not in what the machine does.
How is capacity added in a later phase?
Chambers are added against burner headroom, so the phasing plan is really a burner-sizing decision made at the start. A burner at 60 % of rating on day one has room for two more chambers; one at 90 % does not, and the second phase then means replacing the heat plant.
Processing at cooperative scale?
We size to real member production and simplify the controls to match.
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