Operational Case & Comparison
Throughput · labour · energy intensity · comparison vs sun-drying, smoke kiln, gas hot-air
What this page answers
"How does this dryer compare to what coconut farmers use today — and what does it deliver in practice, not just in theory?" This page frames the design in operational terms (throughput, labour, energy) and compares it against the four drying methods common in tropical copra regions.
Throughput & output
| Fresh shelled halves per batch | 1,819 kg (~10,004 halves) |
| Copra out per batch (at 5.0% MC) | 957 kg |
| Water removed per batch | 862 kg (litres) |
| Batches per day | 1.1 (19.7 h drying + 2 h turnaround = 21.7 h cycle) |
| Monthly output (22 working days) | ~21.1 tonnes copra |
| Annual output | ~253 tonnes copra |
Labour requirement
| Task | Time | Staff |
|---|---|---|
| Load trays at docking station | ~45 min | 2 operators |
| Wheel trolleys in, connect, start batch | ~15 min | 1 operator |
| Monitor (HMI check every 2 h) | ~30 min total | 1 operator (shared) |
| Unload copra, reload fresh | ~45 min | 2 operators |
| Cleaning (trays, floor drain) | ~20 min | 1 operator |
| Total active labour per batch | ~2.5 h | — |
Drying runs unattended overnight. One operator can manage the room alongside other duties during the day.
Energy intensity
| Electricity per batch | 214 kWh |
| Electricity per kg copra | 0.22 kWh/kg |
| Electricity per kg water removed | 0.25 kWh/kg |
| SMER | 4.03 kg water/kWh |
Why this matters
At 0.22 kWh per kg copra, the energy cost is a fraction of conventional alternatives. For context, a gas-fired vented hot-air dryer typically consumes the equivalent of 1.0–1.5 kWh/kg (including gas), and a smoke kiln uses 2–3 kWh/kg of wood energy. The heat pump's advantage comes from recycling the latent heat — the energy that evaporated the water is recovered at the evaporator coil and reused, rather than vented to atmosphere.
Comparison vs tropical copra drying methods
| Method | Cycle | Energy | Quality | Throughput | Risk |
|---|---|---|---|---|---|
| Sun-drying (traditional) | 5–7 days | 0 (solar) | Poor: dust/insect contamination, weather-dependent, aflatoxin risk, uneven MC | Low: batch limited by floor area and weather windows | High food safety, spoilage |
| Smoke kiln (direct combustion) | 24–48 h | ~2–3 kWh/kg (wood) | Brown colour, smoky flavour, PAH contamination (not food-grade for white copra) | Medium: ~0.5–1 t/batch, labour-intensive | High food safety (PAH), fire |
| Gas-fired hot air (vented) | 18–24 h | ~1.0–1.5 kWh/kg (gas + elec) | Good colour, but all evaporated moisture + heat vented to atmosphere | Medium: 1–2 t/batch, similar room | Medium energy cost, carbon, gas supply |
| Heat-pump dryer (this design) | 19.7 h | ~0.22 kWh/kg (electricity only) | White copra, food-grade SS, controlled profile, MC uniform ±0.5% | High: 1,819 kg/batch, 1/day | Low controlled, modular, low fire risk |
Production flexibility
The same room and heat pump can dry other products by changing the temperature/RH profile and tray loading: fruit slices (55°C, 8–12 h), fish (45°C, 12–18 h), cocoa beans (60°C, 24 h), chili (60°C, 10 h). The heat-pump dehumidifier approach suits any low-temperature drying task where product quality and energy efficiency matter. The U-flow air path and trolley system adapt easily — only the control recipe changes.