What is IDEC? Indirect Direct Evaporative Cooling explained

IDEC in one paragraph

IDEC — Indirect Direct Evaporative Cooling — cools air in two stages using water instead of refrigerant. In the first, indirect stage, outdoor air passes through a heat exchanger whose other side is wetted and evaporating; the supply air is cooled without gaining moisture. In the second, direct stage, the pre-cooled air passes through wetted media and cools further by evaporation. Because the first stage lowers the air's wet-bulb temperature, the combined system reaches supply temperatures that a plain evaporative cooler cannot — often 20°C or more below outdoor temperature in Riyadh conditions — while consuming only fan and pump electricity.

Why it matters in Saudi Arabia

Cooling is the single largest electricity load in the Kingdom’s buildings. Conventional air conditioning recirculates indoor air and spends most of its energy on compressors. IDEC supplies 100% fresh, filtered outdoor air and removes the compressor from the equation. The result for owners: up to 90% lower cooling electricity — and up to 70% lower total running cost once water is included — better indoor air quality, simpler maintenance and lower peak demand — with the greatest gains in the dry inland climate of Riyadh, Qassim, Hail and the north, and strong results in Taif, Al Kharj and the Eastern Province with the right design.

Where it fits — and where it doesn’t

IDEC excels in spaces with high fresh-air needs or high heat loads: factories and workshops, warehouses, showrooms and malls, halls and mosques, kitchens and food production, schools and sports facilities, and semi-outdoor areas. It is not a like-for-like replacement for a sealed office with very low fresh-air rates, and in humid coastal climates the application is validated case by case with a full-year psychrometric study. A short check of your city and application tells us quickly whether IDEC is the right answer.

Proof from the field

Dosan Energy, sole Oxycom partner in Saudi Arabia, has delivered the two largest IDEC installations in the Kingdom: the Alfanar HVDC factory in Riyadh (117 IntrCooll Plus units over 88,350 m² — the largest IDEC installation in the world) and Tera Mall in Taif (51 units). Retail, food & beverage, education and restaurant references are in our projects.

See the Alfanar HVDC factory →

What is the difference between IDEC and adiabatic pre-cooling?

IDEC supplies cooled fresh air to a space. Adiabatic pre-cooling (PreCooll) cools the air entering chillers and condensers so existing mechanical cooling uses 20–40% less energy.

PreCooll chiller pre-cooling →