Summer – Humid operation (A)

The by-pass valve is closed. The water leaving from the cooling tower side of the plate heat exchanger is first conducted to the air/water battery. It is then distributed by the nozzles over the tower packing.

The water is cooled down for a first time inside the battery thanks to convection and a second time thanks to the transmission of latent heat (via the evaporation on the packings).

In humid operation, 5 to 10% of the capacity is evacuated thanks to the cooling of the water inside the battery. The remaining capacity is evacuated through evaporation on the packings.

The drop eliminators above the nozzles make sure that the water drops don't leave the cooling tower.

Spring/Fall – Humid/dry operation (B)

Part of the water that needs to be cooled runs through the by-pass directly from the battery to the basin, without passing over the packing. A temperature probe (optional), installed on the cold water exhaust tube of the plate heat exchanger, sends a signal to the regulator (optional) which proportionally opens the by-pass valve in order for as little water as possible to run over the packing.

This operation allows to limit the use of direct water-air exchange in favor of the dry exchange inside the battery, however without limiting the water-water exchange inside the plate heat exchanger.

Depending on the external circumstances, 30 to 70 % of the capacity can be evacuated only through dry cooling. The remaining capacity is evacuated through evaporation on the packing.

The drop eliminators above the nozzles make sure that the water drops don't leave the cooling tower.

Winter – Dry operation (C)

The by-pass valve is completely open and the entire water flow is led directly to the basin. Consequently, no more water is distributed over the packing nor is any water evaporated.

The full capacity is evacuated through the battery.