Cooling towers are a part of a central cooling plant supplied on a turnkey basis which can be controlled by a fully programmable microprocessor. They are used to carry off heat from production plants with higher temperature levels and work according to the principle of evaporation. To prevent pollution by contaminated water from the cooling tower circuit, the cooling circuits and cooling tower are separated by an installed plate heat exchanger. This is an important consideration for environmentally conscious industries. Covering a range of capacities from 50 kW to 1200 kW, all-plastic cooling towers resist the most extreme climatic conditions, because all the parts are produced from durable plastics. Axial fans with pole-changing motors are matched to the capacity and operate at a reduced noise level.