Ozone has been successfully applied to industrial cooling water systems with the resultant improvement in operational efficiency due to increased heat transfer, reduced system corrosion, improved environmental impact and reduced on-going chemical expenditure. The aim of this paper is to provide practical advice on the options available for the application of ozone and the potential benefits which can be realised.
Open evaporative cooling systems are used extensively throughout industry to remove heat from process systems and modern buildings for the purpose of air conditioning. Heat is dissipated to atmosphere by the evaporation of water and energy removed due to the latent heat of vaporisation of water, achieved by bringing the cooling water into direct contact with the surrounding air. As a result, open type evaporative cooling systems are subject to potential biofouling problems as a result of micro-organisms from the surrounding environment. They are also prone to corrosion due to the establishment of corrosion cells within the system fabric in contact with the aqueous medium and to scale formation due to the increasing concentration of scale forming hardness salts as a result of the cycling of mineral salts present in the system make up water due to the evaporation of “pure” water from the cooling circuit.
For optimum performance the above problems must be minimised, heat transfer surfaces maintained in a clean condition, corrosion controlled to maintain system integrity and to avoid unexpected outages and microbial activity controlled to prevent the build-up of biofilm and the proliferation of legionella bacterium. Traditional methods utilise a chemical programme incorporating chemical inhibitors and biocides which, in themselves, also present particular problems of storage and handling and potential environmental impact issues.
Economical calculations for the use of Ozone in Cooling Towers