Technical Reference For Water Conservation In Cooling Towers

Preface
In hot and humid Singapore, water-cooled chillers are one of the ways to keep buildings cool for its occupants. The air-conditioning systems rely mostly on wet /evaporative cooling towers (smaller percentage on air cooled towers) that eject heat from the building by evaporating water. Even manufacturing plants and industrial plants adopt these cooling towers to meet the cooling demand of their processes. Although cooling towers are the best available technology to meet cooling demand, competing forces such as drought conditions, growing population and increasing water demand for various uses are diminishing the water availability in Singapore. Every day a significant amount of energy is also wasted in the form of water and waste heat from air-conditioning and evaporative cooling systems. It is estimated that more than 30 mgd (million gallons per day) of water is used by evaporative cooling towers in Singapore. Reducing that water demand — and saving energy in the process — is a matter of PUB’s interest to stem further water losses to the atmosphere and instil water conservation among users. The aim of this technical guide is to provide cooling tower users, developers, building owners and managing agents with a basic knowledge of cooling tower management, and proper operation and maintenance of these equipment in their premises. By adopting this set of guidelines, PUB hopes to instil discipline and equip users on the technical knowhow for the management of these devises to maximise water savings i.e. optimise the cycles of concentration, while still meeting cooling demands for buildings or industrial processes. The topics covered seek to address concerns on the existing requirements for control of scale, corrosion, deposition and biological fouling associated with the operation of a cooling tower water system. In addition, increased efficiency in the use of energy and control of both makeup water and discharge of residual concentrate will be highlighted as well as health and safety hazards, environmental challenges, and non-chemical systems.