The Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH) has developed a cooling tower water efficiency calculator at www.mycoolingtower.com.a
The calculator and website initiative, which provides best practice information and tools, has been developed with the support of the Victorian government and water corporations.
The project aims to raise water conservation awareness to promote water efficiency in the operation of cooling towers by businesses.
The calculator provides users with an ongoing indication of the water efficiency of their cooling tower relative to its operational capabilities, which can be checked at anytime.
As stated on the website, the evaporative cooling tower was originally developed as a water conservation device and designed to reduce dependence on ‘once through’ cooling systems. It has also expanded the ability of designers to provide efficient cooling in areas without large water supplies.
With the advent of green buildings and green HVAC&R systems, today’s designs need to be energy efficient. Systems have to be commissioned, fine-tuned and periodically recommissioned under most rating schemes.
Owners want sustainable building systems as well as optimised and integrated systems that reduce operating and compliance costs. Green leases now include water and energy targets and requirements for optimised building operation.
According to AIRAH, the opportunities for improved energy and water consumption are undeniable and tower and component manufacturers have risen to the challenge.
Drift is reduced, fan efficiency is improved, fill and tower effectiveness is increased, towers are smaller, lighter and more corrosion resistant than ever before.
Previously visible plumes can be made to disappear, water consumption can be reduced, and system energy consumption can be reduced. Advances in cooling tower engineering and design means that towers can be constructed on site faster and cheaper than was previously possible.
The benefits that cooling towers offer over competing heat rejection systems, in terms of energy savings, space and capital costs continue to be a significant driver for their inclusion in HVAC&R systems.
Following is a list of the relevant industry standards provided by AIRAH.
The primary design standard for cooling towers and cooling water systems is AS/NZS 3666.1. Its primary focus is the control of microbes such as Legionella in building water and air handling systems, particularly cooling water systems and cooling towers.
AS/NZS 3666.2 is a sister standard and is concerned with the operation and maintenance of air-handling and water systems.
Both AS/NZS 3666 part 1 and part 2 are called up in the Building Code of Australia as primary referenced standards and both are mandatory in all states and territories of Australia.
Apart from building legislation, there is individual state specific legislation and regulations relating to cooling towers which should be complied with as they are relevant to both installation and maintenance.
AS/NZS 3666.3 is the third standard of the series and deals with a performance-based approach to the maintenance of a cooling water system with respect to the control of microorganisms.
The AS/NZS 3666 standards reference a series of associated documents and standards which also form requirements of the standards.
AS 5059 is a risk management standard specific to the design and operation of cooling towers associated with power stations.
There are no cooling tower product standards developed for the Australian/New Zealand application, but there are standards for components and materials used in the manufacture of towers.
Drift eliminators are assessed by the laboratory test method AS 4180.1.
AIRAH’s technical application manual, DA17 Cooling Towers, has been updated for the first time since 1997.
The recently released DA17 is the third edition of this resource and builds on previous editions by including comprehensive information on new cooling tower technologies, management strategies and applications.
In many buildings cooling towers can account for up to 50 per cent of water use, so there are new technologies outlined in the manual that minimise tower water consumption.
The AIRAH Water Conservation in Cooling Towers Best Practice Guideline is also available.
This document has been prepared to assist the owners and operators of cooling towers and evaporative cooling systems in reducing the water consumption of cooling systems while still retaining performance.
The intention is to identify the ways in which a cooling tower consumes water and outline a series of best practice recommendations to assist the tower operator or water treatment service provider in the reduction of overall tower water consumption.