AIRAH hopes to enhance the sustainability of Australia’s built environments by showing owners and operator how to best conserve water.
With cooling towers accounting for as much as half of a building’s total water usage, AIRAH, the acknowledged voice of the Australian HVAC&R industry, has released a video exploring water conservation measures and other ways to improve efficiency.
“Cooling towers are effective heat rejection devices. However, they’re responsible for the use of large volumes of potable water,” said AIRAH COO Neil Cox. “Considering the increasing cost of water and concern for its future scarcity, we really need to think about managing and reducing cooling tower water consumption where possible.”
Specifically aimed at building owners and operators, the video assists in reducing the water consumption of cooling systems while maintaining required performance.
“Our aim, with the video, is to identify how a cooling tower consumes water, and outline a series of best-practice recommendations to assist tower operators or water treatment service providers in reducing the tower’s overall water consumption,” Cox said.
The video takes viewers to Federation Square in Melbourne, a site that has achieved substantial water consumption reductions by looking at its cycles of concentration. It also stops by at 1 Spring Street, a conference centre in the heart of Melbourne, and observes the building’s tower and operators in action.
From the start of 2008 through to June 2013, Federation Square has saved approximately 89 million litres of water through initiatives which have included installation of water tanks, the installation of a rainwater filtration system in the car park, and the installation of waterless urinals and AAA showerheads.
Arguably the greatest impact, however, has come from the upgrade works to the Cooling Towers.
The towers are integral to the air-conditioning of the complex. For example, the artworks in the Ian Potter Centre need an atmosphere which is precisely controlled 24-hours-a-day to 50 per cent humidity and 22 degrees, plus or minus a small margin. This system needs water, and the cooling towers previously accounted for more than 60 per cent of the precinct’s total water-use (about 90 million litres annually).
Cooling tower experts CORE Water Management Solutions recommended that it could be made more efficient by increasing its ‘cycles of concentration.’
Demand for cool air determines the load carried by the four interconnected towers. If the system works hard – for example, on a hot day – increased evaporation leads to a build-up of contaminants (salts and minerals) in the water. But if the water has too many contaminants, they encrust the pipes and the equipment becomes less efficient.
Through a series of simple adjustments to the cooling towers’ float valves, which had become unbalanced over time, and the installation of a filter on the towers’ discharge lines, which removes solids from the water discarded by the system, significant improvements have been made.
The bottom line is that this will save almost $10,000 a year in water and sewerage charges.
The video, which was created in conjunction with the Victorian Government, is just part of a comprehensive suite of communications tools that have been produced by AIRAH with the goal of optimising water usage in cooling towers.
In addition to this there are best practice guidelines, a series of case studies, an online cooling tower calculator and a series of training sessions.