How do cooling towers affect IAQ? What possible adverse impact does chemical treatment of cooling towers have on the environment? What is the present outlook of the cooling towers sector in the region? Jerome Sanchez turns to industry players to gather their perspectives and insights on various issues surrounding cooling towers.

Several cases of outbreak of Legionnaire’s disease from around the world point to cooling towers as the possible cause of its spread. The biggest risk of Legionella infection reportedly occurs when people breathe in miniscule droplets of infected water. Evaporative cooling towers are said to spray such droplets on their fill to maximise heat transfer and, by doing so, create the risk of spreading Legionella. In the light of these reports attributing the spread of the disease to cooling towers, there has been an increased attention on their management and maintenance and the best ways possible to keep them clean and, therefore, safe.

The cooling towers sector in the region

Aslan Al-Barazi, Executive Director, IMEC Electro Mechanical Engineering, shares his insights on the present status of the cooling towers sector in the region, particularly in the UAE and Qatar, where his company is heavily involved. “The last few years have surely not been good, neither for the cooling towers industry, nor for the contractors,” says Al-Barazi. Despite this, he observes that at present, he can sense a positive outlook and hope for the sector. “What is interesting, though, is the contrast in their answers when you spoke to them, say, in September and when you speak to them now,” he reveals. He points out that the tenders moving in the market now are more “solid” and more viable than they were in the last few years. “The bottom line is that the market is moving positively; now and the next year – 2013 and 2014 – are expected to be the turning point for the industry – a recovery scenario,” he comments.

Georges Hoeterickx, Director of Business Development, Evapco Europe, shares the same positive outlook when he says that projects that were being drawn up since 2008 have already reached the market. He also points out that though the cooling towers market got reduced in size in some parts of the region, it has actually flourished in other parts, like in Saudi Arabia and in Qatar during the downturn. This, he continues, prompted many Dubai-based contractors to look for projects in the Kingdom and in Qatar.

Al-Barazi supports this observation. In his opinion, the Saudi market is very “bullish” and has the ability to thrive despite the recession. “The Saudi market is a large market, which stands, in my view, as an independent market from the rest of the GCC markets,” he says. “It has economic strength and the ability to move forward independent of the negative economic figures of both the local and the global economies.” Similarly, Al Barazi expresses his optimism on the Qatari market as he expects that the World Cup 2022 will have a positive effect on the industry. “Current work is mainly focused on infrastructure, though the MEP industry is beginning to feel its effect at present, with many consultants on the design board,” he observes.

Ashwani Koul, Managing Director, GEA Polacel Cooling Towers, agrees with the other two industry players, as he notes that Saudi Arabia and Qatar always had the potential as markets. He, however, points out that the countries have very slow implementation processes. Koul adds that, in addition to looking for projects in these two countries, GEA’s strategy to thrive during the downturn was to diversify its product line to give them access into other market segments. “GEA started operations in 2008, exactly when the downturn hit the markets,” Koul says. “UAE was the biggest casualty of the downturn. However, the losses in the UAE were recovered in [some other parts] of the region. Also, despite GEA Polacel’s strength in the HVACR market, the global structuring of its product line gave it a small window into other markets.”

Antoine Stephan, General Manager, Hamon CTC, points out that, in his opinion, the economic downturn has not passed, and the recovery has been slow and has not been steady. In his estimation, it will still take one or two years before one can sense an economic recovery.

IAQ and cooling towers

Both Al-Barazi and Hoeterickx regard the connection between cooling towers to IAQ to be indirect, if not remote. Despite this, they do not discard possible scenarios when IAQ could actually be affected by cooling towers. Hoeterickx explains: “There is no direct relationship between cooling towers and IAQ. The only possible relationship could be that contaminated discharge air from the cooling towers could enter the air intake system and, as such, reach the occupants.”

He believes that cooling towers, like any other product, need to be designed to operate safely and efficiently. “Safe does not only mean [the availability of] mechanical protection like fan guards, safe access platforms, and the like, but it also means that cooling towers should be designed to minimise the potential development of bacteria in the cooling tower water. These bacteria can eventually cause Legionella disease outbreaks,” he warns.

In this regard, Hoeterickx reveals that, in his opinion, many cooling towers sold in the GCC countries do not meet the normal requirements to minimise or eliminate the growth of bacteria. “Cross flow type towers, despite their drawbacks, are still used in spite of the fact that sunlight can enter directly into the water basin and, thus, enhance the development of algae in the water,” he says. He adds that the presence of algae in cooling towers is a precursor to the growth of bacteria.

Al-Barazi provides another scenario, saying that the location of cooling towers could perhaps affect IAQ. “Cooling towers have a remote effect on IAQ if they are wrongly situated in close vicinity to the air intake side of the consumer circuit or if they are situated outdoors and are very close to the surrounding buildings,” says Al-Barazi.

He adds that in the early design stage, the wind direction should be carefully considered, and suggests that the location of the cooling towers relative to the surrounding buildings should be at a minimum of 50 to 100 metres in plant rooms or district cooing applications. For the package range cooling towers, he proposes that they be placed on the roof or as distant as possible from passersby or occupants, if placed on the ground.

A few dos and don’ts

The industry players are unanimous in saying that regular maintenance and cleaning is still the best way to prevent the presence of contaminants and bacteria, such as Legionella, in cooling towers. “Needless to say, a good water treatment programme is the best preventive medicine against dangerous airborne contaminants and bacteria, like Legionella,” says Al-Barazi.

He emphasises that the presence of algae and scaling inside cooling towers create a prefect breeding ground for Legionella. This, he adds, is not only dangerous for occupants but also for workers who breathe the air in the vicinity of cooling towers. He, then, offers a piece of advice for anyone maintaining or inspecting a cooling tower: “Do not open the access door of the cooling tower and put your head inside for inspection while the tower is in operation, as you would expose yourself to the risk of inhaling airborne bacteria, like Legionella.” In this context, Al-Barazi stresses the importance of educating and training maintenance personnel and of entrusting the operation and maintenance of cooling towers to experienced and reputable facilities management companies.

Koul shares his observation that, owing to lack of experience and expertise on the part of some cooling tower maintenance providers, problems such as corrosion, scaling and biological fouling continue to exist unaddressed. “The [persistence of the] afore-mentioned problems are due to lack of proper maintenance and management of cooling towers and water treatment,” explains Koul, and offers a solution: “If clients, as in mature markets like the US, Europe or India, give the responsibility of managing and maintaining the equipment to the product manufacturers, this problem will not happen or will be drastically reduced.”

More than the elimination of bacteria and contaminants, regular maintenance and cleaning are extremely important for the lifetime of the equipment, keeping the performance and efficiency as per design and avoiding the development and growth of bacteria, believes Hoeterickx. Al Barazi, on his part, points out that regular maintenance and cleaning ensures that the critical parts of the cooling tower, like the PVC fill and the water distribution system, will not clog and, hence, last much longer, reducing the life cycle costs for the clients.