I was on a trip passing through Delaware, the first state, when I noticed this cooling tower installed at grade level. It looked strangely out of place, so I took a closer look. Now, Whitney Houston said, and most would agree “I believe that children are our future.” However, the installation of this cooling tower may not support that statement. It has been installed at grade level adjacent to a children’s playground.
Before we go into why this is not safe and could be dangerous to the health of children that use this playground, let’s look at how this HVAC equipment works.
Cooling towers dissipate and remove heat from water-cooled refrigeration and air conditioning systems, such as chillers. Basically, what this means is that when chilled water passes through the air conditioning unit in the space being cooled, called the evaporator, directly or indirectly, it picks up the heat from the space. This water which has now increased in temperature needs to be taken outside so it can lose this absorbed heat, and reduce its temperature back to where it can be used again. It’s all a cycle.
This is where the cooling tower comes in. The cooling tower takes this “hot” water from the condenser side of the refrigeration cycle, and exposes it to a very large area that comes in contact with the atmosphere. This process can be done with spray nozzles for the water, and fans move atmospheric air through the spraying water.
When this happens, some of the water coming in contact with the air uses some of the previously absorbed heat energy, to change state from liquid to vapor. This leaves the water cooler and the air warmer. The heat that is exchanged and used to bring about this change of state is called the heat of vaporization.
Okay, so what does this have to do with the safety and wellbeing of those children? Well, the water vapor produced and atomized water from the spray is released into the ambient air surrounding the cooling tower, and it usually has the ideal temperature range for Legionnaires disease bacteria growth, 20°-50°C (68°-122°F). Also a small pool of water collects at the bottom of the cooling tower, that’s ideal for bacterial growth. And, air blowing over this pool of water adds to the water vapor being released.
Below is a schematic picture of this type of cooling tower, called a blow through type.
Cooling towers dissipate and remove heat from water-cooled refrigeration and air conditioning systems, such as chillers. Basically, what this means is that when chilled water passes through the air conditioning unit in the space being cooled, called the evaporator, directly or indirectly, it picks up the heat from the space. This water which has now increased in temperature needs to be taken outside so it can lose this absorbed heat, and reduce its temperature back to where it can be used again. It’s all a cycle.
This is where the cooling tower comes in. The cooling tower takes this “hot” water from the condenser side of the refrigeration cycle, and exposes it to a very large area that comes in contact with the atmosphere. This process can be done with spray nozzles for the water, and fans move atmospheric air through the spraying water.
When this happens, some of the water coming in contact with the air uses some of the previously absorbed heat energy, to change state from liquid to vapor. This leaves the water cooler and the air warmer. The heat that is exchanged and used to bring about this change of state is called the heat of vaporization.
Okay, so what does this have to do with the safety and wellbeing of those children? Well, the water vapor produced and atomized water from the spray is released into the ambient air surrounding the cooling tower, and it usually has the ideal temperature range for Legionnaires disease bacteria growth, 20°-50°C (68°-122°F). Also a small pool of water collects at the bottom of the cooling tower, that’s ideal for bacterial growth. And, air blowing over this pool of water adds to the water vapor being released.
Below is a schematic picture of this type of cooling tower, called a blow through type.
Lastly, the water passing through the cooling tower is chemically treated. And, you guessed it. Those chemicals also get released into the atmosphere.
So what is Legionnaires disease? The Mayo Clinic have the best definition:
So what is Legionnaires disease? The Mayo Clinic have the best definition:
And a little history from Wikipedia:
Legionnaires' disease is a severe form of pneumonia — lung inflammation usually caused by infection. Legionnaires' disease is caused by a bacterium known as legionella. Most people get Legionnaires' disease from inhaling the bacteria. The legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Separately or together, the two illnesses are sometimes called legionellosis. Pontiac fever usually clears on its own, but untreated Legionnaires' disease can be fatal.
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