Cooling Tower Maintenance: Prepare Now for the Next Summer Heat Wave
Factory Authorized Service Inc.
Heatwaves in California have become a national concern. The Association of Pacific Coast Geographers says that heatwaves have more than tripled over the past 100 years as a result of the steady warming of Los Angeles.
Even more concerning is that global climate models have predicted more intense, more frequent, and longer-lasting heat waves in North America in the future.
And the problem is not restricted to summer. Last month, the Los Angeles Times published an article with the headline “Fall heatwave turns ‘happiest place on Earth’ into hottest place in America” saying that the temperature in Anaheim – where Disneyland is – had reached 98 degrees.
The heat is brought by a mixture of high pressure and offshore winds with temperatures much higher than usual. It not only makes people’s lives very uncomfortable, but it also threatens their health and their homes, fueling dangerous brush fires like the Kincade Fire that burned nearly 80,000 acres between the end of October and the beginning of November.
Your HVAC system also suffers at such high temperatures. Heat rejection can become a problem, and not taking the necessary actions to keep it running smoothly during these harsh times can lead to a complete breakdown.
Most long-term solutions to beat the heat involve building envelope improvements such as insulation, windows and doors upgrades, and specific roofing materials. The downside of these changes is usually the cost, and how long it takes to get them done.
A more cost-effective and quicker way to prepare for the next heatwave before it strikes is through cooling tower maintenance.
In a hydronic system, the cooling tower is the piece of equipment that rejects waste heat to the atmosphere through the process of evaporation. Therefore, your cooling tower has a major role when it comes to cooling your building.
If the cooling load is larger than the rated capacity of your cooling tower, it will affect performance. Factors that could contribute to efficiency loss are scale, loss of airflow across the heat exchanger surfaces, and improper water flow.
There are three major factors to consider if you want to be ready for the next heatwave.
1) Is your cooling tower tuned for the design conditions?
2) Is your system balanced to the proper flow and Delta T?
3) Do you have a good water treatment system?
Let’s look at each of these questions in depth.
1. The Importance of Your Cooling Tower Design Conditions
Cooling towers are sized to cool a specific water flow rate from one temperature to another at a design wet-bulb temperature that varies according to your geographic location (information that you can easily get from ASHRAE).
Your cooling tower gearbox, fan, fill, and the motor all contribute to achieving the desired temperature.
It’s important that each of these components is working perfectly and that they are all working in harmony.
Inspect one by one and look for signs of unusual wear of parts or maintenance requirements. This goes from oil levels to excessive vibration.
Here is a list of the basic things you should inspect on each component.
Gearbox: Sound and vibration levels, bearings, pinion shaft, lubrication, and gear teeth.
Fans: Check blades, cylinder, hub and bolts, belt, sheave, motor, VFDs, air static pressure, and speed.
Fill: Check for scale build-up and damaged fill.
Motor: Check connections, bearings, electrical balance, air gap, rotor balance, fan, and excessive heat.
2. Proper Flow and Delta T Balance
There is a big misconception that we need to address here. Some people believe that to increase cooling capabilities, you must increase water flow. By doing this you're actually decreasing the cooling tower performance because the airflow remains the same.
The cooling load of a building may change over time, and you may need to increase capacity and add redundancy to the tower.
You may be able to add more fill to a unit or install a larger fan motor to provide airflow. Sometimes you may need to add another tower cell. But, all these decisions need to be explored, you can’t just “add more water” and think that the problem will be solved.
Ultimately, make sure that your system is balanced for the proper flow and Delta T of the tower, or you can make things worse when the next heatwave comes.
3. Cooling Tower Filtration and Water Treatment
Cooling tower filtration systems help maintain heat transfer efficiencies and reduce the cost of chemical water treatment because it removes both inorganic and organic particulates from the water.
In addition, a good cooling tower water treatment plan will help prevent organic growth and scale in your tower, which also affects the cooling capability of your unit. That’s because any particulates added to the water will increase thermal resistance. As the resistance to heat transfer increases, your system requires more energy to heat or cool the water, increasing operating costs, and energy bills at the end of the month.
Removing scale from the water is an expensive, intensive and complex process, so it’s always better to prevent than to fix.
If you think that a water treatment program is expensive, take the time to compare how much you could be saving in energy consumption with maintaining your heat transfer efficiency.
Finally, if you've been spending a lot in water treatment chemical products and are worried about exposing your team to the hassle of storing and handling such hazardous substances, consider changing to a non-chemical water treatment option. There are several available now, and cutting-edge technology make them as effective as (or more than) many chemical water treatment solutions.
We can beat the next heatwave in California together. Give us a call and get ready for it ahead of time!
Factory Authorized Service is the only company you’ll need to plan a proper maintenance plan for your cooling tower—and the rest of your industrial HVAC system. We have experience in servicing all the major brands, including Evapco, Baltimore Aircoil, Marley, Recold, and more! Contact us today to start the process of ensuring your cooling tower is reliable, safe, and performing at optimum energy efficiency.