Cooling Tower and Air Cooler

Cooling Tower and Air Cooler

Differences between the Cooling Tower and the Air Cooler

Many people who are inserted in this environment have doubts about which is the best option for their needs and how each one works. Although the final objective of both is the same, that is, to carry out the thermal exchange of a cooling liquid, the Cooling Tower uses a specific method to carry out the thermal exchange, and, an Air Cooler system uses a different approach.

In an industrial plant, such as a petrochemical or refinery, there is an enormous amount of equipment that generates heat, such as engines, centrifugal pumps, condensers, and chillers, among others. For this equipment to work efficiently, it is necessary to cool it down. We can make an analogy with the processor of a notebook or desktop, which also needs to be cooled to work properly. The Cooling Tower's main function is to dissipate heat, allowing equipment to operate at an ideal performance level. There are different types of cooling towers, each with its particularities and specifications, such as Counter Current and Cross Flow Towers; however, it is not our objective to carry out a comparative analysis of them.

The Cooling Tower captures water from an industrial plant, which usually comes with a high temperature (around 40°C), and cools this liquid (treated water) by reducing its temperature (≈°C). By cooling it, it returns to the system and refrigerates the equipment and engines, making the system much more efficient and performance increases significantly.

The Air Cooler has the same purpose of cooling a liquid coolant, but the process is completely different from the one used in the Cooling Tower. In the cooling tower, the saturated water directly undergoes an evaporation process so that heat exchange occurs and it is possible to remove heat from hot water, releasing it into the atmosphere in the form of steam. In the Air Cooler, the thermal exchange is indirect and the functioning is similar to that of a car radiator. A set of ventilators cools the finned bundle tubes so that the refrigerant fluid inside can be cooled.

The function of the Air Cooler is also to cool the refrigerant, but it differs in the way it is done. The fluid used in the Air Cooler is often not a liquid, but a gas. Most refineries and petrochemical plants that use Air Coolers, work with hydrocarbons, which are even used to produce final products and by-products, such as diesel and gasoline in refineries or solvents in petrochemical plants.

So it not only refrigerates the liquid or gas used to cool other equipment, but it can also cool the industrial plant's product. In a nutshell, these are the main differences between the two cooling systems.

FanTR in the improvement of cooling systems in Brazil

In Brazil, there are around 3,000 Air Cooler cells in operation, each one with its respective ventilator. Over the past five years, FanTR has been dedicated to improving the performance of these systems, seeking to work with the same operating points, with a lower power drained from the electric motor or, the same power consumed from the engines, using a higher dynamic pressure (airflow), thus providing a better thermal exchange to the system. 

The operating point is a set of variables that define the working conditions of a piece of equipment or system. In the case of the Air Cooler fan, the operating point involves the flow of air it works with, the static pressure it is subjected to, and the density of the airflow, which is influenced by the temperature, humidity, and altitude of sea level, the ventilator speed, the diameter of the equipment, among other factors. In short, the operating point represents the set of parameters that the ventilator works within a given working condition, and FanTR has been working on improving the performance of these systems while maintaining the same operating point.

One of the possibilities for gains by increasing the efficiency of the system is to maintain the airflow but with a lower power consumed. Another option is to increase the efficiency of the system through a higher air flow, maintaining the power consumed. The choice between these two options depends on the customer's needs and desires. If the current thermal exchange is satisfactory and there is no need to increase it, the customer can choose to maintain the airflow conditions, but with a lower consumption of power.

Since there is an improvement in the efficiency of the system, consequently, there is a reduction in the consumption of electricity. These savings are significant and maybe even more significant when we consider that many plants have hundreds of Air Coolers in operation. On the other hand, if the objective is to obtain a better thermal exchange, it is often necessary to increase the airflow that passes through the system. In this way, the system efficiency increases without the need for an increase in consumed power.

In most cases, customers seek to maximize the gain provided by the refrigeration system, and this involves not only energy savings but also a more efficient heat exchange. This can result in a significant increase in production, which has a direct impact on the company's profit. That's why our approach is based on understanding each customer's actual operating conditions and adapting a FanTR model design that operates most appropriately for their point of operation. In this way, we were able to significantly increase the efficiency of the system and provide benefits both in terms of energy savings and possibilities for production gains.

There were improvements that FanTR was able to provide to its customers, around 10% to 30% of real efficiency, which can represent a reduction of almost half of the power consumed previously. In other words, the customer may be operating today with a FanTR ventilator that is consuming half the power it originally worked on. In addition, there have been cases where the improvement in thermal exchange was so significant that it resulted in a 3% increase in plant productivity, specifically in the battery of Air Coolers that were replaced by our FanTR ventilators.

Henrique Braskulki - Application & Sales Engineering Department

Author: Henrique Braskulki - Application & Sales Engineering Department

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