Cooling towers are vital for many industries that need to remove excess heat from their processes, such as power plants, manufacturing, and HVAC systems. Without cooling towers, these industries would face higher operating costs, lower efficiency, and potential equipment damage. Therefore, designing cooling
towers that are efficient, cost-effective, and durable is a crucial task for engineers and buyers. In this article, we will discuss two key considerations for cooling tower design that can help you achieve these goals: operational excellence and material selection.
Key Considerations
1. Operational Excellence over Capital Expenditure
One of the main challenges for cooling tower design is finding the optimal balance between power savings, minimal footprint, and advanced engineering practices and technologies. While capital cost considerations may tempt designers to choose smaller cooling towers and fans, this can result in higher power consumption and operational costs in the long run.
To reduce operational costs, designers should select lower power motors and use high-efficiency fills, larger cooling towers, and other upgrades in fan cylinders,
water distribution systems, and drift eliminators. These features can enhance the cooling performance and reduce the energy consumption of the cooling tower.
For example, suppose a design engineer has to design a cooling tower of specific specifications. Two options are available: Option 1 with a 10m x 10m cooling tower, 5.5m fan diameter, and a 45-kW motor, and Option 2 with a 7.5m x 7.5m cooling tower, 6.1m fan diameter, and a 63-kW motor. Option 2 may seem cheaper upfront, but when considering operational costs, Option 1 is the more cost-effective choice, leading to significant savings in the long run.
2. Material Selection & Filling Type
Another major challenge for cooling tower buyers is choosing the right material and filling type. To ensure long-term success and cost-effectiveness, it is vital to select materials and fillings that match the specific surroundings or applications. Survival of the fittest principle, akin to Darwin’s theory, emphasizes that those best adapted to their environment have the highest chances of success. Likewise, cooling tower design must select structures and filling types that are most suitable for the specific operating conditions.
Choosing the wrong material or filling can cause operational and maintenance problems, leading to substantial financial losses. Therefore, careful consideration and proper selection of cooling tower materials and filling types are crucial to avoid such issues and ensure long-term success.
Some other factors to consider when selecting a cooling tower material and filling type are:
Cooling tower type: Tower design can vary based on draft (natural or mechanical), flow (counter-flow or cross-flow), and loop type (open or closed). Each design has its own advantages and disadvantages in terms of performance, efficiency, cost, space, noise, etc. The optimal design depends on factors such as heat load, water flow rate, wet bulb temperature, environmental conditions, etc.
Available space and budget
Environmental conditions such as wind speed, humidity, ambient temperature, etc.
Noise level and vibration tolerance
Maintenance requirements and serviceability
Energy efficiency and sustainability goals
At GS Cooling Towers, we aim to offer the most appropriate solution to the client based on their specific operating conditions. To better explain this, we would
like to share two recent case studies of cooling towers installed by us.
Case Study 1: Rebuilding Cooling Towers with Pultruded FRP Structure and Lower Operating Cost
In one of the leading steel plants, the client was facing several problems in their old 29 units of cooling towers installed by a US-based company. They took proposals for the complete rebuilding of cooling towers from several companies, but were not satisfied with the solutions provided by them.
Our engineering team, with the help of principles specified in this article, took the task of re-designing the cooling towers from scratch. Satisfied with our proposal, the client allowed us to conduct a pilot in one of the cooling towers. With the pilot being successful, we were awarded the order for complete rebuilding of 29 units, which we completed to the client’s satisfaction.
Among the many improvements, two major solutions executed were closely related to the principles discussed in this article. Firstly, the old towers constructed with hot-dipped galvanized steel experienced heavy corrosion due to the plant’s corrosive environment. To address this, we chose Pultruded fiberglass Reinforced Plastic (FRP) as the construction material for the tower structure. Pultruded FRP is lightweight and offers excellent corrosion and rot resistance.
Secondly, the old towers featured a belt and pulley drive system for the fan, which frequently broke down and had low availability of spares. We replaced it with a high efficiency, energy-saving fan coupled with a direct drive low-speed motor. This modification reduced energy consumption by 25%, resulting in significant operational cost savings with a payback period of two years.
Case Study 2: Replacing Film-Type Filling with Splash-Type Filling
In another major plant in Orissa, the client was facing several problems with their cooling tower due to issues of poor performance and very frequent maintenance. The cooling tower was a cross-flow type wooden structured tower with film-type filling.
We understood the site conditions and concluded that the site environment was dusty, due to which the film type fills were getting constantly clogged leading to poor efficiency and frequent maintenance. The wooden structure of the cooling tower was also requiring frequent maintenance.
So we redesigned the cooling tower and changed the structural material from wooden to Pultruded FRP, and the filling from film-type to splash-type while maintaining the required operating parameters. The splash-type filling is more suitable for dusty environments as it has less chances of clogging. It also has a lower pressure drop than film-type filling, which reduces energy consumption.
The solution turned out be a huge success and helped the user to run his plant at its full efficiency.
Conclusion
Cooling towers play a crucial role in many industrial operations, but they require thoughtful design to achieve efficiency, cost-effectiveness, and long-term success. By prioritizing operational cost savings over capital expenditure, and using advanced engineering practices, designers can create cooling towers with enhanced power efficiency. Moreover, by selecting suitable materials and fillings that are most suitable for their specific operating conditions, they can ensure optimal performance and longevity.
Ultimately, well-designed and sized cooling towers contribute to improved industrial operations, reduced energy consumption, and increased sustainability in the long run.