Cooling towers remove the waste heat from a building or facility. Hot air or steam is brought into contact with water, reducing the temperature while some of the water is evaporated and rejected from the tower.
It is an effective and efficient cooling method. However, the reliance on water for cooling raises challenges in cooler climates. If the water freezes, the cooling method fails, and damage can occur in the system.
Freeze prevention is an important consideration for cooling towers in cold climates. Due to the thermal reaction and expulsion into the environment, they cannot use antifreeze. As such, cooling towers rely on active heating systems to prevent freezing.
Here we look at some of the heaters used to overcome this challenge.
Immersion heaters are the most efficient way to prevent freezing. These heaters are submerged in the basin to keep the cooling tower’s water above its minimum temperature threshold.
Because they are immersed in the water, they provide direct heating, so there is no energy lost in the transfer. They offer 100% efficiency, with no lost heat.
The most common immersion heater used in cooling tower basins is the screw plug heater. They are designed to screw directly into the basin, usually near the bottom. They are capable of achieving target temperatures quickly, and evenly throughout the basin.
Screw plug heaters are usually used in smaller tanks, although they are generally sufficient for cooling towers. However, a larger basin may require a flanged heater. With custom configurations and still providing direct heat transfer, flanged heaters are still a highly efficient option.
In addition to the water basin, heating is also necessary for the piping. Frozen water can damage piping, block or slow flow, and prevent cooling operations. To prevent this, heat trace cables and/or pipe heaters are common solutions.
Heat trace cables are a cheap and fairly effective option. The cables are on the outside of the pipe, providing indirect heating. Although this design leaves them vulnerable to the elements and prone to damage, they are easy and inexpensive to replace.
Pipe heaters are welded directly into the tank. This means they take more effort to install. However, they are beneficial long term as they are less susceptible to damage and offer greater efficiency. For new projects, they are well worth installing instead of relying on heat tracers. Even older cooling towers can benefit from an upgrade to pipe heaters.
Digital control panels make your immersion heater intelligent. They monitor temperatures and tell your heaters when they need to turn on and off. This way, you only run the heater when necessary, minimizing your heating costs. With full automation, digital control panels require no extra manpower and maximize your operations.
In addition to controlling the heaters and monitoring temperatures, control panels can be connected to all sorts of accessories, such as low-level monitoring devices.
Using a low-level monitoring device in the cooling tower’s basin is important for safe and effective operations. If the water level gets too low, the control panel shuts the heater off. This prevents the heater elements from operating while exposed to the air, which has the potential to cause fire or explosion.
As well, this notification indicates a problem, allowing operators to get ahead of it before the issue becomes serious. It could indicate a potential leak or other problem.
Wattco custom manufactures electric heater systems for all climates and industries. Our team works with you to select the right heater types, materials, design, configurations, and wattages for your project and budget.
Contact us today for electric heater quotes and information.