There are few things that will derail a business more quickly than attempting to operate old, unreliable and inefficient equipment. So when a client in the pharmaceutical industry found themselves in exactly that position with their cooling towers, they reached out to Longo to provide some major upgrades.
When we went out to the project site, we were faced with malfunctioning instrumentation, inefficient and obsolete motors, and motor controls that were not optimized for energy usage. What we learned was that the outdated system was operating on a two-motor, two-speed system with one common shaft. When the low-speed motor was in use, it would also have to drive the high-speed motor in an idle mode. Because the system could only operate at either high speed or low speed, it was very difficult to maintain a constant water temperature, and it would often end up either too hot or too cold. Our client tasked us with removing and replacing both motors on a total of six cooling tower cells. The old temperature measurement instrumentation was replaced with new modern design sensors, and all control wiring was upgraded in accordance. Each new cell is now equipped with a single energy-efficient WEG Electric drive motor and a new Eaton variable frequency drive (VFD) to enable variable speed and ensure maximum efficiency.
Because of the critical nature of these cooling towers, we had to operate on a delicate schedule. To start, only one tower could be taken offline at a time, so we coordinated our work schedule with their production requirements to ensure their operations would not be interrupted. All of the work – rigging the new motors in place; installing the VFD power and control wiring; and instrumentation and integration – was performed by Longo’s own labor force, which meant that we were able to not only control the schedule to meet our client’s needs, but we were also able to ensure reasonable costs and high-quality service. The new equipment allows the cooling system to constantly fine tune the optimum operating speed and ensure a constant water temperature. The temperature sensors are designed to monitor the cooling of the water and send feedback to the VFDs, which then translate that information into a speed reference signal that, in turn, tells the motor what speed it needs to operate at to maintain the desired water temperature. Although all six towers are now fully upgraded, the project remains ongoing. Eventually, we will tie in the new controls and instrumentations with the company’s plant-wide supervisory control and data acquisition network (SCADA), which will allow for remote monitoring of the cooling tower operations and performance efficiency.