Piping Freeze Protection for Cooling Tower
This downtown NYC financial district building requires year-round cooling tower operation. A sophisticated powerline-based monitor and control system was selected by the consulting engineer to be the most cost-effective method to protect the piping from freezing and to monitor the pipe temperatures. Forty-five remote temperature transmitters are located at every pipe location that could contain standing (non-circulating) water, based on valve positions or pump operation. All monitoring is performed without any wiring, other than power to the heater cables.
Mission critical 24/7 cooling in this financial district building requires operating cooling towers and external water piping as large as 24" in the winter. Any pipe or valve freeze-up (and burst) would be catastrophic, so a fully-supervised system of monitoring and controlling heat tracing was specified.
Distributed pipe temperature sensing was determined to be the most accurate method of verification that pipes were not in danger of freezing. A patented powerline-based heat trace monitor and control system was determined the most cost effective method of providing distributed pipe temperature monitoring. Sensors were placed in the worst-case locations, namely between each isolation valve and the corresponding pipe connections to the cooling towers. Based on valve position and pump operation, these remote locations could contain non-circulating water, which is most likely to freeze.
Remote temperature sensors (the black junction boxes) are fully addressable, self-diagnostic, and "ruggedized" for industrial, transit, and low temperature/high vibrtion installations.
A modular control and monitor panel is provided to monitor the 5000 feet of heater cable and 45 temperature sensors. The spread-spectrum powerline communication technology utilized does not require filters or isolation transmitters, making it ideal for existing and retrofit applications. The only wiring required for this system is the power feed to the heater cables. All monitoring occurs over these wires.
