Challenge
Bring laboratory-grade water analysis and chemical feed control to large-scale commercial and industrial water cooling tower systems.
Solution
A custom designed, solid-state, highly accurate multi-channel fluorometer combined with a microprocessor-driven chemical feed controller.
Summary
Accurate chemical monitoring and feed control of chemicals in cooling tower water systems is required to reduce mineral scale, corrosion, and microbe growth. Relatively high volumes of expensive chemicals are required to protect these systems. /chemical_feed_controller.jpg "chemical_feed_controller")
Discharge water can create significant waste and additional demand for fresh water to replace it.
Previously existing chemical analysis systems fell into two categories: (1) low-cost, inaccurate, and wasteful, or (2) very large, expensive, and accurate. The more accurate systems were based on short-lived, power hungry lamps and expensive photomultiplier tubes that required frequent and costly maintenance. The cooling tower water industry lacked efficiency needed in a world with an increasing concern for cost-efficiency and protecting the environment from unnecessary waste.
The world's leading manufacturer of water treatment chemicals approached Tecnova with a need to reduce the costs of the monitoring and control hardware while maintaining or increasing accuracy. Tecnova designed a long-life LED and photodiode-based fluorometer. The device performs low power, high resolution, and simultaneous multi-channel analog-to-digital conversion using an Altera CPLD instead of a traditional A/D converter. The new fluorometer allows chemical concentrations to be accurately measured to parts per billion (PPB) levels.
First-generation controllers were based upon a Zilog web-enabled processor with battery-backed SRAM. Current controllers utilize the capabilities of 32-bit Philips/NXP ARM7 processors with large FLASH memory spaces. The controllers have interfaces for Ethernet, modem, USB, 4-20mA current loop, RS-485, RS-232, MODBUS, SCADA, and various sensors.
The resulting design is solid-state, web-based, with data logging, and offers flexible control with performance data viewable from any company location over the worldwide web. The system based upon the hardware and firmware developed by Tecnova earned the customer national environmental awards. These awards recognize the reduction of chemical consumption and the saving of tens of billions of gallons of water annually.
