November 2021 Volume 3

EQUIPMENT & TECHNOLOGY

Cold Water, Winter Weather and Your Power Supply By Josh Carney

With the change of seasons and the cold weather expected by those in the Northeastern and Midwestern states, a little preparation is needed if one desires to do well in the coming winter months. Is the home heating source operational? Check. Mud and snow rated tires? Check. De-icer? Check. Snow scraper? Check. Hot beverage? Double-check. Likewise, our water-cooled induction power supplies need specific preparations for the coming cold season as well. Indeed, we need to inspect items like cooling tower controls, heaters, glycol/anti-freeze content, and water leaks. All this ideally before the freezing weather arrives. Cooling Towers Generally, cooling tower operation is governed by automatic controls. The fans, open-loop spray water pumps, make-up water, chemical addition, and tower heaters- if so designed, should operate automatically. If this is not the case, special procedures and precautions ought to be in place governing the operation of these controls in the event of freezing weather. Cooling tower freeze-up can cause significant damage to the tower coils and pump systems. Operating the spray pump during freezing temperatures without a heat source, either the process waste heat or tower heaters, can cause damage to the pump, spray nozzles, exchanger tubes, tower fill, and cooling fans. Automatic controls which operate tower fans and spray pumps based on the process cooling water temperature (water that cools the power supply and other equipment) can prevent unnecessary operation of these motors. This practice not only extends the life of the equipment but also saves money by minimizing utility costs.

Heaters Cooling tower heaters are often installed to prevent the open-loop water from freezing when the process waste heat or environmental heat is unavailable. Cooling tower heaters, power supply enclosure heaters, water line trace-type heaters should be checked before they are needed. Power supply enclosure heaters are uncommon; however, some customers use these when locating the power supply in a building without climate control. The advantage of heating the enclosure is that it raises the dew point, thus reducing the ability for condensation to form on the non-water cooled components. One disadvantage of enclosure heating during cold weather is that if an internal water leak is present, the warm air can become saturated with water vapor. Moisture may then condense on water- cooled components leading to corrosion. Enclosure heaters should: circulate the air, not be adjacent to any energized components, and not cause excessive heating of control circuit boards or temperature- sensitive components. Anti-freeze Solutions Solutions of propylene glycol or ethylene glycol can be used to lower the freezing point of cooling water and prevent caused by ice. When considering the use of anti-freeze chemicals, always refer to the manufacturer’s recommendations. We recommend a concentration of no more than 40% uninhibited ethylene glycol to 60% distilled water. When blended with water, the glycol/water solution should have a basic pH of between 7 and 9.

Ice and debris can damage circulation pumps like the one pictured. Photo source: Integral Power Technologies

Pocket sized refractometer for measuring the glycol content in cooling systems. Photo source: Integral Power Technologies

FIA MAGAZINE | NOVEMBER 2021 11