Ways To Improve Water Consumption In Cooling Towers
Evaporative cooling towers are one of the most popular forms of cooling methods used in thermal power plants. The water that is used in these evaporative cooling towers is often wasted and not reused. This high-temperature water when released into the natural environment causes damage to the flora and fauna in the form of thermal pollution.
Cooling tower efficiencies at power plants can be greatly improved by better management of the re-circulated water. Mentioned below are some of the major ways in which cooling towers can lower their water consumption and improve their efficiency.
- Maximizing Concentration Cycles- The cycles of concentration in a cooling tower are the number of times water is recycled before it is discharged. This number is also known as blow-down. It is also the number of times fresh water can be run through the cooling towers before the dissolved minerals drop out of the solution. A cooling tower is operating at its minimum efficiency if the number of cycles of concentration is three. The number of concentration cycles is primarily dependent on the quality of water that is being used and the water treatment process that is being used. Modern systems have been developed that reduce the dependency on chemical treatments. This reduces the possibilities of scaling and corrosion. Increasing the cycles of concentration from three to six will result in a 20% reduction in water consumption.
- Plan set points for reducing blowdown- Increasing blowdown water for preventing biological growth and corrosion is an inefficient method and causes loss of water. Installing a conductivity meter at pre-planned points can not only help in conserving water and you’ll also reduce sewage generation.
- Install conductivity controllers for automatic blowdown control- Conductivity in water is generated by the dissolved minerals. An automatic conductivity controller measures the pH of the water, determining the number of dissolved minerals and then discharges fresh water when it exceeds a given threshold.
- Install flow meters- Installing flow meters on make-up and blowdown lines can help in measuring the ratio between make-up water and blowdown water. The ratios should ideally match the targeted cycles of concentration. If the ratios are not equal, then it indicates leakage in the tower or some form of unauthorized draw-off. If the targeted cycles of concentration are not reached, then the systems must be checked, especially the blowdown valve and make-up valve.
- Conduct routine maintenance of air handler coils- These air handler coils become dirty with time and this increases the cooling load on the water systems. This additional load also increases electricity consumption and puts stress on the evaporative process.
- Carefully monitor water levels- Continuously monitoring water levels will allow easy identification of leaks and valve malfunctioning. If the water levels are set too high, then it might result in water loss since strong airflows can result in choppiness of the water surface and flow of water. The water levels in the sump should be regularly checked and maintained and excessive use of water can be avoided.