While recirculating water and due to evaporation losses, the amount of dissolved minerals increases in the cooling tower. Ffbe armageddon redditДepending on the type and material of the cooling towers, several parameters shall carefully monitor to prevent corrosion, fouling and scaling. Ryznar indices less than 6 indicate that calcium carbonate is likely to precipitate from the water, and values greater than 6 suggest the water will dissolve calcium carbonate, i.Depending on water source and its properties, treatment might be required. The Ryznar index uses the same operating variables, but the index value is always positive. In the case of the Langelier Index, positive index numbers indicate a scaling condition and negative numbers a corrosive or non-scaling condition. The pH s is the theoretical pH at which calcium carbonate is in equilibrium with the calcium hardness and total alkalinity. These indices use the total dissolved solids, temperature, calcium hardness, and total alkalinity of the cooling water to compute the pH of saturation or pH s. The Langelier and Ryznar Indices are often cited as the best indicator of the scaling or corrosive tendency of the recirculating water. Unfortunately, because of the numerous variables involved in cooling water chemistry, there is no universally accepted method for determining the maximum cycles of concentration. Since the purpose of the cooling tower is to conserve water, it is desirable to operate at the highest concentration ratio, while, at the same time, staying below the solubility limits of the dissolved minerals in the makeup. These relationships indicate that the higher the cycles of concentration, the lower the bleed rate and, therefore, the lower the makeup rate. The relationship between the required bleed rate and the cycles of concentration is given by the expression.Д¬ycles - 1. The water lost by evaporation and bleed off is replaced by fresh makeup water.

The bleed off water discharges the concentrated solids in the cooling water to drain. The cycles of concentration are controlled by the deliberate bleeding of water from the system.

Generally the chloride ratio, conductivity ratio, or magnesium ratio is taken as the indicator of cycles of concentration, since these impurities are relatively soluble as compared to calcium carbonate. The cycles of concentration or concentration ratio is defined as the ratio between the impurity levels in the recirculating water to the same impurity level in the makeup water. Here the dissolved solids precipitate to form a mineral scale or sludge deposit in the system This normally occurs in areas of high heat transfer such as in a heat exchanger. If left unchecked, the solids eventually concentrate to the point of saturation. As the evaporation process continues, these mineral solids concentrate in the recirculating water. The heat picked up in the heat exchanger is returned to the cooling tower where it is rejected to the atmosphere by evaporative and convective cooling.

The purpose of a cooling tower is to conserve water.

Cooling tower makeup water rate