Open cooling

We meet with many types of cooling towers or evaporative condensers.



Open cooling systems come up to cooling thanks to water evaporation. Cooling towers evaporate 1% (at old) and 2% (at new)of curculating water. Delta T (temperature of hot water on top of the tower minus temperature of cooled water down) is about 5 oC. Water is cooled below the current T of air just above the wet bulb temperature. In summer, 90% heat leaves by evaporation (we get on a minimum temperature 25 oC). In winter only 25% leaves by evaporation and 75% by cooling of cold air (we get on a minimum temperature between 5 oC-10 oC).

If you need to lower or negative temperatures, we can´t do it without compressor cooling (freon, ammonia). The evaporative condensers get on delta T to 10 oC. We have to look difference not at the bottom or and the top of the condenser, but at the layer of water on the tube plate. The layer is the highest at the metal top and it decreases toward the edge of the water layer.

Cooling towers

Scale causes insufficient splash, water flows only by local”trickle”. This leads to lower evaporation and cooling operation of tower. Biological slime can also cause the same problem.

The incidence of limescale on the tower is usually caused by insufficient or unsuitable treatment of water. Nowadays, we use chemicals based on organophosphates which increase solubility of calcium carbonate, and so it is maintained in solution even at concentrations which would otherwise have long been precipitated. Many suppliers of water treatment inform customers on ways to save water insufficiently. You can create economic balance, how much does water cost during current treatment and how much does water cost, for example, when the involvement of cation exchanger or better using of chemicals. Huge savings can also be achieved by measuring the evaporation. Erudite supplier of water treatment chemicals calculate you all this and ensure economical operation of your device.

Evaporative condensers

Scaled tubes have a strong influence on consumption of electric energy. In adition it´s possible that customer don´t refrigerate. Consumption of electric energy based on worsten tranfer of heat from refrigerant medium caused by scale (ammonia, freon) to water. Sufficiently, ammonia doesn´t refrigerate and higher pressure (more electric energy) is useful to it liquefaction. In comparison with clear condenser these costs can create 20% of energy consumption extra. For a year that is ten thousand till hundred thousand. Another condenser´s bogy is corrosion of zinc, called white corrosion. Steel is protected by a galvanized layer under it. It is really sensitive to pH, especially if we get over 8,5. White specks of zinc oxide can arise. It easy washes off by water so steel appears under it. There is one complication. Optimal pH of steel is higher than ph of zinc. We should get under 9 that means if we have both metals here, we are not able to meet both at a blow. Only one aprooved chance passivates surface by increased concentrations of phospate. Concentration aprooved us about 15 mg/l. This concentration provides to keep rests of zinc layer and together with it protects surface of steel tubes. Among other risks belong a corrosion caused by biocide treatment insufficiently. The best combination is shock dosage and alternating oxidizing and nonoxidizing biocide.
Dalším rizikem je koroze zaviněná nedostatečným biocidním ošetřením. Nejlepší je kombinace oxidačního (na bázi halogenů, Cl2, Br2) a neoxidačního biocidu, které se dávkují šokově a střídají se.

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    Česká republika 700 30
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