Open Cooling Water System

Cooling Systems are not the first part which comes into mind when thinking about processes and machinery. But for sure they often are a crucial part. A cooling liquid is used to cool down a product, process step or even room. Usually it circulates between its "point of use" where it is heated up by the process and a cooling tower to be cooled for example.

There are closed cooling systems in which the cooling water recirculated without any contact to the environment. Here we will talk about an alternative: The open cooling water system, which is more common in most industrial sectors.

Operating Principle of Open Cooling Circles and Cooling Towers

Open Circuits are open to the environment and ambient atmosphere. In a very simple system water cooling is used in form of a flow-through system. Fresh Water (e.g. from a river) is led into the system, cools down the process and is led back into its source or in general out o the system. For this principle an ample supply of water is necessary such as seawater, surface water or bore well water.

As this is not always possible moreoften loop systems for example with cooling towers are installed. Here the water cools down the process via heat transfer, is led into an cooling tower where it cools down by evaporation. Thus the cooling water can be recirculated several times. Fresh water is added constantly to replace the evaporated or drifted water.

Where water treatment is needed in Open Circuit Cooling Towers

Due to this evaporation of water, the concentration of the minerals in the cooling water gets higher and higher (see also: COC - Cycle of Concentration). Therefore there has to be a regular blowdown / bleed-off of the cooling system, where the used water is drained and replaced with fresh water with a lower concentration of foreign particles.

Nevertheless the design of open cooling towers leads to several issues where water treatment can be necessary:

  • Using the sea or a river as a source of water, there is always the risk of higher TDS, which might cause scaling or corrosion in the system.
  • When using bore well water, the risk of having high amount of TDS, or iron content.
  • City Water is usually of good quality but relatively expensive.

All these sources of water bear the risk of microbiological contamination. Algae growth and biofouling are often consequences.

Cooling Water Treatment can be an important element in order to guarantee a smooth operation. Either for preventing problems in cooling tower or the whole cooling system or for solving existing problems caused by corrosion, desposits or fouling.

Finding an alternative to chemical water treatment - The Merus Ring

Chemical water treatment is used to change the properties of the water. It often contains biocide to eliminate biofilm which is critical when leading the water back to nature.

This "traditional" water treatment is tied to permanent costs for chemicals and disposal.

The Merus Technology is an innovative alternative to chemical treatment in cooling water systems. After the installation chemical dosing can be reduced significantly or even fully replaced. In general we advice on starting with chemical dosing and the Merus

installation as a combined water treatment in order to ensure continuous cooling. We then reduce the chemicals step by step while monitoring the performance of the system until we reach the most efficient solution. In average our customers save up to 50% of chemicals some changed completely to the Merus Technology.

The Merus Technology

We offer physical water treatment with our Merus Ring. It is installed around the pipe and works with oscillations without changing the water's chemistry. In effect the solubility of foreign substances in the water is increased. Therefore deposits, corrosion and microbiological growth like fouling, algae or bacteria is reduced significantly.

We are successful since 1996 in the following major fields of application in open cooling water systems:

    • Treating only the cooling tower(s).
      In these cases we install the Merus Ring at the raisers or on the return line of the cooling water. This keeps the cooling tower free of algae and bacteria without biocides.
    • Treating one or a few heat exchangers or machines in the cooling water loop.
      To start we offer to choose the most critical heat exchanger(s), with a high tendency of fouling for the cooling water treatment. Of course it works also on other components of the open cycle like pumps or compressor coolers.
    • Treating the entire cooling water system.
      When having a corrosion problem in the cooling loop or a microbiological problem with algae in the cooling tower and biofouling in the system, we need to treat the entire cooling loop to solve the problem. Treating only part of the loop, leaves microbiological organisms in the system which can settle in other parts.

In addition, when using Merus for the cooling water treatment we might be able to run the system with higher TDS rates than usual. This enhances the COC and reduces the necessary frequency of blow down which can be a huge cost saver.

In case you are facing a problem in your cooling loop, please don't hesitate to contact us, we are sure to find the right solution for Your problem as well.

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