
Excel Consultant And Services Pte Ltd


Background
Ammonia refrigeration systems utilize ammonia to absorb heat from one area and transfer it to another for dissipation. Due to its ability to remain at significantly lower temperatures compared to room temperature, ammonia is an excellent choice for efficient cooling. Typically, evaporative cooling towers facilitate the heat removal process in these systems. However, the skin temperature in the cooling coils often exceeds 60°C, with some systems reaching temperatures as high as 70°C or 80°C. At these elevated temperatures, mineral scaling becomes a common issue, and traditional phosphate treatments often fall short in preventing scale formation.
Challenges Faced
Mineral scales precipitate in cooling water once they exceed saturation thresholds. To mitigate scaling within the coils of evaporative cooling towers, systems are often operated at lower cycles of concentration (COC). Conventional phosphate treatments are less effective, as they can lead to the formation of calcium phosphate scale on the hottest surfaces of the coils. This scaling impedes heat transfer efficiency, causing the compressor to operate under higher loads and increasing energy consumption. In severe cases, this can necessitate costly piping replacements.
Results Achieved
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Increased COC: The cooling system successfully increased its cycles of concentration from the previous range of 4-5 to an improved 7-9, enhancing operational efficiency.
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Reduced Cleaning Frequency: With effective scale control, the need for monthly cooling tower cleanings has been eliminated. The current schedule has transitioned to bi-monthly cleanings, with plans to move to quarterly cleanings if results remain favorable. This change not only conserves water but also reduces manpower requirements.
These outcomes demonstrate the effectiveness of the new treatment approach, optimizing the ammonia refrigeration system's efficiency while minimizing maintenance needs and operational costs