Water Contamination and Water Removal in Industrial Ammonia Refrigeration Systems by Hansen Technologies Corp.

Effects of Water Contamination Water contamination in an industrial ammonia refrigeration system can lower system efficiency, and increase the electrical costs required to run the system’s refrigeration compressors.

By Control Engineering Staff April 6, 2006

Effects of Water Contamination Water contamination in an industrial ammonia refrigeration system can lower system efficiency, and increase the electrical costs required to run the system’s refrigeration compressors.

For a given pressure, the addition of water to the ammonia will raise its temperature. At typical suction pressures, the addition of 10% water by weight will increase the evaporator temperature by about 4°F (2°C). Stated another way, for a given required evaporator temperature, the addition of water to the ammonia will require a lower suction pressure.

For example, pure ammonia at -4°F (-20°C) has a saturation pressure of 12.9 psig (0.90 barg). An ammonia-water solution of 10% water and 90% ammonia by weight, at the same -4°F (-20°C) has a saturation pressure of 10.2 psig (0.72 barg). Therefore to maintain an evaporator temperature of -4°F (-20°C) in a system with 10% water contamination, the suction pressure would have to be run at 12.9– 10.2 = 2.7 psi (0.18 bar) lower than if the water were not present.

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