<![CDATA[Natural gas, that has been processed and met certain specifications, is sent to consumers through pipeline. Gas condensation within the pipeline should be avoided because it has negative impacts. Hydrocarbon dew point is a measure of the easiness of gas condensation. To meet the hydrocarbon dew point, heavy hydrocarbon should be extracted in dew point control unit (DPCU). The extraction is done by gas cooling in gas chiller followed by separating the liquid formed in low temperature separator (LTS). The gas chiller functions as an evaporator in the DPCU refrigeration cycle. Propane is a common refrigerant in the DPCU. In addition, ammonia is also a potential refrigerant due to its normal boiling point being close to the hydrocarbon dew point. Refrigeration cycle performance depends on evaporator temperature, condensor temperature, and the inherent pressure-enthalpy (PH) characteristic of the selected refrigerant. This study aimed to compare the performance from ammonia and propane against the change of evaporator and condenser temperature. This study was a dry research using Aspen Hysys V11.0 simulation software (academic license). The refrigeration cycle was a simple cycle with fixed variables in the form of evaporator load, saturated liquid at outlet condenser, and saturated vapour at outlet evaporator. This study indicated that at the same evaporator load, evaporator temperature, and condenser temperature, ammonia refrigeration cycle was better than the propane because coefficient of performance (COP) of ammonia was higher than propane. This study also modeled COP changes of propane and ammonia as mathematical equation. Quantitatively, it appeared that COP of propane was more sensitive than ammonia against both evaporator and condenser temperature changes.]]>
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