A refrigerating system operates with a suction pressure of 10 kg/cm² gauge and condensing pressure of 67 kg/cm². What is the refrigerant________________?
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Answer: B. Carbon dioxide
Explanation
Carbon dioxide operating pressures are notably high, with typical suction and condensing pressures matching these values in CO2 refrigeration systems. Refrigeration cycles utilizing carbon dioxide operate at exceptionally high pressure ratios compared to conventional halocarbon systems. Pressure levels around 10 kg/cm² suction and 67 kg/cm² condensing are characteristic of transcritical carbon dioxide refrigerant circuits. Carbon dioxide, designated as refrigerant R-744, operates at significantly elevated thermodynamic pressures in refrigeration cycles. High-pressure refrigerants require heavy-duty compressor designs and reinforced piping to withstand extreme mechanical stresses. Thermodynamic property charts for carbon dioxide display high critical pressures and unique saturation line characteristics.
Ammonia systems operate at much lower, moderate pressures compared to the high-pressure demands of carbon dioxide circuits. Freon refrigerants operate at lower pressures and cannot sustain the high pressure values specified in this problem. Brine acts as a secondary liquid coolant rather than a high-pressure primary phase-change refrigerant gas.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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