A refrigeration cycle functions between a condenser temperature of +27°C and an evaporator temperature of -23°C. The Carnot coefficient of performance (COP) for this cycle will be_________________?
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Answer: C. 5
Explanation
Carnot COP for refrigeration is calculated by dividing evaporator temperature by temperature difference. Converting Celsius temperatures to Kelvin gives 250 Kelvin for the evaporator and 300 Kelvin for condenser. Dividing 250 by the temperature difference of 50 yields a coefficient of performance of 5. Absolute temperature scales like Kelvin must always be used in thermodynamic efficiency and COP calculations. The condenser temperature of 27 degrees Celsius converts to 300 Kelvin by adding 273. The evaporator temperature of negative 23 degrees Celsius converts to 250 Kelvin similarly.
Engineers use Carnot COP as an upper theoretical benchmark when designing efficient commercial chillers. Comparing actual refrigeration system performance to Carnot limits highlights potential energy efficiency improvements. Temperature lifts directly impact power consumption in HVAC systems across industrial and residential buildings. A COP of 0.2 represents an inverted ratio and violates fundamental thermodynamic refrigeration principles. A COP of 1.2 underestimates the theoretical efficiency of a Carnot cycle operating between these temperatures. A COP of 6 or 10 incorrectly calculates the refrigeration cycle formula instead of the heat pump.
- Subject
- Engineering
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- Mechanical Engineering
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- —
- Difficulty
- medium
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