A question about refrigerators and energy

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SUMMARY

The coefficient of performance (COP) of the refrigerator discussed is 5.40, with the compressor consuming 30.0 J of energy per cycle. The heat energy exhausted per cycle is calculated to be 192 J. For part b, the problem requires determining the lowest possible temperature of the cold reservoir given a hot-reservoir temperature of 27.0°C. The relationship between the temperatures and the COP is defined by the equation K=TC/(TH-TC).

PREREQUISITES
  • Understanding of thermodynamic principles, specifically the coefficient of performance (COP).
  • Familiarity with the equations governing heat transfer in refrigeration cycles.
  • Knowledge of temperature scales and conversions, particularly Celsius.
  • Basic algebra for solving equations related to thermodynamic systems.
NEXT STEPS
  • Study the derivation and application of the coefficient of performance (COP) in refrigeration systems.
  • Learn about the Carnot cycle and its implications for refrigeration efficiency.
  • Explore the relationship between heat transfer and work input in thermodynamic cycles.
  • Investigate temperature conversion methods and their relevance in thermodynamic calculations.
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Students studying thermodynamics, engineers working with refrigeration systems, and anyone interested in understanding the principles of energy efficiency in cooling devices.

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Homework Statement



The coefficient of performance of a refrigerator is 5.40. The compressor uses 30.0 J of energy per cycle.

a) How much heat energy is exhausted per cycle?
b) If the hot-reservoir temperature is 27.0C, what is the lowest possible temperature in C of the cold reservoir?

Homework Equations



K=TC/(TH-TC)

QH = QC + Win

The Attempt at a Solution



solved part a) and found the energy to be 192 J

i keep on getting part b) wrong though and I ran out of chances to try.

please help!
 
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What is the COP (coefficient of performance) in terms of Qh, Qc, and/or W?
 

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