5.43 A refrigeration cycle operating between two reservoirs receives energy QC from a cold reservoir TC = 275 K and re…
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Question “5.43 A refrigeration cycle operating between two reservoirs receives energy QC from a cold reservoir TC = 275 K and re…”
Answer
Heat:
Heat refers to the energy that flows from one body to the next due to temperature differences.
Energy:
It is the ability to work. It is a complex property. It also includes potential energies and kinetic energy. In a closed system, energy transfer occurs across the system boundary using only heat and work.
Refrigerator:
It’s a device that transfers heat from low temperature mediums to high temperature media.
First law of thermodynamics
It says that energy can’t be destroyed or created, but that it can be transformed from one form to the next. Energy is therefore conserved. Energy imbalance is a difference in energy entering and leaving a system.
As an example, energy balance is calculated without taking into account the potential and kinetic energies.
Figure (1) shows the schematic diagram for a refrigeration system.
Coefficient of performance (COP) for a refrigerator
The coefficient of performance is used to indicate the efficiency of a refrigerator. It is determined by
This heat is removed from the refrigerated area is while work input to this system is .
The energy conversion in the refrigeration system can be expressed using the first law thermodynamics
The heat is rejected from the warm environment by .
This is how you can express the relationship between heat transfer and temperatures in a refrigeration system.
Here, the temperature in a warm environment is while the temperature in a refrigerated area is .
The COPH of refrigerator can be expressed using the relation (1) and (2).
Calculate the maximum performance coefficient between two temperatures.
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(a)
For given conditions, calculate the new CO
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