What Is the Maximum Ambient Temperature for Effective Refrigeration with R-134a?

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In summary, the maximum value of the atmospheric temperature for a refrigerator using R-134a as the working fluid and operating on an ideal vapor compression refrigeration cycle with a mass flow rate of 0.05 kg/s is determined by the requirement for a minimum 5 deg-C difference in the condenser design for effective heat transfer. This sets an upper limit for the ambient temperature at the higher pressure, where the working fluid must condense.
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Homework Statement


A refrigerator uses R-134a as the working fluid and operates on an ideal vapor compression refrigeration cycle between 0.15 MPa and 1 MPa. Mass flow rate is 0.05 kg/s. If a minimum of 5 deg-C difference is used in the condenser design for effective heat transfer, what is the maximum value of the atmospheric temperature under this operating condition?

Homework Equations

The Attempt at a Solution


No idea. Wouldn't it not matter since its atmospheric temperature? Or would it be the lowest temperature in the cycle?
 
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The working fluid has to evaporate at the lower pressure and to condense at the higher pressure. The saturation temperature at the higher pressure has to higher (by five degrees as specified) than the ambient temperature. That sets an upper limit to the ambient temperature !
 

Related to What Is the Maximum Ambient Temperature for Effective Refrigeration with R-134a?

What is ideal vapor-compression?

Ideal vapor-compression is a thermodynamic process used to convert a low-pressure vapor into a high-pressure vapor by compressing it in a compressor. This process is commonly used in refrigeration and air conditioning systems.

How does ideal vapor-compression work?

In ideal vapor-compression, the refrigerant vapor is compressed in a compressor, which increases its pressure and temperature. The high-pressure vapor then flows through a condenser, where it is cooled and condensed into a liquid. The liquid then passes through an expansion valve, which reduces its pressure and temperature. The low-pressure liquid then enters an evaporator, where it absorbs heat from its surroundings and evaporates back into a low-pressure vapor. This cycle continues, providing the cooling effect in refrigeration and air conditioning systems.

What are the advantages of ideal vapor-compression?

Ideal vapor-compression has several advantages, including its efficiency in converting low-pressure vapors into high-pressure vapors, its ability to provide a constant cooling effect, and its versatility in use for refrigeration and air conditioning systems. It also allows for the use of different refrigerants, making it a flexible choice for various applications.

What are the limitations of ideal vapor-compression?

One limitation of ideal vapor-compression is that it is only an ideal process and cannot be achieved in real-world systems. There will always be some energy losses and inefficiencies in the compression and expansion of the refrigerant. Additionally, ideal vapor-compression is not suitable for all temperature ranges and may require additional components for optimal performance in extreme conditions.

How is ideal vapor-compression different from other refrigeration cycles?

Ideal vapor-compression is just one type of refrigeration cycle, but it is the most commonly used. Other refrigeration cycles, such as absorption and steam jet refrigeration, use different principles and processes to achieve cooling. While ideal vapor-compression is the most efficient and versatile, other cycles may be more suitable for specific applications or conditions.

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