Consider the following statements: High condenser pressure in a refrigeration system can occur because

The water flow rate is lower than the desired value.

Non-condensable gases are present in the system.

Of accumulation of lubricating oil in condenser.

Of low charge of refrigerant in the system.

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BPSC AE Paper V Mechanical 2024 Official Paper

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Answer 1

Explanation:

High Condenser Pressure in Refrigeration Systems

High condenser pressure in refrigeration systems can significantly impact system performance and efficiency. Understanding the causes of high condenser pressure is crucial for diagnosing and addressing the issue effectively. The correct answer to the question is Option 2: 1, 2, and 3 are correct. Let us analyze each of the given statements in detail.

Statement 1: The water flow rate is lower than the desired value.

This statement is correct. A lower water flow rate in the condenser cooling system reduces the heat transfer capacity of the condenser. As a result, the refrigerant cannot reject heat efficiently, leading to an increase in condenser pressure. Proper water flow is essential for maintaining optimal heat rejection and ensuring the condenser operates within its designed pressure range.

Statement 2: Non-condensable gases are present in the system.

This statement is also correct. Non-condensable gases, such as air, can enter the refrigeration system due to improper maintenance or leaks. These gases accumulate in the condenser and reduce its effective heat transfer area. Additionally, non-condensable gases increase the pressure inside the condenser because they occupy space and do not condense like the refrigerant. This results in higher condenser pressure and decreased system efficiency.

Statement 3: Accumulation of lubricating oil in the condenser.

This statement is correct as well. Lubricating oil can accumulate in the condenser due to improper oil return mechanisms or design issues in the refrigeration system. When oil accumulates on the heat transfer surfaces of the condenser, it creates an insulating layer, reducing the heat transfer efficiency. This causes the refrigerant to retain more heat, leading to an increase in condenser pressure.

Statement 4: Low charge of refrigerant in the system.

This statement is incorrect. A low charge of refrigerant in the system typically results in reduced system capacity and lower pressures, including condenser pressure. While an undercharged system can lead to other issues, such as reduced cooling performance and evaporator freezing, it does not cause high condenser pressure.