Air-Conditioning System Performance Quiz

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Questions and Answers

What is the refrigerating effect per Kg of ice when it melts at 0°C?

100 K.cal
50 K.cal
80 K.cal (correct)
120 K.cal

How is the theoretical Carnot efficiency for a refrigerating machine calculated?

T2 / (T1 - T2) (correct)
T1 / (T1 - T2)
T2 / (T1 + T2)
T1 / (T1 + T2)

What does the Co-efficient of Performance (C.O.P.) measure in a refrigerating cycle?

Efficiency of the compressor only
Latent heat of the refrigerant
Refrigerating effect per unit heat supplied (correct)
Total heat supplied to the system

Which of the following factors does NOT directly affect C.O.P. in refrigerating systems?

Cost of installation (D) Signup and view all the answers

What does the KW per ton ratio measure in refrigerating systems?

Efficiency of the refrigerating machine (B) Signup and view all the answers

What is essential to consider when selecting a refrigerant for better performance?

Refrigerating effect (D) Signup and view all the answers

In the formula for efficiency of a heat engine, 'Efficiencyc = (T1 - T2) / T1', what does T1 represent?

Condenser temperature (B) Signup and view all the answers

Which of the following represents the correct relation stated for the efficiency of a refrigerating machine?

Efficiency = T2 / (T1 - T2) (A) Signup and view all the answers

What happens to the refrigerating effect if the latent heat of fusion decreases?

Decreases (D) Signup and view all the answers

Which of the following best describes the role of the compressor in a refrigerating cycle?

Pumps the refrigerant to high pressure (B) Signup and view all the answers

Which factor is critical in determining the refrigerating effect of a refrigerant?

The latent heat of fusion of the refrigerant (B) Signup and view all the answers

What does a higher C.O.P. indicate about a refrigerating cycle's performance?

Greater heat absorption relative to energy input (A) Signup and view all the answers

In the context of efficiency calculations, what do T1 and T2 represent?

T1 and T2 represent the absolute temperatures of the evaporator and condenser respectively (C) Signup and view all the answers

How is the theoretical Carnot efficiency for refrigeration calculated?

By subtracting the evaporator temperature from the absolute temperature of the condenser (A) Signup and view all the answers

What does the KW per ton ratio help assess in refrigerating systems?

The actual cooling capacity versus power consumed (C) Signup and view all the answers

Why is it important to select a refrigerant with a better refrigerating effect?

It ensures maximum heat removal efficiency at minimal energy cost (C) Signup and view all the answers

What happens to the efficiency of refrigerating machines if the temperature difference between T1 and T2 is reduced?

Efficiency decreases because more energy is needed for lower temperatures (C) Signup and view all the answers

In the formula for C.O.P. of a refrigerating cycle, what does the numerator represent?

Heat absorbed from the refrigerated space (C) Signup and view all the answers

What is the relationship between the latent heat of fusion and the refrigerating effect based on the given content?

Higher latent heat correlates to a greater refrigerating effect (D) Signup and view all the answers

What key factors impact the net refrigerating effect in air-conditioning systems?

Refrigerant used, efficiency of components, temperatures of evaporator and condenser (A) Signup and view all the answers

Which of the following best describes the refrigerating effect?

It represents the heat absorbed by each kilogram of refrigerant (A) Signup and view all the answers

In the efficiency equation for a refrigerating machine, what does T2 represent?

The temperature of the evaporator in absolute terms (B) Signup and view all the answers

Which scenario reflects an increase in the efficiency of a refrigerating machine?

Descending T2 while maintaining T1 constant (B) Signup and view all the answers

What key role does the refrigerant play in the performance of an air-conditioning system?

It determines the heat exchange capabilities within the system (D) Signup and view all the answers

How is KW per ton ratio significant in assessing refrigerating machine efficiency?

It indicates the energy efficiency of the refrigerating process (A) Signup and view all the answers

What happens to C.O.P. as the efficiency of the refrigerating cycle improves?

C.O.P. increases with enhanced cycle efficiency (B) Signup and view all the answers

In terms of selecting a refrigerant, why is a better refrigerating effect important?

It ensures faster evaporation at lower temperatures. (C) Signup and view all the answers

Which factor can negatively impact the performance of an air-conditioning system?

High evaporator temperatures (A) Signup and view all the answers

What is the refrigerating effect of 1 Kg of ice melting at 0°C?

80 K.cal (A) Signup and view all the answers

Which formula represents the theoretical Carnot efficiency for a refrigerating machine?

$\frac{T2}{T1 - T2}$ (D) Signup and view all the answers

What does the Co-efficient of Performance (C.O.P.) in a refrigerating cycle express?

The ratio of heat absorbed to equivalent heat supplied to the compressor (D) Signup and view all the answers

How does a reduction in the temperature difference between T1 and T2 influence the efficiency of refrigerating machines?

Decreases efficiency (D) Signup and view all the answers

Which factor does NOT affect the refrigerating effect in air-conditioning systems?

Compressor size (A) Signup and view all the answers

What is the importance of selecting a refrigerant with a good refrigerating effect?

It enhances system efficiency and performance (B) Signup and view all the answers

Which of the following best describes the KW per ton ratio?

It is a measure of refrigerating machine efficiency under standard conditions (A) Signup and view all the answers

What happens to the C.O.P. of a refrigerating cycle as its efficiency improves?

It increases (B) Signup and view all the answers

What does a higher coefficient of performance (C.O.P.) imply about the refrigerating cycle's efficiency?

It reflects an increased cooling capacity per unit of energy consumed. (A), It suggests a higher ratio of heat extracted to energy input. (D) Signup and view all the answers

In the formula for theoretical efficiency of a refrigerating machine, which relation accurately reflects the temperatures involved?

Efficiencyc = T2 / (T1 - T2) (A) Signup and view all the answers

Why is it critical to ensure that a refrigerant has a better refrigerating effect?

It increases the total heat absorbed from the refrigerated space. (C) Signup and view all the answers

What does the KW per ton ratio primarily assess in an air-conditioning system?

The relationship between input power and cooling capacity. (B) Signup and view all the answers

What is the significance of latent heat of fusion in determining the refrigerating effect?

It defines how much heat is absorbed during a phase change. (C) Signup and view all the answers

Which of the following best describes the impact of T1 and T2 on efficiency in refrigerating systems?

Lower T2 values increase efficiency. (C) Signup and view all the answers

What would be the effect of using a refrigerant with poor refrigerating effect in air-conditioning systems?

Lower cooling capacity and increased operational costs. (C) Signup and view all the answers

How does the theoretical Carnot efficiency formula for refrigerating machines relate to actual performance?

It provides a baseline for expected performance compared to real-world conditions. (B) Signup and view all the answers

What does the refrigerating effect measure?

The amount of heat absorbed from the refrigerated space per unit mass of refrigerant (C) Signup and view all the answers

Which formula represents the theoretical efficiency of a refrigerating machine?

Efficiencyc = T2 / (T1 - T2) (C) Signup and view all the answers

What does the Co-efficient of Performance (C.O.P.) compare?

Heat absorbed from the refrigerated space to the energy input to the compressor (A) Signup and view all the answers

Which of the following factors is critical for the performance of an air-conditioning system?

The refrigerating effect of the refrigerant used (A) Signup and view all the answers

What is the significance of KW per ton ratio in refrigerating systems?

It measures the energy consumption relative to cooling output. (C) Signup and view all the answers

When selecting a refrigerant, which characteristic is most essential?

Refrigerating effect of the refrigerant (D) Signup and view all the answers

How does the temperature difference between T1 and T2 influence the efficiency of refrigerating machines?

A larger difference leads to lower efficiency. (A) Signup and view all the answers

What does a higher C.O.P. indicate about a refrigerating cycle?

Greater efficiency of the refrigerating cycle (B) Signup and view all the answers

Flashcards

Refrigerating Effect

The amount of heat absorbed per kilogram of refrigerant from the refrigerated space.

Refrigerating Effect Example

Melting 1 kg of ice at 0°C absorbs 80 Kcal of heat.

Refrigerating Machine

A reversed heat engine designed to absorb heat from a cold space.

Carnot Efficiency (Heat Engine)

Theoretical maximum efficiency of a heat engine, calculated as (T1 - T2) / T1, where T1 and T2 are absolute temperatures.