Question Set 115

· What are applications of the refrigeration ?

Answer: Ice making, Preservation and transportation of the perishables, Industrial Purposes, Air conditioning.

· Show the classification of air-conditioning systems .

Answer : air-conditioning systems are classified on the basis of 3 major points

a. Major functions : It involves  1. comfort air condition systems and 2. Industrial Air conditioning

b. Season of the year : 1. Winter air-conditioning  2. Summer air-conditioning  3. Year round air-conditioning

c. Equipment arrangement : 1. Unitary Systems 2. Central Systems

· What are applications of air-conditioning systems ?

Answer : Air conditioning application involves human comfort. Summer air conditioning is very popular in offices and large industries.

· Give example of a system having two phases .

Answer: A system involving water and  water vapour.

· Show the change of state by the help of a figure / Show temperature versus enthalpy diagram for water at various states/ Show the phase transition of water.

Answer: 

· Differences between heat pump and refrigerator .  Show with figures.

Answer:  Heat pump and refrigerator are the same devices but different names are implied for their applications. Heat pump is used for heating and refrigerator is used for cooling. In this diagram heat pump and refrigerator is shown for vapor compression cycle.

·  What is the theoretical basis of all practical refrigeration systems ?

Answer: Reversed Carnot Cycle.

·  What are the limitations of the Reversed Carnot Cycle ?

Answer: The efficiency of the reversed Carnot cycle is the highest among the cyclesoperating between two given temperatures. This happens because all the processes in reversed Carnot cycle are considered reversible which is impossible to attain in actual case. And thus reversed Carnot cycle is not useful for practical application.

· Write down the processes involve in reversed Carnot Cycle .

Answer:  For the T-s diagram look at question 11.

1-2 Isentropic or adiabatic Compression

2-3 Isothermal Heat Rejection which happens in condenser

3-4 Isentropic expansion (Produces refrigeration effect)

4-1 Isolthermal Addition of Heat

· Show the T-s Diagram of Reversed Carnot Cycle.

Answer: 

· What is the index of performance of a refrigeration cyle called ?

Answer:  Co-efficient of Performance , COP

·  What is practical refrigeration cycle ?

Answer: Reversed Rankin Cycle.

·  Show the differences between theoretical and practical refrigeration cycle or Show the differences between reversed Carnot and reversed rankin cycle or explain Vapor compression Refrigeration Cycle with subcooling and superheating .

Answer : Follow this link for the answer of the above questions.

Refrigeration Cycle with Sub-cooling and Superheating Explained 

· What are the differences between vapor compression and vapor absorption Cycles ?

Answer : Differences between VC and VA Cycles