L$.$a$.$ Define refrigeration

b$.$ State the full meaning of HVAC &R and its importance in the maritime industry,

c$.$ List three $(3)$ applications of process air conditioning systems.

$2.$ Explain the five essential requirements for refrigeration.

$3$a$.$ Why is the reversed Camot cycle considered as the most efficient refrigeration cycle operating between two specified temperature levels?

b$.$ With the aid of TS diagram explain the working principle of the reversed Carnot cycle.

$4$ a $.$ What is heat pump?

b$.$ Show that the $CO{P}_H=CO{P}_R+1.$

c$.$ State two $(2)$ disadvantages of the atmospheric air $($air$-$lo$-$air systems$)$ heat pump.

$5$a$.$ Write short notes on primary and secondary refrigerants.

b$.$ Give two $(2)$ examples of primary and secondary refrigerants and state their characteristics.

c$.$ Explain any two methods for producing refrigeration.

$6$a$.$ A cold$-$storage warehouse uses a refrigeration system to keep groceries at $2C$ while the temperature outside the warehouse is $30C.$ The groceries and the outside air act as thermal reservoirs in this process. Although the warehouse is insulated, it absorbs heat from the surroundings at a rate of $775$ kW $.$ Determine the power requirement and COP for a Carnot refrigeration cycle.

b$.$ The food compartment of a refrigerator, shown in the Fig, is maintained at $4C$ by removig heat from it at a rate of $360k\frac{J}{m}in.$ If the required power input to the refrigerator is $2$ kW $,$ determine $($a$)$ thes coefficient of performance of the refrigerator and $($b$)$ the rate of heat rejection to the room that hovess the refrigerator.