Assignment-1.
Q1. Answered the following
a. Write the units of C.O.P., Refrigerating Effect, Work Done, Specific volume,
Dryness fraction.
b. Define C.O.P., One tonne of refrigeration, Refrigerating effect.
c. Draw P-h and T-s diagram for wet and dry vapour compression cycle.
Q2. Q2 a. A certain machine works on reversed Carnot cycle between temperature limits of –20 0c
and 40 0c. Find the c.o.p, when working as:
i.
ii.
iii.
A refrigerating machine
An heat pump
An heat engine
b. A Carnot refrigerator requires 4 kw per tonne of refrigerator to maintain a region at low
temperature of -20 0c. Determine :
i. C.O.P. of Carnot Refrigerator
ii. Higher Temperature of the cycle
iv.
The heat delivered and C.O.P. when this device is used as heat pump
Q3.A food storage requires a refrigeration capacity of 60 Kw. It works between a condenser
temperature of 40 0c and an evaporating temperature of -5 0c. The refrigerant is ammonia .It is sub
cooled by 15 0c before entering the expansion valve and the dry saturated vapour leaving the
evaporator. Assume a single cylinder single acting compressor operating at 1200 r.p.m. with stroke
equal to 1.5 times the bore. Determine:
i.
ii.
iii.
iv.
The power required
The mass flow rate
The C.O.P
The Cylinder dimension