R & AC RK 4

In a vapour compression cycle , the refrigerant immediately after expansion valve is

• Liquid
• Sub-cooled liquid
• Saturated liquid
• Wet vapour

One ton refrigeration corresponds to

• 50 Kcal/Min
• 50 Kcal/hr
• 80 kcal/hr
• 80 kcal/min

The vapour pressure of refrigerant should be

• Lower than atmospheric pressure
• Higher than atmospheric pressure
• Equal to atmospheric pressure
• Could be anything

In S.I. unit, one ton of refrigeration is equal to

• 210 kj/min
• 210 kj/hr
• 210 kj/hr
• 70 kj/hr

For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be

• Equal
• Anything
• Small
• High

Which of the following refrigerants has highest refrigeration efficiency

• R-113
• Freon-11
• Freon-22
• R-12

Chilled water with the application of principle of flash cooling is obtained by following system

• absorption refrigeration system
• vapour compression system
• electro-mechanical system
• steam jet refrigeration system

Presence of flash gas in the liquid feed to the expansion valve can cause the problem of

• feeding the evaporator unevenly
• loss of cooling capacity
• damage to the valve
• all of the above

An evaporator pressure regulator performs the following function

• monitors evaporator temperature
• maintains compressor inlet pressure
• keeps pressure up for system needs
• all of the above

Which of the following refrigerants has lowest freezing point

• Freon-12
• NH3
• Co2
• Freon-22