Question: The advantage of dry compression is that________________?

• 1. it permits higher speeds to be used
• 2. it permits complete evaporation in the evaporator
• 3. it results in high volumetirc and mechanical efficiency
• 4. all of the above

Question: For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?

• 1. bigger cabinet should be used
• 2. smaller cabinet should be used
• 3. perfectly tight vapour seal should be used
• 4. refrigerant with lower evaporation temperature should be used

Question: One ton of the refrigeration is_________________?

• 1. the standard unit used in refrigeration problems
• 2. the cooling effect produced by melting 1 ton of ice
• 3. the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours
• 4. the refrigeration effect to produce 1 ton of ice at NTP conditions

Question: Short horizontal lines on pressure-enthalpy chart show__________________?

• 1. constant pressure lines
• 2. constant temperature lines
• 3. constant total heat lines
• 4. constant entropy lines

Question: Ammonia is __________________?

• 1. non-toxic
• 2. non-inflammable
• 3. toxic and non-inflammable
• 4. highly toxic and inflammable

Question: Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?

• 1. 1 : 1
• 2. 1 : 9
• 3. 9 : 1
• 4. 1 : 3

Question: Where does the lowest temperature occur in a vapour compression cycle ?

• 1. condenser
• 2. evaporator
• 3. compressor
• 4. expansion valve

Question: A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is________________?

• 1. Ammonia
• 2. Carbon dioxide
• 3. Freon
• 4. Brine

Question: Highest pressure encountered in a refrigeration system should be________________?

• 1. critical pressure of refrigerant
• 2. much below critical pressure
• 3. much above critical pressure
• 4. near critical pressure

Question: If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be________________?

• 1. same
• 2. more
• 3. less
• 4. more/less depending on rating