Deck 16: Turbines, Cogeneration, Refrigeration, and Air Conditioning Systems

Question 1

Compounding______________  efficiency at low speed.

A)decrease
B)increase
C)maximizes
D)none of the mentioned

Answer 1

increase

Question 2

In pressure compounded turbines moving nozzles are followed by turbine blades.

Answer 2

False

Question 3

In pressure compounded turbines flow passage is from______________          

A)moving nozzles to fixed blades
B)fixed nozzles to moving blades
C)fixed blades to moving nozzles
D)none of the mentioned

Answer 3

fixed nozzles to moving blades

Question 4

A plant producing both, electrical power & process heat simultaneously is?

A)cogenital plant
B)cogenerial plant
C)cogeneration plant
D)conglomerate plant

Question 5

In a by-product power cycle?

A)the power is produced initially
B)power production is in the middle stages of the cycle
C)power production is after the cycle has ended
D)none of the mentioned

Question 6

In terms of cost per MW compared to condensing sets of the same power, the back pressure turbines are?

A)more expensive
B)cheaper
C)costly
D)none of the mentioned

Question 7

Which of the following is a good medium for constant temperature heating?

A)water
B)steam
C)coolant
D)diesel

Question 8

The cogeneration plant efficiency nCO if WT, Qi, QH represents turbine work, heat input, heat output respectively is given by?

A)nco = (wt + qi) / qh
B)nco = (wt - qi) / qh
C)nco = (wt + qh) / qi
D)nco = (wt + qh) / qi.

Question 9

If e is the electricity fraction of the total energy output, m is the electric plant efficiency and n is the steam generator efficiency; the heat added per unit total energy output is given by?

A)(1 / m) + ((1 - e) / n)
B)(1 / n) + ((1 - e) / m)
C)(1 / m) + ((1 + e) / n).
D)(1 / n) + ((1 - e) / m).

Question 10

Which of these is not considered economical for cogeneration?

A)a high fraction of electric to total energy
B)a low fraction of electric to total energy
C)a low fraction of total energy to electric energy
D)none of the mentioned

Question 11

The energy transfer between the hot fluid and cold fluids is brought about by their complete physical mixing in

A)direct contact heat exchanger
B)regenerators
C)recuperators
D)boilers

Question 12

In vapour refrigeration cycle, which of the following is used for expansion?

A)expansion engine
B)throttling valve or capillary tube
C)both of the mentioned
D)none of the mentioned

Question 13

Wet compression is preferred over dry compression.

Question 14

One tonne of refrigeration is given as the rate of heat removal from surroundings equivalent to heat required for melting one tonne of ice in a day.

Question 15

Superheating of vapour and subcooling of liquid______________the refrigerating effect.

A)decreases
B)increases
C)no change
D)none of the mentioned

Question 16

A condenser must______________and then______________the compressed refrigerant.

A)superheat, evaporate
B)desuperheat, evaporate
C)superheat, condense
D)desuperheat, condense

Question 17

The vapour going to condenser is______________in temperature and______________in ammonia.

A)higher, less
B)higher, richer
C)lower, less
D)lower, richer

Question 18

Water is used as a______________in air conditioning units.

A)absorbent
B)refrigerant
C)absorbent and refrigerant
D)none of the mentioned

Question 19

Which of the following types of filters used in the air conditioning system is made of cloth that is discarded on getting dirty?

A)viscous type filters
B)dry filter
C)spray washers
D)electric precipitators

Question 20

Select the disadvantage of cooling pond out of the given?

A)the area required of cooling in a cooling pond is small
B)spray losses due to evaporation and windage run high
C)there is no control over the temperature of cooled water
D)the cooling efficiency is low compared with cooling water

Question 21

How is water circulated throughout the dry cooling tower system?

A)finned tubes
B)metal pipes
C)porous tubes
D)swirling tubes