REFRIGERATION AND AIR CONDITIONING (2 MARKS)

The temperature limits of a heat pump cycle are +27°C and -23°C, then the Carnot COP will be

• 0.2

• 1.2

• 5

• 6

A cold storage is to be maintained at – 5°C while the surroundings are at 35°C. The heat leakage from the surroundings into the cold storage is estimated to be 29 kW. The actual C.O.P. of the refrigeration plant used is one third that of an ideal plant working between the same temperatures. Find the power required to drive the plant

• 11.58 kJ/s

• 12.98 kJ/s

• 12.90 kJ/s

• 10.98 kJ/s

In a vapor compression refrigeration plant, the refrigerant leaves the evaporator at 195 KJ/kg and the condenser at 65 KJ/kg. For every kg of refrigerant, the plant can supply per second, a cooling load of

• 70 KW

• 130 KW

• 160 KW

• 100 KW

The optimum intermediate pressure P2 in a two-stage air compressor having P1 and P3 as a suction and delivery pressures respectively, equal to

• 
• 
• 
• 

Refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa.

• Class 1

• Class 2

• Class 2L

• Class 3

In a class B, refrigerant toxicity is identified at the concentration of

• 300 ppm

• 1000 ppm

• 990 ppm

• 450 ppm

100 CFM air flow rate is equal to

• 28.317 liters/s

• 47.195 liters/s

• 57.195 liters/s

• 38.317 liters/s

Consider the following statements: A psychrometer measures,

a. wet bulb temperature

b. dew point temperature

c. dry bulb temperature.

On these statements......is/are correct

• a

• b

• c

COP of a five star window air conditioner is greater than or equal to

• 2.7

• 2.9

• 3.1

• 3.3

If the specific heats of dry air and water vapour are 1.00 kJ/kg-K and 1.88 kJ/kg-K respectively and the humidity ratio is 0.011, then the specific heat of moist air at 25°C and 50% relative humidity will be

• 1.869 kJ/kg-K

• 1.891 kJ/kg-K

• 0.9793 kJ/kg-K

• 1.0206 kJ/kg-K