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4

For large tonnage (more than 200 TR) air-conditioning applications, the compressor recommended is

A. Reciprocating

B. Rotating

C. Centrifugal

D. Screw

Correct Answer :

C. Centrifugal


Related Questions

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4

The capacity of a domestic refrigerator is in the range of

A. 0.1 to 0.3 TR

B. 1 to 3 TR

C. 3 to 5 TR

D. 5 to 7 TR

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4

An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by

A. (e₁ + e₂)/ e₁ + e₂ - e₁e₂

B. 1/e₁ + 1/e₂

C. e₁ + e₂

D. e₁e₂

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4

The coefficient of performance of Electrolux refrigerator is the ratio of

A. Heat supplied by the gas burner to the heat absorbed by the evaporator

B. Heat absorbed by the evaporator to the heat supplied by the gas burner

C. Heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner

D. Heat absorbed by the evaporator minus the heat supplied by the gas burner to the heat absorbed by the evaporator

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4

For large tonnage (more than 200 TR) air-conditioning applications, the compressor recommended is

A. Reciprocating

B. Rotating

C. Centrifugal

D. Screw

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4

The refrigerant used for absorption refrigerators working on heat from solar collectors is a mixture of water and

A. Carbon dioxide

B. Sulphur dioxide

C. Lithium bromide

D. R-12

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4

Which of the following statement is correct?

A. The constant enthalpy lines are also constant wet bulb temperature lines.

B. The wet bulb and dry bulb temperature are equal at saturation condition.

C. The wet bulb temperature is a measure of enthalpy of moist air.

D. All of the above

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4

The relative coefficient of performance is equal to

A. (Theoretical C.O.P.)/ (Actual C.O.P.)

B. (Actual C.O.P.) /(Theoretical C.O.P.)

C. (Actual C.O.P.) × (Theoretical C.O.P.)

D. None of these

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4

Pressure of water vapour is given by

A. 0.622 Pv/ (Pb - Pv)

B. μ/[1 - (1 - μ) (Ps/Pb)]

C. [Pv (Pb - Pd)]/ [Pd (Pb - Pv)]

D. None of these

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4

A refrigerant compressor is used to

A. Raise the pressure of the refrigerant

B. Raise the temperature of the refrigerant

C. Circulate the refrigerant through the refrigerating system

D. All of the above

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4

When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be

A. Cooled and humidified

B. Cooled and dehumidified

C. Heated and humidified

D. Heated and dehumidified

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4

The pressure at the inlet of a refrigerant compressor is called

A. Suction pressure

B. Discharge pressure

C. Critical pressure

D. Back pressure

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4

The specific humidity during humidification process

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

The wet bulb temperature during sensible heating of air

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

Most of the domestic refrigerators work on the following refrigeration system

A. Vapour compression

B. Vapour absorption

C. Carnot cycle

D. Electrolux refrigerator

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4

A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be

A. 1.33

B. 2.33

C. 3.33

D. 4.33

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4

Oil separator in a refrigeration cycle is installed

A. Before compressor

B. Between compressor and condenser

C. Between condenser and evaporator

D. Between condenser and expansion valve

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4

If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of -23°C, then the Carnot COP will be

A. 0.2

B. 1.2

C. 5

D. 6

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4

The alignment circle is marked on the psychrometric chart at

A. 20°C DBT and 50% RH

B. 26°C DBT and 50% RH

C. 20°C DBT and 60% RH

D. 26°C DBT and 60% RH

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4

The lowest thermal diffusivity is of

A. Iron

B. Lead

C. Aluminium

D. Rubber

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4

Wet bulb temperature is the temperature of air recorded by a thermometer, when

A. It is not affected by the moisture present in the air

B. Its bulb is surrounded by a wet cloth exposed to the air

C. The moisture present in it begins to condense

D. None of the above

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4

The temperature of ammonia after compression in a vapour compression system is

A. 20 to 50°C

B. 50 to 70°C

C. 70 to 110°C

D. None of these

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4

Ammonia absorption refrigeration cycle requires

A. Very little work input

B. Maximum work input

C. Nearly same work input as for vapour compression cycle

D. Zero work input

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4

The centrifugal compressors are generally used for refrigerants that require

A. Small displacements and low condensing pressures

B. Large displacements and high condensing pressures

C. Small displacements and high condensing pressures

D. Large displacements and low condensing pressures

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4

During adiabatic saturation process on unsaturated air __________ remains constant.

A. Relative humidity

B. Dew point temperature

C. Dry bulb temperature

D. Wet bulb temperature

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4

When the temperature of the surrounding is higher than the temperature of the body, then the heat loss by convection from the body to the surrounding will be

A. Positive

B. Negative

C. Zero

D. None of these

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4

The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.

A. More

B. Less

C. Equally

D. Unpredictable

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4

Critical pressure of a liquid is the pressure

A. Above which liquid will remain liquid

B. Above which liquid becomes gas

C. Above which liquid becomes vapour

D. Above which liquid becomes solid

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4

Allowable pressure on high pressure side or ammonia absorption system is of the order of

A. Atmospheric pressure

B. Slightly above atmospheric pressure

C. 24 bars

D. 56 bars

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4

Mass flow ratio of NH₃ in comparison to Freon12 for same refrigeration load and same temperature limits is of the order of

A. 1 : 1

B. 1 : 9

C. 9 : 1

D. 1 : 3

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4

The human body feels comfortable when the heat stored in the body is

A. Positive

B. Negative

C. Zero

D. None of these