Pendinginan

Ammonia (R 717) as a refrigerant in industrial refrigeration systems has a

wide range of evaporating and condensing temperatures, but its vapors are

toxic and form flammable mixtures with air

• true

• False

Tubing in ammonia refrigeration units is made of copper

• true

• false

A disadvantage of ammonia as a refrigerant is its low value of latent heat of

vaporization

• true

• false

The higher the value of the latent heat of vaporization of a refrigerant the

lower the required refrigerant flow rate for a given refrigeration load

• true

• false

Refrigerants containing chlorine may reach the upper atmosphere, react with

ozone, and deplete the ozone layer

• true

• false

The higher the temperature difference between condenser and evaporator,

the higher the COP

• true

• false

COP is always less than one

• true

• false

The coefficient of performance (COP) is equal to the ratio of the

refrigeration effect to the net work input

• true

• false

Refrigerant vapors leaving the evaporator may be superheated

• true

• false

The latent heat of vaporization of the refrigerant is absorbed from the

surroundings of the evaporator

• true

• false