PPEQ 6004 - Heat Exchangers for Refrigeration Systems (Chp 19) Flashcards
An evaporator that increases heat exchange surface area by crimping thin metal plates to its form is the:
A) Finned tube evaporator B) Bare tube evaporator C) Shell and tube evaporator D) All of the above E) Plate surface evaporator
A) Finned tube evaporator
The refrigeration plant condenser which is very expensive to clean which requires the tubes to be cleaned with acid and neutralised is the:
A) Air cooled B) Evaporative condensers C) Shell and tube condenser D) Shell and coil condenser E) Baffle condensers
D) Shell and coil condenser
The amount of water used in an evaporative condenser is only a small percentage of that used in a water-cooled condenser of the same capacity. This is due primarily to what?
A) Evaporating condensers also use air to cool the refrigerant
B) Water being recirculated
C) None of the above
D) The evaporating condensers spray refrigerated water onto condensing coil
E) Water evaporating requires a large amount of latent heat
B) Water being recirculated
An evaporative condenser contains condensing coils:
A) Covered in brine B) Enclosed in a cabinet C) Immersed in water D) Which are dry E) Contained in a shell
B) Enclosed in a cabinet
An evaporator that contains the amount of liquid/vapour mixture of refridgerant necessary at any time is what type of evaporator?
A) Dry evaporator B) None of the above C) All of the above D) Flooded evaporator E) A multi coil evaporator
A) Dry evaporator
With respect to water cooled condensers, an evaporative condenser’s water consumption can be up to:
A) 75 % less B) 90% less C) 55 % less D) 25% less E) 15 % less
B) 90% less
Air-cooled condensers of large capacity are found mainly in which of the following locations?
A) All of the above B) Roof tops C) Warm dry rooms D) Cold rooms with low air circulation E) Closed rooms with low air circulation
B) Roof tops
In an evaporative condenser, water is pumped through spray elements above the condensing coils and:
A) The water is used to heat freezer floors
B) Fans draw air through the bottom of the coils
C) Fans draw air from the bottom of the coils
D) The water is piped to waste
E) Air is sucked through by natural draft created
B) Fans draw air through the bottom of the coils
With respect to the dry evaporator, the heat transfer rate of the flooded evaporator is:
A) 10 % less B) Lower C) 80% less D) Higher E) The same
D) Higher
Defective refrigeration plant condenser operation is a result of the presence of all of the following except:
A) Low coolant circulation B) Non-condensable gases C) Scale forming chemicals D) Dirty cooling water E) Loss of refrigerant
E) Loss of refrigerant
