A.molecular fluid vibration
B.energy losses
C.wide pressure variations
D.mechanical damage to control valves
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A.Keeps the refrigerated space cooler
B.Reduces the efficiency of the plant
C.Takes the load off the compressor
D.Has no affect on the system
A.proportional band
B.the error signal
C.the reset signal
D.feedback
A.Dehydrators must be used continuously in a refrigeration system
B.A 25 ton refrigeration system has the same cooling effect as melting 25 tons of ice in 24 hours
C.A thermostatic expansion valve is used to control refrigerated space temperature
D.The liquid receiver functions to collect and remove non- condensable gases
A.Hydraulic
B.Mechanical
C.Pneumatic
D.Electrical
A.Energy can be created or destroyed
B.Energy may not be transformed
C.The total quantity of energy in the universe is always the same
D.None of the above
最新試題
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
The major source of chemical contaminants in hydraulic fluid is （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.