Suction pressure too low might be due to:
System load too high
Not enough condenser cooling water
Receiver level too high
Receiver level too low
Faulty or closed expansion valve
When changing ammonia systems, frost on the drum bottom indicates:
Too much refrigerant
The ambient temperature is too high
Refrigerant drum is empty or very nearly empty
Refrigerant drum is still full
Pressure is too high
A low-pressure control in a refrigerating system can be used for:
Condenser pressure control
Starting and stopping the compressor
Purging non-condensable gases
Keeping the receiver pressure from getting too high
Evaporator pressure control
In an indirect ammonia system using brine and water-cooled condenser, the discharge pressure is controlled by:
The load on the brine
Regulating the expansion valve
Regulating the cooling water to the condenser
Using a pressure release valve
The amount of ammonia refrigerant used
Where public occupancy is a concern when using Safety Group 2 refrigerants the safest systems are:
Direct refrigeration
Indirect systems
Any available system
Automatic refrigeration
The C/S/A approved refrigeration systems
The most efficient method of condenser cooling is
Air cooled
Water cooled
Latent heat cooled
Diffusion cooled
Cooled by another refrigeration unit
Before changing a new refrigeration installation:
It should be filled with water first
The entire refrigerant containing system must be thoroughly tested for performance
It should be filled with refrigerant and tested for performance
The entire refrigerant containing system must be completely filled with water and hydrostatically tested
It should be filled with hydrogen and tested
In a indirect ammonia vapour compression system using brine, the suction pressure is controlled by:
The flow of the cooling water to the suction side of the compressor
Throttling the metering valve
An equalization valve
The flow of the condensing water to the condenser
Refrigeration application uses could include:
Heating methods in industry
Gas distillation process
Refrigerant oil purification
Air conditioning humidifying
Air conditioning or gas dehydration
The capillary tube has a
Very small diameter
Medium sized diameter
Large diameter
Convergent-divergent cross-section
Concaved cross sectional area
