Liquid Overfeed vs Flooded Systems Methods of Ice Manufacturing

The difference between liquid over feed and flooded ice production systems comes down to the method for managing flow of liquid refrigerant into an ice maker and how the system is designed to prevent liquid refrigerant from getting back to the compressor.

For a liquid overfeed system, the liquid is continuously pumped into the ice maker from the recirculator during the freezer cycle and is typically overfed into the system at a rate of 3:1 (3 times more refrigerant than required).  The liquid refrigerant and gas exit the ice maker and go back to the recirculator vessel which is designed to separate the liquid and gas.  The liquid is collected in the vessel and pumped back into the ice maker. The gas then goes to the compressor to complete the refrigeration cycle.

For a flooded system, a float is used to maintain the liquid refrigerant at a level in the ice maker where mostly gas and very little liquid refrigerant exits the ice maker.  This gas and minimal liquid refrigerant mixture then exits the ice maker and goes to a suction accumulator that separates any liquid from the gas.  To get the liquid that accumulates out of the suction accumulator you either utilize a boil out coil inside the accumulator or you use a transfer system to send the liquid that accumulates back to the receiver.

Ice Maker Method Comparison:

Liquid Overfeed (LOF) Flooded
Ideal for large installations of four or more ice makers (requires at least two to operate) Ideal for small and medium size operations (typically less than four ice makers)
Approximately 5-10% higher output of ice production making more ice per harvest. At 150 Tons of production with two P34 ALXL ice makers, you will get an additional 10 tons of ice production per day More cost effective with marginally more energy efficiency and requires lower overall refrigerant charge
Allows ice to be made to the top of the barrel which results in less shelling of ice and better quality cubes Suction accumulators are less expensive than recirculators (pump package)
Settings on the liquid expansion valves are not as critical with LOF ice makers making them easier to adjust
Recirculator offers less risk of shutting down on high liquid and comes with dual pumps allowing one to be utilized as a backup.
Cons Cons
Requires a recirculator package instead of suction accumulator which requires more upfront capital however a LOF ice maker is slightly less cost which helps offset recirculator price Liquid float controls can become a maintenance issue which could cause an accumulator to flood and shut down the system
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