AIREDALE R410A - Refrigerant Piping Design Considerations; Liquid Line and Pipe Insulation; Discharge Riser Design

Horizontal Sections
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used.
Liquid Line
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the static head of liquid refrigerant and can results in poor operation of the evaporator and expansion device.
Careful pipe sizing is recommended to ensure that the liquid line does not have excessive pressure drop.
Increasing the liquid line tube size can minimses pipe pressure drop.
However as a fail safe it is recommended that the condenser is installed above the indoor unit to allow for correct liquid
drain.
Pipe Insulation
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Insulating the discharge line can also reduce any potential noise.
Discharge Risers
Consideration must be taken when designing vertical risers. Refrigerant velocity
must be ensured in vertical risers at a minimum of 8m/s.
If required double risers must be designed into the system. Pipework must be
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The double riser must be sized so that the refrigerant still maintains adequate
velocity for the oil to travel around the system.
At part load the velocity is reduced in the larger diameter pipe (and cannot
carry oil). An oil trap is formed forcing vapour up the smaller tube which still has
adequate velocity due to its size to continue carrying oil around the system.
The trap at the base of the riser must be as small as possible. This ensures that
the trap causes a pressure drop causing vapour to pass up the smaller tube.
When the load increases the velocity of the refrigerant ensures that oil carries up
both tubes.
t
6m
t
Condenser above Air Handling Unit Condenser below Air Handling Unit
Discharge Line Liquid Line
SmartCool™ 16 - 60
Precision Air Conditioning
34 SmartCool Technical Manual 7525371 V1.2.0_03_2013
Installation