Why a Water-Cooled Rear Door May Need Fans
A rear-door heat exchanger captures heat from server exhaust before that air returns to the room. Water carries the heat away, but air must still reach and pass through the coil.
Follow the air through the process
First, follow the server exhaust
Server fans move air through the chassis. The warmed air enters the rear-door coil instead of going straight into the room.
Air and water stay separate
Air travels between fins while water stays inside tubes. Heat crosses the metal into the water. This is a rack exhaust heat exchanger, not liquid flowing through the server chips.
A passive door adds an air-side load
With no door fans, the server fans must overcome the added coil resistance. Check the combined operating point: the same fan speed does not guarantee the same airflow.
An active door shares the air-moving duty
An active door adds fans to help pull air through the coil. Their controls must work with the server airflow and rear pressure conditions as the rack load changes.
Airflow function
- On the rear-door coil, assisting the server fans in moving warm rack exhaust through the air-to-water heat exchanger.
- An EC axial family can be evaluated for a suitable door air path and depth. Door fan control must coordinate with the server airflow and rack pressure as the load changes.
What can change the result
- Adding a coil changes the server fan operating point; unchanged speed does not ensure unchanged airflow.
Start with the complete air path
Share your layout and the information you already have. Unknown values can be identified before a configuration is selected.
Match the fan to this air path
LONGWELL EC axial families are candidates for a compatible fan-assisted door. Send the coil pressure drop, target airflow, door space and control needs. Confirm the selected fan and assembled rack behavior together.
Where it sits
On the rear-door coil, assisting the server fans in moving warm rack exhaust through the air-to-water heat exchanger.
Why consider this configuration
An EC axial family can be evaluated for a suitable door air path and depth. Door fan control must coordinate with the server airflow and rack pressure as the load changes.
Check the result in your equipment
Discuss your rear-door airflow
Send coil pressure drop and server fan duty, door depth, airflow and control range, water conditions and rack integration. Ask LONGWELL to review a suitable configuration, fan curve, drawing and control details. A layout or existing fan model can start the review.
A layout, installation photos or your existing model is enough to start the discussion.