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Condenser Intake and Discharge Duct Separation
- Thread starter montoy
- Start date
You really want to avoid recirculation of the discharge into the intake.
If there is a prevailing breeze the discharge should be downwind.
If you can't count on a breeze then the discharge should have a sufficiently high velocity to achieve dilution quickly, and should be directed away from the intake.
If there is a prevailing breeze the discharge should be downwind.
If you can't count on a breeze then the discharge should have a sufficiently high velocity to achieve dilution quickly, and should be directed away from the intake.
MechEngNCPE
Mechanical
I think no less than about 3000fpm on the discharge would prevent short circuiting.
I doubt it can work as those few condensers who are constructed for indoor use mostly have high-flow/low pressure fans. Pressure is just slightly higher than with "ordinary" condensers, as they would be very noisy.
If you ever can, you should make additional louver to supply make-up air for room, and duct exhaust only.
If you ever can, you should make additional louver to supply make-up air for room, and duct exhaust only.
- Thread starter
- #7
@marcoh - they are horizontally separated, 12" apart. The Louver is 70"W x 25"H and our discharge and intake ducts are both 24"H.
@mechengncpe - "I think no less than about 3000fpm on the discharge would prevent short circuiting."
Do you suggest making the discharge duct a little bit smaller to achieve 3000fpm? Would that increase the noise?
@mechengncpe - "I think no less than about 3000fpm on the discharge would prevent short circuiting."
Do you suggest making the discharge duct a little bit smaller to achieve 3000fpm? Would that increase the noise?
- Thread starter
- #8
AnotherEllis
Mechanical
This can be made to work. Look at the equations governing air flow in suction.
An application engineer at Titus once told me when I was going through a similar issue that you can visualize it with a match. "It's easy to blow a match out... but you ever try to 'suck' one out?" <insert inappropriate but well deserved comments now>
Just get your discharge velocity up enough to satisfy the equation and you should be fine.
An application engineer at Titus once told me when I was going through a similar issue that you can visualize it with a match. "It's easy to blow a match out... but you ever try to 'suck' one out?" <insert inappropriate but well deserved comments now>
Just get your discharge velocity up enough to satisfy the equation and you should be fine.
- Thread starter
- #10
Intake and discharge louver can be in separate frames or, for a VertiCool ... same blade design and angle). The discharge louver blades should be ..... ASHRAE HVAC Applications Handbook - Building Air Intake and Exhaust. Design, Chapter 44 ... “System Effects, How Do They Impact The Performance Of A Fan?”
Found this:
The combination intake/discharge
louver design offers an advantage
over separate louvers because
it requires only one wall opening
which decreases installation costs.
However, the blades cannot be
of uniform configuration (i.e. the
same blade design and angle). The
discharge louver blades should be
angled to direct the airflow straight
out horizontally from the unit and
the intake blades should be angled
down at approximately 45°.
Found this:
The combination intake/discharge
louver design offers an advantage
over separate louvers because
it requires only one wall opening
which decreases installation costs.
However, the blades cannot be
of uniform configuration (i.e. the
same blade design and angle). The
discharge louver blades should be
angled to direct the airflow straight
out horizontally from the unit and
the intake blades should be angled
down at approximately 45°.
I am not sure that high velocity by itself can solve the problem.
High velocities undoubtedly create effective dilution which is useful in many exhaust application, and even necessary in some.
In this particular case, however, one other aspect could be relevant - high velocity creates ejection effect.
Whatever jet pattern exhaust flow develops, there will be lateral streams and the one on side of intake lover could significantly reduce effective area of intake opening.
I am not sure whether HVAC Applications manual mentions it, but combined louvers were mostly related to limited flow applications
High velocities undoubtedly create effective dilution which is useful in many exhaust application, and even necessary in some.
In this particular case, however, one other aspect could be relevant - high velocity creates ejection effect.
Whatever jet pattern exhaust flow develops, there will be lateral streams and the one on side of intake lover could significantly reduce effective area of intake opening.
I am not sure whether HVAC Applications manual mentions it, but combined louvers were mostly related to limited flow applications
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