Air flow direction across condenser.

[cliffjohns]

We manufacture chillers and have always assumed the air should be pulled through the condenser rather than blown into it. Has anyone seen a difference?

[absolute-zero]

We manufacture chillers and have always assumed the air should be pulled through the condenser rather than blown into it. Has anyone seen a difference?

cliffjohns, Welcome to RE community:)

I have not seen this in anything I work with, as well never gave it much thought.

A-Z

[nike123]

All chillers and majority of condenser of refrigeration plant that I worked on till today uses same principle.
Than again you have window shakers (window air conditioners) who have inverse approach and works perfectly. I think that has to do something with fan design and ability to draw or blow required and uniform amount of air threw coil, and nothing with direction of air.

[paul_h]

Older a/cs were often blow through, the biggest disadvantage is the dirty side is not accessible for cleaning as easy as draw through. The other disadvantage was the air from the fans hit the coil and then lost velocity depending on the fans static pressure abilty, so poor air flow through the coil, especially if the outside fins get bent or really dirty.
You can never change the fan direction if you encounter this setup either, as the coils are always designed for the hottest discharge gas to be the last coil on the circuit, reversing it would mean the last loops of the coil gets heated up by the first loops.

As far as is there a difference? Yes, all the older blow through designs stuggle in the high ambients here in australia, while all new units are draw through and cope better. I guess it wouldn't matter too much if you had a fan with enough static pressure, but then you'd have a noisier unit, and all manufacturers are trying to limit the noise these days as well.
edit, the only benefit I see for blow through is if it's neccessary, like for wall/window RACs, or to keep the fan motor and compressor cooler, as ambient air goes over those motors before being blown onto the coil

[NoNickName]

It doesn't matter which way the fan is and which way it rotates, but what matters is the side the air enters the coil compared to the warmest row, which is the one connected to the compressor discharge.

[Samarjit Sen]

The direction of the air flow depends on the application of the system. For units which operate for units suitable for extreme and severe conditions, the air flow should be of blow through type. As this will remove the congestion over the fins and keep them clean. It is also to be seen that the hot air from the condenser does not blow over the compressor.

The fans should be located at such a distance so that wether it is of the blow through or draw through, the entire surface area has an equal distribution of the air.

[absolute-zero]

I think all the factoras listed in this topic will dictate air flow for opitum subcooling.

Application and design.
Noise reduction
ambient conditions
optimal subcooling

I am in belief if you can pull air across the coil vs forcing air acorossed, this would be better as the coil will get a more evenly distributed heat transfer from start to finish of the subcooling cycle.

It would seem if you forced air acrossed the coil, the air current will flow more in the direction or against the coil in the fan pattern, traveling the least path of resistance,

A-Z

[US Iceman]

The reason you want to use draw-thru air flow is due to the uniform flow pattern this creates over a coil. A blow-thru design has areas of the coil where higher air velocity occurs directly in front of the fan. On those adjacent areas farther away from the fan discharge the air velocity will tend to be much lower.

The different air flow patterns through the coil affect the heat transfer and eventually the capacity is degraded.

[absolute-zero]

The reason you want to use draw-thru air flow is due to the uniform flow pattern this creates over a coil. A blow-thru design has areas of the coil where higher air velocity occurs directly in front of the fan. On those adjacent areas farther away from the fan discharge the air velocity will tend to be much lower.

The different air flow patterns through the coil affect the heat transfer and eventually the capacity is degraded.

Iceman I think you said it best, This is what i was trying to say, but the terms were just going blank to me. ;)

Nice Post :)

A-Z