What is the best location for a evaporator fan?

[Jasno999]

Here is a question I have been askign myself and I am not sure what the best answer is.

You have a system where the condenser section and the evaporator sections are located in different areas and have different fans and motors.

When you configure your evaporator layout is it better to place yoru supply air fan prior to the evaporator (so you push air thru the evaporator) or is better to place the fan after the evaporator (so you pull air thru the evaporator)?

I would think that there are benifits to each location but I wanted to see if there was a standard used in the industry or if you guys had soem suggestions on which setupt to use and why.

[The Viking]

For the Evaporator it doesn't matter as long as the airflow is there (there will be a heat-gain from the fan-motor but that are generally too small to bother about which side it's on)

The big question as to determine on which side the fan goes is the fan type, some will cope better with the resistance in front of them others wants it behind them. (So the best answer is to ask the fan manufacturer)

[US Iceman]

From a practical viewpoint the fan location should be on the outlet side of the coil. This is a draw-thru relationship. Installed in this manner the coil sees a uniform air velocity through the coil, which helps the coil performance.

When the fan is located on the inlet side of the coil, it is a blow-thru configuration. This tends to create different velocity vectors through the coil, so you have localized higher static losses in certain areas of the coil.

Also, these higher velocity vectors tend to pull water of the coil if the face velocity is too high in those areas.

Almost all of the refrigeration evaportors are now made in the draw-thru configuration for these reasons.

[Jasno999]

Thanks ICeMAN. That is what I was thinking but wanted to see if somebody else looked at it the same way.