Installing PS in Case

I have a LIAN LI Lancool PC-K62 Mid-tower case (http://www.newegg.com/Product/Product.aspx?Item=N82E16811112239), it has 4 fans: 1 intake, 2 on top and 1 exhaust in the back. The PS installs on the bottom where there is a vent. My question is, to get good airflow do I install the PS with the fan down or up. Thank you for your help.

it should be down so it sucks air up then spits it outside the back of the case

Thanks for the replies, but that is no help.

Excellent choice for a pc case. I plan on getting that one for my next project.

Originally bottom mounted power supplies were installed with the fan on top. The fan pulls in warm air from the case and exhausts it out the rear of the case. However, there was another design change. Some cases with excellent ventilation, air flow, and cooling such as yours come with a an opening directly below the power supply which would allow the psu to be mounted fan side down. The concept is that with the psu fan side down, it could pull in fresh air and cool itself. There is a down side if you place the case on the floor. If you place it directly on a carpet air flow will be restricted. In addition, dust will be a problem. A few years ago I built a small inexpensive black and chrome stand to avoid those problems. I also added casters so I could move the pc easily.

Not much space at the bottom of a case for cool air if the PSU fan is facing down - you can try either way and see wht gives you the best results. My personal preference is to have it facing up - simply because the great airflow accessible to the PSU fan means its not working so hard to do the same job

Thank you for the help, I will be doing my build this week and wanted to get all my ducks in a row before I started.