The reason I thought nozzles are typically placed on top of the equipment is so that fouling materials or solid objects cannot settle in the nozzle thus blocking the safety relief path.
Stampe
The relief needs to be on the top. The point of the relief is to let gas exit the exchanger. If you put it on the bottom all the liquid will have to drain out before the gas can escape. You would then have to size the relief for a liquid relieving rate.
Pkpbip makes some good points about plugging as well.
Liquid drain out was my main concern with respect to safety especially due to potential pressure built-up on the shell side, but also due to high velocity liquids in the flare system.
The case is that a vendor has supplied this to us on a 250 barg compressor CM after cooler and I just wanted to make sure that this was not common practice.