water cooled precoil before evaporator coil?

[stevehull]

It has been beastly hot here in central Oklahoma. To be accurate, not so hot (mid 90s F; ~36 C), but very humid. I literally don't recall dew points in the upper 70sF (25C) here in Oklahoma.

Am looking at my open loop, one ton unit that I put together and the condensate is just pouring out. It is in the 2400 sq ft (~240 M2) shop made of SIPS and it is doing a great job. Keeps the inside temp about 20 degrees F below the outside and lowers humidity dew point to the mid 50's F.

One ton per 2400 sq feet . . . . SIPS are simply wonderful.

Noticed the cold water line going into the unit. My cold water input is about 64F. What if I plumbed in a very crude coil BEFORE the cold evaporator coil. The air would be precooled by first passing through the water cooled coil. Then the far colder evaporator coil would remove even more moisture.

This water, having gone through the "precooler" would then go into the cold water input line maybe just a few degrees warmer, but insignificantly so. Remember, this is an open loop or "pump and dump" set up.

I know that with colder water (40-45F) you could chill the coil sufficiently to condense latent water. Before I make a mess and cut up yet another defunct 12KBTU air conditioner (to get out a coil that I can use as a water precooler) - is this worth it?

I am wondering if the difference in the entering air temp (78F) and the input water temp (65F) is a large enough delta T (~13 degrees F; 8 degrees C) to sufficiently cool the input air. Assume about 500 cfm.

I could drag out my coil heat transfer tables, but I value the group's input.

Steve