Ice water pumping through AC Evap coil?
 

As I'm starting to plan out my build for my '98 Neon, I'm trying to figure out the most efficient ways to keep cool during the hot summers... (Idaho, stays a pretty constant 90+ all summer)

The only thing left installed is the evap coil system. Looking around my parts bin, I have a 12v water pump from when I used to water cool my computer... so it's a pretty strong pump. I'm thinking about simply putting a few barbed fittings on the evap coil, building an ice-water chamber (likely out of 4" ABS or PVC), then pump the iced water through. Hook the pump up to where the compressor clutch engage wires were, so it turns on just like the AC used to.

The ice container would have the pump at the very bottom and feed the water returned water back through the top to go through the ice. I'd put a drain on it towards the bottom to remove enough water to put fresh ice back in w/o making a mess.

The biggest idea behind this is that it would function similar to how the old AC system worked and wouldn't need any interior modifications, as well as having to take up any space inside with coolers or such the like. I'd just have to throw in ice before making a trip. Most of my trips are fairly short and I find myself having a lot of old, funky ice left over in my freezer anyways...

Attached is a "throw together" MS paint style diagram.

I realize that the system wouldn't keep it that cool for too long. I have pretty tinted windows on the car and will likely go beaded-seat covers, but just trying to come up with concepts to really keep cool, without too much drawback.

Let me know what you think.

Uhm... Why not just re-install the A/C?

How long do you plan on driving? You would need a HUGE reservoir to do any substantial trip.

Installing AC would be the best option.

Alternate options:

Cool-shirt (DIY setup info all over the lemons forums: Summer Approaches : share your best cool shirt/seat setup links (Page 1))

Cool seat. IIRC someone on the lemons forum did a cool seat as well. Just took the cover off the seat, pushed some copper tubing into the foam, and put a little bit of foam on top. This could easily be converted to a warm seat in the winter as well :)

(The above was with a fixed back seat which is well insulated on the backside due to the fiberglass construction)

Hi NoD,
An average car A/C provides about 50,000 BTU/H of cooling with an added engine load of about 6 HP. A ton of ice has the cooling power equivalent to 12,000 BTU/H over 24 hours. So to have the same cooling as an average A/C means melting ice at the rate of 1 ton every 6 hours. If you don't need the A/C on full blast, and as you say, your trips are short, maybe you can figure on an hour at 24,000 BTU/H. So you'd need to load up with 166 lbs of ice. In your car an extra 166 lbs might increase fuel consumption by 1 mpg. That's a block of about 3 cu. ft. of ice, which doesn't sound like much space to me. The local liquor store sells crushed ice: 10 lb bags for about a buck each, and 2 bags are a little less than 1 cu. ft.
If you have a lot of free ice, and space to carry it, this should work fine.

-mort

idaho has very low humidity.

you are better off figuring out an EVAP system - swamp cooler style.

+1

Trying to find a way to reduce weight and engine parasitic loss, while keeping cool on most short trips. Plus, just trying to think creatively.

Some neat DIY stuff there! ;) I'll have to keep some of those in mind.

Average trip time: ~10 minutes.

Thanx for the math skills in use. I think this is more what I was after, just didn't know how to go about asking it I guess. Looks like it was take WAY more storage (as well as weight) put into the ice alone to make this work.

That was my 2nd thought on the matter if a small ice canister was just not going to work. Would replacing the evap coil of the AC with a simple high-pressure mister system work decently? Would be easy to wire up the pump to turn on with the AC switch and wouldn't take very much water...

Try ducting your fresh air intake either below the car, or to an area that doesn't always get sunlight or air flowing over hot parts. Somewhere under the car usually stays slightly cooler due to the lack of sun, and the airflow there is generally somewhat cooler as well.

It won't get "cold", but it might help a little. Other than that, consider personal comfort rather than making the car a colder place to be. A small ice chamber with fishtank lines through the seat back and bottom with a small pump will function far better than running ice water through the A/C condenser, and take less space/weight for a 10 minute trip. Turn the pump on a minute or so before you leave on your trip, and the seat should cool right down for you.

Keep the car from getting hot in the first place - park under cover, windshield heat reflector, etc. There's a huge difference between starting with the car 90 degrees inside vs 150 degrees.

I really like the idea of melting ice for cooling, but this is better. If the air is dry enough it would take about 3 gallons of water to provide the same cooling, 1 hour at 24,000 BTU/H.
-mort