Evaporative coolers: maintain FE and stay cool?
 

As we all know one of the biggest concerns when driving a hybrid (or an car) is the impact of AC on fuel economy. In the newer hybrids like the Prius and HCHII (and newer models) this is no longer as bad, due to electronic AC. Older HCHs and Insights are left out in the cold...err heat.

Anyway, I stumbled across this evaporative cooler for cars on an alternative energy store site. The benefits of it are two fold. First of all, evaporative coolers are supposed to be much more energy efficient than normal air conditioning (which I can totally believe, as there is not much out there that is more of an energy hog than AC). And, of course, second would be the fact it runs off the car's electrical system, rather than loading the engine as it does on the Insight/HCHI.

Evaporative coolers are supposed to work best in dry climates, like that usually found in the South West. It seems like this might be something worthwhile for consideration for those who can't bear to do without AC, or who have family members who refuse to do without it. I haven't personally bought one of these yet, but I am seriously thinking about it. :shade:

Anyone have any thoughts or feedback?

Re: Evaporative coolers: maintain FE and stay cool?
 

Thanks for the link and they are entirely feasable in dryer climates. Typically these units move a volume of air and work best on 'one pass.' I would be more impressed if the evaporator was instream with the existing ducts so you could use the built-in vehicle ducting.

Right now, my focus is on getting ready for the cool weather. I've got a block heater for the engine and pan heater or the transmission. I've got thermister control circuit to put together and wiring but once done, I'll be ready for the cold. During the winter, I'll think about how I might implement what we used to call, a 'swamp cooler.'

Bob Wilson

Re: Evaporative coolers: maintain FE and stay cool?
 

Nagorek. I didn't look at the link, but you're correct in that they work best in dry climates for a couple of reasons. Evaporating water has a chilling effect which works well in those climates. In muggy areas the water won't evaporate, hence no cooling. Also, what's needed as much as chilling in muggy areas is the removal of water from the air, which is the opposite of what evaporative coolers do. In the proper climate (e.g. Arizona) they work great, but they're limited to those climates.

Re: Evaporative coolers: maintain FE and stay cool?
 

Another low-energy option (with some drawbacks) is to use Peltier effect thermoelectric cells. They are effectively low-draw electric heat pumps that suck thermal energy from a heat sink on one side of a plate to another heat sink on the other side. They are commonly found in electrically-cooled ice chests. Since they don't rely in evaporation, they work equally well in humid climates.

The biggest problem I can think of is that they really don't get all that cold, and it would take a relatively large unit to get the vent temps far enough below ambient to be considered useful. The other problem is that, like a conventional A/C system, they do need to dump the heat into the outside air. In other words, one side of that chip needs to have a thermal path outside of the cabin, and preferably to free-stream air.

I've noticed that my ventillation system always gives me air that is warmer than ambient on a warm day unless I run the compressor, presumably because the sun heats the black paint and plastic, baking the air path between the base of the windshield into the cabin. These might be used not to make things "cold", but a bit more tolerable when flow-through ventillation is almost good enough but not quite.

Cars in the 1950's had them hanging on the side and roof.
 

In the 1950's I remember seeing a few cars with these bulky "things" hanging on the side window and roof.My father told me they were "water coolers" or something like that.I didn't realize until much later(I was 4-7 years old when I noticed them) that he meant they cooled water to cool the air.I figured he meant they were to cool water to drink.
Funny how things are "rediscovered" every so often as things change.These gadgets were obviously aftermarket-you could tell from the contraption aspect.I'm considering getting a room type "swamp cooler" for the Pilot to save gas when we drive to Arizona from New Orleans.It should start to work well by the time we get to Wichita Falls,TX,and certainly by Amarillo.You wouldn't need a very big one-especially at night.We sleep at rest stopsin the vehicle, and it would be nice not to have to run the engine.We could just use a 12v jumper/charger/air pump gadget and an inverter for power(might need 2 or 3).
They are a great idea for long hy trips when weight isn't much of a concern(just drag).Thanks.Charlie

Re: Evaporative coolers: maintain FE and stay cool?
 

It would be nice to be able to put them in-line with the ducting, but I don't know how easy that would be to accomplish. I am thinking I may pick one of these up, not just for use in my Insight, but also in my Suzuki Swift (Geo Metro) that doesn't have an AC. Even if it's not the greatest, I figure I could just use it in the Swift, since it must be better than nothing.

With the Insight it seems like you could just mount it in the rear hatchback area, maybe with the cargo net over it for safety. Since the Insight isn't especially large and you have the hatchback area anyway, I figure it also might be worth a shot.

I guess I can understand planning for winter during the summer months. Maybe some places winter will be here soon enough, but here in Southern California I'm not sure what we get really counts as winter, hence my focus on heat. ;)

It seems to me that the evaporative cooler should work pretty well here as we don't generally have that much humidity (maybe more than in say Az, but still not much), except a couple weeks ago when we had a bizarre heat wave. Not just hot, but extremely humid. I honestly can't remember any time in recent memory where that has happened.

Re: Evaporative coolers: maintain FE and stay cool?
 

In Oklahoma, my grandmother had flour sack cloth over the screen doors. It it got too hot, a quick splash was all it took and the nearly constant Oklahoma wind did the rest. It didn't really cool the whole house as much as made some parts, particularly the kitchen, less dreadful.

What I would do is locate the floor exhaust ducts and fit / construct a segment wth an internal loom to hold a mesh cloth. The loom folds the cloth to increase the surface area and reduce back pressure.

On one side of the cloth, I would use fish tank tubing to make a water manifold. On the other side, I would have a water sensor that operated the water feed pump at a low rate. Once the switch was thrown, it would try to keep the cloth damp enough to provide evaporative cooling.

The water sensor would be a pair of thermisters, one at the cloth and the other upstream, feeding a comparitor that operated the 12 VDC relay to power the water feed pump. I would probably use an air entrapment type pump (small bubbles of air that transport the water up to the manifold.

Due to the risk of mold forming, I would recommend an anti-fungal additive to the water. Realize that these are often corrosive so a plastic unit would last longer than most metal adapters. Foam and fiberglass construction would be a good approach. Annual replacement another good idea.

The interior of the car will be subject to a more humid environment. This may lead to rusting of exposed metal parts. Replace them when you replace the traction battery. <GRINS>

Bob Wilson

Right about Okie winds.
 

Bob. Boy, are you sure right about your Okie winds. I driven I-40 from OKC to Amarillo many times, and the wind blows like heck for no apparent reason.By no reason I mean no storm, not a cloud on the horizon and the wind will be blowing a steady 20-35 mph.I have been in those winds when they were so strong that when stopped for gas you literally have to lean waaaaay into them to stay upright(probably 50+mph. The TX panhandle is about as bad-sometimes.
I can sure see how they could turn it into a dust bowl if the scrubby vegetation was stripped by a drought!
I guess everyone knows about the wind farm on I-40-near Weatherford,I think. It fillls your entire vista on both sides of the road-maybe 100 HUGE towers with massive blades at least 200 ft. in diameter.Worth a trip just to see them.
The manufacturers will never use evap coolers, but they are perfect for use in a moving car, or even better while sleeping in a vehicle at a rest stop.Thanks.Charlie
PS I have no idea why they are frequently called "swamp coolers." You would figure a swamp would be one place they wouldn't works so well in.They can work in a swamp of course-during the day we probably drop to under 60% humidity when it is 95 degrees-but the SW is perfect for their use.

Re: Evaporative coolers: maintain FE and stay cool?
 

I have an evap cooler on my house here in Az. It is off right now because of the high dew point. When it gets above about 65degF (the dew point that is) the cooling effect is pretty minimal, and the added humidity would make the comfort factor vs temperature worse. I agree with the thermionic cooler approach. It would give a boost so the engine could shut off on really hot days while at lights. And, it doesn't suffer the inefficiency of an electric A/C compressor. I also think a simple solution to current approaches would be a temperature sensor that causes the ICE to come on when the temperature of the cabin reaches a certain point. That way for most of the waiting at a light, the ICE can be off, but just when it gets unbearible the A/C would kick in.


JG

Re: Evaporative coolers: maintain FE and stay cool?
 

The W. Texas home I grew up in had an evaporative cooler. They work great in low relative humidity (and W. Texas RH often goes down into single digits!). But they don't work in high humidity, which is why you'll never see any around here.