Indirect Swamp Cooler???

[bandaidqueen]

Has anyone heard of an "indirect" swamp cooler, that works in high humidity and actually helps de-humidify the air, but runs on very low power? A mod on another forum writes about it (Van_Dweller on projectvanlife) but I can't find good information on Google and so far, he hasn't given me a direct answer as to brand, a link, and/or where I can buy one (or if it's something I'd have to build myself). Here is the thread where he talks about it: https://forum.projectvanlife.com/t/ventilation-without-windows/4838.  It's super hot at night and very humid where I live, but I remember when I visited China they used swamp coolers for AC and although it was unbearably humid, they still worked quite well. They were much larger than regular AC units though. Anyone with knowledge or experience? HDR, any thoughts? Thanks guys!!!

 

[abnorm]

I don't know.....Well he describes it :

""The other two types use a small radiator (think heater core) for an actual heat exchanger, with the cold water created by the evaporator circulated through it. When the hot humid air hits the heat exchanger, it condenses and drips down into the water reservoir, thus dehumidifying the air. With these, outside air is drawn in through the wet pad, and exhausted back outside, so no extra moisture is added to the inside air, but the process cools the water in the reservoir, which is then circulated through the heat exchanger (radiator). One type draws in the circulation air from outside, through the radiator, and out into the interior. The type I have, recirculates the inside air through the radiator.

It’s 90°f outside right now, with 94% humidity. I’m parked in direct sunlight with no window shades, and with my swamp cooler on low, which is under 1 amp @ 12vdc, it is 70°f inside with 29% humidity. It would be colder inside but I have a couple of windows cracked because it was getting too chilly inside, and I already have light sweater on. I think I’m going to open the windows a little more to raise the temp a little. In this climate anything below about 75° starts feeling really cold. I have no divider between the cab & cabin either…""

He gets COLD water from ?

 

[bullfrog]

We use one that sits on top of a large cooler, actually built on the original lid. It uses a pump not only to pump water to the fiber evaporation pad but also to circulate the chilled water through the heater core. It uses an inline bank of 4 computer fans and if run on high melts the fuse into the plug and drains a Goal Zero in about 4 hours even with the factory solar panels plunged in. Extended use on high has also burned up one of the units fans. It does not get things as wet as a mister and does cool the air directly in front of the outlets but you don’t feel it three feet away. Standing in a mister fan a few seconds then drying off in front of a regular fan is much more effective. It doesn’t use as much water as the mister fan but has to have 10 or 15 gallons in the bottom to begin with and we use ice so we start out with cold water which it works better with. Both units blew fuses and eventually burned up the plugs in one season of use. The excess water after draining from the evaporation pad and heat exchanger is cooler by several degrees than the air temperature. Humidity is very low where we are in southern Utah. I personally didn’t care for it as it takes up a lot of space and used a lot of battery power and therefore only good for part of the heat of the day.

 

[bandaidqueen]

FYI - Van_Dweller (from ProjectVanlife forum) sent me these Swamp Cooler tutorials - link http://pdxweb.com/vandweller/ac. Don't know if I'll be able to figure out how to make one, just glancing at them I'm still confused. But I'll print them out and take a harder look this weekend and maybe I can come up with something that can help in my humid climate. Anyway wanted to re-post the tutorials in case they might benefit someone else.

 

[jonyjoe303]

I decided to build one to see if I can get any improvement over just a regular swampcooler. I bought a heater core radiater (20 dollars) and all the assorted hoses/fittings.

I usually build small swampcoolers because of limited space in my van, the heater core is a large part in the indirect cooler and the intake/exhaust water tubes also stick out beyond the container I'm using but nothing that should get in the way. Because of the heavy weight of the core, I been using 1/2" pvc pipe as a frame to hold all the parts together.

So far I ran limited tests to see what the temperatures are between the water and air coming through the heater core. One thing I notice is once the water goes though the heater core it heats up when it goes back into the bucket. The air coming out of the core does cool down and after 20 minutes both temps equalize. The air temp got reduce by 2 degrees. I was only using about 1/2 of gallon of water for the test. A normal swampcooler holds about 2 gallons of water.



The plan is to use only one pump, after water goes to the heater core, it will be directed over the evaporater pad. Then recirculated again. If the water can stay in the 80 degrees which is what it usually is on a normal swampcooler that should hopefully bring the temp of the air down before it hits the evaporater pads. The swampcooler needs very cool air going into the evaporater pads for best results. Even a 5 or 10 degree lower outside temp will make a big difference.

Normal swampcooler temps on a hot day


Its a work in progress, but I got most parts.

 

[bullfrog]

On our commercial one the water that condensates on the heater core goes back into the cooler as well as the surplus water which drips off the pad. Both the pad and the heater core are enclosed by a box that seals them to the sides so all the air flow must pass through the pad and then the heater core that sits on the cooler lid before exiting through directional vents. Air flow coming out is cool but in our 8’x8’ booth doesn’t have enough flow to feel it more than a few feet away. We do ventilate in order to keep the humidity down by taking in outside air through the cooler fan and opening a window slightly. The idea is water returning to the cooler that drains off the pad will be cooled by the evaporation caused by the air being blown through the pad. That cooler water is then pumped through the heater core so that when the moist air passes through the fins the water will condensate on them and the dry cool air will exhaust into the space you are trying to cool.

 

[bagabum]

I decided to build one to see if I can get any improvement over just a regular swampcooler. I bought a heater core radiater (20 dollars) and all the assorted hoses/fittings. Its a work in progress, but I got most parts.

Very interesting. You know, if you had solar panels above your van, it would be interesting to see the affect of blowing the discharge of the outside evaporator assembly between the top of the van and the bottom of the solars to cool  the skin of the roof vs just discharging into atmosphere , removing direct heat from the sun and lowering ambient to the 80's.  A WELL insulated van will help in this application.  Nice work.

 

[gapper2]

Has anyone heard of an "indirect" swamp cooler, that works in high humidity and actually helps de-humidify the air, but runs on very low power? A mod on another forum writes about it (Van_Dweller on projectvanlife)  https://forum.projectvanlife.com/t/ventilation-without-windows/4838. 

Never heard of "indirect" swamp cooler.  I visited the website and looked over the info.   I have seen similar systems work in NC but that was only because they had an endless source of very COLD water from a mountain stream.  Overcoming the higher humidity levels we have in N. Georgia can maybe be obtained with higher airflow and very cold water.  But I have good results from a simple spray mister, fan and dampened wash cloth.  Fortunately a little cooler nights are just around the bend.

 

[bandaidqueen]

I decided to build one to see if I can get any improvement over just a regular swampcooler. 

Jonyjoe303 - please let me know how it works out over time! And any tips you have along the way. Also what kind of climate are you in - humid or dry? (I have read that the indirect swampcoolers actually don't perform as well in dry climates, but there's so little information about them it's hard to know.) Please keep me posted, and if I have more success with mine I'll update everyone as well.

 

[jonyjoe303]

The area I'm in is mostly dry (southern california) but right now its going through a heat spell with temperatures in the 90's and lot of humidity. My regular swampcooler is keeping me cool as long as I stay next to it.
The indirect swampcooler is almost complete, all the parts are installed including the 2x 120mm fans, I already got the evaporator pad (celdek) positioned in front of the radiator. The only thing left is to finish the top body that encloses the radiator/evaporator pad.

 

[bagabum]

 finish the top body that encloses the radiator/evaporator pad.

Do you have any idea of what your water consumption rate will end up being? 

 

[bandaidqueen]

In my version, the air that goes over the cooling pads (the swamp cooler section) would ideally never come into contact with the air that is being cooled inside the van. Other designs take the air that exits the swamp cooler and put it through the radiator, but I'm trying to dehumidify the air as well (which will make it cooler). So in my unit, the air that goes through the swamp cooler goes back outside. The radiator part circulates inside air. BUT the fans I have in front of the radiator aren't nearly strong enough, so it hasn't worked yet. I got a bigger fan and I'll try taping it together this weekend to see if I can get a better result.....
Pictures of barely working version 1:
<a data-flickr-embed="true" href="" title="Frankencooler Back"><img src="https://live.staticflickr.com/65535/50247161843_91b8ac3109_z.jpg" width="480" height="640" alt="Frankencooler Back"></a>
This is the back side of Frankencooler. Air goes in the Igloo through the fan, and back out through the same hole the water hoses come out of (have to move the hoses too, because they restrict the air flow too much). Eventually I would have old dryer hose or something to direct all this airflow - both in and out - to go out a window or vent. The top box, holding the car heater core, takes air from inside the van and pushes it through.

<a data-flickr-embed="true" href="" title="Frankencooler Front"><img src="https://live.staticflickr.com/65535/50248005017_0b753da8c6_z.jpg" width="480" height="640" alt="Frankencooler Front"></a>
This is the front (where cold air is SUPPOSED to come out lol)

<a data-flickr-embed="true" href="" title="Frankencooler Inside"><img src="https://live.staticflickr.com/65535/50247161773_ae76b2ae9f_z.jpg" width="480" height="640" alt="Frankencooler Inside"></a>
Inside the Igloo - just a standard swamp cooler.

I'll update if I get any better results with version 1.1!!! (Wish me luck)

 

[gapper2]

FYI - Van_Dweller (from ProjectVanlife forum) sent me these Swamp Cooler tutorials - link http://pdxweb.com/vandweller/ac. Don't know if I'll be able to figure out how to make one, just glancing at them I'm still confused. But I'll print them out and take a harder look this weekend and maybe I can come up with something that can help in my humid climate. Anyway wanted to re-post the tutorials in case they might benefit someone else.

 

I looked over some of his tutorials as I found his claims about temp and humidity a little far fetched.  Then I backed up one folder and went to some of his other links.  http://pdxweb.com/vandweller/  This person is an internet "snake oil" salesman.  I think indirect swamp cooler can be made at a cost and size would be a factor.  I wouldn't trust that person.

 

[MrAlvinDude]

Well, the principle about cooling the water that collects in the bottom of your red bucket is sound.

It might be useful to have some kind of thermometer dipped in the water, to be able to keep an eye on the temperature of that water, at the bottom of the red cooler box.

The temperature of the water at the bottom of the red cooler, will dictate how low the temperature of the air coming from the car radiator is able to get down to.



Once your setup is running, and if it turns out that you would like to improve its performance, then the ability to cool down the water at the bottom of the red cooler, is the first step.

The more air you can get through the chicken-wire-mesh-area, the better your cooler will be able to function, up to a point. At that point you will need to increase the surface area of the water-evaporator, in the straw-mesh, so more evaporation can occur.

The evaporation will cause the water that recirculates down into the bottom of the red bucket, to become cooler. So it is important that enough water is flowing down the mesh, so not all of it is evaporated, but that no less than, lets say at least a quarter of the water, returns down to the bottom of the cooler.


Also, once you get those air-duct tubes added to your setup, then it will be a good idea to direct the out-going air, from the red cooler box, to point away from the area of the mouth of the intake-air, going into the red cooler box. As the outgoing air is already loaded with evaporated-water, and you want the air going into the red cooler box, to be as 'dry' as possible. As in; having a lower level of humidity, than the outgoing air has.

Looking forward to hear more about your progress.

 

[bagabum]

Banaidqueen, maybe you could  conquer  this equation by concentrating your actions   in two phases. First phase would be to get the chilled water evaporator optimized, concentrating only on water and air flow across the evaporator straw pad to get the lowest reservoir temperature possible.  Then phase 2 would be concentrating your efforts on the heat exchanger flow rates for optimal performance (actual cooling the air) Note:   To me, if you  cant get phase 1 reservoir temperature to drop at least 15 deg lower than ambient, I'm thinking the effort will be fruitless and no need to fuss with phase 2.  All of the claims made  by   pdxweb are malarkey, bologna,  horse manure:  (your choice.)  I have played around with swamp coolers for ever, but I never had the luxury of playing with them in a low humidity climate.

 

[jonyjoe303]

I tried the heater core first and got some results that look promising but didn't have enough thermometers to get good readings. I ran the heater core/swampcooler unit and got about a 4 degree difference at 12 noon between the indirect swampcooler 84.8f and also the regular swampccoler 88.9f that I was running at the same time. I did notice running 2 swampcoolers at the same time did reduce the temp in my van to 89f from 94f, to verify I turned 1 swampcooler off and temp started to climb again, I ran the test last week when outside temp was 84f 60% humidity.

I decided to get a 8x8 air to water heat exchanger (55 dollars). This has copper tubing and should work better with water.

The only problem I had was the both that both the heater core and heat exchanger were both too large to make a indirect swamp cooler that would fit in the corner that I have setup for a swampcooler. I built a seperate container for the heater exchanger and ran my test

Todays outside temp as per weather channel at 1:30 pm 98f with 24 humidity

First I just use the water in the indirect container to run through the exhanger. From 12:03 to 1 pm, notice the water temp kept getting hotter 101f as the test went on.
At 1:30 pm I decided to use 5 feet of tubing to connect directly to the swampcooler water reservoir. Note the temperature of the water drop, and stayed consistent below 87 f.

The air intake was from the roof vent located under the solar panel, I had 4" flexible ducting to bring the air into the indirect cooler and then more flexible ducting to take it from indirect section to the swampcooler. I had 4x thermometers to measure the temperatures. The outside temp is accurate, the flexible ducting was hot to the touch and heating up the van. At 2:30pm was the hottest temp I recorded the intake was 116f, the exhanger reduced it to 102f, then it went to the evaporator pads where it got reduced to 90f. The exterior of the heat exchanger was hot to the touch but the copper tubing stayed cool. From the test, the best results from the heat exchanger was when the outside temp was the hottest.

Even though 90f seems high it felt cool to me. The inside of my van was 100 degrees but the humidity was low and the swampcooler was keeping me cool. The swamp cooler I'm using has a very small evaporator pad, so that can be improved. And the 5 feet of flexible ducting I using will heat up the air before it gets to the swampcooler, making it shorter will also improved performance. On a hot day like today the swampcooler by itself would be struggling to keep me cool, I would have to pour water on me to try and stay cool.

From the test I done, using a heat exchanger/ heater core to cool the air before it gets to the evaporator pads does work. The cooler the air before it hits the evap pads the better your results. The only drawback is the size problem but I will have to do some modifications to get it to fit in my van. One thing I found out was the small 12 volt water pumps will push water at least 5 feet without any problem, that opens the possibilities of keeping cold water in a cheap 12 volt fridge and pumping it into the indirect cooler to cool it even more.

           air      exhanger      
time    intake exhaust  water     swamp cooler exhaust
12:03 114f    105.7f    99.7f      90.8f
1 pm  112.4f 105.3f    101.3f    90.5f

1:30   116f    103.3f     87.7f      90.6f
2 pm  115.5f 104f        86.8f      90.3f
2:30   116.2f 102.8f     86f         90.4f
3 pm  107.5f  98.6f      85.3f      89.7f
4 pm  104.5f  96.4f      83.2f      87.1f
5 pm  95.4f    93.2f      84.8f      88.5f


temp readings


indirect section shown, actual swampcooler is 5 feet away connected with 4" flexible ducting and 5 feet of plastic water tubing.

 

[bullfrog]

That thing is big. Could you mount it outside on a rear door replacing a rear window like some do with ACs on on a hitch mount cargo carrier?

 

[bagabum]

 that opens the possibilities of keeping cold water in a cheap 12 volt fridge and pumping it into the indirect cooler to cool it even more.

Forget the fridge, whole set of new problems,  heat of condenser will have to be vented outside, and 50 watts of cooling into the water is barely detectable after 5 minutes of use.

 

[jonyjoe303]

ideally I want to mount it somewhere inside my van by the side vents. I been planning on enlarginging the side vent grills and this winter it will be my project. I only have to mount the actual heat exchanger, all the tubing will be go directly into the swampcooler. It only looks large on the picture because of the water container and all the flexible ducting which won't be needed once properly mounted.

The use of a 12 volt fridge to cool the water would be for extremely hot days. Run 40f water through the heat exchanger for a few minutes at a time with a timer relay its something I have been wanting to do. Originally my plan was to run cold water over the evap pad but the only thing holding me back was I had no room to put a fridge near the swampcooler. Now that I tested using the water pumps to move water over a distance, I can place a fridge anywhere.
As far as heat from the fridge, I solved that problem this summer. I been venting the fridge heat exhaust (up to 110f) to the outside using flexible ducting, its been a non issue in my van. I almost got rid of the fridge after I bought it due to the heat output. I keep the fridge set to 12f so it runs more then usual but introduces very little heat inside the van.

I measured the temp from the air coming in from the side vents and its over 120f during hot days, about 10 degrees hotter then the roof vents, so the heat exchanger will help in reducing the temp and since the swampcooler is right next to the side vents there should be no extra heat added to the air from long runs of flexible ducting.


siide vents that I will be enlarging

 

[bagabum]

The use of a 12 volt fridge to cool the water 

Before you make a (copper cooling coil with supply and return hoses, pump, switches etc )  to place in fridge, try pouring a quart of chilled water in your evap cooler reservoir to evaluate performance, put ambient water in that same quart container and place in refrigerator to determine chill down time, do this a few cycles to establish feasibility.  Evaluate, and then purchase/make all this stuff it proves effective.