Smaller 12V A/C options

[posplayr]

Originally Posted by jonyjoe101

This is a picture of one of the swampcoolers I built, it has 2x 120mm fans. It works good when its not too humid. With both fan running on max and water pump it maxes out at about 3 amps. Note the 2x 4 inch output ports in front, thats so I can attach 4 inch flexible ducting and redirect the air. On the rear are also 2x 4 inch port for the air intake. Those 4 inch ports are required on swampcoolers, I learned from trial an error.

Thanks for the info.

If I figure you are pulling air through 2x 4" ports you have 25 square inches of wetted media that you are pulling air through.

The preliminary design I'm looking at is 37 square inches so that is close to 50% more area.

That celdek looks pretty thin (1"-2" maybe). The commercial cooler we have on the roof pulls air through 8" pads of similar material.

I was going to try 4" material (3.5" x 10.5" x 4"). While there is probably more resistance to airflow, the thicker material probably has a chance to cool the air more.

anyway based on your numbers, it looks like my early design has a fighting chance.

[jonyjoe101]

I use the 3" celdek, its about the thickest that will fit in one of the smaller swampcoolers I build.

The intake port has to be large enough for the fans you are using. At first I was only using 1x 4" intake port and that was restricting the air coming out of the output. I figure about 1 4" intake port for every 120mm I'm using.

The way I look at it, if the swampcooler isnt working, use a bigger swampcooler. But in a vehicule you run into space limitations. Thats why running 2 swampcoolers produce results I could feel on a hot day. Your idea of using a larger evaporater pad will work better then the smaller ones I been using, you might need a larger fan.

I built a larger swampcooler using a car radiater fan but it was too large for my van. Also it was using too much power (6 amps) for my solar system I had at that time.

[posplayr]

Originally Posted by jonyjoe101

I use the 3" celdek, its about the thickest that will fit in one of the smaller swampcoolers I build.

Thanks for the pictures and dimensions. From what you say it is difficult to really cool even the smallish van so it is making me put my thinking cap on to improve the efficiency.

I'm going to try and shoot for you double cooler level performance by ducting all air from the roof fan through a fully saturated media. I will have to see how it works out but it seems like I can get 4.5" x 12" x 6" (HxWXD) inside a 6" little extension to the standard vent fans.

I will have to trim the media down from standard dimensions so I will make adjustments as required. This piece of media should fit under a 9" tall cover


So for example Comeco makes a standard size cover that is 7.2" and an XLT that is 10.5" tall respectively. So I will try and stay at 9" or less.

From the picture, you can see about a 9" height required for that vent cover opening and there is just about 6" of room behind the vent assuming I remove that work light above the upper brake light. So the whole evaporative section will go behind this installed vent/fan. I will have to make a custom fiberglass cover due to the contained space limitations.

You cant see it very well but there is a solar panel and a PCV solar water heater in front of the roof vent. You can see the brass fittings for the liquid vent and pressure relief valve.

You can also see a schematic of the setup. I have a water pump and accumulator so I'm using the main potable water supply to feed the evap-cooler through a standard float valve. There are two pumps one for recirculation and the second for a periodic dump of the water to keep things clean. There is also a cutoff valve which helps to save water during maintaance.

At 9" I can just keep it installed during summer months (May to October LOL) or leave it on all the time. I want to make maintenance easy even though this will have a dump feature to reduce hard water deposit build-up.

I'm still working on the actual dimensions. I plan to plastic weld some 1/8" ABS into rectangular shapes for the three sections of the cooler (upper media drizzle tank, media section, and lower reservoir). If I can keep this precise enough then the size should remain pretty compact.

[Twoxentrix]

I came across this a while back when searching for something simple, compact, and wouldn't require a lot of Fab work.
This unit is currently my main contender for an independent A/C unit for mounting inside & rear of the Van. Considering making a separate box to carry it, that still fits in the area I anticipated for the install, so its easily mobile. Planning on only using it in Summer, so wanted it easily removable to allow for more space in the Van the rest of the year. The holding box could also serve as a "catch tray" for any condensation, with a drain plug at the bottom of one of the sides. If I read it through correctly, other tasks would be to have a "quick connect power source hook-up", and a single hole drilled to the outside to accommodate a drain tube.
https://www.restomodair.com/shopprod...ditioning-kit/

https://www.restomodair.com/wp-conte...B-03-04-20.pdf

https://www.restomodair.com/wp-conte...08-31-20-1.pdf

[posplayr]

Originally Posted by Twoxentrix

I came across this a while back when searching for something simple, compact, and wouldn't require a lot of Fab work.

It seems like this is intended for mounting at the firewall and assumes that there is a compressor on the engine of the car. I'm not sure why this is really much different from a stock rear AC/Heater unit? Yea it has Bluetooth and a phone app but you can probably get that with a $50 thermal controller.

At one point I had grand plans for an on-demand water heater, heat exchanger, and radiant floor heating in the van utilizing the stock AC/Heater unit. This was going to be in conjunction with a pop-top.

In the end, that was all too much work and a definite possibility of never getting it done LOL. I have decided to focus an attached drive-away tent and on Evap cooling.

Home Smart Thermostat Programmable Wifi Wireless Room Sensor Digital App Control

https://www.ebay.com/itm/28422172699....c101195.m1851



Honeywell Home Lyric T6 Pro Wi-Fi Programmable Thermostat for up to 2 Heat/1 Cool Heat Pump or 2 Heat/2 Cool Conventional Systems

https://www.build.com/product/summar...E&gclsrc=aw.ds

Watlow’s EZ-LINK™ Mobile App Makes Setting Up, Monitoring and Adjusting EZ-ZONE® PM Controllers Easy and Painless

https://www.watlow.com/about-watlow/...-bluetooth-app

[b. rock]

If you didn't need one of the rear windows, something like this wouldn't be hard to attach since they're bolted in place: https://www.builditsolar.com/Project...wampCooler.htm

I like the idea of using standard a roof fan though. Not sure I'll be crawling on the roof to add/remove the assembly with a high top though. Although not super polished, this kind of idea would work out pretty well for interior assembly/removal, and you could take it with you when needed and leave it at home otherwise.
https://www.promasterforum.com/threa...-cooler.50722/

[posplayr]

b. rock. I'm sure a swamp cooler can be very effective in a small van it is just a matter of what works best.

For me, I'm going to make the rooftop evap cooler removable with bulkhead connections for both maintenance and seasonal removal. The Fantastic fans are pretty efficient as I recall and sized well for just the purpose.

I just got in those small pumps I linked above. They are specified at 1m head and 15 gallons per hour. I only need about 7-8 inches (my freshwater pressure pump pushes the water into the roof top reservoir) and 15 gal/hr seems plenty to keep the media wet.

For a manual purge, I can shut off the water and really drain the briny water completely (normally the float valve just keeps letting water in and dilutes your brine while you are trying to pump it out) .

Also I was reminded to get one of these (this remains totally seperate from the freshwater)so I'm hoping maintenance remains a seasonal even and not weekly LOL.

Dial*Plastic, Phosphate Evaporative Cooler In-line Scale Inhibitor

https://www.lowes.com/pd/Dial-Plasti...Up-Kit/3092909

Here are some more A/C options

https://www.ford-trucks.com/forums/9...-van-door.html

[posplayr]

Does anybody have an idea on what water consumption would be for a standard-sized van in 20-30 deg temp drop? I'm getting some wildly differing numbers.

This reference is quoting 0.29 Gallons per hour (GPH) per square foot of wetted area. A Small van cooler wetted area I'm planning might be only 12"x6" or 1/2 square foot.For a 1/2 square ft (12"x6") that is only 0.145 GPH.

https://newprairiepress.org/cgi/view...context=kaesrr

You would probably need to run this most of the day even if you are not in the van figuring at 24 hours a day max that would be .145*24= 3.48 gallons per day! This is pretty high consumption but tolerable for my 20-gallon water supply.

The problem is the reference below uses a formula for a much high consumption rate.

https://phoenixmanufacturing.com/wat...-our-products/

Assuming just 20 deg delta temp, 93% efficiency and a Fantastic fan (920 CFM max) at 920/460/230 (for Hi,Med,LO) https://www.etrailer.com/question-255037.html

I come up with 1.97/0.98/0.49 GPH for Hi/Med/Lo respectively. Even on the low rate, this is 12 gallons per day and at the high rate 47 gallons per day. These not make much sense!

Any ideas on how much water consumption you have to get to your double the cooler cooling performance?

Basically (for an E-250/E-350 RB no pop-top or similar), if you can get from 115 degF to a tolerable 90 degrees in dry heat how much water are you using per hour/ per day?

[posplayr]

I just found this guideline performance for a 20-25 ft RV at 3 gallons per day. I can safely adjust this down to 1.5 gallons per day for a much smaller van.

Sound about right?


Looking at the size of this it is a bit of a monster. 35x22x11.5 !!!

I'm figuring about (14+2*2+7=25)"x16"x10" at most which is just enough to cover the flange with a 7" bump out at the rear.

https://www.rvupgradestore.com/RV-Ev...RoCf-EQAvD_BwE

[b. rock]

I haven't sat down and done any calcs on it yet. I see the assumptions on the wetted media size and CFM, but what are you assuming for ambient temp and RH? Pick your worst case scenario if your main concern is water consumption. Once you have evap cooler effectiveness (or an approximation - 93% might be optimistic) it shouldn't be too bad to walk through with a psych chart and back into water usage from there. Or, just find out what a turbo kool or fresair would use and ballpark it from their usage.

A couple other notes: unless you're in death valley, it probably won't be running 24/7 as at some point (usually close to dawn) the temp will drop and RH will spike. However your 3.5 gallon # is probably close or even a little high. A quick off the cuff guess would be in the 1-2 gallon usage over the course of a hot, dry day, running for ~14 hours.