Staying cool with out air conditioning

[oil pan 4]

I would like to build a modular seat cooler. Modular for 3 reasons, one I don't want to build it all at once, I want to be able to use 1 in multiple vehicles and 3 some part of this rig may start leaking (yes it will be full of liquid).

This is using targeted ice and water to stay cool.
The numbers say it could work.
10lb of ice will require some where around 1,440BTUs to melt all that ice. Then require an additional 100BTUs to warm the water from freezing to the minimum useable cooling temperature which we will say is 42'F.
So 10 pounds of ice gives us an number we will just round to 1,500BTUs.
At rest I believe a person puts off something like 400 BTUs per hour at rest and 500 to 600 per hour walking around.
So in theory you could cool your seat for a few hours with 10 pounds of ice (plus some added water to start the heat transfer).
That should work great if you were only trying to cool your back and bottom.

This device will be powered by very small amount of intermittent 12 volt vehicle power and the ice will obviously be frozen elsewhere.

The description will start behind the scenes moving to the outer covering. From the cooler, pump, controller to plumbing and what covers it.

For my cold reservoir I have an old tall narrow party cooler with its lid broken off that would be perfect for this. I want it tall because I would like to attach the pump to the cooler and it would be advantageous to put the pump hardware above the water line. I would like to maybe put the pump inside the cooler for added sound control.
It even has a drain plug for easy removal of spent ice.

The pump I want to use will be a sureflo diaphragm pump. These surflow pumps typically produce 1 to 2 gallons per minute up to 60psi and draw 2 or 3 amps. This system should operate at less than 15psi.
The pump has a built in adjustable pressure switch that I will set low to turn off the pump in case of a pinched main line.

The controls, 2 gallons per minute is just about the entire mass of the cooling reservoir so there is no need to run the pump continuously. Plus the pump will hopefully be inside the cooler so it doesn't need to put off any additional heat.
Good news is there is something specifically designed for a 12 volt application to cycle a pump on and off. Its called a adjustable livewell timer. It cycles a boats live well air pump or live well water pump on and off to save battery power and keep dinner alive.
These timers typically run for 30 seconds, then stay off for a variable amount time, that can be set from a few seconds up to 5 minutes.
30 seconds on and a minute or 2 off should be more than enough.
So simple a drunk redneck can wire it up and get it correct, first try.

To get the cool water from the cooler to the seat I was going to use 3/8'' silicone heater hose I have left over from another project. Its very plush, flexible and kink resistant.

To get the cold water to person interface going I am going to use 4mm lines under the seat. The collector lines will be 7mm and the cross lines will be 4mm. They are thin, you can sit on them and not even feel them and I have like 30 feet of soft made in Germany 4mm soft PVC line.
Run the water in parallel loops using these:


Tie the lines and tees to a plastic mesh backing with some padding.
I will have to pick up some odd size 7mm line and that's about it.

To cover it I was going to take the zip up cover to one of my dogs beds, wash it a few times and use it. Its already the correct size, shape and material.

We are pretty sure this doesn't work:
http://ecomodder.com/forum/showthrea...ers-32359.html

We must salute dremd for paving the way for how to do this, 7 years ago. Here: http://ecomodder.com/forum/showthrea...ject-3884.html

[Daox]

Sounds like a fun project. I look forward to pics.

[oil pan 4]

I have a left over foot valve from a chemical pumping setup I will use as a pickup.
A foot valve is just a gravity check ball inside of a weighted body with a strainer around it.
Then poach the 1gpm surflo pump from my water injection setup. I would like to upgrade my water injection pump to a 3gpm pump. Now I have an excuse.

[Hersbird]

They make a T-shirt with cooling tubes built in. I have considered that but I have to get in and out 100 times a day so disconnect and reconnect would be a messy pain. Just cooling the seat is a good idea.

[aerohead]

The larger the cooler size the greater the cooling mass per unit of surface area you get as far as loosing ice in the cooler itself.
Doubling the size would cut heat transfer to 1/4th with no more R-Factor in the cooler's envelope.(same wall thickness).

[roosterk0031]

Don't know if a $15 bilge pump would put out the pressure you need but be easy to test, go buy one hook up a hose and see how high it can pump. Take it back to walmart if it isn't up to the task. I'd freeze 1/2 gallon milk jugs or 32 oz Gatorade bottles instead of loose ice. No need to drain the water.

Or go manual pump and use a squeeze bulb from a boat fuel tank.

Last idea cordless drill with $7 pump, pull the trigger when you need some more cooling.

[NeilBlanchard]

Kool Ties are cheap ($11) and easy - and very effective:

Kafka's Kool Tie - REI.com



Soak them in water, and the beads inside swell up and hold quite a bit of water right against your neck. It lasts several hours, and they work well.

[oil pan 4]

This is what I was working on today.
Removed my old water injection pump. Then screwed it to the top of my old cooler.
I stuck a 6 foot long length of new premium fuel line, I wasn't going to cut it down. Then on the discharge end I put a 1/4''OD push fitting and a little length of line.
I measured it putting out a half gallon of water per minute powered by my jump starter pack.
Installing a shorter length of 1/2''ID line will greatly reduce suction lift head and going to 3/8''OD or 8mmOD line on the discharge and powering it with full 14.4v power should help.
Even a half gallon per minute should be more than enough.

[oil pan 4]

I did I very simple proof of concept functional check.
Took the cooler put almost enough water to cover the foot valve and about 3 to 4lb ice in it, ran 10 feet of 1/4 inch line to a Y splitter then stuck 10 more feet on each end of the Y then just looped everything together where I could sit on it and ran the 2 ends of the Y back to the cooler. It works a lot better than I thought it would.
I am using about 1/3 to 1/4 of line I am planning on using in the bottom part of the seat.
I want the seat cooler to have the ability to make the seat occupier uncomfortably cold on a 109'F day, then just turn down the pump cycle timer as needed or just turn it off all together.
After this test I would be shocked if it didn't work extraordinarily well.
The cooler should hold at least 20lb of ice.

In other news I picked up my upgrade water injection pump, 2gpm 60psi Delanvan "assembled in USA" extreme duty 12v pump. I thought it was $90, rang up at $150. It was in the wrong spot, just like everything else on a shelf at tractorsupply.
The bigger pump is to handle the expanded water injection roll I have planned.

[oil pan 4]

After an hour of very cool bum the ice melted.
I put almost a gallon of room temperature water in the bottom to start off the cycle then put around 3 or 4 pounds of ice in there.
The lines running to and from the cooler were uncovered too, collecting condensation and I ran the pump constantly. This adding additional heat to the ice.
So the ice lasts longer than I thought it would.
With efficiency add ons like covering the exposed lines and cycling the pump the ice should last even longer.

Toward the last of the ice I tried cycling the pump on and off.
To swap the warm water out for cold through 20 feet of line takes maybe 10 seconds. Then stays cool for around 2 to 3 minutes.
A live well pump timer runs 30 seconds on then stays off up to 5 minutes.
So the live well timer I was thinking about using should be perfect.

My amp meter says the pump draws a little under 2 amps at 11 volts (the jump pack is getting low on power).
If we say the pump runs for 30 seconds then stays off for say 90 seconds.
At most its only average of a half amp.
Even 30 seconds on, 30 off is 1 amp average, so it will work well with an alt delete. It will use a fraction of the power of the A/C where you need a few amps to energize the magnetic compressor clutch, then 10 to 20 amps to run the blower fan.

The numbers say it should work well, in practice it works a lot better than I ever expected.
I am not often surprised like this.