Solar powered AC air conditioning, a bummer or a challenge?

[SunEagle]

Fresh Fog Fresh Fog Cooling Mist System | 80042-MISTER

http://www.sears.com/fresh-fog-80042...-SPM7555082402

Works best in dry climates but even here with 75% or more humidity it cools well.

Ahh. I understand now. My Daughter in law has a fan where you can connect a water hose creating a fine mist which is then blown out. Worked real good during their 4th of July picnic.

[russ]

Ahh. I understand now. My Daughter in law has a fan where you can connect a water hose creating a fine mist which is then blown out. Worked real good during their 4th of July picnic.

In Vegas street cafes use them - an umbrella of the fine mist.

Here they do help

On an industrial basis the dry fog is used for dust suppression in material handling systems. The water droplets are fine enough that you can run your hand through the mist and it comes out dry - hene "dry fog".

It is a high pressure system with special nozzles but nothing exotic.

[Mike90250]

The big problem with the peltier module, is only a 40F difference from the hot to the cold side. Second, is the waste heat that has to be discharged from the hot side. About 70% of the power consumed is simply converted into heat, and only a small amount of heat can be pumped from the cold side.

Then you also have to discharge the condensate water that will collect on the cold side.

[PhillyTitan]

Hello,

Evaporative cooling (swamp coolers) only work is dry climates... I am basing this in climates with 70% to 80% humidity.

Alan

Alan, my point was that the air conditioner you built had a power consumed to btu ratio that was 3-4 times higher than a window unit. I don't see how you can run that entire ship with so little cooling power.

[Sunking]

Alan, my point was that the air conditioner you built had a power consumed to btu ratio that was 3-4 times higher than a window unit. I don't see how you can run that entire ship with so little cooling power.

What you think he claims is completely false, and was the point of my intervention. A window shaker is 4 times more efficient than any Peltier unit.

[PhillyTitan]

What you think he claims is completely false, and was the point of my intervention. A window shaker is 4 times more efficient than any Peltier unit.

No room for misguided enthusiasm on this forum.

I wonder if a truck/van air conditioner could be a solution for small rooms. There wouldn't be any inverter efficiency loss in that scenario. Nor would there be the inflated cost of a home DC air conditioner....
Thoughts anyone???

[SunEagle]

No room for misguided enthusiasm on this forum.

I wonder if a truck/van air conditioner could be a solution for small rooms. There wouldn't be any inverter efficiency loss in that scenario. Nor would there be the inflated cost of a home DC air conditioner....
Thoughts anyone???

Nice idea but most vehicle air conditioners use the engine to run the compressor not the battery or alternator.

My RV has two roof top units but they will only work when I have the generator running or I am plugged into a grid connection. They are just too big to run off the coach batteries.

[jimindenver]

What about passive cooling? You don't to go down very far before the ground temp drops down to around 50 degrees. Did a trench, lay tubing and pump water through it to a exchanger in the shack with a fan behind it. 50 degrees isn't exactly cold but it is cool enough that it would keep the temperature in the room down.

[russ]

What about passive cooling? You don't to go down very far before the ground temp drops down to around 50 degrees. Did a trench, lay tubing and pump water through it to a exchanger in the shack with a fan behind it. 50 degrees isn't exactly cold but it is cool enough that it would keep the temperature in the room down.

Sorry Jim but that is a green myth - to get the heat transfer it would take a very long tunnel plus the 50° is an old wives tale. You also end up with a real potential for a mould problem - nasty!

[billvon]

What about passive cooling? You don't to go down very far before the ground temp drops down to around 50 degrees. Did a trench, lay tubing and pump water through it to a exchanger in the shack with a fan behind it. 50 degrees isn't exactly cold but it is cool enough that it would keep the temperature in the room down.

Earth tubes can work well in good environments (i.e. cold earth) but don't work well in southern climates where the ground is warmer year-round. As with any cooling system you have to be careful with condensate management; if the water is allowed to sit in the tube you get mold and other problems. They also take up a lot of space. You need hundreds of feet of tubing to get good coupling to the earth.

But if you can manage all that you can get very cheap cooling, at least on days that aren't _too_ hot.

[russ]

Earth tubes can work well in good environments (i.e. cold earth) Please name a few places

but don't work well in southern climates where the ground is warmer year-round. Ground temps don't vary like that

As with any cooling system you have to be careful with condensate management; if the water is allowed to sit in the tube you get mold and other problems. How do you prevent the condensation?

They also take up a lot of space. You need hundreds of feet of tubing to get good coupling to the earth. At least that I can agree with

But if you can manage all that you can get very cheap cooling, at least on days that aren't _too_ hot.

If frogs had wings they wouldn't skin their butt hopping. It is an idea flogged on green sites from time to time but not worth the problems plus a rather large volume of air is required.

[Sunking]

I wonder if a truck/van air conditioner could be a solution for small rooms. There wouldn't be any inverter efficiency loss in that scenario. Nor would there be the inflated cost of a home DC air conditioner....
Thoughts anyone???

No sir the AC power comes from the engine. Now there are DC air conditioners made for Tractor Trailers and trains that use 24, 48, and 96 volt DC, but again the power is coming from the alternators.

Only way remotely possible is with DC powered Split Air Conditioning. There are quite a few out there. Marv Air makes one for Marine environments in 12 and 24 volts with 5000 and 7000 BTU models. The 5000 BTU 12 volt units pulls 400 watts and one of the least expensive at $4000.

[inetdog]

No sir the AC power comes from the engine. Now there are DC air conditioners made for Tractor Trailers and trains that use 24, 48, and 96 volt DC, but again the power is coming from the alternators.

There is a growing market for DC A/C for tractor trailers that can run off battery while the engine is shut off because of idling restrictions. In those cases efficient operation with minimal battery drain is a selling point. But the recharge of the batteries ultimately comes from the main engine alternator or from a small quiet auxiliary generator.

[jimindenver]

Earth tubes, we called it ground cooling when I was in school for HVAC in the late 70's. We built homes with extremely low heating and cooling bills. People just didn't seem to like having their homes half buried in the ground and dealing with the limitations and maintenance of the systems. They only accept those things if there is really no other choice. Back then it was the embargo, today it's the environment driving it. Nothing has changed though, if it isn't plug in and turn on, it's a compromise.

As far as mold goes, you probably have some in your air conditioner but that's nothing compared to the average swamp cooler. Along with their limitations they can be nasty after not being run for a while.

[russ]

People just didn't seem to like having their homes half buried in the ground and dealing with the limitations and maintenance of the systems. Don't confuse a home built underground with earth tubes meaning tubes/tunnels that air can be drafted through. The underground home concept is valid. It takes advantage of low swings in ground temperature as compared to the atmospheric temperature swings.

As far as mold goes, you probably have some in your air conditioner but that's nothing compared to the average swamp cooler. Along with their limitations they can be nasty after not being run for a while.

Mould can grow anywhere true - a few hundred meters of dark and cool earth tube is a heck of a lot more problematic than an AC or swamp cooler that can be cleaned.