Solar Air Conditioner

A buddy of mine has a 80's era VW Westfalia that he, wife and dog camp in. Problem is, we all live in AZ and his Westie has no AC, which is actually probably for the best, because he doesn't think he could pull the 6% grades here with AC on if he had it anyway, what with that small motor.

So he found that youtube vid a while back, and made a cooler of his own using a trucker's 12V fan and a sytrofoam ice chest. They use it when driving to and from Phoenix to the pine country. He says of course it doesn't do the job of a full AC, but it certainly helps some. And he doesn't have to shut it off to make it up the long grades. :)

The other part of covering your roof with solar is that you reduce the heat load.
So even if plugged in the solar helps.

We lived in New Mexico as kids and adults and swamp coolers worked great except for the months of July and August when we had our "monsoon" and we got 3/4 of our precipitation, maybe 6" and the humidity negated their capability. A normal RV a/c is 13,000 to 15,000 Btu and would require 2 kW of solar panels to operate. We have 1400 W and about 9.6 kW-hrs of LFP and have operated 3.5 hours as combination, dropping 1200 kW-hrs per hour. We could go for six hours and still be above 80% Dod but do not like going below 60%. The last several days have gotten back to rig in late afternoon with sun at low angle or in shade. Internal temp was in low to mid 90s and just ran a/c on battery suite for half an hour or so and got temp down to low 80s. We have two to four 12V outlets in each room aka cigarette lighters

After that, we use a couple if 12 V fans that make things comfortable.
Reed and Elaine

Of course you could always get the real thing like this:

http://www.hotspotenergy.com/DC-air-conditioner/DC-AC-Complete-Systems.php

Their smallest complete solar ac system will provide 12,000 BTUs of cooling for 10 hours during the day and 5 hrs in the evening for under $4k. (about 600lbs)

Their medium system provides 15 hrs of cooling (10 hrs without sun) for under $5k (about 1,000lbs).

And their big system (too heavy for most RVs at around 1,700lbs) will provide round the clock cooling for under $7k.

Yes it can be done - no it ain't cheap. If weight is an issue, for a few grand more you can switch to lightweight lithium-ion batteries and save several hundred pounds per system.

All it takes is money.

Chip

I really like the idea. Most places we go we have 120v shore power, but the roof mount a/c barely keeps up in the middle of the day. May be just the little extra boost needed during the hottest part of the day.

I was basing that on your previous port which said to run the a/c all day you'd need about $2600.

l use a CPAP - not sure I understand your last point above. They don't use a lot of power.

wmoses wrote:

Golden_HVAC wrote:
However it would be just as easy to spend $1,000 on a solar system, $400 on 4 batteries, $1,200 on a good pure sine wave inverter, and be able to run the rooftop air conditioner all day long.

That is my dream one of these days - going full solar. :)

Why dream. For the cost of a tank of gas, you can buy a solar panel. I bought a pair of 10 amp solar controllers for $13 each. These are prices that where not thinkable 20 years ago. When I bought my first pair of 45 watt panels, wiring, mounts, instructions and a 15 amp controller it was $750.

Now days you can buy a 100 watt solar panel from SunElec.com for only about $100 - $120.

THe controller you can get from AliExpress.com for $13 to get a PWM 10 - 20 amp model. If you plan on installing 300 watts, get a 20 amp controller for each 250 - 300 rated watts. You can use multiple controllers in one system.

For mounts, I used 6" long 2" angle aluminum from HOme Depot, with 3 each 3/16" holes in one side to mount to the roof, another 5/16" hole for a 1/4-20 bolt to the solar panel.

WIth the 90 watt system, it was almost a requirement to tilt the panels. Once I installed a $375 75 watt panel in 1997 and a pair of $429 120 watt panels in 1999, then I no longer needed to tilt the panels. In the meantime I installed a $300 or so controller - MPPT type rated at 50 amps. I had been thinking that I might need to expand the solar system beyond 315 watts, but that is not required, unless I start using a CPAP machine. In that case, I will need more roof space for more panels.

Fred.

Yup pretty much a swamp cooler, although I would imagine puts a little less water into the air if you use a frozen milk jug like he did.
It also would be good for localized cooling and when not extremely hot out and as pointed out above a ready cheap supply of ice! :B

The propane to make the frozen jugs might be more than running the genny to get the a/c to run!

Golden_HVAC wrote:
However it would be just as easy to spend $1,000 on a solar system, $400 on 4 batteries, $1,200 on a good pure sine wave inverter, and be able to run the rooftop air conditioner all day long.

That is my dream one of these days - going full solar. :)

It may work OK if it isn't too humid but that device doesn't "condition" the air - just cools it. Really it's more of a swamp cooler.