smallest, most efficient A/C ?

notsobright · August 2009

Hi all,

Im looking for the smallest and most efficient air conditioner available and I dont want a water powered air cooler.

this will be for a Van RV (very small space) Ive searched a little but guessing the best search phrase for a "tiny ac" is tricky.

any suggestions? basically I want the smallest A/C unit there is.

thanks!

BB. · August 2009

Re: smallest, most efficient A/C ?

I don't know that it meets your requirements--but this thread or two lists a small A/C system that plays well with Off-Grid systems:

Sanyo mini split AC (inverter/variable speed)
Sanyo Single Split systems (3,000-9,000 BTU)

-Bill

FL SUN · August 2009

Re: smallest, most efficient A/C ?

notsobright wrote: »

this will be for a Van RV .

any suggestions? basically I want the smallest A/C unit there is.

The smallest window unit I've come across is a 5,000 BTU. A mini-split unit installed in an RV van may be difficult, but could be done if you have the skills.

A high efficiency mini-split beats the pants off any window unit AC as far as operation cost per BTU.

dwh · August 2009

Re: smallest, most efficient A/C ?

notsobright wrote: »

Hi all,

Im looking for the smallest and most efficient air conditioner available and I dont want a water powered air cooler.

this will be for a Van RV (very small space) Ive searched a little but guessing the best search phrase for a "tiny ac" is tricky.

any suggestions? basically I want the smallest A/C unit there is.

thanks!

I have a Class B camper van I bought a couple of months ago, and I've put some hours into researching this very subject.

What I came up with is this unit here:

http://www.frigidaire.com/products/air-conditioners-dehumidifiers/window-air-conditioners/FAA055P7A

It's a 5,200 btu unit - but because it has an EER of 11, it actually uses a bit less power than the Frigidaire 5,000 btu unit which has an EER of 9.

It also has a feature called "Low Voltage Start-Up". I have no confirmation of what exactly that is...but I'm guessing it is very likely something like this:

http://www.modmyrv.com/2009/05/27/rv-air-conditioner-hard-start-capacitor

Best Buy has them, but you can find them all over the place if you look:

http://www.bestbuy.com/site/olspage.jsp;jsessionid=84FCEB2A13BB7BF73B79DB6974F8D0FB.bbolsp-app06-10?_dyncharset=ISO-8859-1&_dynSessConf=4218108564152049168&id=pcat17071&type=page&st=FAA055P7A&sc=Global&cp=1&nrp=15&sp=&qp=&list=n&iht=y&usc=All+Categories&ks=960

I haven't bought one yet, and since the summer is almost over I'll probably hold off awhile.

notsobright · August 2009

Re: smallest, most efficient A/C ?

thanks for the suggestions but those are more than I need. I found this thread:
http://forum.solar-electric.com/showthread.php?t=5095&highlight=portable
where N3quik posted a link to this unit:
http://www.globalindustrial.com/gcs/prod/30127522/i/productInfo.web?utm_source=google_pr&utm_medium=cpc&utm_campaign=AirConditioners--google_pr&infoParam.campaignId=T9F

seems more like what I had in mind but Im wondering.. Ive read about people converting freezers for refridgerator use, would it be possible to convert one (freezer) for air conditioning use? hmmm.

n3qik · August 2009

Re: smallest, most efficient A/C ?

I thought about the same thing. A co-work gave me a water cooler. They have a small compressor, so gave that a try. Problem was not enough surface area on evaporator coil. It would just freeze up. The ice got 1/4" thick. After that, it seam to stop cooling the air.

Cariboocoot · August 2009

Re: smallest, most efficient A/C ?

notsobright wrote: »

thanks for the suggestions but those are more than I need. I found this thread:
http://forum.solar-electric.com/showthread.php?t=5095&highlight=portable
where N3quik posted a link to this unit:
http://www.globalindustrial.com/gcs/prod/30127522/i/productInfo.web?utm_source=google_pr&utm_medium=cpc&utm_campaign=AirConditioners--google_pr&infoParam.campaignId=T9F

seems more like what I had in mind but Im wondering.. Ive read about people converting freezers for refridgerator use, would it be possible to convert one (freezer) for air conditioning use? hmmm.

The main advantage in converting a chest type freezer to a 'frige is that the cold air doesn't "pour out" when the door is opened. This would be irrelevant if used for AC purposes.

It takes a lot of power to pump heat energy from one location to another. The only thing that helps is to have a wide temperature difference between the heat you're 'dumping' and the area you're dumping it in. That's why ground-source heat pumps work well; the temperature several feet below ground is much lower than the ambient air in mid-summer.

dwh · August 2009

Re: smallest, most efficient A/C ?

notsobright wrote: »

thanks for the suggestions but those are more than I need. I found this thread:
http://forum.solar-electric.com/showthread.php?t=5095&highlight=portable
where N3quik posted a link to this unit:
http://www.globalindustrial.com/gcs/prod/30127522/i/productInfo.web?utm_source=google_pr&utm_medium=cpc&utm_campaign=AirConditioners--google_pr&infoParam.campaignId=T9F

I can see that unit being used as described - in a cubicle.

For a Class B RV (a van) I'd be interested in how well it works. And exactly how would you plan to vent the hot air out of the vehicle without sucking in hot air from the outside?

If you try it, I'd be interested to know the results.

Still, at 2.1a for 1000btu vs. 4.9a for 5200btu - I'd still go with the Frigidaire. That little unit will have to work non-stop I think, whereas the larger unit would run less - and no issue with venting the hot air out (simultaneously drawing hot air in).

Photowhit · August 2009

Re: smallest, most efficient A/C ?

Might look into a Petcool basicly a 2500 btu AC for a dog house, unit lives out side and runs air through an insulated duct, @350 watts as I recall though.

If the van has no added insultion you might need 5200 btu during hot weather.

I trust you'll run this docked to the grid? I run a 5300 btu for a few hours a night but have 1000 watts of panels more than what would fit comfortably on a van.

dwh · August 2009

Re: smallest, most efficient A/C ?

Photowhit wrote: »

I trust you'll run this docked to the grid? I run a 5300 btu for a few hours a night but have 1000 watts of panels more than what would fit comfortably on a van.

Well, as for myself, I have an old Class B camper van that I picked up cheap a few months back (for $200.00...there was no way I could say no). My plan is to A) add a generator,

add battery capacity, C) add an air conditioner and then D) add solar.

There isn't room on the roof of my van for more than perhaps 2 130w panels. I might get three on it if I relocate the 14" roof vent from the middle to the rear.

Which means that for the most part, the a/c would only be running when the generator was running. I like that the Frigidaire 5200 only uses 4.9a running, and has the "low voltage start-up", which I believe to be equivalent to a "hard start" kit for an RV a/c.

So, I should be able to run that a/c from a small inverter generator. I was just about sold on the Generac Guardian 3600 inverter gen due to its electric start and hard plumbing to the vehicle's fuel system, but now I think it will just be too much generator for such a small RV. (Microwave? Bah! We don't need no steenking microwave!) Also, there is a shelf on the outer left back door which from what I was told was used to carry gas cans for dirt bikes. That is the perfect place to build a box for a generator.

Right now, I'm looking very hard at the Honda EU2000i (98.5cc engine, 1600w rated continuous load), the Robin-Subaru R1700i (86cc engine, 1400w rated continuous load) and the Honeywell HW2000i (125cc engine, 2000w rated continuous load).

I'm planning to install 2 12v 105ah Deka AGM batteries and probably an Iota 45a or 55a converter/charger. The converter/charger will run from either shore power (usually only at home) or from the gen when camping. The decision about which converter/charger to use will have to come after I decide which generator to buy. The 45a Iota specs show "Maximum AC Current @ 108VAC 11 Amps" whereas the 55a shows 13a.

IF there is a problem running (compressor hot starting) the a/c from the gen, then I might add a third battery and put in an inverter to run the a/c - not to actually run it from the batteries, but to buffer the startup load. Even if I do that, the a/c won't be used unless the gen is running (or shore power) and the converter/charger is online.

[The pic was taken the day I bought it, it hadn't been moved in 15 years.]

[EDIT: As for the a/c, I plan to cut the hole for it in the fiberglass roof above the rear doors, as you can see in the pic it will easily fit.]

Photowhit · August 2009

Re: smallest, most efficient A/C ?

Looks like you have a rack for a small generator ready to go!

For what it's worth, when the fan went out on my semi pure sine wave inverter, basicly a MSW with more steps, I tryed to run my AC a couple times on a 1200 watt MSW inverter. it must be right on the cusp of what it takes to start the AC. When the sun was shinning during the day it kicked off, but it wouldn't start at night. Higher Dc voltage? not sure why. The next day I had the original inverter apart and had a small fan running 24/7 on it to cool it down.

Always nice to run motors on a true sine wave inverter. the generators will produce a pure sine wave, but cheap inverters create a MSW, which can be hard on motors.

dwh · August 2009

Re: smallest, most efficient A/C ?

Yes, if I decided to install an inverter to run the a/c, it would be PSW. I am planning to install a Morningstar SureSine 300w PSW which should be quite enough for whatever I need to run on AC in the camper:

But a PSW inverter big enough to run (start) that a/c unit won't be cheap and I'm hoping to avoid it if I can. (Unless I can find a used one for lowbucks - I'm always keeping my eyes open.)

dwh · September 2009

Re: smallest, most efficient A/C ?

FYI UPDATE

I emailed Frigidaire and asked about running that 5200btu EER11 a/c unit from a generator. It took a while, but I finally got a reply.

"Product = Air Conditioner
Model Number = FAA055P7A

Low Voltage Start-Up: Systems are designed to start at 10% below their name
plate rated voltage under normal operating conditions.
This is the voltage requirements: Read the manual for generator to
understand about start up voltages and requirements.
Electrical Information
Voltage 115
Amps - Cooling 4.5
Watts - Cooling 475
Starting Amps 11.5
Starting Watts 1,322.50 Note: Generator must be capable of
handling this amount of wattage for start up plus whatever else is on the
generator.
Fuse/Breaker (Amps) 15
Power Cord Amps Min 13"

EDIT: I inquired further about how low-voltage start-up is achieved (actually, repeated my original query). I quickly received a reply:

"However to answer your question the fan comes on first and about 3 min
later the compressor comes on to keep the starting wattage down. The
wattage I gave for start up is absolutely required or it could damage the
product."

So the "low-voltage start-up" on the Frigidaire units is a timer delaying compressor starting until the fan is up to speed.

The RV "hard start" mod adds an additional capacitor, and *usually* that capacitor has a timer to delay firing - which achieves both easier compressor starting AND compressor delayed starting.

mike95490 · September 2009

Re: smallest, most efficient A/C ?

Sounds like they did it basackwards. (Starting the fan first, then compressor)

I would start the biggest load first (compressor) and then after it's spinning, get the fan going. (I think the compressor is the tough load to start)

notsobright · September 2009

Re: smallest, most efficient A/C ?

the petcool looks intresting but for what it is the price seems too high.

http://www.americas-pet-store.com/details/prodid/1486.html

what a deal dwh! now if we can find or design a cooling system that will run on 300w!

any refridgeration hackers on the board? Im thinking its project time..

Dave Angelini · September 2009

Re: smallest, most efficient A/C ?

I think you guy's are just alittle ahead of what will be available soon. The work I did on the Sanyo mini split (in this section) is what the industry will go to eventually. They are expensive now but one of the best things about the inverter variable speed is there is no surge. If set to run on 300 watts it will slowly ramp up from 0 watts to 300 watts with no overshoot in current. You can run the unit on the little Honda 1KW generator up to the middle BTU range on the 9000 BTU Sanyo.

Sanyo told me that they will build a wall (one piece) unit this way eventually.

And there is just about no sound from this AC unit. The Honda will be what you hear!

2manytoyz · September 2009

Re: smallest, most efficient A/C ?

I built a Class B many years ago. I put a 7200 BTU Coleman Rotary Mini-Mach (no longer available IIRC) A/C unit on the roof. It was insulated, but very hot in FL. During the day in full sun, the A/C ran constantly to keep up with the heat load. It just did. At night, more than enough cooling capacity, and could throttle it way back.

I'm not certain a 5000 BTU A/C unit would have enough capacity in these conditions. It's plenty big to chill down my master bedroom as I learned when the central A/C croaked. No problems keeping that room icey.

This was a Goldstar 5000 BTU from Home Depot. About $80.

Running current, 4.9 Amps (fan on high speed):

Now here's what get you into trouble. The startup current was 22.6 Amps! I bought this Fluke meter which has an In Rush feature. Most meters aren't fast enough to catch this spike:

My Yamaha EF2400iS generator had no problem starting or running it. My Prosine 1800 Watt inverter also ran it easily. A smaller generator, or inverter, might not be able to give it enough kick to either start it initially, or restart the compressor once a head pressure has built up. Food for thought.

dwh · September 2009

Re: smallest, most efficient A/C ?

Dave Sparks wrote: »

I think you guy's are just alittle ahead of what will be available soon. The work I did on the Sanyo mini split (in this section) is what the industry will go to eventually. They are expensive now but one of the best things about the inverter variable speed is there is no surge. If set to run on 300 watts it will slowly ramp up from 0 watts to 300 watts with no overshoot in current. You can run the unit on the little Honda 1KW generator up to the middle BTU range on the 9000 BTU Sanyo.

Sanyo told me that they will build a wall (one piece) unit this way eventually.

And there is just about no sound from this AC unit. The Honda will be what you hear!

Aye, all absolutely correct.

However, the Frigidaire costs around $160 (I've seen it as low as $151), and it's pretty small - the outdoor part of the Sanyo split unit is 22" x 29" whereas the Frigidaire site shows 18-1/2" W x 12-1/2" H x 15-1/2" D for the FAA055P7A.

I can easily hack a hole in the back of the fiberglass top to fit the 5200...but where would I hang the outdoor part of the Sanyo? I could see maybe on a Class C or A, but on a B...probably not.

dwh · September 2009

Re: smallest, most efficient A/C ?

2manytoyz wrote: »

At night, more than enough cooling capacity, and could throttle it way back.

Yea, at night is where I would be using it. During the day fans are fine for me, but I don't sleep well when sweating.

Now here's what get you into trouble. The startup current was 22.6 Amps!

My Yamaha EF2400iS generator had no problem starting or running it. My Prosine 1800 Watt inverter also ran it easily. A smaller generator, or inverter, might not be able to give it enough kick to either start it initially, or restart the compressor once a head pressure has built up. Food for thought.

This is why I've spent so much time researching before I buy. I decided to go ahead and buy the Honeywell HW2000i generator. $499 on Amazon with free shipping. 2 year warranty and there are several authorized repair places around here who I called and all said they would do warranty work if it needs it.

http://www.amazon.com/Honeywell-HW2000i-Portable-Generator-Compliant/dp/B001DSGBZQ

The engine is a bit larger (25%) than the EU2000i (125cc vs. 99.5cc) but not as large as the 171cc engine in your Yamaha (and don't the Yamaha 2400, 2800 and 3000 all use that same 171cc engine? whacky).

I wanted the 2000w continuous load rating, so that I could (theoretically) run the a/c and the battery charger/converter at the same time.

I still need to find an induction type hour meter. I'm going to check locally and see if I can find a Briggs & Stratton "Maintenance Minder" meter:

http://www.briggsandstratton.com/maint_repair/parts_supplies/details.aspx?pid=5081

Which looks like around half the price of the SenDAC. It doesn't have a tach, but I don't need a tach, just hours.

2manytoyz · September 2009

Re: smallest, most efficient A/C ?

dwh wrote: »

The engine is a bit larger (25%) than the EU2000i (125cc vs. 99.5cc) but not as large as the 171cc engine in your Yamaha (and don't the Yamaha 2400, 2800 and 3000 all use that same 171cc engine? whacky).

I wanted the 2000w continuous load rating, so that I could (theoretically) run the a/c and the battery charger/converter at the same time.

I still need to find an induction type hour meter. I'm going to check locally and see if I can find a Briggs & Stratton "Maintenance Minder" meter:

Yea, little known fact. The Yamaha 2400 uses the same sized motor as the 2.8 and 3.0 as you noted. But the 2800 isn't near as quiet, and 3KW weighs double that of the 2400 (70 lbs vs 140 lbs). I've been told that the 2400 uses an aluminum block (I can verify that), and the 3KW uses a steel block. Don't know that for a fact, but might help explain where the additional 70 lbs comes from.

FWIW, my generator will run that 5000 BTU A/C unit from idle, producing only 53 dB (VERY quiet). When the compressor re-engages, it "might" bump the throttle for a split second before it settles back down. Doesn't always do this, usually stays at idle.

If you're interested, here's an article I did on this generator: http://www.2manytoyz.com/yamaha2400.html

Here's an hour meter/tach kit ($39) I installed: http://www.alpharubicon.com/warlord/altenergy/genmeter2manytoyz.htm

dwh · September 2009

Re: smallest, most efficient A/C ?

Heh, 2mT...I've read your entire site several times over...and referred a few others to it as well.

The Yamaha is rated at 2000w continuous and 2400w surge, the Honeywell is rated at 2000w continuous and 2100w surge.

Also, your 5000 Btu with EER 9.7 apparently draws more than the 5200 Btu Frigidaire with EER 11 - substantially more at startup - so I think it should be no problemo.

I saw your Yamaha meter. I was thinking that I don't really need a tach. If I can't find the B&G cheapo, then I'll probably go for one of these:

http://autonnicmanufacturing.com/Home_files/Page624.htm

2manytoyz · September 2009

Re: smallest, most efficient A/C ?

Hey, you're not supposed to be poking around on that website!

Yamaha is kind of grey on their rating of the 2400. You are correct about the 2000 Watts continuous, but here's where things get fuzzy. It will carry a 2400 Watt load for who knows how long. Hayes Equipment load tested this generator and it will carry a 3000 Watt load for 10 seconds before going into overload. It will also start a 13,500 BTU A/C unit, which I measured an instantaneous spike of 50.5 Amps.

Once it started, the current settled down to a reasonable 10.5 Amps.

FWIW, this has been a hot topic on the Motorhome Magazine Forum for quite a while. A Honda 2KW generator can't reliably run this same sized A/C unit. Most of them can't initially start them, the rest overload when the compressor tries to cycle on again after a head pressure has built up.

Often said the startup current can be 5 times that of the running current... just proved it.

If you get that A/C unit, let us know how it works out for you.

dwh · September 2009

Re: smallest, most efficient A/C ?

2manytoyz wrote: »

If you get that A/C unit, let us know how it works out for you.

No doubt I'll do a full report on that and the Honeywell generator (and whatever charger and batteries I end up with) as well.

I looked at RV a/c units, but decided against them because A) even the small ones are too big (the inside of the camper is only about 300 cu'),

they take up space on the roof which I want to have available for PV, and C) the generator issue (though quite a few people seem to have solved that one with a hard-start kit).

I need to buy a Kill-A-Watt as my antique analog Amprobe just won't cut it (but it's still great for checking panel load balance

).

I also need to buy a digital camera because my Sony finally died. It was a gift from a friend who took it on a 2 year motorcycle trip around the world and when he got home he bought a new one and gave me the round-the-worlder. Most of the pics on his site were taken with it. It was a bit of a pain to use, since about half the writing was worn clean off it, but it was a good camera - top of the line Cyber-Shot when he bought it.

http://www.strikingviking.net/

Here's the bad boy:

http://www.steves-digicams.com/camera-reviews/sony/dsc-f717/sony-dsc-f717-review.html

GreenerPower · September 2009

Re: smallest, most efficient A/C ?

smallest, most efficient

BB. · September 2009

Re: smallest, most efficient A/C ?

I can imagine various "models" of "human powered" versions from history--this is not going to end well...

-Bill

dwh · September 2009

Re: smallest, most efficient A/C ?

BB. wrote: »

I can imagine various "models" of "human powered" versions from history--this is not going to end well...

-Bill

It put me in mind of the old automotive 2/60 air conditioning system...

2 windows down, 60 miles per hour.

niel · September 2009

Re: smallest, most efficient A/C ?

hey, mine was better as it was 4/60.:p

crewzer · September 2009

Re: smallest, most efficient A/C ?

Check out these DC units:

http://www.dcairco.com/DC4400.html
http://www.dcairco.com/DC9000.html

HTH,
Jim / crewzer

BB. · September 2009

Re: smallest, most efficient A/C ?

Looks like really nice specifications...

Out of the UK, the "small unit" seems to be around £2,545.00 (another in GB quotes $4,255.75 USD).

No heat pump option?

-Bill

crewzer · September 2009

Re: smallest, most efficient A/C ?

Yep, but they are efficient!

More:

http://www.dometic.com/enus/Americas/USA/RV-Products/
http://www.dometic.com/enus/Americas/USA/Truck/

HTH,
Jim / crewzer

notsobright · September 2009

Re: smallest, most efficient A/C ?

dwh wrote: »

I also need to buy a digital camera because my Sony finally died. It was a gift from a friend who took it on a 2 year motorcycle trip around the world and when he got home he bought a new one and gave me the round-the-worlder. Most of the pics on his site were taken with it. It was a bit of a pain to use, since about half the writing was worn clean off it, but it was a good camera - top of the line Cyber-Shot when he bought it.

http://www.strikingviking.net/

your friend and his photos are very popular on some of the moto forums. I have terrible luck when combining moto and photo together, cant even get a year out of them. next one I purchase with extended warranty.

Ive got an old coca cola 12v fridge from one of their company vans from years ago its really small and needed a charge so I gave it to a friend who does grocery store refridgeration work unfourtunately he put too much pressure in it and blew out the condensor. I'll have to pull it out and see if it might be of some use.

smallest, most efficient A/C ?

Comments

Categories