High Efficiency Air Conditioning Units for non-generator powered campers

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S2DM

Adventurer
Been researching the feasibility and utility of off the grid AC use for campers with large lithium banks and large solar arrays (the holy grail!). Our current set up is 400am LiFePO4 Victron Batteries, and around 1k watts of solar. We are considering adding an additional 200ah of battery.

Options I have found thus far. Please double check my math and efficiency ratings, I am a novice to camper electricity.

Indel Sleeping Well Arctic Plus

http://www.indelb.com/products/truck_air_conditioning/sleeping_well/sw_arctic_plus

http://www.driveproducts.com/wp-content/uploads/2014/04/Anti-Idling-Brochure-0913_web.pdf

(Page 16)

Split type system. 12 volt native

BTUs - 6150
Watts 744 or 660 (depending on which source you read)
Efficiency 8.26 or 9.31

Pricing?

Arctic Breeze

http://www.arcticbreeze-truckac.com/content/arcticbreezeintro.html#specs

12 volt system

BTU 8000
Watts 600
Efficiency 13.33

Have read that their is some question surrounding the artic breeze efficiency numbers. I have also read it is possible to separate the components out and install as a split system (apparently this has been done in a sprinter).

This article seemed to indicate it struggled to keep an entire truck and sleeper rig cool when the outside temps topped 100. I am guessing a camper would be much better insulated, but it bears consideration.

http://www.truck-drivers-money-saving-tips.com/arctic-breeze.html

Indel Sleep Well Oblo Twin

http://www.indelb.com/products/truck_air_conditioning/sleeping_well/sw_oblo_twin

Single unit roof mount style. Looks to be 24 V only

BTU 6150
Watts 840 (35 amps on high x 24 volts)
Efficiency 7.32

Dometic Blizzard Turbo

http://dometic3frontend.qbank.se/episerver/4d0b33b5012968d7184664859cf30a80.pdf
Split system. 115V native (requires an inverter, so efficiency ratings for 12v power will have to take into account inverter energy losses). Looks like the condenser unit on the outside runs on 12v and the condenser unit on the camper interior runs on 115v.

BTU 7000
Watts 816.5
Efficiency 8.57

Coleman Mach 8 Polar Cub

http://www.campingworld.com/shopping/item/polar-cub-9-200-btu-coleman-mach-air-conditioner/49864d

Roof mounted
115 V native (efficiency has to be adjusted for 12v power due to inverter losses)

BTU 9200
Watts (11.5x115) 1322
Efficiency 6.95

Dometic Penguin

http://www.dometic.com/USA/MS-7207-...n-II-135K-Low-Profile-Rooftop-Air-Conditioner

Roofmounted, 115 native

BTU 13500
Watts 1460.5 (12.7 x 115)
Efficiency 9.2

Indel Cube

http://www.indelb.com/WS/DownloadPdf.aspx?co_id=201&filename=sw_cube.pdf&pdf=y

12 or 24 v. Free standing, requires vent attachment, or out a window

BTU 3200
Watts (36x12) 432
Efficiency 7.4

DCAIRCO

http://www.dcairco.com/product/truc...24-vdc-direct-current-rooftop-air-conditioner

Note - I have emailed several times for a quote and have not heard anything back

BTU 9000/7650 (unclear which is which here)
Watts 720 (continuous duty)
Efficiency Unclear based on BTU, but seems to be greater than 10

230V Options

Mitsubishi Heavy

https://www.mhiaa.com.au/index.php/component/mitsubishi/products/default/96

BTU 6800
Watts 350
Efficiency 19.5

Truma Saphir

http://www.truma.com/int/en/air-conditioning/saphir-compact.php

Under bench mount unit. 230v native

BTU 6150
Watts 660 (it is unclear if this is with losses from their available, model specific inverter)
Efficiency 9.31

Dometic HB 2500

Under bench mount unit

BTU 8500
Watts 897 (3.9 amps x 230 volts - no 12 V data available for their model specific inverter)
Efficiency 9.47

Dometic Freshwell 2000
http://www.jacksonsleisure.com/cara...c-freshwell-2000-under-bench-air-conditioner/
BTU 6100
Watts 650
Efficiency 9.38

Fujitsu 9RLS3

http://www.fujitsugeneral.com/wallmountedRLS3_specs.htm

BTU 9000
Watts 575 (2.3 x 230)
Efficiency 18 (stated) 15.65 (calculated)

Mitshubishi MSZ-FH09NA

http://www.mitsubishipro.com/en/pro...-zone/m-series-heat-pump-systems/msz-fhmuz-fh

BTU 9000
Watts 560
Efficiency 16
 
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S

S2DM

Adventurer
It seems that the standard, US available, RV roof top units are efficient in the 13.5 btu and up range, but in the lower btu ranges, more compatible with a lithium, high watt solar, off the grid set up, the nod goes to the truck based systems, like the 12v Indels, or the 115 v dometic blizzard. At 13,500 BTU, the penguin boasts an efficiency of 9.2, but the amps per hour would quickly exhaust any but the largest battery arrays. The 9200 BTU polar cub only has an efficiency of 6.95.

The Arctic Breeze boasts impressive numbers, but several big rig reviews have stated it isn't always enough to cool their rig. It also lacks directable air flow. How applicable that is to a well insulated smaller camper I am unsure.

We are looking heavily at the Indel Artic Plus, The Dometic Blizzard, and to a lesser extent the Arctic Breeze. The 12V native arctic plus is very interesting.

We briefly considered a few of the 230v options. The truma is very compact and efficient, I love the under bench design for our build, but they would require a second inverter to supply 230v power, as well as having expense in getting parts shipped from Europe in the event of a failure. It is still an option to consider for U.S. builders though. I believe BlissMobil uses the HB 2500 in their builds which also has heating.

Thoughts between the Indel Arctic Plus and the Dometic Blizzard? Our camper is a hard sided pop top, so my mounting options are more limited, but both of those I can fit.
 
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DiploStrat

DiploStrat

Expedition Leader
Great Work!

S2DM said:
Been researching the feasibility and utility of off the grid AC use for campers with large lithium banks and large solar arrays (the holy grail!).
Click to expand...

Thank you for all of your research! Living in the East, below the Mason-Dixon line, this is a subject of great interest for us too.

The big issues are:

-- Most A/C's are too big; 5k BTU or so is enough for most campers.
-- 110/220v native, requiring an oversized inverter or the kinetic energy of a genset.
-- Appalling ($4k vs. $300) cost of DC vs. AC air conditioners.

A pure DC unit, or a hybrid with a DC compressor should have significant savings as it is the starting surge of the compressor that demands the huge inverter.

Our Tiger uses a 6k BTU residential air conditioner. The amp draw is between 50 and 60A, when the compressor is on. With a 600Ah AGM battery bank, that is still a lot, but naturally, the compressor runs less at night after the sun sets.

One note: All of these systems will be marginal and power hogs, thus it is critical to cool down the cabin while the prime mover is still running. You can't simply stop at 6PM in the summer, in the Red Centre and turn the beast on and expect that it will cool down the camper on batteries!

 
S

S2DM

Adventurer
DiploStrat said:


Thank you for all of your research! Living in the East, below the Mason-Dixon line, this is a subject of great interest for us too.

The big issues are:

-- Most A/C's are too big; 5k BTU or so is enough for most campers.
-- 110/220v native, requiring an oversized inverter or the kinetic energy of a genset.
-- Appalling ($4k vs. $300) cost of DC vs. AC air conditioners.

A pure DC unit, or a hybrid with a DC compressor should have significant savings as it is the starting surge of the compressor that demands the huge inverter.

Our Tiger uses a 6k BTU residential air conditioner. The amp draw is between 50 and 60A, when the compressor is on. With a 600Ah AGM battery bank, that is still a lot, but naturally, the compressor runs less at night after the sun sets.

One note: All of these systems will be marginal and power hogs, thus it is critical to cool down the cabin while the prime mover is still running. You can't simply stop at 6PM in the summer, in the Red Centre and turn the beast on and expect that it will cool down the camper on batteries!
Click to expand...

Would love to hear more about your setup, model, and EER rating!

I am having a hard time conceptually understanding why the split system Leishashannon uses is so much more efficient than the apparent best, truck based solution available. Both the Dometic and the indel use high quality components and are the mini split design, but both are only half as efficient. They are in a similar BTU range as well, 6-7k, but again, just slightly under half the efficiency.

I spent some time looking for 115 native home based mini splits, but it seems that even they aren't nearly as efficient as the 230 volt versions. Although even the 230v versions available in the US arent even 75% as efficient as the MHI unit available in Aus that LeishaShannon uses. Is there something inherent about the higher voltage that allows the efficiency? I have been debating whether it makes sense to add a second inverter, which should hopefully be 90-93% efficient, and then run a 230v 19-20 EER home unit, which should yield a real world EER of 17 or more. Given that I haven't found a US version boasting similar efficiency, I may look to find one overseas, although Ive learned first hand the PITA factor there can be high with trying to import and maintain something not originally for sale here.
 
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S

S2DM

Adventurer
DiploStrat said:


One note: All of these systems will be marginal and power hogs, thus it is critical to cool down the cabin while the prime mover is still running. You can't simply stop at 6PM in the summer, in the Red Centre and turn the beast on and expect that it will cool down the camper on batteries!
Click to expand...

This was our thought exactly, run the AC when you are driving. The heat density of a camper where every surface is 90 degrees and the outside is 100 degrees is going to be impossible to battle. The stored heat density in the walls will take forever to change at 5000 BTU. If you pull into camp with the internals of the camper, walls etc, at 80, your AC should be much more effective.

We are also considering a deployable thermal shade for our bed area, which is a king, but small in a volume sense, so we can just cool the bed at night, and the whole camper during the day when solar is plentiful.
 
DiploStrat

DiploStrat

Expedition Leader
S2DM said:
Is there something inherent about the higher voltage that allows the efficiency?
Click to expand...

Maybe no scientifically, but practically. I would suggest that efficiency, per se, is not the issue, but rather the fact that the A/C's are too large and thus consume too much power.

Our Friend from Oz knows of what he types.

More later.
 
S

S2DM

Adventurer
DiploStrat said:


Our Friend from Oz knows of what he types.

More later.
Click to expand...

Agreed! I may just import the same unit.

The mini split home design would present some installation challenges in my build, but it is in the right BTU range, 6800, and very efficient.

LeishaShannon, are you able to provide any real world wattage numbers in different conditions? Is the 350 watts 100% duty cycle? Has it held up to automotive use, particularly 4wd banging around?
 
L

LeishaShannon

Adventurer
S2DM said:
LeishaShannon, are you able to provide any real world wattage numbers in different conditions? Is the 350 watts 100% duty cycle? Has it held up to automotive use, particularly 4wd banging around?
Click to expand...

The 350W is for the base 6800BTU output.

As the unit has has a variable speed compressor its actually able to output a max of ~10500BTU (3.1Kw) @ ~680W for quickly cooling the camper down , and then assuming your insulation is good enough it can drop its output to ~3070BTU (.9Kw) sipping just 170W

Its a reverse cycle unit and in heating mode the output is even higher @ 8500BTU (2.5Kw) base , with a max of 14600BTU (4.3Kw) although the efficiency while heating isn't quite as good @ ~ 18.8

Actual consumption is going to depend quite heavily on the insulation value of your camper. Ours has 35mm thick high density polyurethane walls which have almost double the R-value of polystyrene and the double glazed windows help too.

acpowe.jpg

This chart shows the AC electrical usage on a typical day , you can see the initial large surge as the unit cools the camper down then the variable nature of the compressor kicks in to maintain the desired temperature.

At the extremes (OK, not very extreme as we're trying to avoid really bad weather) on a warm 35C day we averaged just over 200W keeping the interior @ 23C , and on a cool 1C morning we averaged 370W keeping the camper @ 28C

Because its an inverter model it doesn't have a high startup current. In "silent" mode the consumption is limited to ~250W of electrical energy and for giggles I have run it off our 350VA Victron inverter, but this is neither recommended or wise :)
 
S

S2DM

Adventurer
Haf-E said:
There isn't really any advantage of the higher 230 vac voltage - it just allows the same design to be used in the US and overseas. I did see that the Fujitsu does offer a 115 VAC inverter model with an SEER rating of 16 and a EER value of 10.8 :

http://www.fujitsugeneral.com/wallmounted9-12RL2_specs.htm#specs
Click to expand...

I just havent been able to find a 115 VAC that offers an EER much above 10, whereas I have found quite a few 230s that offer high teens.
 
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