High Efficiency Air Conditioning Units for non-generator powered campers

[campo]

The description concerns the 3 AC systems on the right truck
The left truck has the HB2500 and an extension on the OEM AC system
The middle truck has 1 Dometic HB2500
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Some components of the full 24VDC air-conditioning system
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Part of the OEM extension with a second evaporator
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The integration of a Dometic Freshwell 2000 in 230V/50Hz whilst installing
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[S2DM]

Wow, I thought Australia was bad. We're usually heavily regulated but theres no restriction on mounting a domestic AC on a vehicle here that I'm aware of.




We're treating ours as disposable although we know of people who have got 10+ years out of them mounted to caravans.

Our unit was 1/3rd the price of a vehicle AC (or rooftop rattler as we call them down here) so we can swap it a few times and still be ahead on price.

That was my thought as well. A few advantages to the residential unit I can see over a Caravan/RV unit. Cheaper, so you can have a few replacements and still be ahead (less so in the states, the mitsubishi I am looking at is only slightly less than the rooftop unit). Modular, or two pieces, so, I'm guessing one part is more likely to fail than the other (I'm assuming the blower unit is more delicate) so you'd likely just be replacing half or an actual part in the event of failure. The other thing I'd thought of is parts availability and ease of repair. Any HVAC guy should be able to get parts for and work on a mitsubishi unit, I'm not sure what the process would be for a dometic?

 

[LeishaShannon]

S2DM, Do you guys have an energy regulator or similar that produces comparison reports similar to http://reg.energyrating.gov.au/comp...utput_range=2to3&model_number=&paginate_by=20 ?

Very handy for finding efficient units available locally.

 

[S2DM]

S2DM, Do you guys have an energy regulator or similar that produces comparison reports similar to http://reg.energyrating.gov.au/comp...utput_range=2to3&model_number=&paginate_by=20 ?

Very handy for finding efficient units available locally.

We have the energy star website and I will check for others. The two most efficient I have found are the daikin and the mitshubishi (not Mitsubishi Heavy). The highest EER available here seems to be around 16. The difference seems to be that AU has adopted R32, whereas it was just approved here recently (I believe on a trial basis). All US units are still r410a, which is a combo of r32 and another agent that limits the flammability of R32, but isnt quite as efficient.

Daikin is going to start making units with R32 here at the start of next year.

http://www.coolingpost.com/world-news/daikin-to-build-r32-units-in-the-usa/

I may hold out and put in the hardware to accept the Daikin, and just wait for it to be available.

 

[campo]

Hi guys
I am not specialised in legal and regulations. But I suppose that for the security ones the Australian regulations cannot be that different from the European or US ones.
If I would use a house unit in my RV I would more look at the noise level and the durability and not only at the magnificent EER efficiency values. Don’t forget to do the correct interpretation of these values through comparable norms. Be aware that we do not only have the VW scandal but also the white and brown domestic products are concerned as the manufacturers do these measurement themselves !? Until today I have never seen one installed AC performing like on the specification papers. If there is written 2500 Watt (8530 BTU/h) cooling capacity than I measure after installation only 1800 Watt (6141 BTU/h) Probably lots of specs are the result of testing in some marketing laboratories…
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My warning about using stationary AC units in your vehicles is a general one. Please be clever if you do so. There is the real danger with 110/230V. Water penetration or extreme environments. Car accidents and other unforeseen may and do happen. What when the unit gets older ?
The initial price off the house unit is low but the cost of an AC installation is high and you don’t want to repair every weekend. There is a real concern about the heavy duty usage in a vehicle. Not every vehicle is used as a caravan. Consider that even the strongest heavy travel trucks have serious breakdowns after only 50.000km through Africa. The plastic AC unit will in that cases be the first to die. Replace it every month is not an option.
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The stuff I used is, although made for automotive, is even not strong enough. I opened all the components before installation and made minor modifications to get them more rugged proof. Cable looms, electrical connectors end cupper pipes were rigidified where possible. We used or blocked some rubber silent blocks on some components. The usage of AC systems in severe conditions has to be observed carefully. One day I found out why an AC unit was burned out and the vehicle got almost fire after a trip in the Sahara. There was 4kg of sand inside the unit…
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I love to read your proposed comparisons of COP/EER values for AC units. But please mention if the units that can be used in RV automotive environment or the ones where you have tested and where your experience is that they resist.
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All the best Campo

 

[LeishaShannon]

Until today I have never seen one installed AC performing like on the specification papers. If there is written 2500 Watt (8530 BTU/h) cooling capacity than I measure after installation only 1800 Watt (6141 BTU/h) Probably lots of specs are the result of testing in some marketing laboratories…

This could definitely be an issue, I don't know whether the energy star website I mentioned actually tests output or relies on manufacturer data. Our our own electrical consumption data using both my fluke scopemeter and the VRM portal does appear to line up with the manufacturers claims however.



Thats the last 24 hours of total AC power consumption and SoC, the few spurts above 1000W will be from the espresso machine and microwave while the rest of the usage is pretty much all air conditioning. It only peaked at around 35c here so overall consumption was quite low. The AC is running 24/7 at the moment and set at 22c so we're pretty pleased with the results.

My warning about using stationary AC units in your vehicles is a general one. Please be clever if you do so. There is the real danger with 110/230V. Water penetration or extreme environments. Car accidents and other unforeseen may and do happen. What when the unit gets older ?

Agreed. Ours is isolated for travel to reduce the risk and during operation the trucks AC power system is protected by a RVD ( http://www.safelec.com.au/residual-voltage-device-rvd.html ) as well as RCD

These definitely look more solidly built than ours, we've only been on the road full time for 6 months so it'll be interesting to see how they hold up over the next few years.

 

[david506th]

I really wish there was a decent source for the dometic internal A/Cs in the USA. I have yet to find one.

 

[S2DM]

I really wish there was a decent source for the dometic internal A/Cs in the USA. I have yet to find one.

Ive been looking too and actually contacted dometic via a friend at blissmobil. They stated they arent available here and only operate via 230v. So you would have a double whammy of not serviceable here and requiring a separate transformer or inverter for 230v.

They suggested this which is way too big for our needs but might work for some. 16k btu. Pretty high watt consumption. Its a marine sealed dome split system.

http://www2.dometic.com/46638652-c377-4a6d-914a-e7c9c2ac9332.fodoc

http://www.dometic.com/QBankFiles3/...adome-Installation-Operation-Manual_15324.pdf

 

[campo]

Hi LeishaShannon and all the others !

Sorry for my English, remember that I am not native speaker.
Thank you for the very nice VRM SOC and average consumption charts. At +/- 15h00 your batteries are full again. How much Wp Solar do you have ?
I am quite impressed. Also about your knowledge. I am familiar with Victron but do not use this on my own truck yet. At the time it was concepted this was not ready as it is today. So I did not install touchscreens or Color control.
The three picture trucks are all equipped with a Multiplus 3000VA and 4xGEL 220Ah.
This is a sort of European standard equipment size for this size of budget vehicles.
The installed AC units can only run 4 to maximum 6 hours on these batteries without solar energy.
On my vehicle I can run the smaller 230V unit for 6 to 7 hours and the 24V split AC in the economy 600 Watt mode (only the bedroom) up to 10 to 12 hours overnight. You see that your better EER gives you a big advantage !

RCD/RVD devices we know them but the price here is higher than the 190 AUD that is on the AU webshop. I confirm that it's good to have them.

 

[S2DM]

Hi guys

I guess to my eyes that looks like all of the same components you would see in a residential unit, but in a vibration protection case. For us in the states its not a great option because of the lack of serviceability.

I think it should be possible to follow LeishaShannon's example and tie everything down really well. We are having our copper lines between the condenser and blower units remade out of automotive flexible refrigerant lines to reduce the stress of movement of the vehicle. I have been looking at coupling that with a vibration isolation mount, to soften the jolts from road life. Either a soft rubber bushing mount or a spring isolation set up. Further amplifies the need for the automotive refrigerant hoses if the AC can move independently of the chassis, but I am hoping it will extend the life of the unit.

 

[campo]

This is the newest one. Its name is Freshwell 3000 (and that means 2500 Watt)
Not available yet. Size is smaller than the HB2500 but still same big consumption in 230V
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[S2DM]

Here is a great article on the differences between r410a and r32, and explains why the EU, AU and Asia units seem to be more efficient than the US available ones. It is multifactorial, but in short, R32 has a higher COP than r410, and can be run in smaller hoses. Its also markedly less environmentally risky for several reasons, but does have a very mild flammability profile (discussed in the article, seems to be a non risk).

http://refrigerants.danfoss.com/r32/

Flammability

http://www.coolingpost.com/uk-news/daikin-plans-r32-in-sky-air-splits/

 

[campo]

Hi S2DM !
Sorry that I can not follow.
Are you building a vehicle, in project ,or do you have already one with an installed AC system ?
thanks Campo

 

[S2DM]

Hi S2DM !
Sorry that I can not follow.
Are you building a vehicle, in project ,or do you have already one with an installed AC system ?
thanks Campo

Yes, also building a camper and trying to decide which unit to use. I was going to import one of the hb2500, but I got worried about getting it serviced if it had problems and the efficiency was such I thought it might be hard to run without a generator or letting the truck engine idle.

I think I have decided to install a unit similar to LeishaShannon's, a residential mini split. To clarify, our goals are to have a unit efficient enough to run off of solar alone most days, as we won't be carrying a generator. We have 1300 watts of solar, and currently 400ah of lithium ion batteries.

The dometic is very nice, but its efficiency is 9.47, and it would be very hard to run on solar alone. The unit I am considering uses 1/2 the energy that the HB2500 does. For that reason alone, I don't mind paying the extra money in repairs and likely increased frequency of replacements, because it allows the unit to run off of our solar array and not carry a generator.

 

[campo]

The idea to use this insulation material instead of a metal box comes from Truma.
Truma (blue color) has a similar underbench range as Dometic.
We also see this technique coming on bigger busses AC systems.
Basic idea is to reduce weight.
It is not solid at all. If it slips out of your hands whilst installing it is already broken before you start.
The good thing is that the components evaporater and condenser are not fixed anymore with brackets and screws but just lose fit in the spaces.
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