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Old 05-09-2019, 02:02 AM   #21
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A bit more information I should have mentioned.

The water/condensate outflow connection falls directly over the galley sink. The outflow could be allowed to go into the grey tank, but we catch it in a basin and dump it as it is clean water. To ease the condensate outflow we raise the other via a six-inch piece of 2x4 lying flat.

Gerard M.
Good points. A common shaft for 2 fans would have to be done from the start of the layout design, not really possible in the current layout. I didnít think about different air flow for condenser and evaporator regarding humidity, do you have this option on this unit?

Are you planning to draw condenser cooling air from cooled space?
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Old 05-09-2019, 02:27 AM   #22
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My point was a motor home does not act like a stick & brick house for which an a/c's capacity must be carefully matched to sq. ft., insulation, etc. in order to run enough to control humidity (in my part of the South, especially).

A motor home acts much more like a car due to solar heat gain through glass, poorer insulation, and body heat that adds to the interior warmth. Almost the instant your a/c dash air turns off, it starts to become warm. While a motor home isn't quite that bad, it is much closer to that than your home would be. And from my personal experience related in my first post, 15K in a tiny class b has not been a problem or seemed over-sized at all.

I don't think I've ever heard the complaint "Man, my dash air is just too cold." Thus far, I've not heard that complaint about motor home a/c either. Could it happen, sure, but it's unlikely. That's all I was saying. And I just don't think 1100 btu's would make enough difference to be worth considering, especially at that price.
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I am having trouble following your logic.
IMO, humidity control is much more important than temperature for livability in a van. Any A/C that is cycling on and off is wasting opportunities for humidification. Therefore, an optimal A/C is one that just barely runs continuously to maintain the target temperature. This is just as true in an RV as in a house. My 11K unit certainly cycles under most conditions, so I consider it too big for my van.

For this reason, I am very interested in experiments such as Gerald's. I have long suspected that a small, continuously-running unit would be a good approach to A/C using modest battery capacities.
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Old 05-09-2019, 03:48 AM   #23
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I am having trouble following your logic.
IMO, humidity control is much more important than temperature for livability in a van. Any A/C that is cycling on and off is wasting opportunities for humidification. Therefore, an optimal A/C is one that just barely runs continuously to maintain the target temperature. This is just as true in an RV as in a house. My 11K unit certainly cycles under most conditions, so I consider it too big for my van.

For this reason, I am very interested in experiments such as Gerald's. I have long suspected that a small, continuously-running unit would be a good approach to A/C using modest battery capacities.
I think these BTU discussions should start with people telling us where they are located. Someone in a sunny parking lot in Texas will need a much larger unit than someone in the Rocky Mountains.
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Old 05-09-2019, 04:24 AM   #24
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George

The shower curtain seals against the poly-foam separator I made to fit over the Unit, which keeps the two air-loops apart/independent. As it turns out on the RT190P, the toilet is part of the cool/dry area. This is convenient, as there is normally no need to go into the warm/humid portion of the coach during the night.

The blower on the evaporator side has three speeds, while that on the condenser runs at full speed al the time. We found that the medium speed works well for our purposes. But we will see what other conditions call for.

There is no thermostat or humidistat on the Zero Breeze. It has nothing to control or cycle. Because its BTU rating is so small it appears to be unnecessary. We will just keep it running as long as needed, perhaps to the early morning hours, and then just switch off. We will see how this works.

I must say, I was quite surprized at how much moisture the Zero Breeze extracts from the air. To us humidity reduction is more important than a lowered temperature. One can dress for the latter, but high humidity is another matter.

In the end we will need to experiment to determine the arrangement that suits us best. Perhaps the unit will have to setup/hung at bed-height? We will see.

My wife is delighted with the low noise of the unit. The noise made is very low compared to a large A/C. and does not jar the nerves as it does not cycle.

We plan to only use the unit for sleeping. During the day we are active sightseeing or traveling. The chassis A/C takes care of things then.

Gerard M.
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Old 05-09-2019, 04:47 AM   #25
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The condenser section takes air in from both sides of the A/C and blows the warm air out the rear via a flexible three-inch duct. When expanded the outlet-duct is about 40-inches long and gets aimed upward to the MaxxAir roof-vent running at its lowest speed. I slight open the cab windows to complete the cooling air-loop for the condenser. The shower curtain pulled across the aisle and the open toilet door isolate the cool/dry and warm/humid areas from each other.

Gerard M.
I think your efficiency is going to suffer, perhaps alot, by pulling in warm moist air through the open cab windows to feed the condenser. To work efficiently the shower curtain would need to seal very well, which I think would be very hard to do.

I suggest rigging the outlet duct so it blows out without using the MaxxAir fan; the MaxxAir fan could pull in much more air (hot humid air) than is needed.

Take a look at this video for a portable AC unit. It has a separate condenser intake and exhaust duct. At the end of the video it shows only an exhaust duct mode for hot weather, with the intake coming from the room air itself. There is probably enough air leak sources to feed the condensor. In the van one big air leak source would be the vehicle HVAC that probably leaks a lot of air in through the dash fresh air ducts.

Sounds like some experimentation is in order. I hope you find a setup that works well.

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Old 05-09-2019, 05:20 AM   #26
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George

The shower curtain seals against the poly-foam separator I made to fit over the Unit, which keeps the two air-loops apart/independent. As it turns out on the RT190P, the toilet is part of the cool/dry area. This is convenient, as there is normally no need to go into the warm/humid portion of the coach during the night.

The blower on the evaporator side has three speeds, while that on the condenser runs at full speed al the time. We found that the medium speed works well for our purposes. But we will see what other conditions call for.

There is no thermostat or humidistat on the Zero Breeze. It has nothing to control or cycle. Because its BTU rating is so small it appears to be unnecessary. We will just keep it running as long as needed, perhaps to the early morning hours, and then just switch off. We will see how this works.

I must say, I was quite surprized at how much moisture the Zero Breeze extracts from the air. To us humidity reduction is more important than a lowered temperature. One can dress for the latter, but high humidity is another matter.

In the end we will need to experiment to determine the arrangement that suits us best. Perhaps the unit will have to setup/hung at bed-height? We will see.

My wife is delighted with the low noise of the unit. The noise made is very low compared to a large A/C. and does not jar the nerves as it does not cycle.

We plan to only use the unit for sleeping. During the day we are active sightseeing or traveling. The chassis A/C takes care of things then.

Gerard M.
Best of luck, and looking forward to future performance review.
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Old 05-09-2019, 12:03 PM   #27
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Good point re: dehumidification and continuous running. A variable speed compressor fills this requirement perfectly: they are beginning to appear in home heat pump units so, hopefully, they might be available in units for RVs at some point.
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Old 05-09-2019, 08:17 PM   #28
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This appears to be more promising than any other product I've seen on the market thus far of that type. Price reflects its scarcity, however.
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Old 05-09-2019, 08:33 PM   #29
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$900US for 1100 BTU's? That's an insane price.
Its only $650 if you buy the one without a battery.
I could imagine buying two.
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Old 05-09-2019, 08:54 PM   #30
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peteco

Yes there will be some leakage between the evaporator air-circulation-loop and the condenser air-circulation-loop. A complete seal to separate the two loops is not easily achievable. in our RT190P arrangement the toilet door is open and the shower curtain is drawn across the aisle next to it. The edge of the shower curtian is brought against the front of the lower galley cabinet and it touches the aisle-floor. At the level of of the A/C siting on the galley counter, the shower curtain seals against the polyethelene foam-baffel (I described earlier in this thread) that sits across the Zero Breeze about halfway along its length. If you look at the second viedeo posted in this thread, which shows the internals of the Zero Breeze, you will see why this is reasonably effective place to separate the the cool/dry from the hot/humid airfow loops. You will note that there is only one air intake to the evaporator, and that it is on the aisle side. Therefor foam baffel and the showercurtain can reasonbably well isolate the intakes.

The hot air outlet fom the A/C's condenser is guided up to the ceiling by the three-inch hose/duct, and taken out the roof by the MaxxAir Roof Vent that runs at its lowest speed (!0%). This seems enough speed to draw this hot air out the roof as well as any warmer air gathering at the ceiling.

With the shower curtain against the foam baffel the cooling air taken into the two condenser sections can enter from both the left and right of the Zero Breeze. See the video of the internals refered to above. Essentially only humid outside air is drawn through the condenser. no air treated by the A/C is used for this purpose. Because only air from ahead of the showercurtain is used, and to make airflow as easy as possible, the the cab door windows are opened by about an inch. These windows have an air deflector over them, that also keeps rain out, as does the open MaxxAir roof Vent.

The endresult is that with the A/C operating as described we achieve a pool of reasonably cool and dry air over the beds up to about the height of the galley counter top. Because of the configuration of the RT190P the toilet area is conveniently included in this pool.

Gerard M.
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