Teardrops n Tiny Travel Trailers

Booster fans... The hoses cause the air slow and restrict available exhaust air. As long as you keep re-treating the same cabin air i.e.. less loss of cold from door leaks etc. and less heat gain via insulation, then the game becomes all about removing heat from the condenser more effectively. The warmer the OAT the less heat it is able to remove. If you "supercharge" the exhaust system you will move more air across the condenser and remove more heat. A push fan to force air into condenser intake hose, and a pull fan to suck hot exhaust out.. If the BTU's of the unit are sufficient for the volume of air to be treated, this should maximize performance.
That one is on me.
De Nada.

McDave

Interesting. It sounds like you would want to keep the hoses as short as possible and add fans to help push or pull the air, right? Just checking to make I understood that right. Not impossible, but would take some searching to find the right fan(s).

Look up bilge blowers.

Very cool units. Very small units. Did not check pricing. Many sizes available. http://www.iceqube.com/air-conditioners/qube-series-mm/

phoenixbound wrote:Interesting. It sounds like you would want to keep the hoses as short as possible and add fans to help push or pull the air, right? Just checking to make I understood that right. Not impossible, but would take some searching to find the right fan(s).

I imagine the inexpensive duct fans would do the job.


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All I can say is, if I were to spend $500 bucks on an air conditioner for my trailer, that sucker better put icicles off the ceiling, and it better do it without having to modify it or work around a shortcoming. Just my humble opinion.

Iconfabul8 wrote:All I can say is if I were to spend $500 bucks on an air conditioner for my trailer that sucker better put icicles off the ceiling, and it better do it without having to modify it or work around a shortcoming. Just my humble opinion.

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Checked on Amazon, if needed these should be pretty easy to add:

https://www.amazon.com/AC-Infinity-Cool ... muffin+fan

I used to have a PetCool (now ClimateRight) HVAC in my teardrop. The unit was located in he tongue box with the supply routed through the front wall of the teardrop. The return was located in the galley bulkhead and returned underneath the teardrop to the unit. Initially, the coils would freeze due to the additional "resistance" from the long run of the return air duct. I added a blower in the galley to help "push" the return air back to the unit. This worked fine until the PetCool unit "died".

If you add additional "fans" to the Whynter, be sure to spec/size any fans so that you don't create a worse situation than no fans at all. The specs for the unit are rather vague but the duct sizes are either 5.0" of 5.9". A maximum airflow is given as 212 CFM but it doesn't specify whether this is for the evaporator loop (cool side) or the condenser loop (hot side). In general, I would suggest that our auxiliary fan match or exceed the CFM of the unit.

In my teardrop, I initially tried bilge (axial) fan and "muffin" fans. The bilge fan worked but sounded like a screaming banshee. The computer type muffin fan did not work. Often the CFM ratings for these fans are stated for "free air" conditions. When they encounter any static pressure, the airflow drops dramatically. The muffin fan could not push the air through the return air duct. I ended up using much more substantial 12-volt "squirrel cage" blower fan that maintained the CFM when under static pressure.

I am now converting a window unit for use in my teardrop. It is involving a lot of fabrication work. If I ever need to replace it, I'll have to go through the same drill to replace the unit. Someday, I hope to built a CT conversion. At that time, given my HVAC trials and tribulations, I will use an easily replace-able off-the shelf unmodified window unit.

If you really need a 14,000 BTU and have to do all that to make it possibly work, a rooftop would do it and use no more power or etc. that goes along with a large unit. You will just have to give up your 14" vent up top.

If you put on the recommended hose sizes, it will probably cool the space adequately even though not most efficiently. It is a large unit BTU-wise. Most Roof top units are 13,500 BTU.

If you do not need the BTUs, may be better long term and less expensive for you to design the installation for a window unit. They are tried and proven to do the job in smaller campers. There are many ways to do that as you know. Some are less complex than others. Most all have been successfull if installed with proper air exchange and right amount of insulation and etc..

In any case.. good luck with your project. Probably way more help than you wanted. :-)

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Sorry I didn't get back to you phoenix, this was Bucking Horse Sale week(end).
So, there is no way to know how much is enough without more data and controlled conditions. As a general rule I doubt you could have too much air across the condenser, so more cfm = better. What you do not want to mess with is the evaporator air flow. Let the machine do what It does, just get rid of the heat more effectively. I would start with something cheap and easy and readily available, like a scrap computer fan to push air. If that helps, try it in the pull instead and note the difference, if any. If needed try 2 fans, push and pull. If that does not show significant improvement, you are probably at the limit of the work that BTU's can do.
So to recap, shortest possible length of hose, as straight as possible, if one fan helps but not enough try 2. Those computer fans are everywhere so should be almost free. The booster fan needs to move more air than you are currently moving so as not to further restrict air flow.
Hope this helps. But if you are looking at 500.00 or anything rated over 13,000 btu, just do it right. Rooftop AC.

McDave

flboy wrote:If you really need a 14,000 BTU and have to do all that to make it possibly work, a rooftop would do it and use no more power or etc. that goes along with a large unit. You will just have to give up your 14" vent up top.

If you put on the recommended hose sizes, it will probably cool the space adequately even though not most efficiently. It is a large unit BTU-wise. Most Roof top units are 13,500 BTU.

If you do not need the BTUs, may be better long term and less expensive for you to design the installation for a window unit. They are tried and proven to do the job in smaller campers. There are many ways to do that as you know. Some are less complex than others. Most all have been successfull if installed with proper air exchange and right amount of insulation and etc..

In any case.. good luck with your project. Probably way more help than you wanted. :-)

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Thanks Don! My trailer will be 8.5x24 with 2 fantastic fans. I’m now looking at a window ac since it makes much more sense and cheaper. With the two fans and a 10,000 BTU ac, will that be effective in a trailer that large? I’m also trying to get away from the noise of a rooftop unit. I feel that there are easier ways to isolate vibration and sound on the window units. Thoughts?


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rmcrist wrote:

flboy wrote:If you really need a 14,000 BTU and have to do all that to make it possibly work, a rooftop would do it and use no more power or etc. that goes along with a large unit. You will just have to give up your 14" vent up top.

If you put on the recommended hose sizes, it will probably cool the space adequately even though not most efficiently. It is a large unit BTU-wise. Most Roof top units are 13,500 BTU.

If you do not need the BTUs, may be better long term and less expensive for you to design the installation for a window unit. They are tried and proven to do the job in smaller campers. There are many ways to do that as you know. Some are less complex than others. Most all have been successfull if installed with proper air exchange and right amount of insulation and etc..

In any case.. good luck with your project. Probably way more help than you wanted. :-)

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Thanks Don! My trailer will be 8.5x24 with 2 fantastic fans. I’m now looking at a window ac since it makes much more sense and cheaper. With the two fans and a 10,000 BTU ac, will that be effective in a trailer that large? I’m also trying to get away from the noise of a rooftop unit. I feel that there are easier ways to isolate vibration and sound on the window units. Thoughts?


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8.5*24 is a good size trailer so first let me say I do not think you can go wrong with a 13,500 BTU roof unit in this case. We all know it will do the job. With good insulation, a 10,000 BTU properly installed would probably do it fine also if you just do not want a roof unit. However, the larger BTU window size, weight, power requirements, costs, etc. all start to diminish some of the attractiveness a small window unit has for the smaller campers to start with.

Personally, because you have two vents... you can go with a roof unit and keep one fan which I think is important... if you hate the rooftop, you can always take it out and sell it after a season. You could then buy the 10,000 BTU unit with the proceeds and possibly a Fantastic Fan for the second vent hole the AC left. This way.... worst case.. you are only out about $300. (I have seen roof units going for $650 or so new these days).

The problem here would be if you put in the 10,000 BTU unit first and it just isn't doing it for you.. then you have holes in your camper where they may not be useful and are having to rebuild things. That will get expensive plus you still need the larger unit.

I hope this helps.. These are tough decisions... but is how I'd make it given your trailer size, margin for size needs, and etc.. .