Quote:
Originally Posted by fry5family
I'm looking for information on a portable air conditioner to use in two circumstances -- 1) Sometimes we have to camp in locations where our two air conditioners can't keep up (50 amp power, 110v available on power pole); and 2) we have 1100w of solar and 824ah of lithium and would like a unit that is very energy efficient to take the edge off sometimes (we do have soft starts on our RV air conditioners).
"Just drive somewhere cooler" is not always available to us.
What portable air conditioner is working, or not working, for you?
Michael and Deborah Fry
2005 Monaco Knight 38PDQ and 2014 Honda CRV toad
|
Here's a reply that I created to an earlier inquiry. The info may help...
= = = =
Here's my cut-and-paste writeup regarding portable air conditioners. Note that this writeup is my personal experiences, your mileage may vary...
I have an old front engine gasser motor home, with the back of the engine positioned between the driver and co-pilot seats.
= = =
An air conditioner (a/c) cools by taking air from the room, cools it, and returns it back into the room. It does the cooling by extracting the heat from the air passed through it and sending that heat outside.
That said, when researching a portable a/c you will find single hose units and dual hose units.
The single hose units have 3 ports. They draw a quantity of air from the space being cooled (port 1), pass it through the cooling unit and return most of it to the room (port 2). The rest of the input air is blown across the heat exchanger and sends the now-heated air to the outside through the exhaust hose (port 3).
The problem is that that the portion of the input air that was sent outside reduces the air pressure in the room... i.e. it creates a slight vacuum in the room... what some call negative pressure.
That negative pressure inside the coach draws warm outside air inside from any outside-to-inside air leak (like the skylight, bathroom exhaust fan, propane fridge vent, over-the-stove vent, hot water heater door, etc... ). And the air that is drawn in is (naturally) HOT outside air.
As said above a dual hose unit has 4 ports and doesn’t have to work nearly as hard as the single hose version since it does not create negative pressure - it is therefore much more efficient. It draws air from the room (port 1), cools the air, and returns it to the room (port 2). It simultaneously takes in outside air through the intake hose (port 3), dumps the heat removed from the room air into that outside air, and sends the heated outside air back outside through the exhaust hose (port 4).
One thing you can do to really help it cool well is to insulate the exhaust hose. Some units have their port 1 as a grille on the back side of the unit, so those units can draw in air that was heated by the non-insulated exhaust hose. Since that hose is transporting hot air it heats up quite a bit.
I borrowed and used a single hose unit the first summer after I got my MH. In my coach the negative pressure situation caused the outside warm air to come in mostly through the dash air conditioning ducts (if you placed your hand by the windshield you could feel a warm draft coming through the windshield defroster ducts), a little from the shower skylight / vent and some from around the air stack behind and around the propane refrigerator. After I fixed the dash air system that leak was resolved, and I discovered incoming warm airflow around the over-the-stove vent, and around the water heater, and a can of spray-foam fixed both. The final fix was to purchase a slightly used dual hose unit on Craigslist and return the single hose unit.
There were times that the exhaust hose of that borrowed single hose unit was almost too hot to touch.
Once I had the two hose unit I discovered that you need to position the two hoses so that the intake hose does not collect any of the hot air being ejected from the exhaust hose. On my RV I made up wooden panels that clamp in the drivers side and passenger side windows (mine crank up and down, just like in a 1950s car) using pool noodles that I slit with a bread knife and fitted over the window glass top edge and around the wooden panel. The intake hose goes to the wood panel on one side of the RV, and the exhaust goes to the other side (if there is a breeze I position the exhaust hose downwind). When it is in use the air conditioner sits in between the front seats next to the engine cover.
A bug screen on the outside intake hose helps. I used a piece of mosquito netting.
More info: https: // learn.allergyandair.com/portable-air-single-hose-vs-dual-hose/
Note that any portable air conditioner is going to generate condensate (water).
Some vaporize it on the heat exchanger and dump the vapor outside, others have some form of a condensate collection tank. Most of those have a full-tank shutoff switch. Some units can have a condensate drain hose connected, some can be modified to use a hose.... but there's that pesky gravity and none of the cheap ones have a condensate pump that will direct the water up and out. For those that have a hose it's best to not to have the hose dump into a sink as you can fill your grey tank remarkably quickly... especially in a humid area. It's best to run the condensate hose outside. I ran the hose out through a hole in the floor and to a nearby planter.
If sound level is important in your purchase selection then look for the Sones rating. Sound level on commercial products is measured in "Sones" (pronounced like "Zones" but with an "S"). Lower numbers are better (quieter). A level of 4.0 sones is the sound of normal conversation. 1.0 sone is the sound of a quiet refrigerator. I helped a friend swap a bathroom fan in his sticks and bricks house, his new Panasonic fan is almost inaudible... rated at a ridiculously low 0.8 sones.
Lastly, you can increase the effectiveness of an a/c unit by reducing the heat leakage level in your RV. Check around any hole in your outside walls... outside power outlet, furnace, water heater, the over-the-stove vent, roof shower fan etc.
Read here:
https: // rvblogger.com/blog/12-best-ways-to-insulate-a-travel-trailer-for-winter
I disagree with one item in the blog article: dual pane windows are a good idea but not in a rolling earthquake. They can be a future problem as they are created by bonding two pieces of glass and a center spacer into a sandwich. Road vibration cracks the seals and a fog (usually white) develops between the dual panes. A decade or so ago a friend replace most of the dual pane windows in his RV and the new windows eventually fogged just like the first set. He finally went to single pane. Maybe newer dual pane windows have better seals ???
I agree with the Reflectix... but I’d personally order the more fancy, durable, lightweight and more compact stuff. The most important part is to get the “no tear” durable radiant barrier if you want it to last through multiple uses. Yes it’s expensive but it’s worth every penny. Finally make sure you put the reflective foil on the outside of the windows with removable painters tape (the blue stuff), as putting reflective material on the inside of the windows won’t be as effective... if you mount it inside then by the time the heat hits the reflective surface it's already inside the RV.
Reflectix – https: //
www.amazon.com/Reflectix-BP48010-48-Inch-10-Feet-Insulation/dp/B000BPAULS
This is another option:
https://www.amazon.com/Window-Daytim.../dp/B00CWGIHBE
Don't forget the window in your side door.
= = =
Mike
Linear Mode
