Portable Room Air Conditioners?

[ST Gui]

Some units have concentric hoses (hose in hose) and would require one opening only.

Obo mentioned that his is post. Either way would require the same concept so whichever I ended up with would make little difference.

 

[ST Steven]

In case it was covered earlier, just skip over...

There's a few types of portable AC units.

Basically there's a single hose and a double hose unit. The double hose can be 2 hoses or a hose within a hose.

A single hose draws air from the room in order to discharge the heat outside. A dual hose brings in outside air to take the rooms extracted heat heat outside.

A dual hose has the advantage that it doesn't create a negative pressure in the room you are cooling. A negatively pressurized room will ultimately draw in the hot air from outside, which is the opposite of what you want.

A portable unit also has all the compressor & hot bits inside your room, unlike a window mount or mini split. This too adds heat into your room.

This is why most portable AC's have 2 thermal ratings, a higher BTU rating and an adjusted lower BTU SACC rating. Effectively it's the unit's capacity and it's adjusted effective cooling capacity allowing for the drawbacks mentioned above.

Don't get me wrong, portable units will certainly cool a space if adequately sized. It's just a matter of efficiency. There are also places where no other type of AC unit will really fit in the space. Other AC types are also not portable.

If you can, get the "dual hose" style over the single as it will be cheaper to run in the long haul.



For those of you who can use a window mount style, Midea makes a very neat unit that's also really quiet. It's designed in a bit of a U shape so the cooler section is inside and the noisy & hot compressor section is outside. It minimized how much your window is open and how much sound transfers in. It does it by having the window close INTO that U gap. Here's a video of one installed etc. It's almost designed like an all in one mini-split.

I'd buy one of these over a portable unit if I had single or double hung windows. All my windows though are casement (side swings) so these are out and it makes it challenging to even vent portable AC units out them. A mini split isn't really an option due to the lack of electrical breaker capacity in the current panels & no space to add additional sub panels. (I have 2 entrances, 2 full main panels and 3 sub panels already....)

I bought one of these last year, really love it

 

[Obo]

I bought one of these last year, really love it

I see GE has a new model that is inverted so it sits over the window sill like a horse on a saddle. It would certainly have it's advantages over this design.

 

[tpasco1995]

I have a heavy suggestion toward the Whynter ARC-14S.

Dual hose (which is more effective than single hose), insanely quiet, has a dehumidifier option in the menu, and is 14,000 BTU.

I've had it for about 3 years, having bought it used, and they still manufacture and sell the same model/revision, so it holds up pretty well.

 

[MidLife]

I have a heavy suggestion toward the Whynter ARC-14S.

Dual hose (which is more effective than single hose), insanely quiet, has a dehumidifier option in the menu, and is 14,000 BTU.

Good to know. Thanks,

What size room are you cooling with it?

Was looking at it, but see the SACC rating is 9500 BTU.

With our high wet bulb temp here, their ARC-1230WN , also a 14000 BTU unit, but 12500 SACC, may be better suited....but more expensive......

 

[tpasco1995]

Good to know. Thanks,

What size room are you cooling with it?

Was looking at it, but see the SACC rating is 9500 BTU.

With our high wet bulb temp here, their ARC-1230WN , also a 14000 BTU unit, but 12500 SACC, may be better suited....but more expensive......

This is a weird spot: I don't think the SACC ratings are as effective as they intend to be. The measure of how heat pumps work is a direct physical phenomenon that's reliant on the compressor and evaporator, and essentially nothing else. That said, I'll answer your question before the rabbit hole...

The area being cooled with the 14S is close to 700 square feet, and it does it INCREDIBLY well. I re-installed it yesterday and brought temperature down from 82 to 70 in about an hour. That's about what I would expect from a 12,000 BTU window air conditioner, and portables have some efficiency loss because of heat transfer through the hoses.

So now to what lands me at not trusting SACC numbers. The compressor and evaporator size in both the Whynter units are identical. They have the same power consumption, the same heat pump capability of ASHRAE 14,000 BTU.

With that, a dive into the mundanity.

The DOE rule assumes a certain efficiency loss due to infiltration for dual-hose units that isn't actually there. It states that they pull negative pressure on a room, just like a single hose unit, which isn't accurate and is the whole reason for dual hoses. As such, there's a modification to the rating for dual-hose units that is adequate so long as no manufacturers decide to put the intake and exhaust in the same hose... which is what the 1230WN does. There's also no consideration in the testing methodology for the fact that such a design as the two-in-one hoses puts heated exhaust air right against intake air, heating it up further and reducing efficiency versus maintaining separation of several inches.

Anyway, the rule change allowed manufacturers to claim a "single hose" design and get a different modifier to what's actually a dual-hose design in every way that matters and milk a higher score by certifying really highly as a single-hose unit.

The other issue at hand is that there's a loss of reflection of real-world use in the SACC standard that the ASHRAE doesn't have to worry about.

ASHRAE certifies BTU at 80°F and 51% relative humidity. SACC directs for the BTU exchange average over the whole operating range. Nobody is going to use an air conditioner over the whole operating range. What it means is that a manufacturer can cut off the bottom of the thermostat at, say, 68°F (so they only have to test with ambient air at 69°F) and not deal with the efficiency loss of temperatures near 60° if they have a lower thermostat cap. Again, it can be gamed. Doesn't matter if the top-end efficiency is identical if you can artificially add a cap at the bottom where people don't use it anyway.

Point being, I'd definitely suggest shopping based on ASHRAE BTU numbers and not the SACC ones. If your room is over 500 square feet, anything 12,000 BTU or higher will be sufficient to do what you want it to do, whether window or portable. But avoid single-hose units.

 

[MidLife]

The compressor and evaporator size in both the Whynter units are identical. They have the same power consumption, the same heat pump capability of ASHRAE 14,000 BTU.

Excellent info to have.

Baffling that the same exact set up can have two different SACC ratings, but I think I can see the trick now.

--- It looks like the 1230 has an "inverter" to modulate the compressor speed once the temperature has been lowered and stabilized, which could be what is allowing them to claim higher efficiency out of a unit that is otherwise the same as the 145.

In the worst of the Summer heat here, the AC runs nonstop and hardly ever reaches the set temp, so there would be no gain at all from this "Inverter".

Money saved. Thanks!

 

[Chris09]

I like the saddle design; looks like it puts the compressor not only out and over but down from the window opening bet it makes a difference in noise. I agree with the point of heat transfer with the concentric pipe, especially if there's any appreciable length but I'd take it over a single pipe discharge where air entering the condenser has to made up by infiltration into the zone. It's unlikely anyone is going to actually depressurize a room, air will be made up through door undercuts and so on.
A single pipe only discharges condenser leaving air and kind of steals it from the room that you've already been cooling so they're just not good.
As far as I know, the only real improvements in SEER ratings or whatever is used in the US has to do with the size of evaporator and condenser [or for heat pumps indoor and outdoor coil] and the type of compressors used. Compliant Scrolls [over recip and rotary] I think have the best COP but on a compresssor performance chart you can see how that deteriorates rapidly as condensing pressures rise. I recall some comparisons in higher tonnage systems where scrolls were worse than reciprocating once condensing temperatures reached 125 to 130 F.

 

[mortenk]

If you are looking for a permanent solution, I highly recommend mini splits. You can buy them on Amazon and they are actually not hard to install if you are handy with tools (which most of this forum surely are). The only special tools you need are a vacuum pump and a gauge set. I have installed about 10 of these now for friends and relatives. A single room system can be fully installed in less than six hours by a single person - as long as electricity is available via a disconnect box near the outside unit.

Typical cost: 1 room: $700, 2 rooms: $1000

 

[ST1100Y]

The only special tools you need are a vacuum pump and a gauge set.

And a tube cutter, a flaring tool, torque wrench kit (recommended), leak detection spray (recommended)... and last but not least: know how to use it all...
PS: you don't cut refrigeration copper pipes, you "break" them (only cut them slightly till you can snap them off by hand, prevent swarf inside the pipes/on the flares by all means)

 

[Obo]

If you are looking for a permanent solution, I highly recommend mini splits. You can buy them on Amazon and they are actually not hard to install if you are handy with tools (which most of this forum surely are). The only special tools you need are a vacuum pump and a gauge set. I have installed about 10 of these now for friends and relatives. A single room system can be fully installed in less than six hours by a single person - as long as electricity is available via a disconnect box near the outside unit.

Typical cost: 1 room: $700, 2 rooms: $1000

You can also buy DIY kits that don't require a vacuum pump or gauge for the 1st install. No idea on how well those work though or the models. Just know they are out there. I assume they work as good as any but you pay extra for the simple DIY convenience.

 

[tpasco1995]

You can also buy DIY kits that don't require a vacuum pump or gauge for the 1st install. No idea on how well those work though or the models. Just know they are out there. I assume they work as good as any but you pay extra for the simple DIY convenience.

The Mr Cool units are actually fantastic.

The line sets are shipped vacuumated and the compressor unit has the refrigerant pressurized to liquid inside. The fittings are similar to air line fittings, where the pressure actually establishes a seal in the fitting that prevents air infiltration at the expense of minimal refrigerant loss.

 

[tpasco1995]

And a tube cutter, a flaring tool, torque wrench kit (recommended), leak detection spray (recommended)... and last but not least: know how to use it all...
PS: you don't cut refrigeration copper pipes, you "break" them (only cut them slightly till you can snap them off by hand, prevent swarf inside the pipes/on the flares by all means)

Just want to point out that a deburring tool is magical and resolves the swarf issue while preventing copper tubing seam splits from stress.

 

[tpasco1995]

Excellent info to have.

Baffling that the same exact set up can have two different SACC ratings, but I think I can see the trick now.

--- It looks like the 1230 has an "inverter" to modulate the compressor speed once the temperature has been lowered and stabilized, which could be what is allowing them to claim higher efficiency out of a unit that is otherwise the same as the 145.

In the worst of the Summer heat here, the AC runs nonstop and hardly ever reaches the set temp, so there would be no gain at all from this "Inverter".

Money saved. Thanks!

Probably so. The whole issue is that it can't possibly have an effect other than to game the test.

It's like the issue with space heaters. Every space heater, for all intents and purposes, is 1500W. None of them are "more efficient" at making heat because heat is literally just wattage. Efficiency loss is impossible with a heater because efficiency in a system is a measure of how much work becomes heat. If the heater has a fan or a light, that energy becomes heat basically as soon as it hits a wall, so there's still no efficiency loss. So a ceramic IR dish heater will heat a room exactly the same as an oil heater. The oil heater holds more energy in itself longer and heats up the room more slowly, but then when turned off lets heat off longer than the IR heater.

Every heater is identical.

Air conditioners are essentially the same. If the compressor/evaporator/condenser is sized for 14,000 BTU, that's the peak cooling capacity. Adding a buffer that allows variable speed at the compressor to stabilize temperature versus having an I/O compressor that cycles with temperature flux is no more efficient, but the metric being used for new testing lets it look more efficient.

14,000 BTU is a measure of 4,103 Watts of heat being moved out of the air in a space. Full stop.

 

[ST1100Y]

Just want to point out that a deburring tool is magical and resolves the swarf issue while preventing copper tubing seam splits from stress.

Unless mentioned abomination throws the swarfs right into the pipe, raising all kinds of havoc within the refrigeration circle... hence are deburring tools frowned upon...

 

[Obo]

Unless mentioned abomination throws the swarfs right into the pipe, raising all kinds of havoc within the refrigeration circle... hence are deburring tools frowned upon...

Isn't an air conditioner actually designed to be a Brrrrrrrrrrr-ing tool?

 

[Chris09]

The topic is portable so I won't digress too much, my interest is that while I have qualifications, tools, everything [including wholesale accounts] to install anything, I'll likely sell soon and my buyer will be a developer who knocks the building down. I want something I can take with me and plug in the wall elsewhere.
I agree that the mini splits are the way to go if you can, and pre charged condensing units / evacuated line sets have been around for as long as I remember. Couple things to know about new systems is Inverters and R410A.
Inverters mean that under sustained reduced load / compressor speed hence refrigerant velocities drop, and compressor oil may hang up in line set droops or risers. Some controllers may periodically increase compressor speeds for the purpose of sweeping oil back through the suction line but you might want to know that if you're at any distance and / or substantial difference in elevation between your condensing unit and fan / coil.
R410A mean properly rated gauges, hoses connection accessories and safety glasses, I'd look for a pair that would fit under a goalie mask, and if it's the first time you've worked with R410A, wear the goalie mask. If you're not trained, it's like Pauly said to Henry - just don't do it. Check out the difference in condensing pressures of R22, what we used almost exclusively for A/C in the last hundred years or so, and R410A.
But if you're able to buy direct and set your outdoor unit, mount your wall unit, rough in your line set and electrical, you'll know it's done right and there's not much left to evacuate the system start up and assess / adjust refrigerant charge.
Not sure about the aforementioned tube quality or cutting and flaring methods; ACR grade soft copper has no seams, and sure, break the last bit where convenient but no big deal either way, touch the end with a file before flaring. The 45 deg SAE flare tool used in the refrigeration and air conditioning trade has flat lands on the cone which kind of spread the soft copper as the flare develops, if yours doesn't, toss it or give it to someone you don't like.