Inverter window air conditioner with a high power factor

[Hedges]

I'm interested in a high power factor combined A/C and heat-pump.
Preferably saddle shaped (hangs over window sill rather than blocking lower half of window.)

Any suggestions of something available in the US?

The reason I want high PF is that I use AC coupling for my backup (off-grid operation) system, SMA Sunny Boy with Sunny Island.
Sunny Island battery inverter powers 2 HP pool pump with VFD just fine, but Sunny Boy GT PV inverter observes the poor AC waveform and refuses to connect.

 

[timselectric]

I wonder if a Medea window unit could be mounted at the top of a double hung window.
Probably not enough gap for the wall thickness.

 

[Hedges]

Nor enough height above the window, below the ceiling. Maybe 8 or 10 inches.

I'm thinking of window units to spot heat/cool without operating central system. Also for efficient electric heat as I add PV.

Alternative would be something in the ducts of central heating system (no A/C at this time.)
Easiest to place in air inlet to furnace. Don't want excessive temperature if electronics are in the air stream as they are at my other place.
Mini-split mounted there? Have a thermostat enable heat pump and central fan, if temperature gets too low then furnace kicks in.

 

[timselectric]

Maybe a ducted (not so) mini split in the return ductwork?
I have pondered this option for my gas furnace.

 

[AntronX]

Even with the transformer buzz did the unit run?

Yes, I ran it for an hour. It seems to run fine except that inverter runs at lower efficiency. But it was small 800w inverter.

 

[Hedges]

Maybe a ducted (not so) mini split in the return ductwork?
I have pondered this option for my gas furnace.

My San Jose place has horizontal mounted gas furnace with forced air exhaust.
A/C cooling coils after furnace, then manifold to four flexible ducts leading to floor registers.
Air return comes from high on wall. Electronics, which I've replaced once, is in the air compartment by fan.

I added 5, 10kW resistive duct heater, mounted between furnace and A/C.

If Oakland place also has electronics in the air flow, think cool air is OK so long as it doesn't cause additional condensation after coils, on electronics.
Heating, would be concerned about how hot. Probably heat pump wouldn't raise temperature as much as the 10kW setting of duct heater.
Discharge air would be the better location, but at the very least I have to cut into duct. That's probably the thing to do. Return air in that system comes through large floor register (hmm, wonder if it was repurposed floor furnace opening?) and duct.

 

[740GLE]

I wonder if a Medea window unit could be mounted at the top of a double hung window.
Probably not enough gap for the wall thickness.

That and how are you supporting the weight? The window?

The midea has a pretty complex bracket to support the weight and keep it supported due to it not being balanced at the window U frame.

 

[Consumerbot3418]

I'm interested in a high power factor combined A/C and heat-pump.
Preferably saddle shaped (hangs over window sill rather than blocking lower half of window.)

Any suggestions of something available in the US?

I've spent quite a bit of time looking into this, aside from the PF issue. There just don't seem to be many window-mounted AC/heat pump options in the US. I have a Midea and Frigidaire unit, both of which are the traditional window AC shape, neither saddle nor u-shaped, and neither are actually available for retail purchase at the moment. More details here. I measured the PF of the Frigidaire at 0.98, but the compressor does clunk on and off as it cycles. Another detractor is that it switches seamlessly to aux heat when the outdoor temp drops below circa 45ºF. I drove an hour to buy mine from either a Craigslist or FB Marketplace ad...

Meanwhile, I've come across some articles like this one about how NYC had some kind of engineering contest for window heat pumps, and the winners were Gradient and Midea. I guess Midea is going to build a bespoke u-shaped unit for NYC? Gradient's units are available for $5,000 and I've no clue what the power factor might be.

This unit may be your best bet. Looks like it really has a heat pump--I didn't even know it existed until just now. Don't see any reviews about the PF, and there are a fair number of unhappy customers...

The reason I want high PF is that I use AC coupling for my backup (off-grid operation) system, SMA Sunny Boy with Sunny Island.
Sunny Island battery inverter powers 2 HP pool pump with VFD just fine, but Sunny Boy GT PV inverter observes the poor AC waveform and refuses to connect.

I doubt you'd have any trouble with your SB/SI setup. I have two Midea inverter-based AC units running every morning when my SB connects to my SI, not even a hiccup thus far. (I have seen SB drop offline for a few seconds when switching on a 55 amp RV converter/charger, though, without any messages in the logs, strangely)

 

[timselectric]

That and how are you supporting the weight? The window?

Definitely not.
It would require a support structure of some kind.

 

[Vigo]

In my mind basically any appliance that has a rectifier on its front end to convert ac to dc should be fine running on any kind of inverter, even modified sine wave. The exception ive heard was @RCinFLA at one point posted that a UPS might be looking for a point in the sine wave that wouldnt exist as part of its ‘return to grid power’ conditions and thus might not be ok between an MSW inverter and some other load. But other than that one exception i dont know of any other reasons why something with a rectifier in its input section wouldnt be happy with basically any inverter powerful enough to run it.

Furthermore, if the appliance DIDNT have a voltage boosting circuit which relied on the switching of the input (from it being ac) to do its job, you could also just feed it dc right through the ac plug it came with and it would just pass right through the rectifier with slight losses but would still power the device normally.

So me personally, i am not afraid to hook ANY inverter to my Midea. PF aside i doubt it will damage anything on either end.

Im happy to learn of that Soleus heat pump window unit just because i didnt realize it existed. It may suck, i’ll research, but since those options are few and far between any new option is a welcome discovery. Unfortunately unlike a Midea that one is currently ‘actually as expensive’ as a low end mini split, so unless price drops it has no prospects with me personally since i am not against just installing a ‘real’ mini split in my applications. Still, good to know its out there.