Anyone have experience with these "solar assisted" air conditioner/mini split?

[Gilligan]

They connect to pv panels for "most"o their power needs but still have a 220 line. Supposedly uses about 80 wattsof electric.

There are other brands and larger units are available but here is one:

https://www.amazon.com/YMGI-18000-Assist-DUCTLESS-Conditioner/dp/B07D3V5SKF/ref=mp_s_a_1_fkmr3_1?keywords=solar+assisted+air+conditioners&qid=1562724742&s=gateway&sr=8-1-fkmr3

[bcroe]

They connect to pv panels for "most"o their power needs but
still have a 220 line. Supposedly uses about 80 wattsof electric.
There are other brands and larger units are available but here is one:

I have not tried the solar assisted version. But if allowed, I might use at least twice the
minimum number of panels, to get the most benefit under varying sun.

Since these can also pick up some (all here) of your heating load, check that the
minimum effective temp is compatible with your lowest temps. Some do 20F,
mine does -25F. Bruce Roe

[Gilligan]

I don't really need to worry about heat in South Louisiana.

I do wish I could over size the panels. Are there and "boxes"that can off load panels if they go above x watts of output?

Given that I don't have any solar now.

[bcroe]

If the unit minimum is 3 panels in series and around 120VDC total, putting 3 more
panels in series and putting that set in PARALLEL with the first set will not increase
the voltage. As before the unit will take the current it needs up to the max available,
no need to worry about boxes. However I would check that the unit MPPT input
circuit is rated for this configuration. Bruce Roe

[Gilligan]

Ok... so solar panels will work like batteries in the sense that you can give a circuit all the (parallel) power you want but it will only take what it needs and (in the case of batteries) it will just last longer. So, in this case, it would just still be able to pull it's 1,000 Watts even if it was shady if you had like 50 panels setup in a 5s10p setup right?

I mean, if I ran say three parallel wired sets of four 325W panels (37v) in series this would be the proper voltage (max 165v open circuit) and would be able to run this unit (1,000 watts) mostly on solar even when there is a bit of clouds?

I know this is all theoretical and hypothetical... but is the math sound enough to make sense?

[bcroe]

That is the idea. What is used here, would be to tilt one string to the E and one
to the W, to the point that mid day power is the same as a single straight south
string. This under full sun will full power for many hours of the day, instead of
just at noon. Here is a curve I did under best sun.

Under some clouds with sharp shadows disappearing, light is dispersed so it
does not matter so much which way they face. You can expect power available
to decrease, but it will still be something like twice as much as a singe string
could provide. Very light clouds will not even reduce power. I would expect
when power definitely drops, the equipment will continue to operate at a
reduced speed, which is normal operation anyway. You will not be needing
as much air cond as sun intensity falls off. It will quit at some level, which
I cannot predict. My 4 mini splits are 240VAC based, but I am surprised at
just how little and how slowly they run for air cond. They work a lot harder for
my winter heat. Bruce Roe


NScurJn17.jpg

[Gilligan]

Nice.

these assisted ones will run off Mains... if need be, I just want to try to keep them on solar as much as possible.

For us in South Louisiana, rain or shine, we NEED the AC. I'm also looking at this with my print shop which needs AC because of the heat generated as well.

Now I have some things to think about. I would want a larger system than this. I need to get my AC guy to look at sourcing some of their larger systems and becoming a dealer for them. That way I can see what the cost of one of these systems are... plus I could get it sans their panels and just get my own.

I could start with two strings and then log the mains demand for a while and see if I needed to add another one. This would be some interesting data for him to use for potential sales of said systems if it turns out to be a good system.

He does feel like mini splits are going to fall by the wayside as larger systems adapt the inverter technology. Mini splits are a pain to clean he says.

[bcroe]

Whatever system fits your needs, most important is a Coefficient Of Performance approaching
4. There are inverter driven systems using R410A, including some minis, that fall far short of
this high efficiency. I noted one that was also a much lower price, not a good trade off if it
will be run a lot. Bruce Roe

[neweclipse]

Rating of COP is for heating mode, (a straight air conditioner will not have this rating.)

Rating of SEER is for cooling mode (can be built to range low from 13 up to high as 37)

[bcroe]

Rating of COP is for heating mode, (a straight air conditioner will not have this rating.)

Rating of SEER is for cooling mode (can be built to range low from 13 up to high as 37)

We are talking about heat pumps. SEER is a decent starting point, COP is more accurate. Bruce Roe

[J.P.M.]

Rating of COP is for heating mode, (a straight air conditioner will not have this rating.)

Rating of SEER is for cooling mode (can be built to range low from 13 up to high as 37)

In real engineering terms C.O.P. relates to both heating (heat pump) and cooling (refrigeration) modes.

(C.O.P. in heat pump mode) - (C.O.P. in refrigeration mode) = = 1.0

Unless otherwise specified, the term coefficient of performance will usually/always refer to refrigeration mode.

EER = C.O.P. * 3.412 in either mode.

SEER is a somewhat variable number with its origin in EER that attempts to account for particular system variables as they may affect performance due to seasonal/regional weather variations. In spite of it's somewhat authoritatively sounding presentation, it's kind of a slippery number and open to some interpretation by vendors. FWIW, I believe it's mostly a bunch of marketing hype and B.S. foisted on the public as a smoke/mirrors gimmick.

[bcroe]

That about covers it, thanks. Bruce Roe

[J.P.M.]

That about covers it, thanks. Bruce Roe

If that was meant for my last post, you're welcome.

[neweclipse]

This thread title is air conditioning and mini-splits...all mini-splits are NOT heat pumps either.

No consumer Label for an air conditioner or A/C only mini-split will revel a listed C.O.P., but engineers sure would get a chub if the label did.

That about sums that up...

[bcroe]

This thread title is air conditioning and mini-splits...all mini-splits are NOT heat pumps either.

No consumer Label for an air conditioner or A/C only mini-split will revel a listed C.O.P., but engineers sure would get a chub if the label did.

That about sums that up...

No doubt there is an exception somewhere. COP of course IS NOT on the label, but can
often be found with a little research. I would not risk buying some energy inefficient unit,
that refused to admit (because they are so bad) what the performance numbers were.

Just maybe, you could figure them out for yourself by comparing power input and BTU out.
1 KWH = 3412.142 BTU Bruce Roe