Newer technology A/C systems

[Pelagic]

Something that has always confused me?
What is the proper abbreviation for Air Conditioner..... A/C or AC?
Also How does you abbreviate and differentiate it from Alternating Current......A/C or AC?

[a64pilot]

Originally Posted by Pelagic

I have 1040 Ah batteries @ 24v + 1673w of Solar

Seems to me that with a large 24v house bank and sufficient Solar a 24v Air Con unit like this would make optimum use of Solar, when your SOC is at 100% by noon

In eco mode it would seem many could run it as it only draws 200W, I’m sure that doesn’t include the waterpump but that ought to pull about 60?
I’m eco it’s a 3900 BTU system, but that’s still pretty good.

[john61ct]

Best to use "aircon" when there is any chance the context could also imply mains style AC power

[john61ct]

Using stored battery power to run aircon off grid accomplishes little but timeshifting, at maybe 100Ah added capacity per hour's usage.

Might as well run the genset concurrently.

Thousands of kW solar panels won't fit on most boats.

[a64pilot]

Originally Posted by john61ct

Using stored battery power to run aircon off grid accomplishes little but timeshifting, at maybe 100Ah added capacity per hour's usage.

Might as well run the genset concurrently.

Thousands of kW solar panels won't fit on most boats.

Well go back and look at the posters bank and array size.
I believe he could do it easily, I believe in Summer I could do it with the machine in eco mode, it’s only 200W and 3900 BTU would go a long way toward cooling our stateroom. I have a 6000 BTU in there now and it pulls 4.5 amps or 540 Watts and that’s more than is realistic for my Solar, but theoretically possible. But 200W I could manage.

[john61ct]

The greater efficiency and variability certainly help, as does LFP

Details to account for:

feeding directly off "excess free" solar is a very limited time window

banks need to get recharged concurrent with feeding the aircon

actual total consumption is likely higher, solar production lower than in theory, in each direction, Ah per 24hrs is the key

IMO 1200W of extra panelage just for the aircon loads, and at least 100Ah of extra bank per hour of timeshifting desired

realistic minimums, ballpark

So, entirely do-able for some, but not inexpensive.

Personally, aircon is a luxury, I would rather do without, just don't need it living out on the hook.

[TCM1968]

"Personally, aircon is a luxury, I would rather do without, just don't need it living out on the hook."

Not sure where you are but here on the the Gulf coast of South East Texas in the summer months, aircon is definitely a necessity and not just a luxury.

[TCM1968]

Originally Posted by a64pilot

Well it is off the top 32% more efficient as it draws 1000W as opposed to my 1320W.
However it’s also variable speed so as long as 16k BTU isn’t needed it can slow down and use less power where a standard shuts down and uses none.
Motor wise it’s a BLDC and they are extremely long lived motors, I’d be interested to know if the fan slows down with the compressor too to reduce noise.
I also wonder can you manually set lower outputs or is that only automatic, it has an eco mode, but can you set higher manually as eco is very low power. Probably be good for night though.
It’s weak link is the electronics, but nearly everything has electronics now.
It’s also apparently twice as expensive

On edit looking at the spec sheet again, it’s efficiency gain at 16kBTU is slight, it pulls 10 amps to mine pulling 11 and on mine that includes the water pump. So it would seem it pulls less power only when the cooling capacity is reduced, or it’s very inefficient running wide open or both.

The difference your not considering with this comparison is the variable speed ability. Yes it may be true that when both are at max output of 16000 BTU's then the amp draw is close to the same, but 16K BTU is only needed to bring the temp from temp A to temp B. Once temp B is achieved a significant less amount of BTU's is required to maintain that temp. These motors are way more efficient at slower speeds. You can't look at it as a straight give and take. Lets say the variable speed slows down to 8000 BTU speed but now runs twice as long to maintain the desired temp, the KWh's used will not be the same. The variable speed compressor may only be putting out half the BTU's but it can do that at at considerably less than half the wattage.

[a64pilot]

I understand that, but it’s really not just the motors efficiency, it’s more likely from oversized evaporators and condensers for the btu output of the compressor.
With the BD refrigerator compressors the slower speed let’s them operate at a much higher COP, or coefficient of performance, I’, sure the same is true here, it’s a matter of scale.
But it’s also $3,000 per unit or twice the cost, and for many like me, to run the AC’s means running the generator and pulling 15 amps instead of 25 amps from the generator is irrelevant, and when running from shore power the power savings will likely never pay for it.

Now if the fan slows way down and becomes quiet in eco mode and especially if the fan turns off when the unit is off like it’s done in a house, well then maybe it’s worth it for other reasons.

Now so far as start up surge, it doesn’t reduce it like a slow start does, it simply has no start up surge, if the literature is to e believed and I think it’s true, it starts at 2 amps and then ramps up to whatever running amperage is needed, so no surge at all.

But surge isn’t a problem for me on generator or shore power, my Nexgen 3.5 gen has a 6KW gen head so the generator can easily supply the surge and apparently the flywheel momentum of the motor can supply it for a short while.

However if surge is a problem, then it may well be worth it, and it may well be worth it in a new install.
But to tear out good operating units and replace them at $3,000 a pop to solve a surge problem as opposed to installing slow starts, I’m not so sure that is worthwhile, unless as I said it’s a much quieter unit fan noise wise or other appealing reason, but of course that has a lot to do with how often you need AC and well frankly how much money you have to spend.
For me, when my current units wear out, I’ll take a hard look at these, they are I believe the future of air conditioning

[ranger58sb]

Originally Posted by TCM1968

Compressor motors can a do draw 7 to 10 times the running amp draw during start up. They want to be at full speed and torque the instant you apply power. A soft start device will control the voltage and amperage during start up so that it builds up to full speed and power gradually.

Now as far as the new systems my OP is referring to not only to they already have a soft start but they are variable speed. This means that instead of the compressor running at either off or full speed that once your room temperature is reached instead of turning off and allowing room temperature to rise a couple of degrees and then starting up again it just slows down the compressor to a speed require to maintain the temp where required. It uses considerably less energy to maintain that slower speed than to continually start and stop from from full speed.

Ah. Got it. Guess it's been a non-issue, for us; I don't really notice the small temp swings, and apparently we have energy to spare...

Originally Posted by a64pilot

Most every boat AC’s fan runs continuously, moving air continuously across the coils and through the filter, so most of those advantages are diluted some.

That's just a setting on ours: continuous, cycle with compressor, reverse force on heat vs. AC, etc. I usually vary the continuous/cycle setting depending on time of year...

-Chris

[TCM1968]

Originally Posted by a64pilot

I understand that, but it’s really not just the motors efficiency, it’s more likely from oversized evaporators and condensers for the btu output of the compressor.
With the BD refrigerator compressors the slower speed let’s them operate at a much higher COP, or coefficient of performance, I’, sure the same is true here, it’s a matter of scale.
But it’s also $3,000 per unit or twice the cost, and for many like me, to run the AC’s means running the generator and pulling 15 amps instead of 25 amps from the generator is irrelevant, and when running from shore power the power savings will likely never pay for it.

Now if the fan slows way down and becomes quiet in eco mode and especially if the fan turns off when the unit is off like it’s done in a house, well then maybe it’s worth it for other reasons.

Now so far as start up surge, it doesn’t reduce it like a slow start does, it simply has no start up surge, if the literature is to e believed and I think it’s true, it starts at 2 amps and then ramps up to whatever running amperage is needed, so no surge at all.

But surge isn’t a problem for me on generator or shore power, my Nexgen 3.5 gen has a 6KW gen head so the generator can easily supply the surge and apparently the flywheel momentum of the motor can supply it for a short while.

However if surge is a problem, then it may well be worth it, and it may well be worth it in a new install.
But to tear out good operating units and replace them at $3,000 a pop to solve a surge problem as opposed to installing slow starts, I’m not so sure that is worthwhile, unless as I said it’s a much quieter unit fan noise wise or other appealing reason, but of course that has a lot to do with how often you need AC and well frankly how much money you have to spend.
For me, when my current units wear out, I’ll take a hard look at these, they are I believe the future of air conditioning

Now I think we are on the same page I think this assessment is spot on. Surge is an issue for me as I have five 16K BTU units on my boat that at some times of the year need to all run at the same time and although possible on my current 100amp shore power pedestal not so much for my 12.5kw gen or most 50amp marina setups where a y-adapter is used. And I also agree not worth the cost if present units are all working fine, but I have 2 that need replaced before summer next year. It would also be nice if they are quieter. So a cheaper electric bill would be a nice bonus to offset the cost but that is not my main driving factor for considering these.

[a64pilot]

I wish my fan cut off with the compressor but it doesn’t, it runs continuously.
The reason for that is the same as a window unit AC, that is the air temp sensor is in the return air path, so to sense room air temp air flow is required.
A home AC of course has a remote mounted thermostat, if my Webasto’s had that, then the fan could turn off with the compressor.
It has a remote mounted control box of course. But I guess a remote temp sensor would have been another dollar or two.
Soft start wise, I bet there is less than $10 of electronics in one, I don’t know why it’s not a $100 option?

[john61ct]

Originally Posted by TCM1968

Not sure where you are but here on the the Gulf coast of South East Texas in the summer months, aircon is definitely a necessity and not just a luxury.

Tens of thousands of years, billions and billions of humans say otherwise. Words really need to mean things.

You just have high expectations, habituation to a certain level of comfort and cheap access to unsustainable energy resources.

In my case, I prefer to acclimate my body to the heat, and have lived many decades without aircon in places where 35°C is a normal day, dozens of days in a row over 40 are common, including "concrete jungle" cities near the equator with millions of residents packed into a small area.

There is always the option of moving too.

Clean water is a necessity, but having large quantities of it available on tap inside your living space is a luxury.

[Q Xopa]

Originally Posted by john61ct

The greater efficiency and variability certainly help, as does LFP

Details to account for:

feeding directly off "excess free" solar is a very limited time window

banks need to get recharged concurrent with feeding the aircon

actual total consumption is likely higher, solar production lower than in theory, in each direction, Ah per 24hrs is the key

IMO 1200W of extra panelage just for the aircon loads, and at least 100Ah of extra bank per hour of timeshifting desired

realistic minimums, ballpark

So, entirely do-able for some, but not inexpensive.

Personally, aircon is a luxury, I would rather do without, just don't need it living out on the hook.

As previously mentioned last time you said this, '1,000 W's' of solar arent required. This was true 10 years ago.
I posted some figures of currently running systems. Do you have any specifics you care to share?
The typical window or portables use in the magnitude of 8 times the power of some of the current generation units.
However these efficient units are not the cheaper ones, and mostly 230v not 110v.
The big efficiency gains are from as mentioned the compressor variable speed motors, and big condensors etc.
Time shifting, Im not sure what your point is? This is what battery banks do.
Running a generator, some of us would rather avoid it where possible. How to not be popular in the anchorage.

[galynd]

TCM. I hope you'll keep us informed of your progress, especially if you go ahead with the frigomar system. I've been watching it a while waiting for my current Dometic to die. I'd love to have a system I can run, dependably, with my honda 2000.