Author Topic: Solar Split System Inverter Air Conditioners  (Read 641 times)

BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #15 on: July 26, 2019, 05:13:30 PM »
That is ideal, Vege, you need only put a common mode choke or dual stage commercial filter on the AC output, since that's the only wire running to the home and conducted emissions will still be brought in that way.  A CM choke rated in the 16-30 amp range is about $15. new.  Like I said, very cheap health insurance.

My neighbor with ES and I watch with dismay as people retire here (well off grid) to inverter powered homes, and within a year or two have their health problems spiral out of control.  It's an avoidable health stressor, but too new and technical for MD clinicians to grok. Everyone wants to cling to the notion that the power co. cigarette science (where they used super clean 60Hz and hid health effects by statistics, throwing away damaging data and looking only at certain cancers).  Our whole world is based on that convenient lie. 

For now, avoid inverter type split systems.  Because power and control wires are distributed, unshielded, to the interior coil/blower units, which also have switching supplies, it's not very practical to try and clean them up significantly.  For the non-inverter systems, put the compressor unit at least 8 foot from the house, or you've created an ELF magnetic field issue.  An additional 8 feet of copper lines isn't a big deal but again is very cheap health insurance. 

For new construction, doing your home power and data wiring in commercial EMT conduit, with compression fittings, is smart, smart, smart. 



« Last Edit: July 26, 2019, 05:27:55 PM by BruceM »

veggie

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Re: Solar Split System Inverter Air Conditioners
« Reply #16 on: July 31, 2019, 12:10:11 AM »
So BruceM, do we face the same issues with small electric cars? I presume they have some sophisticated motor controllers and push some very high amperage at times. ?
I'm also starting to see a lot of chatter about 5G wireless issues.!
Man, it's hard to keep up on all things that could give us health trouble.
Food additives, pesticides, crop desiccants, and wireless.

and... how do we measure ELF levels in our house ?
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glort

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Re: Solar Split System Inverter Air Conditioners
« Reply #17 on: July 31, 2019, 02:37:00 AM »

Ev's are veritable Microwave ovens!

The motors, controllers chargers and Inverters would be just a few of the major emitters but the small things would add up pretty well also. I have seen reference to EMI emissions in vehicles and shielding and although I have none of the knowledge Bruce does, I highly suspect they basically control it so it does not cook you like a microwave but not much more than that.

When you consider how Crap a regular vehicle is with it's emissions, not hard to imagine what an ev is going to be like especially if you have seen pics or vids of some of the BMS, motors and other things that run them.

Makes me laugh how you are supposed to turn your Phone off in an aircraft in case it interferes with any of it's systems but they are going to have vehicles that radiate all sorts of emissions, including inevitably having your phone on that are supposedly going to be driving you round autonomously.
I don't know much about radio either but I'm pretty sure an aircraft is saturated with all kinds of emissions and frequency's (Doesn't every plane and international airport have radar for a start now?)



BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #18 on: July 31, 2019, 07:14:28 AM »
Electric cars are a tremendous technical challenge-  the one they haven't even started on yet; which is how the heck can you make them safe for near field magnetics and EMI.  I'm not confident it can be done.  IF I was well I'd be pitching some research to the Air Force and Darpa.  The good news is that gas ignition cars are now so bad that matching that will be easier.  Electronic fuel injection, electronic transmission control are both high power, high frequency pulsing quite close to the driver, and battery on the firewall instead of forward near the alternator is also common.  There is huge room for improvements there, just by making it a design issue. 

ELF magnetic fields are measured with a very sensitive AC Gauss meter.  The level we're adapted to is about 0.5 Gauss of DC field with 0.1 Microgauss of Schumann resonance on top; a mix of biological frequencies that match our brainwaves, with a peak at near 8 Hz.  The average suburban ELF magnetic levels in Wye served areas is about 100 Microgauss.  So we have masked the natural signal with garbag 1000x the strength...only because we are idiotic about WYE (all of Canada is WYE) grounding practice.










glort

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Re: Solar Split System Inverter Air Conditioners
« Reply #19 on: July 31, 2019, 02:17:35 PM »

looking at this again, I'm a bit confused as to what you want to do.

First you said:
The during day plug the AC unit into a grid outlet .... THEN connect the solar to the house through a cheap grid tie inverter and let the solar offset the power used by the grid powered AC.

And then:

I don't want to backfeed the grid.

If you want to run a GTI you WILL need it to be grid tied.  If you don't want to spin the meter backwards, the trick would be to match the inverters output to the Ac's Consumption.  If the AC pulls say 1500W, then look for a 1500W GTI. This way you can drop all the panels you have on it and it will still supply the power for the AC later in the afternoon. If the AC runs 1200W, add 300W worth of Dummy load when it kicks in.

As to not backfeeding the grid, how pedantic do you want to get about that? When the AC compressor Cycles on and off there will be an excess of power and given it is likley your main array will be meeting the house hold needs and you will be backfeeding anyway, this power will go back as well.
The alternative to preventing that ( and If you have solar already I'm wondering why? It will be backfeeding and any you add will just go on your credit registered by the meter.) you could do the opposite I do with my AC. Use a DPDT relay coming from the compressor.  With no power the relay could switch to a dummy load, Lights to bleed off the power or a water heater element.
When the compressor Kicks in, the power is diverted back to the circuit and supplies the AC.

I see there are Solar pumps of decent grunt that seem to be supplied by some sort of VFD type inverter. I can't find much on them but maybe they could drive a small ac unit as well.?

BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #20 on: July 31, 2019, 03:20:35 PM »
I'd avoid solar pumps like the plague. Grundfos SQflex is the best but still has short service life compared to conventional centrifugal pumps at a fraction of the price... welldrillers and owners both say about 3-4 years, just past warranty. Both electronic and mechanical failures.  The only exception would be when centrifugal isn't possible due to extreme depth, then the Grundfos SQFlex scroll type pumps can work well (while they are working) at a slow rate to fill a storage tank.  They have an inverter drive built into the pump, which is bad design when it costs $1000 to pull a pump.  They should have just left it a simple 3 phase motor driven scroll pump with bearing design for low speed, and put all the electronics topside.

Franklin now makes a spendy PV direct inverter for their standard deep well pumps of all sizes and types.  They can drive the pumps down to 30 Hz, no lower, lest their hydrostatic bearings fail, according to Franklin.  More practical in most cases to run the well pump off your main inverter, as I do, and keep the pump as small as practical. 

Variable frequency pumps/controllers essentially have VFD/inverter drive, and should be avoided for wicked EMI due to present design.  A great deal of cost, complexity and unreliability to avoid a pressure tank.  Yes, you could filter the dickens out of the line and keep the VFD far from living spaces and other unshielded wiring, but old, cheap, reliable induction motor pumps generate zero EMI except for the damned Triac in the pump start controller, which a single common mode choke will usually solve adequately. 

People don't realize how insidiously and recently things have changed for the worse for the home electrical environment. 

veggie

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Re: Solar Split System Inverter Air Conditioners
« Reply #21 on: July 31, 2019, 05:15:43 PM »
First you said:
The during day plug the AC unit into a grid outlet .... THEN connect the solar to the house through a cheap grid tie inverter and let the solar offset the power used by the grid powered AC.

And then:

I don't want to backfeed the grid.


By matching a GTI to supply equal to the demand from a mini-AC unit (say a 1600 watt GTI at 60% load and a 900 watt single room AC unit)  the GTI would not be backfeeding the grid. Anything produced would be gobbled up by the AC unit. So to clarify what I meant... backfeeding my house yes, backfeeding the grid no.
The GTI would run 8 hrs per day and so would the mini AC unit. Switch them both on during a sunny morning and turn them both off late afternoon. On startup the grid would feed any inrush current for the AC unit.
Meters here do not spin backwards unfortunately.
Im not saying this is a great idea, I'm just exploring ways to utilize some spare 220W panels.
 
« Last Edit: July 31, 2019, 05:23:25 PM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- Kubota Z482 - 4kw
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glort

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Re: Solar Split System Inverter Air Conditioners
« Reply #22 on: August 01, 2019, 01:15:12 AM »

So to clarify what I meant... backfeeding my house yes, backfeeding the grid no.

Yep, thought that's what you must have been getting at.

Quote
Meters here do not spin backwards unfortunately.

Quote
By matching a GTI to supply equal to the demand from a mini-AC unit (say a 1600 watt GTI at 60% load and a 900 watt single room AC unit)  the GTI would not be backfeeding the grid.

Not sure how much you know about GTI's so forgive me if I'm telling you what you already know.
If you have a GTI that is say 1500W with a load of 900W, Unless it is a zero export type set to no backfeed, if there is 1500W or any amount above the 900w load, it WILL backfeed if it is a normal GTI.

Zero export ( pricy) models will " Throttle" , standard units just push back the maximum available to them.
That's why I suggested a " Ballast" load along with the AC to take up the excess.  You would probably want something like a voltage monitoring relay that switched the Dump load so you weren't running it when the solar was equal or less than the AC load.

This is another project devise I have in mind, something that will throttle loads. I was thinking of something that will turn on a water heater when there is excess solar to keep the line voltage stable. If there is still more power it would turn on say a pool  pump. If the heater kicked out then maybe a clothes Dryer etc till all the loads had cycled by which point the sun had gone off it's peak and there was no longer any excess to worry about.

I can use staged Thermostat boards for this, Just have to work out how to create a circuit that will turn Voltage to resistance or if I can switch a voltage to a resistance input to  activate it. I think it can be done simply with a transistor and some resistors but still working that out. Might be able to do it with the battery charger Board I have got as well using a gang of them together with the Voltage Dividers set at different levels to stage them.

I bought another board to test for the solar PWM controller the other day. Probably be 2-4 weeks before it gets here.
Going to be an avalanche of stuff when it finally all arrives, waiting with bated breath every day.

The next question would be do your meters spin forward when Backfed?

One of Mine does  so this would mean you would want to take out the inverter when the compressor of the AC was off. That's what I do with the DPDT.
When the AC or compressor is off and the relay is not powered, the output from the GTI goes to another phase.  In your case it would just be off. When the AC powers up, it switches on the GTI. Will take a Minute to boot up but a minute of power isn't going to add up to much.

To stop the AC cycling as much as possible, I run it to it's lowest setting.  On a hot day it's flat out anyway , at other times I let the place cold sink then turn it off for an hour or whatever and then boot it up full tilt again.

Quote
Im not saying this is a great idea, I'm just exploring ways to utilize some spare 220W panels.

Yeah, I get it. A desire to be efficient or to be independent even if it's cheaper to stay dependent.  I get that bee in my bonnet all the time.  :embarassed:

BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #23 on: August 01, 2019, 03:14:24 AM »
Apparently that same bee gets around.  I'm  building a 1 hp, 230V air compressor to run off my inverter when I've got excess power.  It will keep my 500 gallon, 140psi receiver tank filled up. That and pumping water are the two "whenever I've got enough juice" loads.  Couldn't use a cheap homeowner compressor as they aren't designed to run continuously for 5 or 6 hours, nor 230V. 

I'm cooling the air with a transmission oil cooler, then separating the water with an auto drain.  My line from there down the hill is dry and I want to keep it that way. Cooling was essential since the buried supply line is 1 inch PVC.  I wouldn't want to test it with 300F air direct from a compressor.

I'm using a 3-way motorized ball valve for the connection to the air supply line, so the motor will start with no an open line for a few seconds.  Motorized ball valves don't leak, air check valves all do.

Not economically viable, but satisfying nonetheless.




glort

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Re: Solar Split System Inverter Air Conditioners
« Reply #24 on: August 01, 2019, 03:53:01 AM »

What do you use the air For Bruce? 500gal, 2000L, that's a big air tank.

How are you going to control the switching  to denote when you have excess power? Battery voltage Level?

I was just looking at some little voltage comparator boards. I think these would be good for controlling the PWM solar reg I want to do and switching loads based on voltage when I have excess solar which is starting already. The irony is I have too much for a couple of hours in the peak of the day but not enough over all time wise.
I can over volt all my circuits/ mains like right now in the middle of the day but the ramp up and down is not long enough in hours to make up the Kwh I need. Too many Kw and not enough KWH.   :-[

It's a nice clear mid winters day here and I have the water heater on, 3600W, the clothes dryer, 1700W, the greenhouse tank heater, 1600W and the heat lamps on the bathroom, 550w for a sick cat plus the normal parasitic loads of Computers, fridges etc and I'm still rewinding the meters. That will be good for about another hour and then I can start backing off .  Water will be about done, clothes will be dry, tank heater will still be going but that is ok because I'll still need a little bit of Pull down on that circuit.

I have things hooked to the best thing I have found in years, the voltage monitoring relays you put me onto to use the excess power when it is available and keep the inverters tripping out.   I'd like to be able to build a very simple bare bones version of these as they have been so useful and I would never have got as far with my solar proclivity as what I have without them.

It's just annoying that I so often have power to burn literally to keep the inverters from tripping out that I could well use replacing the power I pull at night but it's too much all at once and not more evenly spaced to give lower output but for a longer time.

Another 3 Months I'll be running the air for cooling and still making more power than I can use with half the inverters switched off.
And I haven't even got all the panels up yet.

This is tiddly winks stuff but it certainly is an insight as to the difficulties of managing a whole power grid  with significant input from RE and the many fantasy's and untruths bandied about with it.

BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #25 on: August 01, 2019, 04:44:37 AM »
You might check your voltage at the panels to see how much you could improve things via wire size upgrade from inverter to panel.

I use the 500 gallon tank to run air tools and air motors for my shop.  A Gast 4AM will suck that tank down below 90psi in less than 10 minutes, so it's not oversized, it's undersized.

My Lister compressor can't keep up with a Gast 4AM, which I use on my table saw and radial arm saw.  The air consumption is a bit more than a high power orbital sander.  If steel pressure  tanks were cheaper I'd have 2000 gallons of storage!


BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #26 on: August 01, 2019, 06:05:41 AM »
I forgot to mention, my power management microcontroller has state (float, bulk or equalize), net charge and load info, but what I need to add is solar potential.  I found that a tiny 6V solar panel oriented similarly to my two arrays, with a power resistor for a load gives me a voltage proportional to sun angle/intensity.  I can use that to calculate estimated available power. 



glort

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Re: Solar Split System Inverter Air Conditioners
« Reply #27 on: August 01, 2019, 01:48:23 PM »

Yes, I can see where a bigger tank would be better. At 78 CFM that thing is an air hog.  It uses 10X what my Compressor puts out.
I have an old LPG tank out of a car I have put fittings on. Whenever I want to do something that has High air consumption like sand blasting or spray painting, I couple up the extra tank and let the compressor charge that up too. Helps keep the pressure up longer between breaks if I have to.

My issue is not from the panels to the inverter, all the cable is well over size there. I have 4mm Cable carrying an average load of under 8A.  The longest run I have would put the carrying capacity at the voltage at around 30A Min.
The issues I have are 2 Fold.  Some of the AC cable is light for the length of the run ( and probably shouldn't have been installed for the rated load as draw it is supposed to carry ) and secondly the line voltage is high anyway.

The Voltage here is supposed to be nominally 230V.  I NEVER see that, even at 3am it's usually around 238 to 249 and that is of course without any solar influence anywhere and when a lot of water heaters are kicked in here.  During the day it's usually Just under max allowable at 255V and then my solar lifts it from there to a max of 260 before the inverters drop out.  That's why I have to keep the Phases loaded or the inverters drop out and I get 50% of the potential I can get out of them for the day.
During summer the voltage wasn't bad, under 240 even in the middle of the day. Probably because everyone had the AC full tilt and probably a few pool pumps too.

Why the need for the solar Potential? Can't you monitor the voltage drop before your Charger?

 

BruceM

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Re: Solar Split System Inverter Air Conditioners
« Reply #28 on: August 01, 2019, 03:08:40 PM »
Thanks for the good suggestion. Yes, the actual voltage drop across my low side (as much as -90V) PV regulator might be a fair stand in for solar potential, though I'll have to think about that a bit.  The commanded current to the linear PV regulator is already a 0-5V signal on my controller board and might also be an OK surrogate for (inverse) solar potential though I think there are some conditions where it's not.  I've got nothing but pain, fog and confusion in my head due to regular wildfire smoke lately.  I try to keep busy but there's a lot of mistakes.






 

veggie

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Re: Solar Split System Inverter Air Conditioners
« Reply #29 on: August 01, 2019, 08:15:02 PM »

A bit off topic, but since we are discussing the storage of excess energy what do you guys think about this ?

https://www.youtube.com/watch?v=U7a_LMM2_fE

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- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- Kubota Z482 - 4kw
- JiangDong R165 Air cooled - 2 kw