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I have been delayed in my quest to go solar. I'm waiting on technology to catch up to my expectations! I have purchased some odds and ends, ( special sales), and because of the high cost of grid tie (and current limitations on capacity, reverse metering, etc,) I would like to put to use my current hardware and electricals in an off grid setup.
I have a very very well insulated house. In the summer, the biggest expense is air conditioning. Since available air conditioners are 120 volt AC, I hope to be able to utilize a solar generating system to supplement my cooling needs. This does away with grid tie expenses, minimizes storage requirements and puts the sun to work to cool the home.
The air conditioner I plan to use for the cooling chore is an LG LP1419IVSM. This model is an indoor portable unit. It requires placement near a window for venting, but a "field test" proved it to be very quiet, and very effective. The critical design feature is the variable scroll compressor, that modulates the units output. It does not really "shut down". By varying the output of the unit, it avoids "hard starts", reducing that hefty amp draw we've all seen with many air conditioners.
LG LP1419IVSM
Frequency 60 Hz
Rated Current 12 A
Max Power Consumption 1370 Watt
BTU rating 14000 BTU
This is utilizing the whole house as a cold storage bank. Window AC's on utility power act as replacement cooling at night or as supplemental on demand cooling when the solar can't keep up with daytime cooling demand. The simple concept is to run the solar powered Air Conditioner at it's max output (Thermostat set to a lower setting by 2 or 3 degrees) and the existing Air conditioners on utility power at a higher turn on 76 degrees) It is not contemplated for night time use when solar power is not available. A battery bank is in the system for "cloud passage" or high power momentary draws. The "cold sink effect"of cooling items in the house will provide some benefit even after the array is off line.
My hope is the 14000 BTU boost to my existing house system will reduce my energy cost without going "whole hog" while the political and regulatory climate is unfavorable for solar grid tie. I haven't installed a super efficient whole house HVAC yet, When I do I could "deal" with my utility to let them control my HVAC central unit to get a reduced rate for allowing the utility to turn off my HVAC system Air Conditioning during peak demand periods.
I have 4 of the Renogy 300 watt 24 volt cells to employ as the PV array. (And can easily add more cells as I have space to expand the array.)
Max Power at STC: 300W
Open Circuit Voltage: 38.80V
Short Circuit Current: 9.71A
Opitmum Operating Voltage: 32.20V
Optimum Operating Current: 9.32A
A power inverter is on hand, a Tripp Lite APS PowerVerter RV RV1512UL rated
* 1500 watts continuous AC output in inverter mode,
* 1500 watts continuous AC output in AC mode
* Double Boost inverter output supports momentary startup loads up to 200% of the continuous rating for up to 10 seconds
* OverPower inverter output supports longer duration overloads to 150% for 1-60 minutes under ideal battery and temperature conditions.
This inverter can draw 175 amps when at full load.
The LG portable will be fed by a dedicated 110 Volt circuit from the inverter. (HARD wired)
So that's the plan. Now what's missing is the charger controller to bring the DC from the PV array to the battery storage and the inverter as the load. Quick and dirty says just get a 60 amp charge controller and wire to the battery (ies). (Switch, Fuse, etc.) Then just wire the inverter to the battery through a relay controlled by the charge controller load port.
An alternative plan is to utilize microinverters on each panel and feed the power inverter AC input from the microinverters. No way I know to kick start this perpetual motion concept! Expense of anti islanding, utility complications, regulatory burden etc. A work around is to use a bulk inverter fed direct from the array and use it as the AC source to the inverter. Need one with a battery charger function but since the battery has to feed DC to my Tripp lite converter I already have...seems like a potential for many problems.
I think I'm best just using a charge controller direct to the battery (ies) and from the batteries to the Tripp Lite Inverter. A relay control system would insure NO Air Conditioner operation during low solar output.
I'm hoping someone with experience in a similar operational setup can give me a few tips, or at least warn me off of frying some expensive components.
I note that many charge controllers seem to be setup for 12 or 10 gauge wire. They are rated for 60 Amp, but never seem to be capable of accepting an appropriate connecting wire gauge. Some 100 Amp controllers seem to be manufactured the same way. I don't like installing "fuseable links". 4 gauge would be my preferred gauge, 6 gauge minimum for charge controller to batteries. As *Short" as possible! That 175 amp max draw to the inverter would require 2 gauge from the battery (ies).
Any suggestions or comments, leads on suitable equipment would be appreciated.
The ideal solar controller would accept an input voltage of up to 48 volts (or better.)
The controller would feed 12 volts to the battery bank for charging.
The DREAM controller would allow the battery current flow to flow to the "load" from the batteries. (The times of reduced solar power when the solar to the controller is reduced, would allow the stored energy in the battery bank to flow and add with the PV output through the controller and supplement the available solar power.
In my "dream" system the total current through this "ideal controller" could be the 175 amps (12 volt) max draw of the inverter. All the solar controllers I've seen have very limited current available at the "LOAD" terminals and are only suitable to flip a control relay.
Thanks,
TDCVA
House Insulation --
The house is a double wide that experienced hail damage. We stripped the old roof and damaged vinyl siding, The sides got one and 1/2 doubled foam sheet insulation over the original "backer board, and then atop this 3 inch foam layer, a 1/2 inch reflective foam. 3/4" firring spaces the vinyl siding (air gap) off this insulation. New Low "E" windows all around. The roof was stripped to the underlayment and double one and 1/2 inches of foam and 1/2 reflective foam was stagger applied. 2*4 strapping was applied over the foam (Lots of 7" screws!) and a new plywood deck atop the 2*4 before the shingle was applied. A peak vent ridge allows air flow to vent from the area between the foam and deck underside. The trim around this super "thick" roof is probably an extra 5 inches, over a normal roof, but it really isn't noticeable unless you know to look for it.
2 days after installl of the insulation and finishing the roof shingle a contractor went to install a roof vent for bathroom ventilator. You should have seen the look of shock on his face when he stuck his hand up into the "attic" and it was cool. (I mean cool as in cool, Not cool as in not hot).
A lean to shed got a new tin roof and we used the left over and scrap insulation under this new tin. Even with the open sides, the area under this structures roof remains cooler than the ambient temperature.
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