Newbie Needs Help With Design

[Superslo]

Hello and thanks to anyone who can help me. I live in Arizona. I recently built a solar array to supply my well pump. The pump is a Grundfos an runs off variable voltage, 640' deep. I ground mounted 8 panels 30 V 255 watts each, 2 groups of 4 and ran everything through a Grundfos CU-200 controller. It works like a charm, and I'm now able to pump water for 'free'. Considering the well pump is 640' deep, this is a good thing.
Now I want to build a system for my house. I'm on grid power, however my meter is 350' from the house. I'm told to tie it into the grid I'd have to run back to the meter. Major deal, no thanks. So I want to build a system for the house that is large enough to run the Air Conditioners during the day. We're getting killed by our power provider and the cost has nearly doubled in the last 2 years, and they're raising rates again. So, my yearly average is 35,000 kw hrs. We have a 2-1/2 ton AC on the house, and 2 RV's that we keep at 80 so they don't bake. Anyway, I want to run on solar during the day, with (Hopefully) automatic switching back to grid at sunset. We're at 2700 feet elevation, so it's not killer hot, but the A/C's run constantly in the summer. I'd ground mount the panel array. We have plenty of land, and plenty of sun. I can either buy used panels, but the tend to be in the 250 watt range, 5 years old. I can get new panels for 100 each in either 365w 425w 545W 695w. I don't know what wattage I should go for, and what inverter. I'm new to solar, with just enough knowledge to be dangerous. Any help I can get would be greatly appreciated, and thanks!

 

[BentleyJ]

First step is always an energy audit. You have a good starting point knowing the yearly average at 35,000kWh. I would recommend going through the utility bills and getting the monthly average. With this info you can model your proposed system using this calculator. It will give a very good estimate of annual as well as monthly production. You may find that the PV array has to be oversized for summer constant A/C usage such that some will not be needed during cooler times of the year. This is why just the annual usage is not enough.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

 

[Tsolar]

I would check with some local installers or talk with the utility company to see what the local inspectors/utility is actually requiring. Where I live, we can just put a disconnect at your meter that is 350' away, but not have to physically bring the solar feed all the way there, it could just tie into the nearest building. In this case, the disconnect they require, is shutting down your entire property, including the solar. Some inspectors and utilitys get retarded, and say the disconnect should only shut off the solar. In the perfect world yes, in the real world, when it means trenching a whole nother feed 350', then no.