New 5.25kW project

solar_dave wrote: »

Well you didn't really address what the summer electric load looks like, Ask APS they have the records.

That being said I have a 2500 sq ft in Arrowhead and have over killed my solar system in anticipation of having 2 Chevy Volts (one in transit already to AZ) I am on the grandfathered 9AM - 9PM Mon - Fri Peak TOU plan, I think you have selected you best available option for APS plans currently available. This property has 2 3ton Trane high efficiency Heat pumps and a swimming pool. We CFL or LED all lighting, increased out insulation changed the pool pump for a VFD based pump, caulked, sealed and foamed every nook and cranny. We also changed out all the appliances for Energy Star, and added Solar thermal for hot water.

As you probably have read everywhere here do some conservation efforts for sure, a watt can be saved for a lot less than produced with Solar.

I think your key is to load shift as much as you can to the off peak rates which are way cheap @ something like $0.055 per Kwh. Laundry, cooking, car charging ... all off peak and you can probably get a sizable reduction in your APS bill. One nice thing in the fall is APS will credit your account for any excess Kwh on EPR6 on the last day of the year, and you can start out the year with a credit. I still have about $80 in credit with APS so far this year.

You don't tell us much about your loads, take a little inventory and understand where you opportunities for improvement lay.

In AZ you will be unlikely to get anywhere near over capacity on a 5K watt inverter using 5.28 Kw of panels. Low winter sun angle and summer heat will be a reduction in panel output.

BB. wrote: »

That is normal... Panels rarely output their "marketing" rated power--Typically closer to 80-85% of their marketing numbers. Solar panels heat up in sunlight and their output voltage falls some as they get hot--Therefore, their output power falls some too.

You could put a 6kW inverter on the 5.28 kW DC array--but you will not gather very much more power (if any) because of the larger inverter--You will probably only clip a couple hundred watts a few days a year for less than an hour a day (giant SWAG). Maybe a few dollars more worth of electricity a year.

More or less, the "law of diminishing return" as one new poster summarized the other day.



I live in Northern California and we had the same thing--an old E-7 plan with peak power from Noon-6pm... And a new E-6 plan (mandatory for new solar RE installs) with partial peaks from 10am to 9pm.

For my family, it was easy to describe when not to "waste" electricity--Noon to 6pm weekdays during "summer".

The new plan had off peak, partial, and full peak, different between weekdays and weekends, different between summer and winter, etc... A real mess--and it was much harder to push electric use to after 9pm (cooking, etc.). But we were able to stay with the old E-7 plan (grandfathered in--in fact, the grandfathered plan was one thing that pushed me to buying/installing solar GT at that time).

-Bill

solar_dave wrote: »

If you haven't already, take a look at the PVWatts site, pretty accurate from what I have seen overall as a great estimation tools

http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/

My system is 12.5Kw (6250 watts per inverter) name plate with two 5.2 Kw inverters and have never actually seen a peak plateau on the inverter data. It has touched the max for a minute or 2 on a very good day. but mostly runs in the 9000-10000 watt range midday this time of year which is optimal angle and temp kinds of days. Yesterday was great one mid 70's with a breeze until the clouds moved in.

solarix wrote: »

You sound good. Must live an exemplary lifestyle to need only a 5kw system when planning for an EV. I do know that Buckeye will require you to put in a superfluous DC disconnect in addition to the one in your inverter. Why did you choose kyocera and power one if I might ask? Are you doing the install yourself? What kind of roof and what racking will you use? The ET-2 rate plan will work great for you if your on-peak percentage is that low. What will it be in August though when peak rate is 3 times higher than the off-peak. The cost effective system size is usually to just replace your on-peak power with solar and pay APS for their off peak power.

sub3marathonman wrote: »

In Arizona, I think I would have opted for a more efficient A/C unit. I think here in Florida they are now requiring 15 SEER. But, there is one more step you can take to make a real improvement, and that is a Heat Recovery Unit on the A/C to heat your hot water. The previous A/C system we had was the 13 SEER with the HRU, and we turned off the water heater from May through October, or sometimes even later. The other side benefit is that it adds 0.5 SEER efficiency to the A/C also. I think a unit would cost about $500 to initially install with the A/C, or now that the A/C is installed it may run about $750. They ran a water line from the A/C into the attic and over to the water heater in the garage.