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Old 07-06-2008, 03:02 PM   #1 (permalink)
EcoModding Lurker
Join Date: Jul 2008
Location: Irving, TX
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Talking Second newguy from Texas today...

Hi, I already posted twice on the home improvement threads... but maybe can introduce myself here more in general.

I do hardware design (power electronics) for living and these "ecomods" as hobby. My main project is that I have quite respectable size PV array on my backyard that is powering my house "supplemental air conditioning"... The system makes about 1200W of AC power that I use to run two window AC units. Those are enough to keep the house reasonably cool during days when sun shines... It is completely off-grid system, since I didn't want to bother going through all these NEC requirements and get the system approved... so here it goes.

Everything started as a small project, but just kept growing... The system consist of about 1800W (STC rating) of solar panels, Outback MX-60 charge controller, couple 100AH AGM batteries and 1500W sinewave inverter. In addition I have a small PIC18F based microcontroller board that measures the battery voltage and controls the inverter ON and OFF and also control the loads. (In the morning and afternoon only one AC will run, but during the day both AC's have enough power to run.) It is workign nicely and even today close to 100F day we do not run central AC at all!

How this started? Two years ago our electric bill just got so high that we decided to do something... The bill was "only $200", but I never though paying over $200 per month for electricity! So that's how it started. Now, at the current state our month of June bill was less than $80... Less than half what it used to be.

By the way, during winter months our house is heated with natural gas. That bill was also getting high... and to help that we use portable AC with heater (heat pump) function in the bedroom. That reduced our peak gas bills to well below $100 per month as well.

I'm not saving everywhere, though. I do drive Explorer with V8 engine and I don't get much more than 13MPG in city driving...

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