Air Conditioning - Solar and 5 ton AC (Can they Co-exist)

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bwong43
12-03-08, 05:38 PM
I am looking at buying a 5 ton AC unit for my home and am looking at Carrier and Trane units (seen great arguments for both). My question is, is it possible to actually power a 5 ton AC unit via stored solar power without ruining the battery? From what I understand using deep cycle batteries is the best option, but I also understand that AC units would simply ravage the battery and it's life expectancy.

I guess this is more of an off the grid question. I realize I can use my local power company for AC and sell back. However, I am looking for "power independence."

I live in Phoenix, have a flat roof, and have a clear shot to south east and west.


Muggle
12-03-08, 10:25 PM
I'm sure that it's possible to power a five ton A/C with the right equipment (inverter, wiring, solar arrays and battery banks have to be sized accordingly), but it would cost a fortune. (You would probably need to produce 60+ kWh per day to do it)

Central A/C units are 240 volts and can draw 4-6 times their running current during startup; the inverter will have to accomodate that.

I know that you live in a hot climate, but 5 tons is still a lot of cooling. Do everything you can to reduce heat gain and install the smallest unit which will do the job. Evaporative cooling might be a good option to consider. (Uses lots of water, but very little electricity)

Net meatering is most likely your best option; heating/cooling is very energy intensive.

badtlc
12-04-08, 07:41 AM
Central A/C units are 240 volts and can draw 4-6 times their running current during startup; the inverter will have to accomodate that.


The batteries will have to, also.

As for the OP. You really need to lower your energy requirements before properly designing a solar system. There are many many variables and you'll want to make sure you don't have to buy anymore solar capacity than absolutely possible. The solar plant should be the absolute LAST thing you spend money on.

Take the money you are willing to spend on the solar array and use it for energy efficiency upgrades throughout the whole house. Get the top windows, foam insulate everything, caulk everything, get white window dressings on every south and west facing window, etc. etc. Once you do that, your HVAC requirements should drop drastically. You could probably get down to 2-tons of cooling. This makes solar energy far more feasible.