Why hasn't anyone invented a cheap solar-powered a/c system? (Phoenix: appliances, house)

[esiebert7625]

Unless you are off-grid, most solar systems do not store power at all as having and maintaining big banks of batteries gets expensive. Also batteries don't seem to last too long in the heat so you would have to replace them more often which further drives up cost. With solar you are typically working with the grid and using it to supplement the power requirements that solar can't handle or when solar won't work (night). When you have excessive solar power when it is greater then demand it dumps it back into the grid and your electric companies gives you a credit for it. Even power companies do not store power as it would be hugely cost prohibitive, all power is generated on demand.

[Lovehound]

^^^^^ what esibert said.

I'm an electronic engineer. Banks of batteries are expensive to maintain. If you want to reduce your electric bill you should get a solar array of the type that feeds power back into the grid when you don't need it. In effect the grid is your battery. As such there are no maintenance costs.

So of you want to save money on air conditioning or electric use of any kind you should get solar and use the grid to store your excess power. Then use it when your AC runs.

[caryberry]

Originally Posted by Lovehound

^^^^^ what esibert said.

I'm an electronic engineer. Banks of batteries are expensive to maintain. If you want to reduce your electric bill you should get a solar array of the type that feeds power back into the grid when you don't need it. In effect the grid is your battery. As such there are no maintenance costs.

So of you want to save money on air conditioning or electric use of any kind you should get solar and use the grid to store your excess power. Then use it when your AC runs.

Lovehound (cool name BTW) - please tell us more. What and how does this work? Not the salesman BS - the real scientific, "reasonable" requirements. Can we get in AZ with SRP? APS?

[esiebert7625]

Originally Posted by caryberry

Lovehound (cool name BTW) - please tell us more. What and how does this work? Not the salesman BS - the real scientific, "reasonable" requirements. Can we get in AZ with SRP? APS?

If you want to know more about solar in AZ there is a pretty good thread on it here that might help

https://www.city-data.com/forum/phoen...lar-power.html

[Lovehound]

Originally Posted by caryberry

Lovehound (cool name BTW) - please tell us more. What and how does this work? Not the salesman BS - the real scientific, "reasonable" requirements. Can we get in AZ with SRP? APS?

Thanks. The concept for my username comes from the Kate Bush album "The Hounds of Love" (1985). She is an English singer-songwriter and musician who was popular mainly in the UK from 1978 to about the mid '90s although she continued to produce albums as recently as 2011. I presume her main popularity today is amongst dedicated fans. I used to be a dedicated fan until the '90s when her style became more new-age and her music is not as appealing to me as it used to be, although I still like her albums up to "The Red Shoes" (1993). Although I have the final 3 albums I rarely listen to them if at all. It's anybody's guess if she has retired or will produce another album some day.


As far as I know solar is available everywhere as long as there is a southern exposure to sunlight. For example somebody living with a large mountain to the south (such as parts of southern Palm Springs which are always in the shadow of Mt. San Jacinto). Others who live in deeply forested areas have faced clearing enough trees for their solar array which is sometimes forbidden by the National Forest Service or other regulations. Most if not all of Phoenix shouldn't have any problems with having an adequate southern exposure.

Typically the solar array is installed on the roof, and an ideal home is one with a roof slope facing to the south. Houses where the ridge of the roof faces south with slopes towards the east and west are less ideal because the eastern array will receive sunlight only in the morning and the western array only in the afternoon. The more perpendicular the array panels are to the sunlight the more electric power they generate.

The power produced is direct current (D.C.) so it must be converted into alternating current (A.C.) by an inverter unit typically installed near your electric panel and meter. Also required is a controller unit that synchronizes your inverter output with incoming A.C. power. Really bad things happen when they are not synchronized! There is also a disconnect switch so that you can remove your solar system from incoming power and power feeding your house, so that your array can be shut down for maintenance or repair.

Once the system is set up and operating it generates power during daylight hours (obviously) and clear sky. Clouds can reduce the effectiveness and at some point of increasing cloudiness the system is unable to produce sufficient electricity and I presume it automatically shuts down. So don't count on your solar during a haboob!

The rest is simple. At night time your house draws its power from the electric grid. During the daytime if your house is drawing more power than the solar array produces it uses all the power it can draw from your array and the rest from the power grid. Here is the good part: If your array is producing more power than your house is using the excess power is fed into the power grid, to be used elsewhere by other customers. When this is happening your power meter actually runs backwards!

That's about it from a technical point of view. Solar companies either sell or lease solar arrays with a variety of payment plans, and often subsidies and/or tax benefits are available to persons who install solar arrays in their homes.

With the large number of sunny days in Phoenix it appears to me that Phoenix would be a great place for solar power. You can Google up any number of companies that provide such systems and I advise you should inform yourself on all the options, subsidies and/or tax benefits before deciding if a solar system is right for you, and comparison shop to find the best company if you decide to go ahead with it.

[Steve Pickering]

Here is one for less than $3,000 with 8 hours of battery backup. http://www.treehugger.com/sustainabl...rket-soon.html

[Steve Pickering]

Here is another at half the price of the one I installed in Maricopa in 1982. Solar Heat Pump - Backyard Energy Products, LLC

This is a heat pump. Guess where heat pumps work best both heating and cooling? at 56 degrees. And where do you find 56 degrees in Arizona? In a 36 inch diameter hole 35 feet deep. That was how mine was installed and it never used electricity except in a monsoon.
.

[hikernut]

Originally Posted by esiebert7625

Unless you are off-grid, most solar systems do not store power at all as having and maintaining big banks of batteries gets expensive. Also batteries don't seem to last too long in the heat so you would have to replace them more often which further drives up cost. With solar you are typically working with the grid and using it to supplement the power requirements that solar can't handle or when solar won't work (night). When you have excessive solar power when it is greater then demand it dumps it back into the grid and your electric companies gives you a credit for it.

True, batteries are not cost-effective. Only if there's no other alternative do they make much sense today.

But for a/c specifically there's a much cheaper way to store energy!

hikernut

[hikernut]

Originally Posted by Steve Pickering

Here is one for less than $3,000 with 8 hours of battery backup. Affordable Solar Powered Air Conditioning in a Neat Little Package is Finally Here : TreeHugger

These are certainly going in the right direction. Use DC power instead of AC, so the expense of extra electronics for DC->AC conversion and/or grid connect are eliminated.

hikernut

[Steve Pickering]

If you have the room, install a 36 inch culvert screened both ends at 10 feet below ground or bermed with 10 feet of dirt over the top and planted. Draw cool air from the culvert into the house. It should be at least 20 feet long. you can use a swamp cooler without water and replace the AC Motor with a DC Motor and solar battery system.

It works. I used it year around in Maricopa.