Anyone using SOLAR as a power source?

randog · « **on:** 3 Jul 2003, 03:02 pm »

I'm considering making a huge investment into solar power for my home to get rid of my PG&E bill... forever.

Is anyone else doing it? Any special considerations for my audio system and how it may be affected?

I'll still be hooked up to PG&E for times of no sun, but the goal is to have the meter run backwards enough during hours of operation to offset whatever PG&E provides in the dark, so to speak. Not intending to use battery storage at this time...

Randog

KevinW · « **Reply #1 on:** 3 Jul 2003, 05:31 pm »

Hey, I'm starting a business called "Solar HiFi"... so yeah I've thought about using solar panels in audio.

Turns out, it's not that easy to build a DC powered audiophile system, since everything is designed to be powered from AC, with a few expensive exceptions. But, with a good pure sine wave inverter, you should get good quality AC power when your solar system is running. If you're serious about doing this, let's talk over email so that we can share research on how to get the most "audiophile" bang for buck from solar powered homes. Perhaps some inverters have better sound than others... etc. I would like to build up a database of how-to articles for combining solar power with audio.

However, there's one really crucial first step in any solar powered design... This step is absolutely essential, because it is a LOT CHEAPER than buying $30k worth of solar equipment. This is maximizing energy efficiency of all appliances/electronics and thereby reducing the energy consumption and load that determines your energy bill and/or the size of the solar array you might need. So that is why I have decided to focus my Solar Hifi on energy efficient audio electronics. Digital amps are 90-95% efficient, and have fantastic sonics. (The best class AB amps can get to 60% efficiency but sound like crap, while class A is lucky to get to about 30% efficiency.) Low powered tube amps are just that... low powered and consume little overall energy. And of course.. high efficiency speakers to go with the low powered, but luscious sounding SET amps.

randog · « **Reply #2 on:** 3 Jul 2003, 06:10 pm »

Hey Kevin,

Yes, it's expensive. I see your point and I think that would be ideal for a new construction but I don't see us upgrading all our appliances, etc, for the solar installation to our existing residence (the costs associated with 'better' stuff would have its own $$$ issues unless we can isolate and kill a major pig or two). OTOH, I would consider changing out my audio video setup since I've assembled it from mostly used equipment and my losses would be minimal.

We have received our first quote for 2 sizes: 5 and 7KW. Even as large as these are, we will need to play some real games with usage and use a time-of-use meter with a lifestyle adjustment to wipe out our power bill completely.

I'd be very interested in what you find out on the inverters. I'm using a BPT unit for my A/V setup so as long as it is getting the proper voltage it should eradicate any additional noise issues (I'm banking). Other equipment include Odyssey Stratos Monoblock amps, an Outlaw 1050, 36" Tube TV... (I think that's all the major draws).

Thanks for your insights. I don't mind carrying on the conversation in a public forum since it could be of value and interest to others as well.

Randog

sjd · « **Reply #3 on:** 3 Jul 2003, 07:00 pm »

Hey Randog,

I have a RatShack 1000W inverter (thing cost $400 I think) that I'd be willing to lend you for audition purposes...I think you are pretty close to me (I'm in Sacto). It is for RV use, but I gather its the same, isn't it? 12v DC-110v AC. PM me.

I am very interested in this topic because I have been contemplating the same thing in the back of my mind. I would venture that digital amplification is indeed the way to go.

Very interested in the topic of high efficiency hifi. I have a flea powered SET that I still think is a relatively big draw. Would be interesting to measure empirically my system's power requirements.

rosconey · « **Reply #4 on:** 3 Jul 2003, 07:20 pm »

solar is no option here in syracuse, we get 2 or 3 sunny days a year-lol

randog · « **Reply #5 on:** 3 Jul 2003, 07:45 pm »

SJD,

Thanks for the offer. I'll definitely let you know should I get in this deep. I may do things somewhat bassackwards by getting solar first knowing that I'll have to play the efficiency game regardless and if I still get a power bill to start hacking away at the sources until I've got it beat.

As of yet, PG&E won't buy back power if you give more than you take. Hopefully that will change someday.

Randog

Sedona Sky Sound · « **Reply #6 on:** 4 Jul 2003, 11:32 pm »

Your number one problem is going to be gettind a DC-AC inverter that produces a true sine wave. Most (all?) of the off-grid home inverters I have seen produce a square wave or graduated step wave. Allmost all commercial UPS use a step wave since since it is so much easier to produce and most equipment (computers, monitor, frig, etc. ) doesn't care. From what I have read (not tried this myself), they sound really bad. I think most of the cost of some of the big $$$ audio isolators is in the computer controlled sine wave inverter.

KevinW, have you come across any low cost/high output (20A+) pure sine wave inverters? I would love to mate one of these with a balanced design for truly "pure" power

.

Julian

KevinW · « **Reply #7 on:** 9 Jul 2003, 06:29 am »

Well I've done a bit more research into pure sine wave inverters, and the "grid-tie" inverters have to output a pure sine wave, or else the electric utilities won't allow them to be tied to the grid. These units cost in the $2k range. However, the question remains whether this power is "purer" than the grid power. Pure sine wave inverters are still bound to have some high frequency noise. I will need to look for someone who has a grid-tied system and see if I can somehow do an A/B test. It would also be cool if I could borrow a high frequency spectrum analyzer to run some tests on inverters.

Another issue is output impedance, which is likely to be higher in an inverter than on the grid. How much this effects the sound is anyone's guess until actual testing is done.

One of the better inverter manufacturers is Xantrex, formerly Trace... http://www.xantrex.com/applications/index.asp?did=379&p=2

JLM · « **Reply #8 on:** 9 Jul 2003, 10:49 am »

Been interested in low energy housing for 25 years and am now planning on finally building my first house.

Over those years much as changed. But a basic principal, as Kevin pointed out, is to plug the hole before looking for cheaper water to keep the pail full. In other words, start by becoming more energy efficient.

Secondly decide if it's worth a life style change, examples: Using much fewer electrical applicances and electronics and using them less often. Giving up air conditioning. Futzing with a generator. Getting more interactive with your windows and applicances. Wash dishes by hand.

Thirdly renovations to become more energy efficient such as: metal halide lighting, converting the house to a 12 volt system, insulate, caulk, ventilate your attic, use daylight/motion sensors for lighting, replacing doors and windows, upgrade the furnance and water heater.

Standard building practices have improved dramatically. In the late 70's people were looking into underground houses, now there's geothermal (groundwater heat pumps) that can heat/cool a typical house for less than $1/day. Precast concrete basement wall/footer panels are available that have less seams and allow for lots of insulation. Structural insulated panels (foam insulation sandwiched between sheets of OSB) were actually invented 60+ years ago for walls and roof insulate better and have fewer seams while not using heart woods. ERV's (energy recovery ventilators) can recoup up to 70% of the heat from exhausted air. And we're planning to use all these products.

25 years ago it was tough to disconnect from the grid. It may be easier now.

KevinW · « **Reply #9 on:** 10 Jul 2003, 04:35 pm »

JLM,
I am quite impressed that you are taking the time and are committed to build an energy efficient house. I really admire people who follow their principles, even if it means not travelling on the easiest path.

I'm also a little envious that you are getting your energy efficient house from scratch. That way, you can do it right the first time. I just bought a house that was remodeled very recently, and the owner didn't know a damn thing about energy efficient design. All the classic mistakes were made, and now I have to clean up the mess (and spend more money doing it right). But at least the house is nice, and I will have fun wiring up my house with data loggers and temperature sensors so that as I make improvements, I can measure the actual impact. As an environmentalist, I am unusual in that I am always trying to find the solutions that are quantitatively significant without sacrificing convenience unless absolutely necessary. For example, an energy efficient dishwasher actually uses a lot less water than hand-washing, if you wait until the dishwasher is full before running it. I drive a biodiesel car because that technology is orders of magnitude cleaner than any other car technology currently available, yet it doesn't sacrifice convenience, car size, or speed.

Regarding your impending dream house, I have done a lot of research into energy efficient design that I would be happy to share with you. Feel free to contact me if you want. Two of the biggest elements to a great design, IMO, are passive solar and radiant floors. Here in Portland, we can get 60% of our heating/cooling/lighting energy for free from the sun with good passive solar design. This also has the benefit of distributing more natural light around the house interior. I highly encourage you to find a good passive solar designer as step #1 of your home design (I may be able to help you with a recommendation).

I am also a huge fan of radiant floor heating. My neighbor just built an addition with a concrete slab with radiant heating, and it is SOOO NICE inside. Even in the middle of winter, his whole house was just comfortable. The temperature is even and constant, as opposed to forced air which is hot/cold/hot/cold/etc... His system was also very energy efficient when we measured it. Radiant floors are the only way to go for new construction, and when combined with passive solar, your energy bills will be practically nil. I will be installing radiant heat in my house at some point.

Of course, a good energy efficient audio system would be appropriate in a house like that, which is something that I hope to make very easy for people

randog · « **Reply #10 on:** 10 Jul 2003, 07:28 pm »

Kevin, I am currently researching inverters for 'pure sine wave' designs. I find it odd that I can find almost no information on the internet about the sine waves these inverters produce. Some, like the Sunny Boy 2500 make a small comment about being a pure sine wave inverter but it's almost completely swept under the rug. My system will require at least 2-2500 inverters, maybe 3. I would think this would be a very interesting topic in solar circles but I can't even find any discussion on discussion forums.

In addition, I would think the inverter companies would use it as a great marketing tool if their inverters really do produce 'pure sine waves' and with it so hard to get any specific info I'm tending to believe that they aren't as up-to-snuff in that arena as they would like to be. A term like that should be quantifiable anyway. If I were to speak with one of these companies, how could I quantify their statements to that end?

I did find that they've made great strides and the old square wave inverters don't even exist anymore, but that's about it. Now I think they may be somewhere in-between.

Have you found anything interesting on your end?

Thanks,
Randog

KevinW · « **Reply #11 on:** 10 Jul 2003, 08:06 pm »

Randog,
I've done a little research, but I haven't actually tried to find out any information on what the so-called "pure" sine waves look like. I am definitely planning on doing it though... I just haven't had time yet. It looks like I will be going to SolWest this year (http://www.solwest.org/), so I'll be asking some tough questions if I actually get to meet any inverter engineers.

The cool thing too is that anyone who drives a biodiesel car to the fair gets free admission.

How soon are you going ahead with your project?

JLM · « **Reply #12 on:** 11 Jul 2003, 08:50 pm »

Kevin:

Michigan is notorius for having the fewest number of sunny days in the winter in the U.S. The big AM radio station in Detroit makes a contest of it each year to guess the minutes of sunshine for the winter. But groundwater geothermal is an indirect solar heating method. And 80% of our windows will face south, most with 2 foot overhangs and the rest with an adjustable awning.

As far as radiant floor heating, it's still a possibility. But the local vendor of the groundwater system calls it an expensive luxury. Part of the reason for that is the relatively low temperature that geothermal run at (140 degrees). Most boiler based system operate at 180 degrees. For that same reason, having a backup of perimeter fin tube heating isn't practical, so it's a full committment. Because of the low temperature the loops are longer/more extensive, and more expensive. And I've been around long enough to see and hear the horror stories of leaks from in slab heating loops. Older ones were copper, not poly, but no one can promise that leaks/failures will never happen.

(I've been a fan of solar and underground designs for 25 years. And here's my chance to really do it, right I hope.)

jeff