there are some posts on going solar with battery back up for your audio system, never got quite that far myself.
20 responses Add your response
My brother is an electrical engineer, and a damn fine carpenter. He's built the current house he's living in as well as the previous one. In both homes (Vermont where they loose power frequently in the winters) he's built a solar panel system that charges a huge bank of batteries. The system is basically large solar panels on the roof, with a wall-mounted unit that probably has the volume of an average fridge or a bit more(though much flatter) , that is mounted in the basement. If he loses power from the grid, the batteries kick in and will power the house with modest usage for about three days. Battery technology, and capacitor technology has been taking some significant steps over the past decade so everything seems to be getting more compact and efficient. My brother says there are now better ways to go, though is happy with that system in general. Ralphmasphere is a wealth of information on this subject and may be able to give you some advice if you ping him. There are certainly manufacturer's like Red Wine Audio, who are using battery technology to power their components as well. As you know, you need a whole lot of juice for high-current Class A monoblocks, especially if they've got the cojones to push those Magneplanars you have.
Besides lowering the power demand of your amps (e.g. Class D), you may want to look into the solar policies wrt the local power company. In some locations, the power company is required to buy back energy generated by solar, and a simpler solar (or wind) system can be installed that doesn't use battery storage but just pushes power back into the grid. This can sometimes be most cost effective and green. Honestly, if you are building a new house or planning major renovations, you can probably make a whole lot more green impact by going for other energy efficient designs for heating/cooling (e.g. heat pumps, passive solar, solar water heating, efficiency via insulation) than by focusing on your stereo. If you're not willing to do Class D amps, there's not much you can do to reduce the consumption. One advantage of a battery bank, if you're going to spend the money, is that you might be able to have your equipment modified to run directly from the battery banks (i.e. no AC noise). As Marco mentioned above, Ralph at Atmosphere would have some good ideas in that area.
I was going to suggest both the battery and the ralphmasphere route. However, almost by definition, there is nothing which is going to make Class A amps efficient enough to be eco-friendly. Running Class A monoblocks to drive Magneplanars is equivalent to running a pair of large hairdryers (or electric clothes dryers) all the time - i.e. a SERIOUS power suck. The easiest way to be 'ecologically friendly' with Class A amps is to get super efficient speakers - probably horn-loaded in some way.
Solar's cost/kWh sweetspot (in terms of capacity or goals) changes all the time, and in the northeast (making an assumption here), solar is a tough way to live sometimes. I am convinced that if you are in the northeast and you want a decent-sized house, the ideal is to build with some active solar, a fair bit of passive solar, lots of insulation, and lots of geothermal; and if you are aggressive, count on being 'net zero' rather than 'completely off-grid.' Why more people don't use geothermal for heating/cooling is beyond me. It pays for itself very quickly (as do passive solar design, insulation, and argon-filled windows, etc), especially if building from scratch in a place where you can dig deep cheaply. thinking about it on an after-tax basis, it makes even more sense. If you live in an area where hotsprings can be drilled to without a huge cost, the whole equation changes because depending on temperature and flow, you can generate electricity from that more easily (though if you do tap hotsprings, I urge you to recycle the waste water back into the system - hotsprings do 'dry up' if not replenished).
You are wasting your time trying to be efficient with your stereo. The average system I've seen around here costs maybe $20 per month. Try to get the whole house off the grid and you will do some justice.
Solar thermal heating with massive concrete mass in the building is a good way to go, given a heavily insulated building. We have solar PV as well and have a five day battery backup, however it requires about 1 hour of maintenance per month, as do our composting toilets.
If you are of the mindset that you take care of yourself, a republican mindset, than the investment will fulfill your principles.
If you are concerned about the planet, the sun can be harvested better today than ever before. Go for it!
Email if you think I can help.
Apologies to CW in advance on going slightly OT... do the heatpumps generate electricity or only generate air/water-heating capacity? I have yet to find a heatpump which can generate electricity well without having the input significantly above ground temperature. Also, from what I have read over the past few years, in colder climes, boring deep and sinking "U tubes" gives better energy efficiency than digging horizontal trenches with a backhoe (which is obviously a lot cheaper); that said, it is obviously not a bad idea in the desert (or in places where the bedrock is very shallow).
Back on topic...
If you just want a system to generate electricity to cover the audio, using efficient speakers and matched 'small' amps will go a LONG way to making it possible, but the first 100 watts of solar installation is the most expensive (per kWh). If you have a large property in windy area, using mini windmills plus a bank of batteries can be a way to generate smallish amounts of electricity. If you want to use "green" power to cover 2kW of usage, then you are probably talking upwards of $10k of kit plus further installation costs. If you want 2kW for the audio and another several kW for the rest of the house, it is a fair bit more.
You're right, they just generate heat, not electricity. If you are going closed loop, I'm not sure of the trenching depth that gets you pretty well far away from the seasonal and diurnal temperature fluctuations at the surface - a borehole definitely does that. Even more efficient (and costly) is an open loop system using two wells, where groundwater is extracted, heat exchanged, and reinjected. It gets you up to an efficiency factor of 4 rather than the low 3's with a closed loop system (for those wondering, efficiency factor means for every 1 watt of energy you put into the system you get 4 watts of heat out of the system).
Water Furnace Envision series (dual-speed versions) will get you a COP of 5 on closed loop, but they are probably the exception as that is the most efficient one out there I think. Disclosure: just based on my research; never bought one or sold one and no economic link to anyone in the business.
If I might point out another aspect of 'green', we have an update program that allows any of our older amplifiers or preamps to be updated to the latest level with full warranty reactivation. This helps keep the product from entering the waste stream, prevents obsolescence and supports the resale value.
If you want class A, which IMO is the best-sounding way to go, to keep the energy aspects down you will want a speaker that is high efficiency so you won't have to make a lot of power to run it.
Atmasphere - average music power delivered to speakers is very low. It is in order of few watts (few percent of max power) while class A takes up to 8x max power. Class A take the same power all the time. When delivers power to speakers (few watts) it dissipates less in the heatsinks.
Cwlondon - Solar panel for class A won't change anything. It is still "polluting" component since you could return this solar energy to grid and reduce emissions.
Same is true for hydrogen - it is very "dirty" fuel since it wastes a lot (90%)of energy in making it using electricity. The fact that energy might be clean (solar, wind etc) doesn't mean anything since, again, it could be returned to grid instead to reduce emissions. Fortunately it will never see daylight since selling hydrogen would be the same as selling dynamite without permit.
Kijanki, if you have been playing with solar power you know that a lot depends on how long you use an electrical item as well as how much power it draws.
What solar systems I have seen vary from a single 12V deep cycle batter powered by a single solar cell, in which case class D seems like the way to go. I've seen larger systems that could easily operate a class A tube system for an evening without strain. I have a set of 45-based Class A push-pull amps at home that I built as a DIY goof-off project, but they have wide bandwidth and low distortion. As long as you had efficient speakers they would be fine.
BTW I'm putting together an electric truck- its been a 3-year project. Looks like I will get a 100 mile range, if the math is remotely accurate. If there is any interest I can post photos...
So far the capacitor storage technology is still 'on the way'. It might be that EEStor is the furthest along. http://theeestory.com/
The other players in the US are Maxwell and Intersil, plus there is still a company here in the Twin Cities that has a technology. I actually went to their place to see it operate and make tests on it, but they had me sign a non-disclosure so I can't talk much about it, but it is a very simple technology. It does seem to me though that they are taking far too long to develop it :(
The truck is a 1990 Ford Ranger extended cab. Its powered by an Azure Dynamics 50Kw AC motor and controller, which reaches its maximum efficiency at 2500 rpm, so I kept the original clutch and transmission. There are 26 flooded lead acid batteries powering it- we had to really beef up the suspension and be creative to find a place to put them all. But they can operate for 2 hours with a 50-amp load, so 100 miles is possible assuming 15KW @ 50 mph. We're down to wiring the harness and figuring out what parts under the hood we no longer need- the entire drive train, battery boxes and the like are all installed. Its been about a 3-year project. Lotsa stalling around... mostly just trying to figure things out. I think in retrospect if I were to do it again with this drive train I'd do it on a Ford F-150. That way it would be a lot easier to install the batteries and there is really not that much additional weight.
As a follow up to this thread, I have just noticed a new commercial for a small, portable solar panel and generator.
It is being hyped pretty hard in an infomercial style TV spot and website, so not so sure about the integrity of its manufacturer or marketing.
However, otherwise it seems pretty small, is < $2000 for the whole set up, and claims to produce 1800 watts of power.
What would that do for storm stranded audiophile?