On 2017-09-06 09:06 AM, Alvin Starr via talk wrote:
A client came to me asking about helping him setup an Etherium mining server pool.
Hey, I know that there are some honest cryptocurrency types out there, but there are some definite shady ones around Toronto. One Etherium joker stole ~$500 of Raspberry Pis and accessories from my employer. Caveat consultor. I'm a (sometime) utility solar designer. The idea's interesting, but the implementation's tricky.
What if you glue a GPU with very little extra hardware to the back of a solar panel.
* Solar modules produce variable I-V output depending on sunlight and air temperature. You'll need to use some kind of inverter to stop your miners becoming puffs of expensive smoke in their first winter dawn.
Stick it out in the sun and let it calculate 8-10 hours a day. Put a big heat sink on the GPU and it should be able to stay cool enough just from air cooling
* Solar modules run roughly 20°C hotter than ambient, often more. The huge project I worked on in Arizona quite frequently hit 45°C in the shade, so your GPU would be around 70°C under no load. * The dead air behind modules is *very* still. Passive cooling would likely melt. * You'd need to weatherproof your GPUs against water, dust and ice. Any crevices attract spiders and ants, and junction boxes in desert locations are a favoured haunt for scorpions and rattlesnakes.
Take a few thousand of these and set them out in a sunny place and you would have a coin generator.
* You'd need a small amount of ride-through battery, as a heavy cloud or shading on the wrong bit of the module can reduce your power output to close to zero.
Once the hardware is paid for then the operational cost would be close to 0 but for some glass cleaner and rags.
* Almost everywhere on the planet requires some kind of permit or environmental impact assessment. Even glass cleaner and rags need an MSDS and hazard management plan. * Some module types (thin film) are in perpetual danger of being classified as hazardous waste due to their cadmium content. * If you're far away from people, network is hard. * If you're in an isolated area, theft of solar equipment is a huge problem. * There's also something about solar modules that attract people with shotguns. It usually ends badly for your installation, unless there's a big fence.
They would need to be networked together but it does not have to be high speed. It could be a low power mesh to an edge that connects via something as simple as cell phone data.
* Solar modules, with all that wiring and semiconductor hanging about, make about the best radio signal attenuator I've ever seen. You only try to make a cell call or get a GPS fix under a solar array once. * The inverters you'll need can produce a fiendish amount of radio interference unless they're shielded in expensive enclosures.
Solar panels cost about $1/watt and there is no ongoing cost but power here costs about $0.08-0.16/KWH.
* Modules are way less than $1/W now. Racking will likely double the cost of your installation, though. * A utility-grade 330 Wp module is about 2 m² and weighs around 22 kg. At these latitudes, you'll get about 40 W average across the whole year. Since you're only proposing running through the day, you'd get more than that. Have a play on PVWatts <http://pvwatts.nrel.gov/> for hourly output. Choose a module like a Canadian Solar CS6U-330M for modelling: it's a solid Mono-Si module with decent efficiency. cheers, Stewart