If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Wind/Solar Electrics ???
RST Engineering wrote:
After much thought and ponderance, I've come to the conclusion that to electrify the hangar using Pacific Gas & Electricity (PG&E -- Pigs, Goats, and Elephants) isn't clever. By the time you get them to hang a meter ($5k), trench from the power pole to the end of the row of hangars, conduit romex to 35 hangars at a cost somewhere around $50k ($1500 per hangar), and then pay the monthly electric bill, you could buy a hell of a wind/solar system and perch it on the (flat) hangar roof. yes, thats when solar pv starts to look good. Before I flail about gathering data, has anybody on these ngs actually installed a design whereby a hefty solar panel charges a hefty battery to run a hefty inverter? It doesn't have to be absolutely "clean" sinewave power as all we are running are fluorescent shop lights (about 400 watts worth), every now and again a small compressor, a small drill press, a small grinder, but none of these last few at the same time. There are 2 main invertor options, sine or modified sine, which is IRL rectangular wave. IIRC, iron fl ballasts and motors can overheat on MSW, so all your apps ideally want sine. However MSW is much cheaper, and there are workarounds. Fl lights can be run at just slightly reduced power, or heatsinks added to the ballasts, etc. Electronic ballast lights would run happily on 150v dc. Motor driven tools would be fine as is unless youre running them to where they already get seriously hot, ie heavy use. There are ways round it if it proves to be an issue. My hit on it is that a 2 kW inverter would be more than enough to handle the AC side of it, and a bank of 12 volt truck batteries would work for the DC side of it, but there are the problems of parallelling large batteries, how to combine the outputs of solar cells and wind generators, and a reasonable source for all this stuff. ok, first with those powers it would make more sense to run your battery back at apx 150v (assuming you want 110v ac) and use a simple chopper to produce the ac. Your output will then have unregulated V_peak and regulated constant rms. That should work for all your loads. You should add a parallel diode across each battery cell, so that one cell going down has little effect on system performance, and enables everything to continue running. Ditto with the panels, there its particularly important to have a diode across every panel when youre running them at HT. This avoids parallelling batteries (not that thats needed anyway), plus reduces cost of invertor and wiring. Also it means you can supply 150v dc to mains CFL bulbs, electronic ballasted fl lights, and anything else that rectifies the mains, again cutting down on system cost and improving reliability. Use a different plug/socket type for the dc supply. One way to shave 10-20% off power consumption would be to up your supply frequency slightly, this would work nicely with magentic ballast lights and brushed motors, but not induction motors. FWIW brushed motors can run on dc anyway - but not @ 150v. Solar pv is cheaper than wind, and has less significantly issues, so I'd stick to solar. There are issues around protecting the solar cells from hail, which we do get from time to time, battery acidic gases inside a hangar where a very expensive lump of aluminum is sitting for months on end, Battery case is vented to the outside. sizing the solar cell and wind generators, and other considerations along these lines. Comments appreciated. Jim alt.solar.photovoltaic is the place to go. Also dont overlook simple ways to cut cost. A minimal cost reflector outside a window can be used to increase daylight levels, and delay lighting dwitch on until later in the day, thus reducing system cost. And of course a switchbank for your lighting will enable you to use the lights only where theyre wanted at the time. No sense lighting the whole place up bright when youre only working in one area. And dont forget batteries dont last forever, you need to account for future replacement. Beating your PG&E costs should not be difficult, as long as its designed competently. NT |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Question on 172 M electrics... (1974 Skyhawk II) | [email protected] | Piloting | 8 | April 10th 04 04:52 AM |