Browse Forums Eco Living 1 Jan 09, 2013 7:54 pm over the last few weeks I've been wondering how exactly I can power most of the home Wisdom are planning out with solar... and as it does idle curiosity turned into a keen interest on just how far building a system within the confines of a normal house could be taken To begin with the maximum power draw had to be estimated, unfortunately this lead to adding up the total power usage if everything in the whole place was lit up at once!! so lets go with 100x 16w downlights (probably not even half that, but lets go wild) 1.6kw 1 x large fridge 800w peak oven (gas cooktop) 2.7kw (!!) 23kw Aircon (actual use seems to be around 20amp 3 phase) Various other devices at once (PC's, Electrical etc) 5kw giving a bit of up and down, lets assume that the conservative estimated peak usage is around 30kw (damn) and I guess it's possible that could be used at any one time (imagine having a party on a weekend?) For the next trick, my estimation on the surface area of the roof... looking over the house plans the ground floor is around 230m2 so lets run with that for the rough roof area. next was to have a look for the best reasonable solar panel, now according to quite a few Australian Bulk solar panel buy sites the cheap end of the reasonable quality solar panels is around $1 per watt, looking at the designs around one that came recommended by some reputable Whirlpoolers was the ET Solar range, specifically the 250w panel, http://www.wholesalesolar.com/products. ... 0245B.html it looks good, 16% efficiency, and $258 is pretty good at the moment Next was the Inverter, there are a whole heap of systems out there (to say the least) and quite a few of them have fairly big shortcommings, issues with the classic inverters in that the solar panels run off a chain (string) that gets up to 800v, in some systems this voltage is unable to be turned off even if you flip the inverter (working with that by your side while replacing a panel?) a lot of other also have issues with enough panels being covered causing a total inverter shutdown (no thanks) so given enough research the Solaredge system ended up looking pretty nice, now keep in mind we need 3 phase to run the Aircon, and somewhere near 20amp of it, the largest single unit that Solaredge make is a 13kw unit (classed as 12.5kw) and to run the unit at it's peak efficiency you then need a $100 Optimizer for each panel. the Optimizer's should pay themselves off by the fact that they will compensate a lot more efficiently for shading and the ability to see if you have a faulty panel rather than just wondering why the inverter is rarely on. Back to roof size, if we assume that it's magically possible to use most of that surface area (maybe pull some more surface area from a few walls? all the houses around me are single story? maybe put up a pergola and throw some panels on it?) we can fit roughly 140 panels (imagine how that would look!), now there is not much point even for a 13kw inverter, of going past around 60 panels as, when you get some nice days you'll be over the inverter capacity HOWEVER, if we get a second inverter, that puts us up at around the 26kw capacity and we can throw on somewhere around 120 panels.... how much? my estimates are $21k for the 13kw system excluding labor/Installation brackets/mounting 44k for a 26kw system (probably the max you could ever hope to fit) and 62k for a 39kw system. fun with figures. if we assume that the average 4kw system in Sydney is capable of 15kw, we take each of our systems and derate their production by 1/4 then assume we use none of that power generated (export all to grid) and workout how much you'd make on the current Feed in Tariff of 8c per kwh: 13kw system 60kw day $4.80 a day $1,752 a year 26kw system 120kw day $9.60 a day $3,504 a year 39kw system 180kw day $14.4 a day $5,256 a year how funny is that if we had a 1:1 Tariff (lets go with 21c per kwh) $12.60 PD, $4,599 per year $25.20 PD, $9,198 per year $37.80 PD, $13,797 per year annnd for those who got the 60 cent input... $36 a day, $13,140PY $72 a day, $26,280PY $108 a day, $39,420PY Slooowwwwly getting a Manhatten 35 in Middleton Grange Re: 3 Phase Solar system Musings 2Jan 10, 2013 11:16 am Interesting link on usage http://www.transgrid.com.au/network/nsd ... taic%20(PV)%20Report-Technical.pdf that document seems to be suggesting that larger solar systems should be installed Slooowwwwly getting a Manhatten 35 in Middleton Grange Re: 3 Phase Solar system Musings 3Jan 10, 2013 2:20 pm When I did my Solar Installation/Design course we where told ultimately we where to look at the Customers last two years of Usage and calculate that to an hourly Figure and design the system based on that Re: 3 Phase Solar system Musings 4Jan 10, 2013 2:25 pm It looks like larger arrays can be useful to provide solar for commercial and industrial area's running off the same substations.... I wonder if the substation was actually receiving more power than it was using, if they would then offload power backup the chain to other loaded area's? (imagine the outlying suburbs supplying the CBD with solar power) if the price of Coal keeps going up maybe we can start getting paid a bit more. http://www.letitgo.com.au/the-facts-abo ... ar-in-nsw/ Slooowwwwly getting a Manhatten 35 in Middleton Grange Re: 3 Phase Solar system Musings 5Jan 11, 2013 10:59 am Found a company (USA) that does the Solaredge power boxes for $85 http://www.backwoodssolar.com/ Inverter pricing here: http://www.choiceelectric.com.au/pdf/pr ... e-2012.pdf keep in mind that does not include the latest solar edge inverters (up to 17kw now) Slooowwwwly getting a Manhatten 35 in Middleton Grange 1 62016 I looked into it a few years ago and my conclusion was to just build a carport that will support panels and get a system installed separately. The company I looked at had… 1 6481 Once you know the basics, the rest is easy. Read my post in the thread linked below. viewtopic.php?p=1919271#p1919271 2 19515 |