First and foremost: This isn't strictly to save money. I'm sure it would cost less to trench conduit out, even with blasting through some of the lava (there's a lot of it, very close to the surface, and it's utterly impossible to dig through - you literally need to blast it).
It's partly because I don't want to trench, and partly because I want to work with solar. So, yes, I know it isn't the most cost effective way of doing this, and I'd rather not hear it, because it's an investment in skills and knowledge for areas I plan to work with in the future.
The building will be used as an office for a while, then a music/art space. I've learned in the past that I cannot separate work and not-work if they're in shared spaces ("a bedroom at home with my general computers in it"), so I need separate, isolated space.
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That said:
I have an 8x10 studio shed set up on a remote corner of my property that I'm going to set up as an office with solar.
The first step is to insulate it heavily - solar based cooling and heating, with propane backup for heat, and I'd rather use as little as possible. It's 2x4 construction, with a 2x6 roof. I'm planning to shove rock wool between the studs, then put 2" of XPS insulation over it (the hard purple foamboard), then use plywood for the interior walls. Partly for the nice wood look, partly because it means I can mount shelves & the like straight to the wall without having to find studs through the foamboard.
Roof will be much the same, just thicker.
Floor... eh. I don't think it's well insulated, and I can't really get under there (it's sitting on gravel now). I'll foam it if it's really annoying.
For power, I'm planning to go with about 1000-1200W of solar panels, a Midnite Solar Classic 150 MPPT charger, a 48v/200Ah string of Trojan T105-RE cells, and an Aims 2000W inverter/charger (possibly another inverter if needed for peak loads - I have some peaky loads like spot welders). 10kWh storage capacity, so I can use 3kWh or so without really affecting longevity. The plan is to have the panels providing the power while I'm there during the day, then use the pack for occasional evening use and for cloudy days (3kWh should get me through a typical day of work).
HVAC will be a window mount heat pump - I found one that gets good reviews for off-grid type use, and it should handle climate control for most of the year. I'll likely use a small propane heater for colder winter days.
I *think* this should cover all my needs. If I find I need more power, I can add a few more cells to my string, and if I'm dealing with endless cloudy days, I can either charge from my truck (which I'm planning to get set up as a high output 12v generator - just boost it to 48v and bulk charge), or figure something else out.
Thoughts?
