Overview:
Passive solar:
elab design as an example (skylights, thermal mass, trombe wall)
benefits: free
costs: must be designed into buildings
Active solar:
usually some sort of collector, and either pump or siphon to storage
Benefits: 95% efficient, cheap, long life, no conflict with power utilities
costs: minimal
PV:
direct current (DC) energy from photons hitting semiconductors (e.g. silicon), electrons move one way, + charges (holes) the other (think of bubbles in beer)
Benfits: no moving parts, not ugly, silent
costs: only 15% efficient, need inverters
CSP:
concentrated solar power: mirrors to some sort of heat collection medium (water, oil, salt).
Benefits: can be stored through dark hours
costs: industrial scale (for now)
Wind:
VAWT/HAWT turbines
benefits: lots of power through dark hours
costs: noise, short life, maintenance, PR issues, ugly
Hydrogen:
Not a fuel source, but an energy carrier
Electrolysis: splitting water into H2 and O2
Fuel cell: H2 + O2 -> energy (DC) and hot water
great for Apollo 13 (for a while-"Houston, we have a problem")
35% efficient unless you use the heat, then 90% efficient
Minilab:
ROI and TCO
Return on investment: amount of time needed to break even (recover cost of device)
Total cost of ownership: cost of device-amount of money earned over life of the device (best if this is negative)
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