PV vs deep mesh economics

[nick pine]

yreysa" <gary@...> wrote:

> A good DIY solar heating collector rated in the same way as PV panels are rated is about 9.1 cents/peak watt.

A large deep mesh solar air heater might cost about 7 cents/ft^2 for
an outer layer of 4-year greenhouse polyethylene film + 8 cents for an
inner layer + 20 cents for 2 layers of 50% black shadecloth + 4 cents
for a layer of weed barrier, totaling 39 cents/ft^2.

In full sun, it might make 0.75x250 = 188 Btu/h-ft^2 of 150 F air, at
a cost of $0.39/188 = 0.002/Btu/h, ie $0.00061 per peak watt.

A 10 mil 20-year outer layer of HP92 flat polycarbonate would raise
the cost to about $1.40, ie $0.002 per peak watt.

A $10 ton of stone can store about 0.16x2000 = 320 Btu/F, eg
(140-70)320 = 22.4K Btu, ie 6.6 kWh, like 6.6 12 volt 100 Ah
batteries. Stone doesn't wear out.

A 4'x10'x3' tall tank with a $75 10'x16' folded EPDM liner can store
about (140-70)7500 = 524K Btu, ie 153 kWh, like 153 50 cent 12 volt
batteries. Water doesn't wear out.

Nick