Thanks for the detailed comment cmhansen
I've written a detailed idea before as well about using an extra heatpump to buffer heating or cooling in a tank of water vs batteries - much more direct than geothermal. This would work as good for non-solar. It is geothermal except air-source and buffered daily not seasonally. Peltier is not (yet) good for cooling at <10% efficiency. In addition for heating, if you had super-icephobicity coating on a heatpump you could use it in colder periods. Ideally batteries are the best and most direct buffer, we'll replace heatpumps for heating before we do for cooling.
I considered heat pump before but the PV energy is so cheap that trying to use a heat pump will not make economic sense. It will when compared to battery but not with my method where battery is not used for heating so cost is extremely low.
Peltier is extremely efficient if used properly as a heat pump and I will do probably a youtube video about that soon. Most care about profit so they use the peltier element at full or almost full rated power but if used at just a fraction of the full power the peltier can be extremely efficient so COP of 3 can be obtained with careful design.
Here is the spec
http://www.thermonamic.com/TEC1-12706-English.PDF of a very common peltier element that cost maybe 2 or $3 in China. Check last page and you can see when used at 3V will take about 1A so 3W of power and be able to pump about 12W when 10C delta is used. For high delta using two or 3 stages may be needed the COP will still remain the same.
When the peltier element is used close to full power say 12V and higher temp delta then module is an order of magnitude less efficient with COP well below 1
Of course the cost complexity of the cooling with peltier needs to be weighted against very low cost of PV energy and some compromise between cost/complexity and efficiency can be selected.
And in fact look at current cost of batteries at nearly $100 / kWh (almost there but it will surely get there soon), at standard 2k cycles this is only $.05 / kWh of battery use. Panels are looking more like $.01 / kWh now... if you use batteries 2/3 the time you easily see (.01 x3 + .05 x2)/3 = $.04333 average per kWh, grid cost alone exceeds this and 'free fusion' would end up costing more!
The cost of battery per storage capacity is not a good indication of anything. Also those $100/kWh (I'm sure are more like $200/kWh today) and only have 500 cycles at 100% DOD so please provide a spec and real price if you have something in mind that can be had today.
LiFePO4 are by far the most cost effective for electrical energy storage and the higher energy density cells while make sense in consumer EV for a few reasons are far from cost competitive in therms of energy storage.
Best real life cost amortization for LiFePO4 currently available is around 25 cent/kWh. The theoretical based on simple calculation as the one you did before is much lower but that is not including the battery aging that affects all batteries much more even than cycle life.
My cost amortization for PV panels of 2.4cent/kWh (USD) is based on (80 cent/Watt acquisition cost, 25 years amortization period and amount of solar at my location ).
While is true that you may be able to get better than 80cent/Watt as PV panel acquisition cost (just seen 67cent/Watt in a US online store) and some panel manufacturer warrant power output up to 30 or 35 years and maybe some areas get slightly more solar than my location the 2.4 cent/kWh is still low enough to make my point that solar PV is the lowest cost of energy currently available for powering an individual house.
With the DMPPT450 and SBMS combination the LiFePO4 can get a better cost amortization than 25cent/kWh (when only SBMS is used) close to half maybe as good as 12cent/kWh becose aging will play a lower role since battery will be smaller and more heavily used so it will last less in time but store more energy in that period (will be cycled more).
And a tricky counter-intuitive bit about amortized cost of the panel not factoring in land cost - tracking actually increases this (for high-insolation areas doubly so!) The reason is simple that the higher proportion spent at higher temps, the lower the lifespan (exponential degradation per degree rise). Meaning colder climates with fixed angle have the least normalized temp degradation per kWh produced, and therefor least cost, and since tracking takes more land than fixed per kWh (I think) this is even more in favor of fixed. (Also consider seasonal tracking is (substantially?) more productive than daily tracking, if highest power per area is needed).
Mechanical solar tracking is for sure a long dead technology and best argument for that is to look at all large scale solar PV installations where 95% of them are fixed PV panels with no tracking at all.
Yes many are told solar takes more energy than it can produce.... though one study I read had solar at 7x, wind something like 21 and nuclear the highest by an order or more). Plus this will only go way down if we get away from thick silicon wafers. Here is a fairly current and concrete (not forcasted) estimate of EPBT that shows solar in an even better 'light':
http://www.apricum-group.com/electricity-payback-time-pv-system-facts/
That is 12.5x - 25x total energy payback (including inverters and BOS) over 25 years! I'm not sure if variable wafer cutting loss is accounted for in that figure, it might assume 'kerfless':
https://www.greentechmedia.com/articles/read/1366-Technologies-to-Build-250MW-Direct-Silicon-Wafer-Factory-in-Upstate
Regardless no dead birds, burning windmills, bad bearings or massive transmissions to overhaul.
That is a false information solar PV can not take more energy to manufacture than it produces over is life.
Think about this way any solar PV manufacturer wants to have a profit and will buy energy in order to produce the panels.
Then you pay the cost of production (energy + materials + equipment + labor) + manufacturer profit + reseller profit + taxes.
A simple 250W PV panel can be had easy for $200
This panel will produce 380kWh/year at my location (an average location for solar nothing special).
So say just 25 years (panels can last and produce energy a lot longer) x 380kWh/year = 9.5MWh of energy produced by that panel over is 25 years life.
$200/9500kWh = $0.021/kWh so I also calculated the cost amortization. For solar data go to PVWatt select Regina Saskatchewan, Canada as my location use panel tilt at 50 degree and 1kW PV array since it will not accept smaller then get than energy for a year and divide by 4 for a 250W panel and you will get that 380kWh number.
Now I'm extremely sure that PV panel total energy used will not be anywhere near 9.5MWh for a producing ans shipping a single panel and is probably more like the energy can be recovered in just the fist few months by the panel.
Do not forget that the cost of the PV panel includes so much more than just the energy used to manufacture and transport the panel.