Solar parabolic troughs to run my whole house: physics gurus needed!

Guys, I need help in the PHYSICS bit. I'd love to hear your suggestions, but please help me in the calculations I ask for below!

I watched the graphite burn away in seconds as I focused sunlight falling over the magnifying glass onto the paper.

I wondered what hell-like energy a series of parabolic troughs could offer. Assume that I adjust the trough rotation for optimal concentration, from dawn till evening. Okay! So, I wrote down a list of applications and what I need to calculate:

Melting a mixture of sodium nitrate and potassium nitrate

The objective here is to store this molten salt in some super-insulated storage tank. This can be readily available in the night to heat food and water. And, if its quantity allows, even generate electricity by steam-powered turbines.

Here, I need to calculate how much salt can I melt in a day. So firstly I need to know WHICH quantities I must know in order to calculate this, and second HOW to calculate it (steps and formulae involved). (Please use sample values of your own choice and solve this scenario with them, as I have trouble understanding without examples)

Turning water in pipes at the focal point (more like focal lines in this case ) into high-pressure steam... to turn turbines or other rotary components

This will provide rotational force (I THINK the right term would be torque, but whatever) to 1) generate electricity (and perhaps use it to split H2O to hydrogen and oxygen ; hydrogen for stored energy ; oxygen as an oxidizing agent) 2) run millstones, pump water, raise masses (again, for stored energy), run fridge compressors directly (why waste energy by converting mechanical energy to electrical only to convert it back to mechanical ), etc.

Here, I need to calculate how much turning force (torque ) the axle, that is turned by the steam in the pipes, will provide. Again, WHICH quantities do I need to know, and HOW to use them to calculate torque using formulae. (Please use sample values of your own choice and solve this scenario with them, as I have trouble understanding without examples)

I believe the answers to this world's energy chaos is in the sun. After all, no sun = no heat = no bacterial activity on soil level = no nitrogen fixation = no plants = no animals = no humans. God bless you permies.com legends!

What about using parabolic lenses, to heat waste glass up enough until it's molten, then casting it into a parabolic lense? Self-replicating parabolic lenses?

Not sure if you've seen this video on youtube...

Dylan, the problems I am facing lie in physics calculations. I need someone to help me out with the math!

A lovely complex puzzle Danielle, not sure quite where it fits into Permaculture...
Did you see Andasol power station on Wikipedia?  It gives some information on output, area and costs of a large salt storage energy generation facility. Which may give some idea of feasibility for you. I guess they get economies of scale.

Oh my! Nancy, you got me gold here! I'll try to downsize the area (200 ha in this case) and see how many gigawatt-hours I can get... looks enormous at first.

Energy = Solar Radiation x Area x Hours x Efficiency
Solar radiation = 600 W/m2
Area = 2 m2
Hours = 10hrs
Efficiency = 75%

Energy = Solar Radiation x Area x Hours x Efficiency
Energy = 600W/m2 x 2m2 x 10h x 75%
Energy = 12000wh x 0.75
Energy = 9KWh

Square Meter (m2) is about 10.8 square foot

My degree was in chemical engineering, with modules in renewable energy, and physics training, so I think I can speak with a bit of authority here.

If what you were envisaging were feasible on a home scale it would already exist and be sold in readily packaged forms. There are good reasons why domestic setups have tended towards either photo-electric, or to passive thermal collecting tubes.

Moving parts makes all engineering substantially more complex, difficult and expensive. Failure modes can vary from catastrophic (parabolic lens sets fire to your house), to annoying (your system is offline for weeks in the middle of winter while you wait for parts and time to repair). Passive systems tend to fail in a more benign way, and less frequently - one solar panel in a set might quit, so your system becomes less efficient.

Giant parabolic mirrors scare the crap out of me. I have seen what a moderately sized fresnel lens can do. An array built of parabolic mirrors and hold be worse. Options range from instant blindness, to deep burns, and setting fire to anything organic that ends up in the firing line. Add in a concentrator that is potentially boiling water, or some kind of molten salt, and we have a whole load more scary things. None of these belong anywhere near a home in my opinion. There is a reason that these solar collector system get build in remote deserts.

If you don’t have a rock solid plan to deal with all these hazards, then worrying about efficiency calculations seems like the wrong path to be on.

I’d really recommend steering your attention to other forms of solar intervention. There are loads of simple yet effective DIY arrangements that, for example, increase solar gain in a property, or pre-warm your water supply to reduce the fossil fuel demand of your domestic hot water.

There are many excellent resources available out there. One of my favourite books is
http://www.withouthotair.com/download.html

It was written by one of my university lecturers, and focuses on the situation in the UK. It is a decade old, but still highly relevant.

Having had to intervene in numerous failed solar thermal installation using benign fluids like glycol, failed fans and differential thermostats in solar thermal air installations and many many off grid solar electric blunders  I would strongly suggest you take the previous poster's advice.
Between net metering, solar electric and heat pumps you can accomplish most of your goals without the risk.
Cheers, David Baillie