The most inexpensive way for LARGE Solar Storage

[Peter K]

mechster like you I also decided to build my house with Solar in mind, not finished ! however we live here in a Round, 7,000 sq ft house. The center tower is cast concrete 6 ft ID * 8 ft OD * 34 ft tall, the bottom 12 ft are for heat storage, with 1 ft insulation 4 ft OD * 10 ft tall, this is for the rocks " not in yet " . My main focus now is to set up small scale Mfg of the Solar Heliostats
" Sunflowers " the task is to make high reduction gear drives for each axis, for the first 20 Prototypes I made double worm drives for each axis so that's 800-1 reduction, the little stepper motors " so far " have no trouble with the load & only step aprox 1 per min.
I think of a radiator " size " heat exchanger @ the focal but for air @ higher temp.
Other heat loads like water, floor heating, electricity & lets not forget food cooking, can all be done with raw heat, so if space is not the problem I would go with the most readily available IE cheapest " Hot Rocks " no maintenance, no leak, with this you can have solar cooking @ night.

still getting a " RoundTuit "
Peter

[mechster]

Peter K,

What is you're e-mail, I'll send you what I have drawn up.  It's simple except for one feature to seal the entire system when not in use.  I read in a few research papers that the main reason these systems don't work is because of the heat losses.  I designed it around that aspect.

Mechster

[Peter K]

mechster I don't think of the system ever being off except in failure, & it must be default safe.
there is no perfect insulation so on the outside of insulated storage is another space for air input into the system IE cold air return, lost heat is captured & directed as needed.
Solar looks to me like a half wave rectified power supply & we need sufficient " Capacity " to allow for missing pulses. You will likely want to direct the heat, need actuators, could be for vents or valves, repurposed windshield wiper motors if your handy. peter " at " microtrendrobotics " dot " ca

Peter

[sparks]

     pump water uphill to a holding pond.  Any rain fall and you get a little bit more solar energy input.

[MarkE]

     pump water uphill to a holding pond.  Any rain fall and you get a little bit more solar energy input.

It takes a big pond and substantial elevation to do much good.  Say that you want to store one therm for overnight heating.  That's 29.3kWh =  105E6J.  At 9.8J/kg/m and 1kg/l for water, you'll need to lift about 10,000,000 liters*meters.  So if your pond is shallow but 4m above grade, then it will have to hold 2.5m liters, the volume of an Olympic size swimming pool.  If you heat water from 25C to 99C and store that, then going down to a comfortable 20C, you get 79C * 4.18E3J/l = 330E3 J/l, and 105E6J requires 317 liters, or about 75 gallons, within the range of a large water heater, or two small water heaters.