Edge Collective

Off-grid heat

Designs for off-grid heating systems

2021-11-22 10:52:14

Terminal type is now 'qt'
gnuplot> set datafile separator ","
gnuplot> plot "output.txt" using 1:2
gnuplot> plot "output.txt" using 0:2
gnuplot>

~/gitwork/offgrid-heater/v1

stepping down at 10 min intervals:

next up:

display in F
record timestamp

~/gitwork/offgrid-heater/v2

2021-11-22 18:37:23

In v3, tried two heaters in parallel. Got:

Now re-trying one without changing position of temp sensor, for direct comparison ...

Now re-trying with three in parallel ...

Testing linearity by plotting equilibrated temp vs pwm for that temp:

2021-11-23 08:03:59

Arduino PID https://www.teachmemicro.com/arduino-pid-control-tutorial/

Three paralllel heaters:

Note that as of now (2021-11-23 08:06:17) the battery voltage is approx 12V; early in the experiments it was at 13V.

Now, return to one heater, repeat experiment, see if lower voltage has had an impact ...

2021-11-23 11:01:49

Results from one heater experiment. Note that the initial temp was higher, so perhaps easier to reach max temp initially; second run seems to reach lower max temp.

2021-11-23 12:52:43

Next step: add a diode and test ... and add a fuse?

2021-11-23 13:13:26

Nice guide to using N-channel mosfet w/ motor control ... https://bildr.org/2012/03/rfp30n06le-arduino/

Carbon fiber heating wire: https://www.walmart.com/ip/Anself-3mm-12K-33-Carbon-Fibre-Heating-Wire-200-High-Temperature-Far-Infrared-Silicon-Rubber-Warm-Floor-Heating-Cable/214637878?wmlspartner=wlpa&selectedSellerId=101001360&&adid=22222222227458777995&wl0=&wl1=g&wl2=c&wl3=538566868938&wl4=pla-1461988039397&wl5=9001876&wl6=&wl7=9002004&wl8=&wl9=pla&wl10=128133340&wl11=online&wl12=214637878&veh=sem&gclid=CjwKCAiA4veMBhAMEiwAU4XRr8JrzrRzHUIx8zmXSVjrAAqEOX5sOsjLmlKgGTlOpF0Q_P1oLxs-eRoCHKsQAvD_BwE&gclsrc=aw.ds

2021-11-29 16:59:02

"Motorcyclists make their own heated clothing ..."

https://www.bimmerforums.com/forum/showthread.php?1563924-Converting-non-heated-seat-to-heated

https://advrider.com/f/threads/35-00-heated-jacket-liner-diy.514532/

Hook-up wire https://www.mouser.com/c/wire-cable/hook-up-wire/?q=83000

https://www.youtube.com/results?search_query=diy+heated+jacket+wire

Interesting -- he threads his own nichrome wire into insulation:

https://www.instructables.com/Solar-Water-Heater-From-Scratch/

advice on copper coil dimensions:

https://youtu.be/4JFdDITCH-8?t=388

Official design for wood-stove hot tub w/ some specs: https://islandhottub.com/wood-fired-heater/understanding-thermosiphon

To produce thermosiphon circulation, the top circulating tube must rise upward to the tub at a rate of 2-inches per foot or greater for the horizontal distance. The steeper the slope, the faster water circulates. Note: Faster circulation does not produce a faster heating rate.

Subtleties in designing a thermosiphon system: https://www.greenbuildingadvisor.com/question/thermosiphon-vs-recirculating-pump

Article on hot water systems: http://www.garykleinassociates.com/PDFs/15%20-%20Efficient%20Hot-Water%20Piping-JLC.pdf

Thermosiphone on appropedia https://www.appropedia.org/Thermosiphon

Hot water heater https://earthshipbiotecture.com/do-it-yourself-solar-hot-water-heater/

Nice review of thermosiphon materials https://www.sciencedirect.com/topics/engineering/thermosiphon-system

Likely reason for use of silicone in heating elements: its unusually high melting / burning point: https://silicone.co.uk/news/temperatures-can-silicone-rubber-withstand/

2021-12-16 16:45:58