Ziege wrote:Electric space heating is notoriously inefficient, this is why using electricity to operate a pump (reverse cycle air-conditioning) is the status quo. hence there are very little to no battery/solar heating solutions, air as a general rule has a high specific heat capacity, and therefore has a greater latent heat capacity, meaning the energy absorbed by it and re-emitted is done at a high rate plus it takes a lot of energy to heat that air before any noticeable change in endothermic emissions from said air takes place, hence why bayonet heaters and coil heaters, and electric oil heaters are usually very inefficient, LPG or Natural Gas heaters are cost effective also but very inefficient as are wood fires. inefficiency based on the fuel in heat out ratio. wood is the cheapest to run, so for Joule to Dollar ratio would be at its best using a log burner in some capacity.
If you are hell bent on using electricity do what everyone else with the knowledge and science and experience has done and stick with phase change gasses aka buy a small aircon.
I can relate to where you're at, I was there a while ago, experimented with a great many concepts, I have a whole file here on solar/storage/heating/cooling solutions, all of them were either tried or hashed out by me and the guy that used to be my tutor in high school and college (a chemical and mechanical engineer that works for Boeing). If I find it in the attic I will take some pics and upload them.
I had a similar concept a while back when I had my son staying in the outside bedroom in the old farm house (while building our new place that is designed by me and needs 0 air conditioner or heater and it gets to -8*c here in winter and 40*c in summer) The solution ended up being an old tile fire setup outside, the water heating element that was made to attach to the Flu on the chimney was close looped onto an old copper that I bronzed a lid onto with a pressure release valve off an old air compressor put on it. the loop consisted of going through the wall and basically was a 1' long windy panel of copper pipe exposed as a "heater" in the room, and I simply insulated the rest of it including the copper with anticon insulation. 0 risk of "smoke" or "co2/co poisoning, and one log on the fire with coals and its good to slowly burn all night. easy peasy.
Agreed - the low draw elec heater doesn’t really exist. It may well turn out not to be viable - but, thus far, it is promising.
I don’t know how old the idea of PTC thermistors is ? if it weren’t for them, then I’d not even attempt this - but they are, pretty darn efficient as already mentioned. 28w for 200degs c...I’m absolutely mind blown how hot they can get from so little power, it’s really quite amazing - but - how long will they last at 200 degs? Being a ceramic resistor, I’d assume a decent time but I know very little about these...
I like the copper pipe heater idea - I could actually twist this and do similar, using the thermistors in place of heating element - similar to Eddies idea. How did you regulate the water element and I assume it was mains ?
I don’t sleep all that well (never have) and end up just thinking about different problems and potentials and all manner of wild ideas and s**t all bloody night...this is but one that grew some legs lol.
Ps Eddie - I researched re turning thermistors on/off and apparently, that will kill them / they have a finite no of cycles available per unit. So with that in mind - 2 options. Try and burn one out on purpose to understand life of, or semi submerge the units constantly to control the heat.