Heat Storage Idea

[Wintergreen282]

Hey Froit1,

Sorry. All the “someone has responded to your comment” emails went to spam for some reason and I just now found them.

Anyway. I heat the gallon of water on a 2-burner Colman camping stove connected to a 20 gallon (pound?) tank that lives outside. The same as if I’m cooking or

heating

water to wash dishes or my hands. I guess, if necessary, I could heat the water on the wood stove, inside the solar oven, or maybe just a solar shower bag, but that would require the wood stove going or sun shining. And take forever. I guess that is where I hit my “less” limit. Lol. I don’t worry about the “gray water”. The wild plants that live around here do esp well under my small deck. They don’t seem to mind a bit of soap and people sweat. Again. To each his own. I don’t have neighbors to worry about. There aren’t multiple people living here. Much of what I do works because it’s just me. Like I explained to my (doubting) brother. If I’m cutting up just one carrot, it’s way more work to drag out the food processer. - Cindy

[skihuckster]

Jafo, you've probably learned a few tricks in 5y on

heating

, but since this thread is fun I thought I'd pass along some of my engineering knowhow.

First, oil doesn't hold more heat than water (few things do). The advantage of oil is that is boils at MUCH higher a temperature, so if you want to hold heat above 212F (100C) without having an expensive high pressure boiler, oil is your fluid. For hot water...hot water will soak up the most heat from the sun.

Second, what you're going after is capturing as much radiative heat from the sun as possible. Not all "black" paints are created equal. Find one with a really high emissivity (near 1 if possible) as that is a measure of how much solar radiation it will absorb. I think wood stove black paints are good ones.

Third, you'll be fighting heat loss at night, or really any time the fluid in your barrel is hotter than the air outside.

Insulation

will keep heat from leaving...but it will also keep heat from coming in.

For showers, you can't beat the cost to benefit ratio of those black plastic solar showers. You fill up enough water for the shower, leave it out in the hot part of the day, do your thing, and then fold it up and put it in the cabinet.