Fire

Fire

November 12, 2021

Stone tools were the first invention, dating back to the beginning of that 2.5-million year period, eventually including simple hand tools such as axes and spears. Maybe a million years later or more, other cavemen learned to control fire, and at some point began cooking their food. They lived in tribes, hunting and foraging together, possibly caring for their weak and infirm, and burying their dead. But other than stone tools, fire, and simple tribal behavior, they had almost nothing else, for most of that 2.5 million years—including at least 100,000 years or more of Homo sapiens existing.

~ Jason Crawford from, https://rootsofprogress.org/the-beginning

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I often joke that there are three thing I can stare at endlessly: Fire, moving water, and other people working. And I’ve often expressed my theory that it’s the movement of those first two, (the third we’ll leave aside for today,) which is the key to holding my attention. Fire and water both dance semi-predictably; But not so predictably that the movement is easily ignored. There’s always just enough movement to hold my attention.

When I let the idea settle in that we’ve been staring at small fires—fires which literally represented warmth, safety, food and tribal companionship—for about a million years… Actually, a “million” is hard to apprehend. Let’s say, there are 25 years per generation. We’ve been staring at small fires for about 40,000 generations. No wonder I’m staring at this fire. We’ve evolved to be attracted to fire!

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The art of starting a fire

November 25, 2019

During heating season, each morning begins with my ducking outside for the ash pail and then shoveling out the stove. Then with a selection of kindling and a medium-sized piece or two, I build a small work of art and set a match to it. I’ve done this, easily, a thousand times. I’ve read one book entirely about burning wood, and several about thermodynamics and chemistry. I understand the different types of wood and how to season it, the convection of air, and I know intimately how the house and stove interact. I’ve intentionally experimented with variations of the art, including working with more stoves and fireplaces than I can recall. Usually, I have a roaring fire in 30 minutes—sometimes 20—with not the least hint in the house of the smell of a fire. Occasionally it doesn’t work well. Most of those mediocre attempts or outright failures are immediately attributable to my having cut some corner. But every once in a great while, the art eludes me despite my best efforts.

There’s a large lesson in that.

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An open door policy

September 18, 2018

Aware of this research, my housemates tested their air quality and got levels between 1000 and 3000 ppm, around the level of the worst high-CO2 conditions in the studies. They started leaving their windows open and buying industrial quantities of succulent plants, and the problems mostly disappeared. Since then they’ve spread the word to other people we know afflicted with mysterious fatigue, some of whom have also noticed positive results.

~ Scott Alexander from, http://slatestarcodex.com/2018/08/23/carbon-dioxide-an-open-door-policy/

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I thought this was going to be an article about fossil fuels and global warming. No it’s much worse. It’s about how some people have measured levels of CO2 in their bedroom that exceed the OSHA workplace safe-exposure limits.

Now i’m wondering if one of the reasons I sleep better in the winter, is the difference in ventilation. Our A/C is a closed system—it only circulates the air in the house. But the wood stove lowers the air pressure slightly and that draws outside air in from the peripheral areas of the house. Tiny cool drafts come out of all the wall outlets and light switches in the winter providing fresh air ventiliation.

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Heating with math

March 10, 2018

Something a little different today: I’ve been considering switching to heating with gas and I recently ran some numbers.

tl;dr: I will be continuing to heat with solid fuel.

Preamble: We have already deeply insulated our attic, upgraded insulation in the walls which were opened during some remodeling, and replaced all windows and doors with modern versions. (Our house was originally built in 1954.) This is the obvious first place to begin improving heating your home.

Electricity: My electricity costs $0.0758 per kWh. I can basically turn on my electric baseboard heaters and this is what I’d pay (per kWh) to heat our house.

Methane: This is the proper way to heat a home in northern climates. Unfortunately, “street gas” is not present in my neighborhood. One block over, yes, here, no. They would install it for me… if I’m willing to pay the entire cost to rip up the street and put in the gas main.

Propane: Chemistry geeks know that propane has about 12% less energy per molecule compared to methane. But generally speaking, appliances (my gas cooking stove, a gas heating appliance I would need to buy/install) can be adjusted to burn either fuel. Anyway. I already have a small propane tank that serves my cooking stove, so I would “just” need a larger tank — possibly MUCH larger, possibly so large that safety ordinances would require me to put it underground. Anyway. My propane costs me $5.999/gal — if you know about petroleum, this is an incomprehensibly high number. Meanwhile, 1 gal propane = 27kWhr of energy. And a gas heater (I’m imagining replacing my wood stove with an appliance that sits in the same space) is effectively 100% efficient at turning that gas into heat. So simple math shows that propane would cost me $0.222/KWh — about THREE times the cost of electricity.

Firewood: This is MUCH harder to compute. First off, I have to estimate how much energy is available in the wood I’m burning; that’s affected by species of wood, and how it’s seasoned and stored (because the MORE water in the wood, the more heat is “lost” to vaporize that water and send it away up the chimney.) Some factors to consider: Where I live, there are several readily available “fuel” species of trees that are sustainably available. I’ve found a reputable supplier who is not hauling it long distances and provides me the right sizes etc for what I want. I also have the absolute best imaginable way of storing the wood in “cribs” that expose it to air drying while having it under cover.

So I’m guessing 20 million BTU per cord. (A cord is a stacked, pile 4 feet tall, with a foot print of 4×8 feet. Technically, it’s a pile of 4-foot LONG logs, 4 feet high and 8 feet wide on the ground. A true wood heating system is a separate unit outside that is meant to take 4 foot long logs. I purchase ~16″ pieces split, which still makes the 4×8 foot print computable. I digress.) Good fuel species can be up to 30MBTU/cord. So I’m being conservative with 20.

20M BTU is 5,861 KWh. I pay $300 per cord (fellow Pennsylvanians just twitched because that is pretty expensive — 225 or 250 is typical — but this is excellent wood species, all cut and split to the correct sizes for stove fuel, delivered early in the season, and dumped exactly where I want it. As usual, I digress. So math happens leading to $0.0512 / KWh. Even if I figure-in that the wood stove is only 80% efficient (we have a great stove made in Scandinavia which really does exceed 80% efficiency when operated correctly), that only bumps the cost up to $0.0639 / KWh.

Update in 2019: My electricity costs $0.07039 per KWh. (That’s down about 1/2 cent.) I’ve a new firewood supplier, with the price down to $225 per cord. That’s $0.038 / KWh, and still only $0.048 / KWh at 80% stove efficiency.

And finally some references…

http://www.propane101.com/propanevselectricity.htm
http://worldforestindustries.com/forest-biofuel/firewood/firewood-btu-ratings/

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