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Heating Water with Fire (2019)
- Darmody 6y agoI discovered their channel a couple weeks ago on Youtube and it's the best thing I've seen in a while. In a video they show their home setup and how the stove is used as a stove, oven, heater and water heater. I wish I could have one of those.
- HenryBemis 6y agoCan you please share the URL or the channel's name?
- throwaway3b03 6y agoI assume it's this one: https://www.youtube.com/user/HomewoodStoves/videos https://www.youtube.com/user/HomewoodStoves/videos
- Darmody 6y agoIt's that one, yes.
- mindslight 6y agoWhy are they only considering the atmosphere for expansion/relief (and consequently multiple heat exchangers)? Why not a standard hydronic heating expansion tank with a pressure/temperature relief valve? Do these systems boil over often enough to make that impractical?
- bacon_waffle 6y agoI'm pretty sure it's historical. Older homes here were set up to use gravity to provide the water pressure, so the obvious thing to handle boiling over (which, yes, could be quite frequent) was to run a pipe through the roof with just a bit more head elevation than the supply. My home for instance was built in the 1950s, and in the attic has a copper "header tank" which has an overflow/vent to outside and a float valve to maintain a set water level in it. That would've supplied one or two heat exchangers in the wood/coal fires, and cold water at the same pressure. Now, the header tank is out of the circuit, the original fires were removed decades ago in a remodel (their water heating functionality replaced with a "low pressure" electric hot water cylinder which still vents through that same pipe), and we're now connected with city water. The current situation is like many homes of similar vintage and has a couple issues: the cold water is substantially higher pressure than the hot, and we now have an Ajax valve which occasionally needs to be checked on in case it's leaking through and pumping electrically-heated water out on to the roof.
- mindslight 6y agoI do admire the passive elegance. It's interesting that your current water heater continues to use the old vent, rather than just ignoring it in favor of being higher pressure with a relatively inexpensive temperature relief valve. Are the hot water distribution pipes not rated for higher pressure? How big is that pipe that goes up to the roof? I assume it's covered with something to avoid random debris or animals from getting in?
- bacon_waffle 6y agoAs is discussed in the article, mains pressure hot water cylinders are more expensive than low pressure ones. Also the installation (ed: of the first mains pressure HWC) is more expensive since it's supposed to be done by a certified plumber where (I'm fairly certain) a homeowner is allowed to replace like-for-like. Anecdotally, it does seem like there is a hesitancy in switching to mains pressure hot water, due to old valves and such failing, but I think the biggest reason is simply that a low pressure hot water system means less heated water going down the drain. From memory, the pipe is just a piece of 1 inch copper. There's nothing on the top, it just points straight up to the sky.
- mdoms 6y agoWetback systems are very common in NZ. I built a home recently and decided not to go with a wetback system because I decided there would be little overlap between times when I use hot water and times when I would use the fireplace. Now since covid I am working from home permanently I kind of regret that choice.
- abraae 6y agoSame. We Built a new house a few years ago and I really wanted a wetback, having had one in a previous house I was talked out of it by the fireplace guys and the plumbing guys. Now I regret it every time I light the fire. The main problem is that wetbacks fall into a gray area, they are mainly plumbing, but plumbers are more used to dealing with standard components and materials. Architects are usually not familiar with them so don't push for them.
- tomrandle 6y agoI’ve recently moved to a house with a wood burner / back boiler and I can’t wait to replace it. It’s made me appreciate what a huge upgrade natural gas boilers were. I spend a minimum of 15 mins a day chopping kindling, fetching wood, starting and feeding the fire. It’s not cheap and it’s not warm! It’s been fun and makes you appreciate your consumption more but the novelty only goes so far!
- xupybd 6y agoI grew up with a wood fire. I love the sound and feel of the fire, but I'm done cutting wood. First you have to buy the wood. A truck load of wood in the driveway means hours of stacking wood and cleaning up. Then to start the fire you need kindling. If I get home at 7pm after a long day of work I don't want to have do this just to start heating the house.
- bacon_waffle 6y agoI also heat with wood, but quite like the occasional breaks from the computer through the day, and sometimes cooking on the wood stove. Here, the obvious alternative is a heat pump rather than a natural gas boiler, and I suspect the total cost of wood heating is a bit lower than with a heat pump.
- danans 6y ago> I suspect the total cost of wood heating is a bit lower than with a heat pump. According to this article from 1993, it was a toss up in terms of cost savings then: https://nasdonline.org/1359/d001154/do-you-waste-money-by-heating-with-wood.html https://nasdonline.org/1359/d001154/do-you-waste-money-by-he... Since that time, heat pumps have become much more efficient at a wide set of operating temps, and the cost of wood has gone up, so it's unlikely that a wood stove is cheaper to operate, unless you have your own forest, and are willing to fell trees and chop and dry firewood yourself.
- Retric 6y agoWood stove tech has also increased quite a bit though it’s still relatively rare to see 85+% efficiency. Access to free firewood is one topping point, but depending on electricity can be a serious issue in some areas.
- jandrese 6y agoThis seems neat, but I only run my stove for roughly 3 months out of the year. It seems like a lot of effort and expense for something that seems to make sense only in the winter. I guess these are more popular in colder climates with short summers?
- chrisseaton 6y ago> I only run my stove for roughly 3 months out of the year Do you not use your stove for cooking as well? I guess most people with a wood-burning stove us it as an oven, a hob, a toaster, things like that, which they want to use during summer as well.
- nerdponx 6y agoThe people I know with wood-burning stoves also have modern electric or natural gas ranges for their daily cooking. Their stoves are primarily for heat, with cooking as an added bonus. But those stoves are more like a metal box with a chimney, not the large cooking-oriented stoves in the article.
- chrisseaton 6y agoThese wood-burning ranges are not uncommon in the UK https://www.google.com/search?q=wood+burning+aga&safe=active&hl=en&tbm=isch&source=lnms&sa=X&ved=0ahUKEwiO5_-n3o3wAhWSYsAKHaHFB9kQ_AUIwgIoAQ&biw=1680&bih=870 https://www.google.com/search?q=wood+burning+aga&safe=active...
- jandrese 6y agoNope, mine is configured purely for home heating. But even then I don't leave my oven on 24/7. This article runs under the assumption that your heat source is constantly running. In fact he advocates for large tanks that take a long time to warm up in most cases because of the assumption that your stove is always burning.
- chrisseaton 6y ago
- DickingAround 6y agoI found this helpful in describing a bit about how to build such a system. As someone that operates solar, it's become quite clear that solar gives very little energy in the winter and water heating is a huge part of winter power use. So if you're going off grid, this seems like a critical part. Now if we just had some better tech around turning felled trees into a furnace without so much human effort....
- eliaspro 6y agoWe're using 2 Paradigma water-based vacuum tube solar panels and pull even during the coldest winter days around 20kWh of thermal energy for hot water/heating out of them - even with just passive/diffused sunlight. Only on really dark/cloudy days it might just get us 1-3kWh. As fallback we still use natural gas, the wood burner which is also integrated in the hot water circuit is out of service since several years, as I just couldn't run it anymore with a good conscience knowing the extreme pollution those cause and the fact that burning wood is possibly the worst thing CO2-wise one could do given the current state of affairs.
- JshWright 6y agoBurning wood is certainly polluting, but CO2 is not the concern. The CO2 released by burning the wood was already part of the global CO2 "budget". As wood is burned, releasing CO2, more wood is grown, capturing it again. Wood burning, from a CO2 perspective, is effectively neutral, and far from "the worst thing".
- bacon_waffle 6y ago> burning wood is possibly the worst thing CO2-wise one could do given the current state of affairs. I'm curious about this. Around here the carbon from the wood (less emissions from a relatively small amount of petrol to cut and transport it) would've been taken out of the atmosphere in the last 20-ish years, where the natural gas carbon is in the millions of years (and additionally a much longer supply chain). I understand that smoke particles are not great in the short term, but assume we're talking about modern equipment.
- waltwalther 6y agoI grew up with a big cook woodstove/oven in our kitchen. It helped heat the house, and my mother cooked on the stovetop and baked in the oven multiple times per day. Even in the summer. We had a regular electric stove that was added shortly before/after I was born, but she still used the woodstove. It was a big cast iron contraption, with what I remember as white powder-coated sides and trim, and she knew how to get the temperature just right for whatever she was cooking. I remember walking downstairs on cold winter mornings to the smell of ham, eggs, and biscuits, all prepared on that thing. One more thing I remember. It was positioned about three feet from the wall. There was enough room to walk behind it (if you ducked under the pipe), and our dog used love napping there.
- jpollock 6y agoIn the UK, there's an aspirational kitchen stove brand - AGA, which are intended to run 24/7. I understand it takes a fair bit of experimentation to learn how to cook on one. :) https://www.agaliving.com/products/aga-cast-iron-cookers https://www.agaliving.com/products/aga-cast-iron-cookers
- deleted 6y ago[deleted]
- anonu 6y agoTangential topic : There was a post on HN a while back about steam heating. This talk on YouTube was linked. It was really informative: https://youtu.be/TQB0KK2rxcw https://youtu.be/TQB0KK2rxcw
- tgsovlerkhgsel 6y agoFor anyone considering this for environmental reasons, I suspect it's one of the dirtiest available technologies, not due to CO2, but due to soot.
- dredmorbius 6y agoVery much this, though newer stove designs and emissions controls help remarkably with this. Specifically particulat matter / PM2.5 emissions, the same factor that causes most concern in wildfire smoke.