[HN Gopher] Heating Water with Fire (2019)
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       Heating Water with Fire (2019)
        
       Author : ciconia
       Score  : 91 points
       Date   : 2021-04-19 08:19 UTC (1 days ago)
        
 (HTM) web link (www.homewoodstoves.co.nz)
 (TXT) w3m dump (www.homewoodstoves.co.nz)
        
       | Darmody wrote:
       | I 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 wrote:
         | Can you please share the URL or the channel's name?
        
           | throwaway3b03 wrote:
           | I assume it's this one:
           | https://www.youtube.com/user/HomewoodStoves/videos
        
       | tomrandle wrote:
       | I'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!
        
         | bacon_waffle wrote:
         | I 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.
        
         | xupybd wrote:
         | I 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.
        
         | [deleted]
        
         | zdragnar wrote:
         | I love the boiler we have, but it is an old pre-gassification
         | boiler amd simply is too inefficient. New boilers are way more
         | expensive than is worth it, so we have switched entirely to
         | high efficiency indoor wood and pellet stoves.
         | 
         | I miss the smell of the oak from the old boiler, but not the
         | smoke or absurd amount of wood we were going through.
        
       | jandrese wrote:
       | This 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 wrote:
         | > 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 wrote:
           | The 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 wrote:
             | These wood-burning ranges are not uncommon in the UK
             | 
             | https://www.google.com/search?q=wood+burning+aga&safe=activ
             | e...
        
           | jandrese wrote:
           | Nope, 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 wrote:
             | > 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.
             | 
             | Yeah that's the way many of these combined heater / oven
             | things work - the oven is literally on all the time.
             | Starting it up can take a full day.
        
               | jandrese wrote:
               | That seems rather inefficient, especially in the summer.
               | I also thought the lossy boilover system seemed less than
               | ideal, but I guess if it takes all day to get the heat
               | going you don't have good alternatives.
               | 
               | Maybe the small tank system would make sense for a
               | bachelor who is ok with taking a shower only at night
               | after cooking dinner. Maybe supplanted with a solar
               | thermal setup to keep the water at an elevated
               | temperature and only topped off with the stove?
               | 
               | I have to admit I thought to myself a few times while
               | reading the article: "Is this better than a solar array
               | and electric water heater?" I guess it has fewer failure
               | points, although a solar panel failure doesn't flood your
               | basement. If you are running a wood stove from trees you
               | chop down on your own land this could be very low cost
               | over the long term I guess. Solar is still fairly
               | expensive, especially if you add battery storage, but it
               | has been falling sharply in the past few years and the
               | price for these systems is basically fixed. At the end of
               | the day it's a decent chunk of custom plumbing and a
               | specially designed appliance. Traditionally that
               | combination would be fairly expensive and I wouldn't be
               | surprised if the price has been increasing slowly as the
               | plumbers who know how to do this retire and the wetback
               | stoves become even more specialty equipment.
        
       | mindslight wrote:
       | Why 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 wrote:
         | I'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.
        
       | jpollock wrote:
       | In 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
        
       | waltwalther wrote:
       | I 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.
        
       | mdoms wrote:
       | Wetback 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 wrote:
         | Same. 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.
        
       | DickingAround wrote:
       | I 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 wrote:
         | We'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.
        
           | bacon_waffle wrote:
           | > 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.
        
             | eliaspro wrote:
             | This is one of the greatest achievements of the Biomass
             | industry - marketing wood as "renewable" and "carbon
             | neutral".
             | 
             | First and foremost - at a time, when every bit of CO2 not
             | emitted counts, we should be happy about CO2 being fixated
             | in trees - once it's released, it doesn't matter whether
             | the it is coming from jet engines or wood - the effect on
             | climate change is the same. Furthermore, burning wood is
             | quite inefficient in terms of mass/energy gain - even worse
             | than coal.
             | 
             | But besides that, there are a lot of systematic effects
             | which make wood a non-neutral source of energy and making
             | use of it as energy source comes with a lot of issues. Even
             | if wood would be completely neutral, it would still be
             | negative due to the energy required to harvest, process and
             | transport it.
             | 
             | Trees don't only sequestrate carbon in wood, but also in
             | the forest soil through their roots. Decaying wood is
             | processed by microorganisms and mycelium in the soil, so
             | it's not only about the tree itself capturing CO2, but also
             | about it being part of a more complex sequestration system
             | which is disturbed by removing the tree.
             | 
             | Cutting down single trees from an otherwise intact forest
             | as part of a "sustainable forestry" strategy is actually
             | often quite problematic, as the sudden exposure to sun &
             | weather leads to decreased survival rates of fresh growth,
             | but also soil erosion and thereby CO2 release - not even
             | taking the damage of harvesting machinery etc. into
             | account.
             | 
             | Those "wounded" forests decrease the Earth's Albedo which
             | also adds to climate change.
             | 
             | Last but not least are forests not simply something that
             | can be "renewed" by replanting trees, but are extremly
             | complex ecosystems which might take millenia to build up.
             | 
             | Right now, we're cutting down massive amounts of old growth
             | around the world which can never be properly restored -
             | we're far from managing wood like a crop on designated
             | "farms".
             | 
             | With technologies available like Passivhaus construction,
             | heatpumps, solar and/or geothermal energy, there's zero
             | reason to add to our systemic issues by using wood as an
             | energy source.
             | 
             | When it comes to particle and toxic emissions, there isn't
             | a single non-industrial wood burner that would only come
             | close to the emissions of a gas or oil furnace (not saying
             | they're good, as they're using fossil fuels). The best even
             | modern filters will get you is still worse by factor of
             | ~400-500 compared to oil.
        
               | alamortsubite wrote:
               | People aren't cutting down live trees to burn in their
               | wood stoves.
        
             | BurningFrog wrote:
             | Wood is a renewable and carbon neutral energy source.
             | 
             | OP is right that it's dirty as hell, by modern standards.
        
               | rmah wrote:
               | Burning wood is only carbon neutral if you plant and grow
               | trees to replace the ones you burnt. It surprises many
               | people just how many trees need to be grown to heat a
               | single home for a year.
        
               | alamortsubite wrote:
               | Is that true? Firewood comes from downed/dead trees
               | (unless a tree is felled for some other reason). I
               | thought the same amount of carbon was released whether a
               | dead tree rotted on the ground or was burned for heating.
        
           | JshWright wrote:
           | Burning 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".
        
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       (page generated 2021-04-20 23:01 UTC)