[HN Gopher] Heat your house with a mechanical windmill ___________________________________________________________________ Heat your house with a mechanical windmill Author : solalf Score : 103 points Date : 2023-08-20 18:23 UTC (4 hours ago) (HTM) web link (solar.lowtechmagazine.com) (TXT) w3m dump (solar.lowtechmagazine.com) | realusername wrote: | > The Calorius type 37 - which had a rotor diameter of 5 meters | and a height of 9 meters - produced 3.5 kilowatt of heat at a | wind speed of 11 m/s (a strong breeze, Beaufort 6). This is | comparable to the heat output of the smallest electric boilers | for space heating | | Well, there you have it of why it's a relatively unknown tech | (that I also didn't know about). The heat produced is very small | for a house yet the blade still needs to be very high, making it | impractical on most houses. On top of that hot water transport on | long distances is a recent thing due to advancement of pipe tech | which made communal version of those impossible at the time. | usrusr wrote: | Wind is just not good at all scaling down, no clever trick on | the every use side or I the side of blade geometry will ever | change that. | seeknotfind wrote: | Essentially, it's more efficient to generate heat directly from a | windmill, than first turning it into electricity. | | That being said, porque no los dose. Efficient heat is great, but | you don't always need it. If you only use the electric generator | a few months a year, it may still be worth it, given you're | investing in a windmill. | bryanlarsen wrote: | Given that a heat pump can be a lot more than 100% efficient, | it's likely more efficient to generate electricity and then use | a heat pump to heat the house. | [deleted] | fancyfredbot wrote: | The article has a long section on using the windmill to | directly drive the compressor of a heat pump using a gearbox. | This is likely to be more efficient than converting to | electricity and then using that to run an electric | compressor. | toast0 wrote: | There's no reason you couldn't run the compressor of a heat | pump mechanically. Then the question becomes is it more | efficient to generate electricity to run a motor (or a linear | compressor, I suppose), or use a gearbox to change the | rotation speed. Plus or minus if you need mechanical air | movement in the conditioned space. | bluGill wrote: | The reason you don't want to do that is you need to store | the energy for times when the wind isn't blowing. | TeMPOraL wrote: | Energy storage doesn't require going through electricity | either; in fact, highest capacity storage systems are | mechanical - flywheels, lifting heavy objects high, or | pumping water up the hill. | LgWoodenBadger wrote: | Mechanical heat pumps are covered in the article. And for | the child response to yours, mechanisms for sourcing heat | for longer periods are also covered (e.g. 10k, 20k liter | tanks of warm water, hydraulic oil vs water as primary heat | transfer fluid) | detourdog wrote: | If one has a solar install already creating a diverse sources | of heat makes sense in the northern climates. | juujian wrote: | For a lot of folks in the Northern hemisphere, heating is the | largest share of domestic electricity consumption. Same for | offices. I would say there is great potential for this to | reduce electricity consumption, plus the hot water can be | stored without the loss at conversion that electricity has. | Rygian wrote: | The spelling that a Spaniard would consider correct is "?por | que no los dos?" and it would still be acceptable as "por que | no los dos?" | tedunangst wrote: | People posting porque on English forums are not trying to | communicate with Spaniards. | mschuster91 wrote: | > Renewable energy production is almost entirely aimed at the | generation of electricity. However, we use more energy in the | form of heat, which solar panels and wind turbines can produce | only indirectly and relatively inefficiently. A solar thermal | collector skips the conversion to electricity and supplies | renewable thermal energy in a direct and more efficient way. | | Ooof. What? The first paragraph and it's just utter bollocks. | Combine a solar panel or a wind turbine with a heat pump and | despite generation losses it will outperform _any_ thermal | collectors - there 's a reason these got virtually phased out! | | And on top of that: local windmills, that may work out on farms | in backwater rural towns with no grid worth calling it that, but | good luck getting a permit for windmills in anywhere else, and | when there's no wind you're straight out of luck whereas an | electric heat pump can always be powered from the grid, or in the | case of a massive power outage, from an on-site backup generator. | aziaziazi wrote: | > Combine a solar panel or a wind turbine with a heat pump | | Two studies did that and mechanical heat pumps win. Here's the | links from the blog post: | | https://elib.dlr.de/103317/1/20160224%20-%20Master%20Thesis_... | | https://www.sciencedirect.com/science/article/pii/S096014811... | mlyle wrote: | You're talking past each other. | | He responded to a statement in the article comparing solar | thermal collection with solar + heat pump. | | The article mostly talks about mechanical heat pumps, and you | leapt to that, talking past him. | | (I think both the article and him are not strictly correct: | solar thermal heating has a place but is not typically a | efficiency win). | ForHackernews wrote: | > but good luck getting a permit for windmills in anywhere else | | Just because silly bureaucracy exists doesn't mean something is | a bad idea. | IshKebab wrote: | For wind sure, but is that true for solar? Solar panels are max | 20% efficient and head pumps typically have a COP of 2-3, so | solar thermal only has to have an efficiency of around 50%. 1 | second googling tells me it is 70%. | | I think the real reason nobody does solar thermal is because | it's just so much less practical to deal with pipes and pumps | and heat reservoirs than wires and batteries. Also it is | useless in the summer when you don't need heating. | | Wind is always going to be niche for most people for obvious | reasons. | veb wrote: | I have seen these turbines within city limits (in NZ): | https://www.powerhousewind.co.nz/thinair-wind-turbine/ | apparently they make a lot less noise. I'm sure some | intelligent people will keep iterating on these technologies. | | They do an awesome solar+wind deal too: | https://www.powerhousewind.co.nz/powercrate/ | atoav wrote: | Having a black water tank on the roof for solar heated warm | water is not uncommon in southern Europe. | | Most camping showers work by the same principle. If you need | warm water and you have enough sunlight to warm it when you | need it, this is not a bad idea | beebeepka wrote: | > I think the real reason nobody does solar thermal is... | | You have a weird definition of nobody. They are not as | popular these days but do exist and are very useful. Don't | even that much sun to produce warm water | mschuster91 wrote: | > 1 second googling tells me it is 70%. | | ... at full sun visibility, that is. However, in winter where | it's cloudy, raining or, worse, there's snowpack on the | panel? Now it's at 0%, right when you actually need it the | most. | | So you have to have the solar heating system and a fallback | for winter/night, and the headaches of all that extra | pipework just don't make it worth the effort because all | you're going to get from it is a few hot showers during | summer. | Retric wrote: | Solar thermal still works with clouds and under light snow, | you might be thinking of concentrated solar but that's a | different story. | | Also, storing a few hundred kWh of heat in a hot water tank | is vastly cheaper than batteries. The real advantage of | solar thermal is it can scale so well, thus allowing the | benefit of a heated pool and later driveway without extreme | expense. An expanded mindset around heat being so cheap | means you can do things like warm an exterior patio for | chilly fall days etc etc. | falsaberN1 wrote: | Being from a ridiculously rainy region and having worked on | solar thermal, I can warrant you that while it's not as | functional when in bad conditions, it still works. | | Consider it's usually set as a setup combined with a | standard heating system (gas, electric...), and while there | are situations where it can't handle the full load | (absolutely horrible darker than night days) it'll always | reduce or nullify costs. And since installation and | maintenance are relatively cheap, it's always going to save | you some money on the long run. | | Also consider some areas can be really hot, but have very | cold water lines. I need to heat my water in summer despite | being above 40oC outside. Having solar negates that cost | entirely, giving you like 9 months where you spend nothing | in water heating. Considering how expensive gas/electric | has become in this country, it's quite the relief for a | wallet. | falsaberN1 wrote: | I worked on solar thermal for a while. It was even mandatory | to install in new buildings in my country for a while (before | all solar was forbidden for personal use until recently, | don't ask, I hated it too. Forced me to become a sysadmin | though, which was a good move). | | You can get pretty good efficiency with solar thermal panels | and indeed they are more near the 70% mark. Just a "black | paint" panel can get "decent" results and it's relatively | cheap. I remember back in the training days, our teacher just | held a metal pane, painted black, into the sun for a | demonstration. And got to 80oC in a few minutes. In January. | | They are not so useless in summer depending on where you | live. In my region, despite being tropical-tier hot, water | comes out really cold from the urban lines, so you always | need to use some gas for a heater (butane or city gas). | Having a solar thermal setup completely nullifies that | (admittedly not large, but existing) expense during summer | and reduces it during winter. Since many buildings here | already have it as a feature, it's a little expense reduction | which is always welcomed. | | I miss working on that field. | rescbr wrote: | > I think the real reason nobody does solar thermal is | because it's just so much less practical to deal with pipes | and pumps and heat reservoirs than wires and batteries. | | It very much depends where one is located. My parents' house, | in a subtropical climate region, has had solar thermal for | over 2 decades. Now they've also installed PV panels, but hot | water is still mainly solar thermal with electrical heating | as supplement. | | New houses also have dual setups like theirs. Solar thermal | collectors for hot water + PV for other electric usage and | selling the excess to the grid. | | > Also it is useless in the summer when you don't need | heating. | | You still do need some water heating in the summer. | littlestymaar wrote: | > there's a reason these got virtually phased out! | | Citation needed. In my country they sell very well nowadays so | they don't look as they've been phased out at all. And for good | reason IMHO: they are much more rustic than heat pumps and are | likely going to live for much longer than the later with | cheaper maintenance. | | Also, as heat can be stored pretty efficiently (and cheaply) | compared to electricity, the day/night intermittency isn't so | big of a deal. | jfim wrote: | That's pretty fascinating. I was looking at off grid setups in | Canada, but the issue there is that peak energy usage is during | winter, which is also the time of the year with the lowest | illumination and snow on solar panels. Having the ability to | generate heat that way would keep the more scarce electricity for | other uses that cannot use heat or mechanical energy as inputs. | AS37 wrote: | Interestingly, winter has the highest windspeed of all seasons, | summer the lowest. | morepork wrote: | Depends where you live, for us it tends to be more cold and | still in winter, but the warmer months are windier | ZeroGravitas wrote: | I always enjoy the articles on this site. | | I'd enjoy them a bit more if they didn't continually insinuate | stuff about modern renewables that they clearly know not to be | true due to the way they phrase it. | | If people leave your article with misconceptions about modern | renewables then that is a bad thing. | MengerSponge wrote: | Lovely, but heat pumps can easily top 300% efficiency. If your | electrical generation and transport is ~50% (which seems | shockingly bad), you get a _lot_ more heating from a heat pump | than from direct mechanical heating. | fancyfredbot wrote: | The article has a long section on using the windmill to | directly drive the compressor of a heat pump using a gearbox. | This is likely to be more efficient than converting to | electricity and then using that to run an electric compressor. | thfuran wrote: | Wouldn't 50% be outlandishly good for solar? I think even 25% | would be exceptional. | mechagodzilla wrote: | Electricity from solar panels on your roof is in the range of | 16-23% efficient, but there are no distribution losses. | Electricity from a coal plant or single-cycle natural gas plant | is ~30-40% efficient, and a combined-cycle natural gas plant | can reach up to 60% efficiency under ideal conditions, with an | additional 5% of produced electricity lost in distribution. | reliablereason wrote: | Seams more useful to generate electricity and use the waste heat | that comes out of the inefficiency of the electricity generation. | | Electricity is a far more useful energy type. | nottorp wrote: | For one this article is wonderfully out of season <wipes | sweat>. | | If you generated electricity you'd be able to also use it for | cooling. | | For two... how much land do you need to have for a 8 meter | windmill and a reservoir with 20 tons of water? Looks out of | the question even with detached house suburbs. | _Microft wrote: | Especially when combined with a heatpump that can move a | multiple of the input energy as heat. | was_a_dev wrote: | Driving a heat pump mechanically with a microhydro system would | be interesting. | | More consistent energy output paired with easy storage. | Gys wrote: | No idea how I can see the contents of this article. I see the | title and a big yellowish area below for comments and signing up. | Maybe because I use Firefox? | drcongo wrote: | Working in Firefox here, though I am using NextDNS for blocking | a lot of annoyances and trackers. | drcongo wrote: | Readers in the UK might like to know you will almost certainly | need planning permission to put one of those in your garden, and | your neighbours will probably never speak to you again. The | latter could be seen as a benefit for some. | brightlancer wrote: | Most incorporated places in the US (city, town, village, etc) | will require permission from the local government to put up a | windmill/ wind turbine; even when it's not required, local | governments find ways to punish legal behavior they don't like. | | In rural and unincorporated areas in the US, folks would likely | be OK. | [deleted] | SoftTalker wrote: | Where I live, there isn't a lot of wind on cold winter nights. | The air tends to be very still in fact. I would not want to rely | on wind for my heat. | actionfromafar wrote: | A large tank, like the huge ones for heating oil in some old | houses, would probably go a long way. | bbojan wrote: | Or generate electricity to run a heat pump for 2 to 3 times more | heat generated than what you get from frictional heating form a | windmill. | aziaziazi wrote: | This method has the drawback to loose energy (with heat!) to | convert motion (windmill) to electricity, and then electricity | back to motion (heat pump stator). This post talks about the | idea of _mechanical heat pumps_ to avoid those losses and cite | two papers that back his claims. | | We shall not be blind on the many avantages of electricity but | on a pure efficiency scale converting motion to heat is a | better idea than motion to (electricity and heat) to (motion | and heat) to heat. | _Microft wrote: | How (im)practical would it be to directly drive the compressor of | a heatpump by a source of mechanical energy? | | For some reason I am almost expecting jacquesm to show up with | some first-hand knowledge ;) | | Edit: there is a section on this the end of the article. | userbinator wrote: | You'd need a system with an open-drive compressor (like | automotive A/C or very early fridges), and a rather high gear | increasion, but it's certainly possible. Imagine something like | this with the motor replaced by the windmill: | | https://www.youtube.com/watch?v=ViO3Xky3nYE | thsksbd wrote: | Boiling water through friction requires seals [1] , and rubber | seals are pretty hard (not impossible) to make low tech. | | The lowest tech solution IMHO is a squirrel cage generator and | ohmic resistors. No magnets or fancy electronics are needed. Just | remnant magnetization of soft iron and some copper wire/tube. | | [1] a demo doesn't need seals, but a heating solution that will | work for ten years will. | aziaziazi wrote: | > seals | | Are they also required bellow boiling temp ? You probably don't | need much more than 55C at home. Increase the temp to store | more energy and use a thermal expending socket to stop heat | production before boiling temp. | | > ohmic resistors | | Isn't it similar to the eddy current generator he talk about ? | http://www.bulipi-eee.tuiasi.ro/archive/2013/fasc.4/p12_f4_2... | lostlogin wrote: | So many neat articles on that site - the obsolete section is | particularly great. | | https://solar.lowtechmagazine.com/obsolete-technology/ | jv0010 wrote: | well while we are on the topic of heating i am still surprised | 'data furnaces' have not been adopted more. | | https://en.wikipedia.org/wiki/Data_furnace | FriedPickles wrote: | Very cool. I wonder if there's an even simpler geometry that | chokes the flow of the air and uses the heat at the construction. | May need to be very large, but it could be an architectural | thing. | borh375 wrote: | > windmill can not only provide mechanical energy, but also | thermal energy. The problem is that almost nobody knows this. | | It can also provide A/C to cool a house then. The problem is that | almost nobody knows this, except Einstein of course | https://en.m.wikipedia.org/wiki/Einstein_refrigerator ___________________________________________________________________ (page generated 2023-08-20 23:00 UTC)