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Heat your house with a mechanical windmill (2019)
- seeknotfind 3y agoEssentially, 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.
- Rygian 3y agoThe spelling that a Spaniard would consider correct is "¿por qué no los dos?" and it would still be acceptable as "por qué no los dos?"
- tedunangst 3y agoPeople posting porque on English forums are not trying to communicate with Spaniards.
- bryanlarsen 3y agoGiven 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.
- toast0 3y agoThere'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 3y agoThe reason you don't want to do that is you need to store the energy for times when the wind isn't blowing.
- TeMPOraL 3y agoEnergy 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.
- bluGill 3y agoTrue, but safety is a concern. Batteries are easiest for consumers to maintain safely. The failure modes of flywheels, lifting objects, or pumping water - when not properly maintained - are disastrous in ways that we mostly are not able to handle. Batteries start on fire, but we have fire codes and fire departments so your survival chances are reasonable. Batteries are also something that are available to consumers in a well engineered (well hopefully) package, while the others are a bit of a DIY hack. Electric implies you can connect to the grid and thus offload the whole concern to someone else for a small cost (this applies to the vast majority of us). In the end you need to consider all the trades offs. Once you do though, electric starts to look good just because of how flexible it is, even if others beat it in any one area.
- avhon1 3y agoFor periods of up to half a day or so, you could store that energy in the temperature of the building.
- LgWoodenBadger 3y agoMechanical 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 3y agoIf one has a solar install already creating a diverse sources of heat makes sense in the northern climates.
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- fancyfredbot 3y agoThe 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.
- fy20 3y agoAir source heat pumps (in heating mode) use the heat generated by the electric compressor so the conversion loses there are negligible. Mechanical gearboxes also generate heat, so you'd need to capture that too.
- juujian 3y agoFor 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.
- Gys 3y agoNo 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 3y agoReaders 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 3y agoMost 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.
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- blitzar 3y ago> your neighbours will probably never speak to you again I am ordering one right now.
- lostlogin 3y agoSo many neat articles on that site - the obsolete section is particularly great. https://solar.lowtechmagazine.com/obsolete-technology/ https://solar.lowtechmagazine.com/obsolete-technology/
- FriedPickles 3y agoVery 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.
- realusername 3y ago> 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 3y agoWind 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.
- jnsaff2 3y agoExactly this. In my local home energy generation group there are a lot of people thinking they are smart by getting wind generators from alibaba and then selling them because it’s really hard to get anything usable out of them. Someone working in the field told that anything below mast height of 30m is going to a toy at best.
- jfim 3y agoThat'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.
- ZeroGravitas 3y agoI 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 3y agoLovely, 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.
- thfuran 3y agoWouldn't 50% be outlandishly good for solar? I think even 25% would be exceptional.
- MengerSponge 3y agoYes, but this isn't solar. And to be a like-for-like comparison, we'd have to incorporate the lost/missed energy in the windmill's vanes.
- mechagodzilla 3y agoElectricity 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.
- MengerSponge 3y agoYes, and wind turbines are 20% to 40% efficient at converting wind into energy
- fancyfredbot 3y agoThe 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.
- MengerSponge 3y ago
- reliablereason 3y agoSeams 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 3y agoFor 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 3y agoEspecially when combined with a heatpump that can move a multiple of the input energy as heat.
- _Microft 3y agoHow (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.
- mr_toad 3y agoAren’t the air conditioning units in cars usually belt driven? I can imagine some post-apocalyptic scavenger rigging up an air-conditioning using using a windmill and car parts.
- userbinator 3y agoYou'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 https://www.youtube.com/watch?v=ViO3Xky3nYE
- mschuster91 3y ago> 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.
- IshKebab 3y agoFor 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.
- atoav 3y agoHaving 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
- Zarathustra30 3y agoI misread that as "(black water) tank" and got worried.
- thsksbd 3y agoBoiling 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 3y ago> 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_2013.pdf http://www.bulipi-eee.tuiasi.ro/archive/2013/fasc.4/p12_f4_2...
- thsksbd 3y agoIf the water is not boiling you're going to need a very large system (for natural convection) or a pump.
- Cerium 3y agoWe should be able to design the mixer fins and chamber such that it generates some pressure differential between the input and output ports.
- aziaziazi 3y agoDo the size of the system need to be that much larger for 95C compare to 100C ? In my understanding the post talk about methods that do not involve pressure. On top of that if you want more heat you may simply use a liquid switch higher boiling temp.
- thsksbd 3y agoYes because at 100C you can use phase change to transport water, which means you've built a primitive heat pipe. At 95C H transport is slow so heat will accumulate until it reaches 100. But then you have boiling and, w/out good seals water loss.
- bbojan 3y agoOr 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 3y agoThis 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.
- was_a_dev 3y agoDriving a heat pump mechanically with a microhydro system would be interesting. More consistent energy output paired with easy storage.
- SoftTalker 3y agoWhere 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 3y agoA large tank, like the huge ones for heating oil in some old houses, would probably go a long way.
- jv0010 3y agowell 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 https://en.wikipedia.org/wiki/Data_furnace
- borh375 3y ago> 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 https://en.m.wikipedia.org/wiki/Einstein_refrigerator
- Tade0 3y agoIf you prefer to go even lower tech, check out compost heating: https://www.happysprout.com/outdoor-living/compost-heating-greenhouse/ https://www.happysprout.com/outdoor-living/compost-heating-g... Unless you have pigs fed with swill, you'll easily produce enough compost to survive the winter in warmth.
- rgmerk 3y agoI get the appeal but there’s a reason commercial wind turbines are really big and located in optimal wind resources. In short, the capacity factor of small wind turbines in the places most people will choose to live is terrible. It may not be as satisfying but some combination of solar panels, batteries, and heat pumps (with the proviso that people in really cold climate either need to go ground based or have a backup) is going to work a hell of a lot better for anyone not living in the furious fifties.
- ensocode 3y agoLow Tech Magazine is a really inspiring page that I love to read, even if I am not particularly interested in windmills. Thanks a lot!
- elihu 3y ago> "A mechanical heat pump is simply a heat pump without the electric motor – instead, the wind rotor is directly connected to the compressor(s) of the heat pump. This involves one less energy conversion, which makes the combination at least 10% more energy efficient than an electric heat pump driven by a wind turbine." Running a heat pump directly from a turbine is a really interesting idea, but they overlook the main benefit that heat pumps achieve well over 100% efficiency, if you're just measuring how many watts of energy it takes to produce some number of watts of heat. A reasonable setup might be to have a heat pump with an input shaft and a differential; one end goes to an electric motor, and the other end goes to a windmill. (Or a water wheel, or some other convenient source of rotational energy.) You could run the heat pump off the windmill, or if you don't need any more heat, the windmill can run into the motor as a generator. If you need heat and the wind isn't blowing, you can run the heat pump off the motor. That's probably a less practical setup than just using an electric generator windmill and an electric heat pump, but one could argue that's in some sense simpler or more elegant.
- 2rsf 3y agoCoincidentally I listened today to a podcast about direct water purification using wind turbines, the turbine is directly driving a water pump instead of going electricity->pump. For water the benefits are not so much about efficiency, direct mechanical systems are the same or less efficient, but about simplicity and cost- those systems can be deployed and maintained in remote and poor areas without a need for costly technicians and parts.
- 20after4 3y agoI wonder if a torque converter from an automobile transmission would make a good "off the shelf" joule machine. It would certainly work for producing heat from rotational motion but I wonder how it compares to using a water-based impeller.
- almostnormal 3y agoThere's a practically infinite amount of sun and wind available. The relevant metric for efficiency is not "heating done" over "sun or wind collected" but "heating possible" over "investment required". A simple solution can outperform a more complex one.
- eek2121 3y agoIt baffles me that (here in the US) we don’t take full advantage of the sun in newly built homes. Use the sun to heat water, generate electricity, etc. I rarely see newly constructed homes include solar panels, much less anything else. It seems like “every new home needs solar power” should be a thing.