7 ms·
Why have I never heard of the Ene-Farm? (2017)
- api 4y agoI've always been surprised that nobody has done home cogeneration for heat and hot water. Seems like an absolute no-brainer way to get a lot more mileage out of gas.
- Jtsummers 4y agoYou can get boilers that generate steam for radiators and hot water for tap water.
- yetanotherloser 4y agoGenuine, this-never-occurred-to-me question: are there lots of people out there with boilers that DON'T do this, or areas where it is not normal? If so - this might explain something that's been mildly irritating me. When looking for alternatives to fuel-burning boilers it seems easy to find positive stories about space heating - and much less info on water heating, to the point where it's starting to look like maybe some of these options might not be great. Water heating is my largest home energy usage and space heating very little because it is grossly overrated; if you are not really unwell an indoor temperature around 10 c is quite pleasant, so I tore my (rubbish) radiators out in 2017 and never looked back. This is making it surprisingly hard to figure out what replaces the boiler. If the marketing is aimed at pure heating boiler replacers, this difficulty is at least easier understood if not easier solved.
- projektfu 4y agoHeat-pump water heater: https://www.ecohome.net/guides/2197/heat-pump-water-heater-with-exterior-compressor/ https://www.ecohome.net/guides/2197/heat-pump-water-heater-w... I would personally not like to live in 10°C but I prefer hot climates. 15°C I could do. How do you keep the temperature above 10°C? Or is the outside temp rarely below 10°C?
- yetanotherloser 4y agoThanks! that looks technically similar to the heat pumps aimed at space heating but a bit better - perhaps there's an efficiency in it being meant to do just one job? It looks like it (or its ilk) might be a good fit for me. Outside wobbles around -2 to 8 in winter here, inside rarely less than 6, which is nippy but not dangerous. A not very insulated house with solid walls (this one's from about 1890 and has only had the easy things done) doesn't really sink to outside temperature if you live in it, cook, have appliances etc. There are plenty of heat inputs, just they do another job first. Hence my interest in water heat, I think it would start to be grim without it. Stove for a small number of really cold evenings, plus visitors. It would be a really bad idea to use it all the time but it would be hard to fit a radiator-type system to the job of "one hot room occasionally".
- ZeroGravitas 4y agoMore generic info on heat pumps for water: https://www.energy.gov/energysaver/heat-pump-water-heaters https://www.energy.gov/energysaver/heat-pump-water-heaters But I think the general assumption is that if you live in a cold place, you'd heat water and your home at the same time so you're a bit of an outlier. Many of them make reference to cooling the air at the same time as heating the water, which makes sense if you love in a warmer climate.
- chrisdew 4y agoHow do you avoid condensation on walls and mould problems?
- masklinn 4y agoWhy would you have "condensation on walls and mould problems"? The heating circuit is a closed loop.
- yetanotherloser 4y agoI think he's asking about the common trap people seem to fall into where, trying to keep heat in, they shut down air changes too far. Human breath puts a surprising amount of moisture into the air, and cooking can too. If you let that build up and have a cold wall it can build up a film of damp very quickly and if it's left damp and cool it can encourage mould. That kind of bad air quality is far worse than a bit of a chill.
- yetanotherloser 4y agoDraughts :-) It's an old place, it doesn't seal. That and sleeping in rooms with the window open just a crack as much as possible. Mould tends to hit when people obsessively seal everything up. I still have a condensation problem in a few specific places I have to keep an eye on. It's not general.
- masklinn 4y ago> Genuine, this-never-occurred-to-me question: are there lots of people out there with boilers that DON'T do this, or areas where it is not normal? I understand that american indoors heating is mostly done through HVAC. Since in that case the heater would be heating the air directly, you'd need a separate boiler. Heating water to heat the air makes sense when water is your transfer medium (e.g. hot water radiators), less so when the air is. So I expect US homes usually have separate air furnace and boiler, whereas in e.g. europe where water central heating is common you'd usually have a combined furnace/boiler.
- yetanotherloser 4y agoahh, makes sense, thanks.
- KiranRao0 4y agoIn Iceland, they cogenerate hot water and power due to the abundance of geothermal. Not exactly a common case that's replicable everywhere, but mildly interesting.
- wffurr 4y agoI read about a Mitsubishi home gas cogeneration system many years ago (10 ish). I think they haven’t taken off because they are expensive, only suitable in certain climates, and significantly less efficient at producing electricity from gas than a recent model combined cycle gas power plant.
- api 4y agoEven if it were pitifully inefficient at making electricity it would still be better than just burning gas for heat, which wastes all of its thermodynamic work potential. Waste heat is still heat.
- digdugdirk 4y agoInteresting. It claims "95% combined heat and electrical efficiency". I'm assuming this number is comparing immediately after the electrical generation occurs (i.e. - this doesn't have any transmission losses, while the electrical grid does). Does anyone have any comments on the comparison in overall gas -> electrical output efficiency between large grid-scale natural gas plants and small natural gas generators like this one?
- jsmith45 4y agoGas power plants on the grid are pretty inefficient. Like a modern furnace they are pretty efficent at getting the heat energy out of the gas. However the efficiency of turning the heat into electricity is low. They get something like an average of 40% overall efficiency. The best gas turbine plants on the market can get about 60% efficiency max. If the power plants were able to provide the excess heat to nearby businesses and the like, they could be a lot more efficient overall, and there are some that have tried to do that, but transporting heat itself is not an easy thing to do efficiently, and many plants are things like peaker plants, which don't run consistently, making it even harder to sensibly use the "waste" heat in the nearby communities. Then there is the grid losses. Grid transmission loses 5 to 6% of the power in the US, making the grid 94-95% efficent.
- Schroedingersat 4y agoIf energy were a little more expensive you could have jerry can sized packs of sodium acetate or similar. But noone really wants to fill up their boot with jerry cans and burn $3 worth of fuel for $2 worth of low grade heat. I wonder if there is a better PCM or thermochemical battery that could be worth moving on a not-train somewhere? Something that beats ice but works at not-4-degrees. Lye is okay but still a bit shy.
- smartmic 4y agoWikipedia has some reasonable figures about Cogeneration fuel cells (Ene-Farm is one of those "MicroCHP" fuel cell systems for home usage[1]: > Co-generation systems can reach 85% efficiency (40–60% electric and the remainder as thermal).[5] Phosphoric-acid fuel cells (PAFC) comprise the largest segment of existing CHP products worldwide and can provide combined efficiencies close to 90% For the "95% […] efficiency", I guess they take the hydrogen heat input for calculation of efficiency. What I miss are the losses from conversion of natural gas to hydrogen. This has to be considered when comparing efficienies eg. with gas fired power plants. So when it comes to large-scale Combined Heat and Power plants [2], it depends. There are not only different types of power plants (coal fired, gas fired, etc.) but also the heating part varies (process steam, district heating, etc.). If you go thermodynamically strict, you would also have to consider the quality of heat (at which pressure & temperature level is the heat extracted). This is normally not considered in the standard efficiency formula. [1] https://en.wikipedia.org/wiki/Fuel_cell#Efficiency_of_leading_fuel_cell_types https://en.wikipedia.org/wiki/Fuel_cell#Efficiency_of_leadin... [2] https://en.wikipedia.org/wiki/Cogeneration https://en.wikipedia.org/wiki/Cogeneration
- arcticbull 4y ago> The most important is that the electricity is generated on site, so there are no losses in transmission. People really overestimate transmission losses. They averaged only 5% in the US between 2016 and 2020. [1] I believe if you wanted to run a power line from Boston to LA you'd only lose about 25%. [1] https://www.eia.gov/tools/faqs/faq.php?id=105&t=3 https://www.eia.gov/tools/faqs/faq.php?id=105&t=3
- pavon 4y agoIn addition, generating electricity in a large power plant is significantly more efficient than doing so on a small scale even after taking transmission loss into account. It looks like the primary advantage of a device like this is that you can make use of heat that would otherwise be waste.
- sidewndr46 4y agoWouldn't that only apply to fossil fuels? I would think the watts per square meter of any solar panel I buy is similar to that of one used in a solar farm. There is no micro nuclear to compare against obviously.
- Schroedingersat 4y agoprivate ones are often available as a little more efficient as the power/area and power/weight matters for things like RVs
- sidewndr46 4y agoActually thinking about it the conversion scheme (DC -> AC) used by the utility scale operator might be a bit more efficient. They'd care a bit more about getting that last 0.5% or 0.1% of gains than a residential customer.
- Schroedingersat 4y ago
- deleted 4y ago[deleted]
- bdcravens 4y agoSo it's basically a Generac? I know that those are mostly for backup, but my understanding that they are perfectly viable for longer term use. (though they would need occasional maintenance)
- NovemberWhiskey 4y agoIf you mean "is this a reciprocating piston engine with a generator that's plumbed for natural gas?" then no ... this is fuel-cell technology, not internal combustion.
- aaron695 4y ago
- Animats 4y agoPanasonic still has some product info.[1] Natural gas powered fuel cells are available from some gas companies.[2] Problems seem to be: * Runs at very high temperatures, around 1000C, which means materials problems. Also, high grade heat is nice, but not that useful for home applications. So actual sales of this technology are to businesses. * There's been recent work on catalysts to bring the needed temperature down to 500C or so.[3] That's easily managed; auto engines run that hot. The catalyst needs ruthenium, which is expensive, although cheaper than platinum. * Sulfur in natural gas messes up the process, although this can be overcome. General problem with fuel cells: they need clean input gases. * Apparently you get a lot of heat and a little electricity. This limits the usefulness. The gas company in the US which sells this services Maine and Vermont. A nice application for this would be a little unit to provide backup power for natural gas furnaces, so you could run the fans without external power. [1] https://www.panasonic.com/uk/corporate/sustainability/products-and-solutions/hydrogen-fuel-cells.html https://www.panasonic.com/uk/corporate/sustainability/produc... [2] https://www.eversource.com/content/ct-c/business/services/connect-to-gas/equipment-technology/natural-gas-powered-fuel-cells https://www.eversource.com/content/ct-c/business/services/co... [3] https://www.sciencedaily.com/releases/2018/10/181029130939.htm https://www.sciencedaily.com/releases/2018/10/181029130939.h...
- Schroedingersat 4y ago> Also, high grade heat is nice, but not that useful for home applications. So actual sales of this technology are to businesses. Haven't there been some recent improvements in TEGs that would allow you to harvest a bit more of the available work whilst reducing the output heat to something useful?
- mikewarot 4y agoYou could use this to power AND heat the cold side of a heat pump, possibly getting far more than the original heat output of the gas into a building in a cold climate that would normally be too cold for a heat pump.
- wishawa 4y agoWhy not heat the inside of the house directly? Having the heat go through a pump just results in more loss.
- mikewarot 4y agoA heat pump can use 1 watt of energy to pull in the same amount of heating from the outside as 2 or more watts of resistive heat. If the "waste heat" allows the intake not to freeze up on a heat pump, it would raise the efficiency of the heat pump, and it's quite possible that 1 BTU worth of natural gas could do the work of more than 5 if burned through a high-efficiency furnace.
- sidewndr46 4y agoThat's not how that works. A heat pump can be more efficient than normal heating in the absence of a heat gradient. If the outside of the house is colder than the inside, there is obviously no heat gradient to take advantage of. Thus a heat pump is a good choice. If you're using what ever this micro fuel cell thing the article tasks about which apparently produces incredibly high temperature heat, you just heat the house with that. It's already hotter than the ambient temperature of the house You can't just slap a heat pump into such a system and have it suddenly gain efficiency. Where would the energy be coming from?
- mikewarot 4y agoYou're assuming the amount of waste heat is greater than the heat required in the house, which could very well be true. I was assuming the heat required was far more than the waste heat output of the device.
- stevehawk 4y agoI'm not smart enough to know what's going on here. This is using solar power to help make hydrogen which is then using the hydrogen to create electricity? And then because of the heat generated it can also be used to heat a structure (to some degree)?
- legulere 4y agoSo it’s just a what we call in Germany Blockheizkraftwerk (literally a block heating power station) for Kraft-Wärme-Koppelung (Power heat coupling). They are very often used for district heating and were seen as the way forward for reducing CO2-emissions before the advent of renewables. It’s still a useful concept for biogas plants and trash incineration power stations. It makes sense though to have them more centrally as that increases electrical efficiency.
- Gravityloss 4y agoIt's called combined heat and power or CHP. Usually used in district heating on a larger scale. For example Helsinki gets some of its heat from the waste heat of coal electricity plants. The electricity produced is also of course used. There are a few plants and the hot water is piped underground to the district heating grid that spans the urban areas. Further away with sparse housing it doesn't make sense. Basically, a heat engine needs a high temperature difference to make electricity. After that, there is still a low temperature difference left (100 C). That's still ok for heating houses. There's a lot of discussion how do you calculate the efficiency or climate effects. You can say the heat is waste and free and no climate effect. Or then that it's 100% fossil. CHP is an alternative to heat pumps. If you use wind or solar, they don't produce waste heat so CHP is not usable. Nuclear on the other hand would be a great fit for CHP, and is used for that in Russia. The temperature in the district heating grid is higher than what heat pumps would prefer but they are still used to create district heat to reduce fossil fuel use.