| ▲ | actionfromafar 3 hours ago |
| This should scale up for heating a house at night, too. |
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| ▲ | gsf_emergency_6 3 hours ago | parent | next [-] |
| Yep! focussed light anything is a hassle really-- mirrors have to be maintained and positioned. For anything larger than a family, mirrors have to be unrealistically large.. There was a concentrated light power station in north of Vegas, but it bankrupted the company that built it. They didn't think about storage at the time https://en.wikipedia.org/wiki/Crescent_Dunes_Solar_Energy_Pr... >As of 2023, it is operated by its new owner, Vinci SA, and in a new contract with NV Energy, it now supplies solar energy _at night only_, drawing on [molten salt] thermal energy stored each day. |
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| ▲ | dagss 3 hours ago | parent | prev | next [-] |
| In buildings with water heating this is already commonly done, accumulating heat in water tanks. Size of water tanks is dimensioned after how much heat you have to store. Electric heating with water heating is sometimes used in Northern Europe at least, often with a heat pump. Ultimate would be solar panels on the roof, heat pump to multiply the electricity 3x-5x and water tank storage to last 24 hours.... Never recoup the investment though.. |
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| ▲ | mrgaro 2 hours ago | parent | next [-] | | At least in Nordics (I'm from Finland) heat pumps are rapidly replacing other forms of heating. One can get a big enough heat pump for a 200m^2 house (including heating hot water) for around 10-15k, with a few thousand more for installation price. Adding 10-15kWp of solar panels to the roof is around 6k more. It's definitively a no-brainer as it will recoup the investment in 5-10 years. | |
| ▲ | actionfromafar 3 hours ago | parent | prev [-] | | Especially if panels continue to drop in price, a heat pump will just add needless complexity. | | |
| ▲ | thyristan an hour ago | parent [-] | | Depends on the location, but around here solar for heating is completely useless. In Germany (which is farther south than the nordics and gets far more sunlight), solar panels are already insufficient for heating half of the year. On a typical single-family home, you will get at most 10kW peak power solar on the roof, which you can reach in the summer months when there are no clouds. In winter, those 10kWp will generate at most 5kWh of energy per day. Which is a factor of 4 to 5 below the 20 to 30kWh per average day for heating (with generous insulation). The farther north you go, the worse this gets. Half of the nordics get essentially no sun at all in winter, and are quite a bit colder than Germany. So you need something other than the sun to heat your home in winter. A heat pump can double, maybe triple the solar energy you might get on sunny winter days, but that doesn't usually cut it. So you need grid electricity, wood or fossil fuels. And when electricity prices are as low as in the nordics (around or below 20ct/kWh), heat pumps are totally viable. Adding solar can be sensible for cooling in the summer months, and maybe a bit of hot water, and heating in late spring, early autumn. But for winter? Totally useless. And while you could do long-term storage, that will cost you several arms and legs, tons of space and a huge maintenance hassle. And if anything should go wrong with your storage, you have no heat all winter and better have an emergency plan... |
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| ▲ | kirab 3 hours ago | parent | prev [-] |
| It even scales up to a whole town: https://polarnightenergy.com/news/worlds-largest-sand-batter... |
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| ▲ | trollbridge 3 hours ago | parent [-] | | For reasons I don’t understand, American cities seem allergic to installing new municipal steam or hot water utilities, even though things like cogeneration were an obvious use case for it, and now things like solar heat storage. | | |
| ▲ | thyristan 2 hours ago | parent | next [-] | | Steam and hot water pipes are extremely expensive to install, far worse than electricity, fibre, water or sewage. You need to be more leak-proof than cold water pipes, because loss of pressure with steam and hot water is much more of a problem than with cold water and cannot easily be solved by just adding more cheap water. Pipe materials have to be more resistant to corrosion because higher temperatures and pressures make them corrode so much faster than with cold water. Closed hot water/steam circuits also mean that there won't be a protective limescale coating on the inside. You need insulation that you can bury and which will last for at least 40 years, which is even more expensive than the pipes. And the insulation will double the pipe diameter. And the insulated pipes have a larger keepout area that needs to be kept free of rocks, other pipes and mechanical strain because the insulation is soft and sensitive to those things. Since usually the pipes aren't operated in summer, and since generally thermal variance is far higher than with cold water, thermal expansion needs to be taken into account, so you need expansion corners, sliding sections, different valve constructions that are tight in all temperatures, etc. And even with perfect insulation, you will loose approximately 30 to 40% of heat in your piping. So all of this is only viable if you don't care about the cost of the heat, your consumers can (be forced to or persuaded to) accept at least 30% higher prices per kWh compared to their local boiler, not to mention the capital cost. There are only some areas in Europe even, where those kinds of installations take place: Densely packed inner cities with largely rented-out flats in appartment buildings. There, the landlords/owners avoid the cost and risk of a local boiler and don't care about the running cost of heat, because they don't pay for it. In smaller towns, like in the example, mostly public buildings like schools use those kinds of district heating systems, because the municipality doesn't care as much about cost of the heat, and more about cost of maintenance of a hundred local boilers vs. one centralized system. And in the end, it's taxpayers' money, so they don't actually care that much, headlines and opening ceremonies are more important than that. Individual home owners usually do have their local systems, which can be run cheaper than what district heating will charge you. And since city density is lower and home ownership is more widespread in the US, district heating is even less competitive there. | | |
| ▲ | adgjlsfhk1 2 hours ago | parent [-] | | lots of industrial processes produce waste heat that can't easily be turned into energy, so the comparison isn't to a boiler, but to not having the heat. | | |
| ▲ | thyristan 2 hours ago | parent [-] | | It is true that the heat can be used if it is there anyways. But usually not in a big city-wide network. Instead a more localized, larger consumer is far better, because running the hot water network is far too expensive. For example, large producers of heat like data centers, dairy processing or chemical plants around here deliver their heat to public swimming pools, schools or greenhouses that are intentionally built nearby. Even the grandparent's article says so if you read carefully: "A large portion of the town’s own buildings, including the municipal school, town hall, and library, are connected to the district heating network.". They didn't even attach all of the public buildings. Not to mention about the rest of the town. |
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| ▲ | quickthrowman 38 minutes ago | parent | prev | next [-] | | There are district heating and cooling in cities where it makes sense, both Minneapolis and St Paul, plus the University of Minnesota all have district heating and district cooling systems. The Minneapolis and U of M systems are operated by Cordia Energy and the St Paul system is operated by Evergreen Energy. This is the coldest large metro area in the lower 48 states, so it’s economical to do district heating and cooling here. | |
| ▲ | blitzar 2 hours ago | parent | prev [-] | | It sounds like communism / socialism / marxism to people that are unable to define what those things are. |
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