Because of their simplicity solar-cell based systems have become lower-cost and easier to install and maintain for water heating as panel + electric water heater, vs a piped direct solar thermal heating system. Higher "efficiency" for the direct thermal system, but overall system costs are lower for panel + heat.
I still love seeing the interplay with different combinations of physical systems and clever things humans figure out. Including with solar panels + other system items.
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
>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.
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..
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.
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.
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.
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.
I was expecting some sort of cool focused-light cooker like a solar oven, but it's basically just an electric cooker powered by solar cells.
Because of their simplicity solar-cell based systems have become lower-cost and easier to install and maintain for water heating as panel + electric water heater, vs a piped direct solar thermal heating system. Higher "efficiency" for the direct thermal system, but overall system costs are lower for panel + heat.
I still love seeing the interplay with different combinations of physical systems and clever things humans figure out. Including with solar panels + other system items.
This should scale up for heating a house at night, too.
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.
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..
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.
Especially if panels continue to drop in price, a heat pump will just add needless complexity.
It even scales up to a whole town: https://polarnightenergy.com/news/worlds-largest-sand-batter...
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.
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.
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.