41–50 of 106 posts
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Why they should use seawater? Fresh water is not in shortage in this region - yearly precipitation significantly exceeds evaporation.
To a first approximation, Finland is on average a swamp. Thousands and thousands of lakes everywhere.
This energy storage system near Helsinki, Finland operated by Helen ( https://en.wikipedia.org/wiki/Helen_Oy ) might be interesting for HN readers. Some facts from previous article ( https://www.helen.fi/en/news/2020/mustikkamaa ), not sure which one would've been better in url field: District heat is stored in two rock caverns in Mustikkamaa. The temperature of the water in the caverns varies between 50 and 90 °C. T…
This is a cool project, and I'm sure it has many benefits beyond just carbon savings. But 21,000 tonnes per year is surprisingly little in the scheme of things. Equivalent of about 150 or so long-haul 777 flights?
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I'm no physicist but I assume that you'd need to put a lot more energy into the system before the water starts boiling, so you wouldn't have to worry about it? If the energy would just be lost otherwise, you might as well go all the way to 100℃? That's at 1 atm, perhaps the water is a bit pressurized as well? A bit further down there's this confusing quote though: > District heat is stored in two rock caverns in Must…
+100°C (relative to some other temperature not clearly explained, probably the rock) vs 90°C absolute temperature.
This energy storage system near Helsinki, Finland operated by Helen ( https://en.wikipedia.org/wiki/Helen_Oy ) might be interesting for HN readers. Some facts from previous article ( https://www.helen.fi/en/news/2020/mustikkamaa ), not sure which one would've been better in url field: District heat is stored in two rock caverns in Mustikkamaa. The temperature of the water in the caverns varies between 50 and 90 °C. T…
This is a cool project, and I'm sure it has many benefits beyond just carbon savings. But 21,000 tonnes per year is surprisingly little in the scheme of things. Equivalent of about 150 or so long-haul 777 flights?
https://julkaisut.hel.fi/en/reports/environmental-report-202...
It looks like the emissions for the Helsinki area are 2,345 kt per year, so I guess 21 kt is only a small part of that.
Of course, no one project should be expected to solve everything! But it is depressing to see the scale of the problem.
Bonus points if one uses the waste heat from e.g. industrial plants to help heat up the water.
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Mustikamaa in Estonian :)
I've heard people joke that if a Finnish person just spends enough time in Estonia they start to understand it :)
Earlier quoted context omitted.
I'm no physicist but I assume that you'd need to put a lot more energy into the system before the water starts boiling, so you wouldn't have to worry about it? If the energy would just be lost otherwise, you might as well go all the way to 100℃? That's at 1 atm, perhaps the water is a bit pressurized as well? A bit further down there's this confusing quote though: > District heat is stored in two rock caverns in Must…
> "perhaps the water is a bit pressurized as well?" I suppose in such a large storage vessel, most of the water is naturally pressurised by its own weight. So most of it won't boil, even at 100°C, except right at the surface?