Finnish City Inaugurates 1 MW/100 MWh Sand Battery
cleantechnica.com
Finnish City Inaugurates 1 MW/100 MWh Sand Battery
1–10 of 190 posts
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#2Very interesting. Did anyone find a ROI calculation?
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#3So, a gigantic sauna heater? Very on brand Tommi and Markku!
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#4It doesn't list the advantages over water, which seems the most common in https://en.wikipedia.org/wiki/Thermal_energy_storage systems.
You'd think water would be easier to exchange heat with since it can slosh around the heat exchanger elements in the tank more easily. Which should translate to lower costs since you don't need as many exchanger structures in the medium.
Any guesses for the motivation in using sand? Maybe it's that you can heat it over 100C? But then big heat differences to the environment mean high conductive/radiation losses or heavier insulation requirements.
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#5It doesn't list the advantages over water, which seems the most common in https://en.wikipedia.org/wiki/Thermal_energy_storage systems. You'd think water would be easier to exchange heat with since it can slosh around the heat exchanger elements in the tank more easily. Which should translate to lower costs since you don't need as many exchanger structures in the medium. Any guesses for the motivation in using sand?…
For this specific use case, you need to heat to far above the boiling point of water to retain some thermal efficiency. Sand/rock is better suited for storing the thermal energy at ~500 celcius.
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#6It doesn't list the advantages over water, which seems the most common in https://en.wikipedia.org/wiki/Thermal_energy_storage systems. You'd think water would be easier to exchange heat with since it can slosh around the heat exchanger elements in the tank more easily. Which should translate to lower costs since you don't need as many exchanger structures in the medium. Any guesses for the motivation in using sand?…
The article mentions that they heat the sand to 500°C, which is not possible with water (well, at least not without turning into steam along the way).
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#7It doesn't list the advantages over water, which seems the most common in https://en.wikipedia.org/wiki/Thermal_energy_storage systems. You'd think water would be easier to exchange heat with since it can slosh around the heat exchanger elements in the tank more easily. Which should translate to lower costs since you don't need as many exchanger structures in the medium. Any guesses for the motivation in using sand?…
perhaps sand is easier to heat to higher temps, and also it's less thermally conductive, so you'd lose less heat in storage for the same sized container.
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#8Helsinki did the same thing but storing the energy in water instead of sand:
https://helsinkismart.fi/worlds-largest-cavern-thermal-energ...
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#9It doesn't list the advantages over water, which seems the most common in https://en.wikipedia.org/wiki/Thermal_energy_storage systems. You'd think water would be easier to exchange heat with since it can slosh around the heat exchanger elements in the tank more easily. Which should translate to lower costs since you don't need as many exchanger structures in the medium. Any guesses for the motivation in using sand?…
The Wikipedia article says:
"Rock, sand and concrete has a heat capacity about one third of water's. On the other hand, concrete can be heated to much higher temperatures (1200 °C) by for example electrical heating and therefore has a much higher overall volumetric capacity."
and
"Polar Night Energy installed a thermal battery in Finland that stores heat in a mass of sand. It was expected to reduce carbon emissions from the local heating network by as much as 70%. It is about 42 ft (13 m) tall and 50 ft (15 m) wide. It can store 100 MWh, with a round trip efficiency of 90%. Temperatures reach 1,112 ºF (600 ºC). The heat transfer medium is air, which can reach temperatures of 752 ºF (400 ºC) – can produce steam for industrial processes, or it can supply district heating using a heat exchanger."
Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery
#10For anyone interested in a breakdown of the basic logic, this recent blogpost that trended on HN is probably the best: https://austinvernon.site/blog/standardthermal.html
Really interested in seeing how it fares in reality, almost sounds too good to be true.