3 ms·
> On hot, sunny days at the end of the summer, warm up the water stored. Phase change stores/requires much more energy than simple temperature change. 0°C Ice
by SECProto 5y ago
> On hot, sunny days at the end of the summer, warm up the water stored.
Phase change stores/requires much more energy than simple temperature change. 0°C Ice to 0°C water transition is 334J/g, 0C water to 100C water is ~400J/g (ie 4J/g per degree C), 100C water to 100C steam is 2260J/g.
To store heat from the summer for winter warming (say best case 40C summer temp) you'd be looking at least 3x as much material for heat storage vs ice storage for summer cooling (at say -10C)
- xvedejas 5y agoThis is a useful thing: storing energy in a phase change makes it easier to keep the energy stored for a longer period of time compared to if there was no phase change. The difficult part is that steam is much farther from ambient temperatures than ice is (and also that it is far less compact). Newton's law of cooling means that the larger the temperature difference, the faster the heat loss, so steam would require much more insulation than ice would.
- sacrosancty 5y agoBesides insulation, there's no hope of storing thermal energy as steam because the density is 1000 times lower than ice or water while the specific heat is similar, so the heat capacity per unit volume is about 1000 times lower.
- SECProto 5y agoStoring heat as steam is actually very good and efficient - as long as you're storing the heat for location shifting, not temporal shifting. It's regularly used in combined heat + power plants (Yeah, I know I'm being both pedantic and off topic, since the discussion here is specifically about seasonal storage)
- sacrosancty 5y agoDoesn't the word "storing" already mean temporal shifting?