6 ms·
> Freeze water in the cellar (speaking of like 30m^3) using thermal pomp during winter to heat house and when electricity costs little, and use that ice in summ
by mabbo 5y ago
> Freeze water in the cellar (speaking of like 30m^3) using thermal pomp during winter to heat house and when electricity costs little, and use that ice in summer to cool down the house.
Unless I misunderstood, the Toronto Zoo has or had such a system setup for one or more of the food pavilions.
What's interesting about this is that the storage grows with the volume (n^3), but the heat/cold loss grows with the surface area (n^2). So you're ability to 'store cold' gets better as you get bigger.
Just the same, you could also use it backwards in the winter time. On hot, sunny days at the end of the summer, warm up the water stored.
- bombcar 5y agoThe cube/square law also applies in the opposite direction, this is why it takes longer for lakes to freeze and why the Great Lakes never do. I believe at least one university on the Great Lakes does heating and cooling with pipes deep under the lake.
- frosted-flakes 5y agoThe Great Lakes do occasionally freeze over significantly, though never completely. 2013-2014 was one such winter, when ice coverage reached 92% across all five lakes. That's quite unusual though. And the city of Toronto uses lake water for cooling. Heat from a downtown cooling loop is dumped into the city's drinking water supply, bringing the temperature up to around 13° from 6° (if I remember correctly).
- mabbo 5y agoNot just drinking water. The cool water is pumped into buildings to work as the air conditioner for a lot of the big buildings.
- deleted 5y ago[deleted]
- 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?
- treeman79 5y agoHow does this compare to hauling ice down from a local mountain lake? Feels like 0-18th century tech. Doesn’t mean it’s bad though.