101–110 of 181 posts
Sorry to a noob can someone explain this please. They are just heating up sand right?
I'm curious about "why sand", is it better at holding heat than say water?
Which means that you have rather little of delta to work with. And at upper end it becomes somewhat risky to have large container of water that is beyond boiling in normal pressure...
With sand you can use very simple heat-exchangers. No need to use exotic heat pumps that require extra energy...
Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate. https://www.youtube.com/watch?v=MB…
Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate. https://www.youtube.com/watch?v=MB…
Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate. https://www.youtube.com/watch?v=MB…
Doesn't this suffer the problem that you're then putting heat into the device, which is in your house, during the warm season when you want your house to stay cool?
In the hot summer the hot air within the house is cooled by heat pumping the heat into the water tank which is slowly over weeks bought up from cold to mean summer tempreture.
In the winter the heat is extracted from the water and transfered to the house.
The house and the water mass are out of phase by six months.
Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate. https://www.youtube.com/watch?v=MB…
Here's a smaller scale water battery that heats an entire house year round. The water tank itself is placed in the center of the house across all 3 floors and actually makes for a quite nice design element as well. The energy is generated in the warm seasons and the volume of water is large enough to last through the entire winter. It's a German vid but subtitles are quite accurate. https://www.youtube.com/watch?v=MB…
Doesn't this suffer the problem that you're then putting heat into the device, which is in your house, during the warm season when you want your house to stay cool?
Earlier quoted context omitted.
> I get that sand is inexpensive It depends where you are. Sand thieves are a thing in many places around the world. Here's a story from 2015 about how residents in one area have lost 25 hectares of land to sand thieves. https://tuoitrenews.vn/news/features/20150524/residents-losi... Or a police captain whose legs were severed while trying to apprehend sand thieves. https://www.vietnam.vn/en/dien-bien-moi-vu-dai-uy-c…
> The sand itself will also be sustainably sourced – it’ll consist of crushed soapstone, which is a manufacturing byproduct of another local industry. The requirement is not really construction grade sand but any substance with a largish thermal mass. Sand/dirt/crushed rock, etc. whatever you have right on your doorstep. There have been plenty of prototypes using such various materials as thermal mass. All you need i…
On a diy scale, there is also this system for passive greenhouse called a climate battery which uses the same principle, storing heat underground and using it in winter. With almost zero energy we can use it to grow bananas in a greenhouse in the Netherlands.
Earlier quoted context omitted.
Just because something seems like should work doesn't mean it will. Air conditioners are simple and cheap to install. An insulated swimming pool in the basement is not.
1 cubic meters of water chilled 10C below ambient is 40MegaJoules of energy. Or in other words: 11kW-hrs of cooling, comparable to an entire Tesla Powerwall. We aren't talking about entire swimming pools here. Just a few cubic meters of water. Shift the temperature delta as you see fit but... It's actually very space efficient.
Earlier quoted context omitted.
Water vaporizes, and at that point blows up just about every container you can build around it. As will ice when it cools down. Sand is just sand, very little difference, very unreactive from way under freezing temps to about 1300 degrees. And you might vent steam, but you should probably take into account that while water < 45 degrees or so is pretty innocent, steam will strip flesh from bone starting at 180 degrees…
That’s the other bizarre thing about water/ice: most things expand as you heat them, but very few things expand as you cool them. Water has maximum density at 4C, so even before you freeze it it’s already starting to expand as you cool it.