I’ve been really curious about the possibility of a small DIY sand battery type system. I currently store my “negative value” midday solar power by dumping it into a water tank and using it to feed my hydronic heating system.
However as we know that results in a tank containing useless low-grade heat on a cloudy day, where a sand battery would result in a small amount of usable high-grade heat.
The cooling equivalent could actually be implemented fairly easily at home with common consumer ice machines (which are effectively heat pumps). Make ice when there’s surplus, dump it in an insulated hopper with a heat exchanger for night-time cooling, recycle the near-freezing melt water to make ice the next day. Water is a lot easier to handle because it can be pumped instead of conveyed, and you get the advantage of phase change storage.
I have been running the numbers on one myself and it seems to me the best case would be to actually have one inside my home, since the waste heat will also end up heating the space. I admit it is similar to just having a lot of thermal mass in the house.
I’ve been really curious about the possibility of a small DIY sand battery type system. I currently store my “negative value” midday solar power by dumping it into a water tank and using it to feed my hydronic heating system.
However as we know that results in a tank containing useless low-grade heat on a cloudy day, where a sand battery would result in a small amount of usable high-grade heat.
The cooling equivalent could actually be implemented fairly easily at home with common consumer ice machines (which are effectively heat pumps). Make ice when there’s surplus, dump it in an insulated hopper with a heat exchanger for night-time cooling, recycle the near-freezing melt water to make ice the next day. Water is a lot easier to handle because it can be pumped instead of conveyed, and you get the advantage of phase change storage.
I have been running the numbers on one myself and it seems to me the best case would be to actually have one inside my home, since the waste heat will also end up heating the space. I admit it is similar to just having a lot of thermal mass in the house.