In Finland in summer you can have around 20 hours of sunlight per day, so there's a lot of energy free for the taking. But could this tech work affordably at th

In Finland in summer you can have around 20 hours of sunlight per day, so there's a lot of energy free for the taking. But could this tech work affordably at the level of individual properties (homes, apartment blocks) ? Could it be scaled down ? And well, if you can have a heat battery then why not a cold battery too ? Winter cold spells in southern Finland can hang at around -20C (subzero F), so you could store that for summer use. Years ago there was a meme that when Helsinki's snow removal created giant piles of the stuff ("lumikasat"), sometimes a pile lasted thru the summer - greatly diminished, but extant. It was a fun meme but then it disappeared from the mediascape: maybe the city thought it was bad PR for tourism.