Hacker News Reader

Comment by bicebird | Hacker News Reader

I was thinking of ways to get around the peak solar generation being when you don't need it for heating and genuinely really heartening to hear about solutions like this.

The article doesn't mention the costs or complexity in building each unit but definitely implies it's cheaper than storing it batteries, which makes sense if it's essentially a heating element buried in sand.

Wonder what the smallest viable size would be, could you have one for each street / block of flats? One of the comments mentions burying them for better insulation which I'm assuming they didn't want to do just for the prototypes?

View on HN

>The article doesn't mention the costs or complexity in building each unit but definitely implies it's cheaper than storing it batteries, which makes sense if it's essentially a heating element buried in sand.

Batteries are more expensive than nuclear power so yes, anything else is better.

The issue is that we can't both electrify everything and use legacy heating applications. Going back the the 20th century idea of central heating/cooling is great until you realize the costs involved with adding all the plumbing to buildings which were never designed with it in mind.

Peak solar is peak A/C usage in the summer, which is typically more expensive than heating. In colder times more energy is used at night, but I think less energy is still used at night in the winter than in the day in summer.

That does not seem right.

A hot day in summer might be 35C->20C (95F->68F). Winter is going to be more like -10C->20C (15F->68F) twice the temperature gradient to overcome.

That does not seem right.

-10С to +20C .. I can't even think of a place with such a swing.

Harsh continental climate winter is maybe -30C to -20C or so.

he's saying that you need to get the temperature to 20 from -10.

Ah. My bad.

Still, if you got this kind of temperature gradients, and I happen to have lived in such a place, you also got at least 100mm mineral wool insulation or eqivalent. Which is poor by the way, and people do invest into 200 or sometimes 300mm. Which makes CO2 and moisture control more of a problem than heating. You basically either heat the outside via ventilation anyway, or invest into heat exchangers. Since complex HVAC systems come with maintenance burden, people just put up 50-100KW-ish heaters, be it natgas or wood and declare the problem fixed.

You could be right, insulation is a lot more effective at keeping houses warm than cold though (greenhouse effect) and heat pumps can dump their waste heat inside.

Using the term "energy" here is suboptimal because it's mixing grid electricity with gas power.

A/C tends to be powered from electrical grid. Heat is often from propane or fracked gas.

More energy overall is used to heat homes in cold climates, but cooling homes in hot climates creates the challenging grid demand.

Reply on news.ycombinator.com