Large-scale ‘sand battery’ goes online in Finland • Hacker News Board

Re: Large-scale ‘sand battery’ goes online in Finland

#151

Post by NavinF » Thu, Jul 07, 2022, 6:10 AM UTC

com2kid wrote: post #60

pkaye wrote: post #48

Earlier quoted context omitted.

If they changed the anode rod on the water heater periodically it might last longer. Also the reality is that HVAC and water heater might need periodic inspections.

I was thankful, and shocked, the one year of my life that my HVAC system didn't break down in some fashion. Hot water heaters should have leak detectors on them. They often don't. The higher end models do. Product differentiation strikes again. Last water heater I had, the anode was A-OK, I had it checked about a year prior to the water heater failing. Thermal stress destroys stuff.

> one year of my life that my HVAC system didn't break down in some fashion

Something’s wrong here. I’ve only seen 1 partial failure (a refrigerant leak reduced efficiency by 5x, but the AC still worked) in the last 15 years across several houses. You’ve got an order of magnitude more failures.

Do you live on a boat? :P

Re: Large-scale ‘sand battery’ goes online in Finland

#152

Post by quickthrower2 » Thu, Jul 07, 2022, 6:11 AM UTC

thematrixturtle wrote: post #55

excitom wrote: post #43

> It has a particularly strong use case in Finland which sees long and very cold winters, and was recently cut off from Russian gas supplies over a payments dispute. Well I guess that's one way to characterize war-related sanctions and their side effects.

It's factual. The gas supplies in question were not covered by sanctions, but Russia tried to unilaterally switch to being paid in roubles and were told to go batter sand (bada bum tssh).

> war-related sanctions and their side effects.

Tick

Re: Large-scale ‘sand battery’ goes online in Finland

#153

Post by randunel » Thu, Jul 07, 2022, 6:13 AM UTC

lachstar-x wrote: post #147

karpierz wrote: post #74

Earlier quoted context omitted.

> Russia demanded payment on their terms only after they were kicked out of SWIFT and their reserves frozen by foreign banks. If only there was something Russia could do to stay in SWIFT and not be hit by sanctions....

Why stay in SWIFT when it's been demonstrated that they can be cut off from global supply on the whims of the US administration? That one decision did more for the death of the American empire than any other.

I don't think "whims" means what you think it does.

Re: Large-scale ‘sand battery’ goes online in Finland

#154

Post by halper » Thu, Jul 07, 2022, 6:13 AM UTC

TheSpiceIsLife wrote: post #67

pavon wrote: post #8

As an American it completely breaks my expectations that district heating not only works can be more efficient that decentralized heating. The amount of heat lost just moving water from the water heater on one side of the house to the shower on the other is ridiculously high in houses here. The idea that you can insulate well enough to efficiently move heat across a city is amazing to me.

Australian here. The idea that anything can be insulated at all is fucking novel . New construction has minimum standards these days, but that does nothing for the majority of older house which have single glazed window, iron roofs, and no insulation whatsoever and, if you're renting, lucky to have a heat pump. And yeah, no insulation on the hot water piping means massive loses from water heater to tap.

As a Swede, I've never been as cold as in Australia in winter! My Australian friends can't believe -20 degrees is survivable, but the thing is that our houses have a different temperature on the inside ;)

In Hobart I once lived in a place that had radiators. I made the mistake of keeping the place comfortable and it cost me $700 of cheap hydro power in a fortnight.

Re: Large-scale ‘sand battery’ goes online in Finland

#155

Post by WalterBright » Thu, Jul 07, 2022, 6:17 AM UTC

moistly wrote: post #148

WalterBright wrote: post #95

Earlier quoted context omitted.

> in America, it is very common for hot water tanks to suddenly fail, leaking water everywhere and causing massive amounts of property damage and even creating health hazards through mold. I've had them fail and leak many times. But I had the water heater put in the basement next to a floor drain, and the floor slopes slightly towards the drain. No damage whatsoever from leaks, and it wasn't an emergency to get it fi…

The BC Building Code mandates a floor pan under the HWH, draining into the wastewater system. The floor will be sloped as well, and the drain within X distance of the heater. I expect it’s a Canadian national standard.

The plumbers are always surprised to find my setup. It's the same for the washing machine, which has also saved me from very expensive water damage.

Re: Large-scale ‘sand battery’ goes online in Finland

#156

Post by WalterBright » Thu, Jul 07, 2022, 6:20 AM UTC

UkrainianJew wrote: post #142

WalterBright wrote: post #113

Earlier quoted context omitted.

How can it not be efficient? The heat to heat a rock is 100% recovered when the rock cools back down. A tank of water works, too, but tanks rust, mildew, and leak.

Heat keeps leaking out. The amount of stored heat is proportional to the cube of the linear size, the leak rate is proportional to the surface area (square of the linear size). Hence, the bigger the storage, the higher the efficiency. Same why a flea can jump >10x its height, and a human cannot (square growth of strength, cubic growth of weight).

Thanks for the answer. I suppose the answer is a decent insulation on the box. It only has to last for a few hours.

Of course, some engineering would have to go into optimizing the size of the rocks and the surface area / mass for the expected use.

Re: Large-scale ‘sand battery’ goes online in Finland

#157

Post by vesinisa » Thu, Jul 07, 2022, 6:23 AM UTC

dwighttk wrote: post #50

gamegoblin wrote: post #14

Earlier quoted context omitted.

Many American universities use district heating for the whole campus. Also, as made famous by the many steam vents in NYC movie shots: https://en.wikipedia.org/wiki/New_York_City_steam_system . More info: https://en.wikipedia.org/wiki/District_heating#United_States

As the first dorm on the loop my freshman year, I’d get back from crew practice, go into the bathroom, turn on all three showers, and flush the three toilets about three times each to flush all of the hot water out of the cold water line so that I wouldn’t burn myself when taking a shower. I never heard if anyone got hurt when I took a day off and slept in.

This is most unfortunate but in proper district heating systems the scalding hot district circulation water never touches your house's heating / warm water. A heat exchanger is employed to insulate the different circulation systems. For example, my house has district heating and the warm water side is capped at +65C to protect against burns.

It's still pretty damn hot of course but I've never had any problems like you described, and I've lived in a dozen different houses in my city - all with district heating. Probably the system in the dormitory was somehow badly designed or incorrectly tuned.

Re: Large-scale ‘sand battery’ goes online in Finland

#158

Post by Ekaros » Thu, Jul 07, 2022, 6:24 AM UTC

GekkePrutser wrote: post #71

konschubert wrote: post #15

Earlier quoted context omitted.

As a German living in a city with mandatory district heating... the end result is to be that people seem pay more for heating than they would with a decentralised system. I think that's mostly due to the high upkeep costs of the system, though, the transmission loss is quite manageable, I think. Of course there are arguments to be made that when accounting for the cost of installing a heating system, and the space it…

Yeah I'd hate having District heating. A friend had this in the past and she couldn't even regulate it. The house was way too hot for her. It would not work for me as I usually have the house around 16 degrees C in winter. Needless to say my energy bill is very low :)

It really shouldn't stop from regulating temperature. It is basically two heat exchangers. One for local central heating which is then controlled by what ever thermostats you have connected and one for hot water...

Ofc, it the thermostats used are bad there might be problems.

Re: Large-scale ‘sand battery’ goes online in Finland

#159

Post by fulafel » Thu, Jul 07, 2022, 6:25 AM UTC

pavon wrote: post #8

As an American it completely breaks my expectations that district heating not only works can be more efficient that decentralized heating. The amount of heat lost just moving water from the water heater on one side of the house to the shower on the other is ridiculously high in houses here. The idea that you can insulate well enough to efficiently move heat across a city is amazing to me.

Traditionally when using combustion plants the great advantage in nordic countries comes from CHP (combined heat and power), you can extract much more energy from the fuel this way vs having separate electricity and heat plants. But yep great insulation in the network is a requirement.

Re: Large-scale ‘sand battery’ goes online in Finland

#160

Post by WalterBright » Thu, Jul 07, 2022, 6:28 AM UTC

olau wrote: post #135

WalterBright wrote: post #113

Earlier quoted context omitted.

How can it not be efficient? The heat to heat a rock is 100% recovered when the rock cools back down. A tank of water works, too, but tanks rust, mildew, and leak.

I'm not an engineer, but I've been following the various rock storage projects, like this one https://www.stiesdal.com/storage/ for some time, and water tanks are simpler. When you set up a water tank, you just pump water into it to get the storage medium, and when you need to extract heat, you can pump out actual storage medium and do the heat exchange directly. With a rock storage, you either need pipes in them or…

Hot water heaters are always rusting and then leaking. Corrosion is always a problem with water and metal, along with sedimentation and the growth of slime.

With the box of rocks, yes you'll need to duct hot air in to heat them, and duct cool air in to extract the heat and blow it through the house. I don't know that this needs a beefy system, if you've got central air there is already most of the duct work in place.