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Large-scale ‘sand battery’ goes online in Finland

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

#81

Post by pfdietz »

mikewarot wrote: post #9
pyrolistical wrote: post #5

Strange they heat the sand instead of moving it around like a pumped battery

Moving sand (an abrasive grit) around is challenging at room temperate, doing it at 1000°F (500-600°C) seems impossible. It makes far more sense not to subject things to that kind of abrasion, and just flow air or water/steam through it.

It's possible. NREL's ENDURING system does just that.

https://arpa-e.energy.gov/sites/default/files/2021-03/07%20D...

Quick stats: stores heat in sand at 1200 C, round trip power->power efficiency of 54%, LCOS of $0.05/kWh for 100 hour storage. Heat is transferred from the sand to the gas for a Brayton cycle by direct contact in a fluidized bed heat exchanger. Babcock and Wilcox is expanding this now to the pilot stage under an exclusive license.

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

#82

Post by sbierwagen »

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.

Anode rods are consumable. Did you personally see the rod itself during the inspection?

They also don't repair damage. A really mean thing to do would be to replace the anode on a nearly-dead water heater right before selling a house. The minute the anode finishes rusting away, the heater could let go.

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

#83

Post by fy20 »

com2kid wrote: post #40
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…

> 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. So, 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. In a not-insane world, all hot water tanks would come wi…

Last year, one of the district heating pipes in my fairly new apartment block (7 years old) start leaking where it enters the building. Once discovered someone from the heating company came to turn off our supply, and then the next day they came to dig up the pavement outside and fix it.

On a side note, it seems like a very bad design choice to have that place be the room where all the electrical meters are. However even where there were large puddles of water over the floor it didn't cause any issues.

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

#84

Post by fy20 »

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 :)

That's only the case with really old apartments. I live in a fairly new apartment with district heating (7 years old) and each room has its own thermostat to control the underfloor heating.

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

#85

Post by tsol »

rcv wrote: post #65
O__________O wrote: post #57

Earlier quoted context omitted.

Read the Wikipedia page, might be missing something, but seems like the system works in summer and winter, but don’t see anything about summer production being used in the winter.

> The borehole thermal energy system (BTES) is located underground to store large quantities of heat collected in the summer to be used in the winter. Basically they heat up the soil and rock beneath their park during the summer using hot water/glycol from their solar arrays, and then during the winter they pump cold water through it which soaks that heat back up. What's amazing is that it apparently took 4 years to…

And there isn't a massive amount of heat loss with that? It's a cool idea, what surprises me is that it actually works

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

#86

Post by ggm »

tsol wrote: post #85
rcv wrote: post #65

Earlier quoted context omitted.

> The borehole thermal energy system (BTES) is located underground to store large quantities of heat collected in the summer to be used in the winter. Basically they heat up the soil and rock beneath their park during the summer using hot water/glycol from their solar arrays, and then during the winter they pump cold water through it which soaks that heat back up. What's amazing is that it apparently took 4 years to…

And there isn't a massive amount of heat loss with that? It's a cool idea, what surprises me is that it actually works

London Underground originally was kept cool because of its thermal mass. Over the last 100 years, it has now turned into a giant heat store, and there is an emerging airconditioning problem. I believe its the resistive heating from the trains passing through, over time, plus the sweaty exhalation of millions of people.

TL;DR ground heat is remarkably persisting and takes years to dissipate, if deep enough. Coolth, the absence of heat, is really the same in this regard, because the heat transport through the ground is not rapid.

This is also why deep hot rocks need fracking to get thermal energy working unless its happening naturally. Rocks all around the place "down there" are hot. Very hot. A lot of ground water comes out hot. Bath (uk) for instance. its hot. So how come the rest of bath is cold and wet? Because ground heat doesn't move fast.

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

#87

Post by [deleted] »

Retric wrote: post #79
barbazoo wrote: post #47

Earlier quoted context omitted.

> Optimal community size would be 200-300 homes to realize the economies of scale. The number of systems would remain the same; only the number of boreholes would need to increase Decentralized systems like this one are cheaper and faster to build so it makes sense that the number of households served is on the low end. That doesn't mean it's not useful tech.

It’s interesting. 7 million in support to supply 97% of annual heat for 52 homes isn’t that far off being reasonable for an early R&D project. An 80% price drop at modest scale, say 100 different 300 home subdivisions actually seems achievable. I think it’s largely a question of how dependent this is on local geology.

[deleted]

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

#88

Post by zajio1am »

ethagknight wrote: post #66
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.

For USA, district heating made sense in the coal power era. Today, why burn natural gas at a central plant and then have to manage a complex steam distribution network with associated losses when you can simply distribute natural gas instead and get 98% AFUE at the point of use? Even better is a heat pump with gas backup at point of use. Triumph of technology. Also, You dont really insulate the steam distribution pip…

District heating can use cogeneration in nearby power plant, so it essentially reuses waste heat from electricity production. There are even district heatings that use heat from nearby nuclear power plant.

Also note that modern systems does not use steam distribution, but high-pressure hot water distribution.

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

#89

Post by taeric »

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.

I've... Never had a problem that was catastrophic in my adult life. Only real issue we've ever had was someone hit the ac unit with their car.

Curious what sort of load you put on yours to have such terrible luck.

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

#90

Post by conk »

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.

Even just adding a little inuslation to a pipe will drop the heat loss down to a few watts/ft when dealing with a pretty large delta T. If you’re using 20k+ watts to heat a home the losses on the pipe are minimal. And I’m guessing these homes are all pretty close together. Not a mile apart.
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