Large-scale ‘sand battery’ goes online in Finland

Post by osigurdson » Thu, Jul 07, 2022, 5:22 AM UTC

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…

Post by pickup191 » Thu, Jul 07, 2022, 5:26 AM UTC

com2kid wrote: post #62

hedora wrote: post #54

Earlier quoted context omitted.

There’s a cheap ($20?) add on for our water heater that adds a conductivity sensor in the drip pan, and a shutoff valve on the inlet. There’s a slightly more expensive variant from another company that supposedly looks at flow for the whole house, and cuts water off due to slow leaks or burst pipes. I’m shocked that the water heater cutoff valve isn’t required by code. In contrast, plumbed drain lines for water tank…

> There’s a cheap ($20?) add on for our water heater that adds a conductivity sensor in the drip pan, and a shutoff valve on the inlet. Oh I know, they are awesome. They should come standard, and more people should know about them. It is one of those things I try to bring up in conversations at random, because holy crap the # of people I know who have had water damage from their water heating dramatically failing is…

Post by olau » Thu, Jul 07, 2022, 5:38 AM UTC

WalterBright wrote: post #113

tjmc wrote: post #101

Earlier quoted context omitted.

HVAC engineer here. At the residential level this is already achievable with hot water storage from either solar thermal and/or heat pumps. Plus you get to use the hot water (assuming you've sized the tank correctly!) Storing heat in rocks or sand doesn't make sense from a thermal efficiency standpoint unless the temperature is high and that isn't economically viable unless you have large volume storage - typically d…

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.

Post by KennyBlanken » Thu, Jul 07, 2022, 5:52 AM UTC

1123581321 wrote: post #97

com2kid wrote: post #40

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. 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…

Disagree with all of this. Hot water leaks are very rare. Water heater failure usually manifests as cold showers and a quick replacement unit from a plumber. Drain pan with a hose is a more reliable protection than a sensor. Sensors are much more likely to give annoying false positives than to prevent damage; you can see from Rheem discussion forums that they’re not appreciated.

Post by com2kid » Thu, Jul 07, 2022, 5:54 AM UTC

KennyBlanken wrote: post #137

1123581321 wrote: post #97

Earlier quoted context omitted.

Disagree with all of this. Hot water leaks are very rare. Water heater failure usually manifests as cold showers and a quick replacement unit from a plumber. Drain pan with a hose is a more reliable protection than a sensor. Sensors are much more likely to give annoying false positives than to prevent damage; you can see from Rheem discussion forums that they’re not appreciated.

Water heater failure is also easy to avoid by annual or seasonal flushing of any accumulated sediment and checking the anode. As long as the anode is replaced, the water heater should be fine. I would expect a large condo association's maintenance staff to be able to handle this sort of thing very easily.