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The humble water heater could be the savior of our energy infrastructure woes

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Re: The humble water heater could be the savior of our energy infrastructure woes

#41

Post by krrrh »

maxerickson wrote: post #32
temporallobe wrote: post #29

I have a tankless hot water heater system in my new home that runs on a city natural gas line. It’s super efficient and thus my energy bills are very low compared to what I used to pay for the traditional electric hot water heater in my previous home, however it’s not a silver bullet. I find myself running the water for a ridiculously long time in order for the water to start getting hot, sometimes for more than a mi…

The problem is the cool water in the pipes. A typical solution is recirculating the water so that it stays hot. (I have a gas tank heater and the faucets far away take a bit to warm up, because of the water in the pipes)

I had a friend who spent months measuring the power output of all his appliances and lights trying to figure out where half his electricity bill was going. He finally realized it was the hot water recirculator.

Re: The humble water heater could be the savior of our energy infrastructure woes

#42

Post by deviledeggs »

temporallobe wrote: post #29

I have a tankless hot water heater system in my new home that runs on a city natural gas line. It’s super efficient and thus my energy bills are very low compared to what I used to pay for the traditional electric hot water heater in my previous home, however it’s not a silver bullet. I find myself running the water for a ridiculously long time in order for the water to start getting hot, sometimes for more than a mi…

Heat pump water heaters mentioned in the article are better for efficiency. They typically use half the energy of a normal water heater.

And they cool the air around them, so if you live in a hot area they save more.

Re: The humble water heater could be the savior of our energy infrastructure woes

#43

Post by jhgb »

toomuchtodo wrote: post #6
cartoonworld wrote: post #4

Earlier quoted context omitted.

>A less-sophisticated approach is to put your tank heater on a timer. Think carefully before you do this. Do not do this without understanding the lifecycle of legionella pneumophila, or you will face a dramatic decrease in your quality of life. https://en.wikipedia.org/wiki/Legionnaires'_disease

Yeah, timer or grid controlled water heaters are old and busted (especially with bacteria concerns due to a lack of in tank convection). New hotness are heat pump water heaters that are very efficient and can even add cool air to a conditioned spaces by their inherent operation. Electric vehicle charging orchestrated as large aggregate loads are what replaces “the humble water heater.” Tankless heaters are great if y…

> timer or grid controlled water heaters are old and busted (especially with bacteria concerns due to a lack of in tank convection)

This is literally the first time I'm hearing of this as a concern. Our local recommendations are to keep tank temperature above 70C and you should be fine.

Re: The humble water heater could be the savior of our energy infrastructure woes

#44

Post by sgc »

analog31 wrote: post #34
maxerickson wrote: post #32

Earlier quoted context omitted.

The problem is the cool water in the pipes. A typical solution is recirculating the water so that it stays hot. (I have a gas tank heater and the faucets far away take a bit to warm up, because of the water in the pipes)

Are recirculating systems safe? Those have to be designed to prevent microbial build-up. I'm thinking of Legionnaire's disease.

They are not closed loop, they just push some water from the hot water line back down the cold line, where it will wind up back in the water heater and be used. They are no more prone to disease than you existing system.

Re: The humble water heater could be the savior of our energy infrastructure woes

#45

Post by elil17 »

Another type for thermal battery: ice thermal storage. Instead of running AC, it’s a freezer that makes ice during the night (using off-peak electricity and taking advantage of the cooler nighttime air) and then melts it during the day to cool large buildings. They’re a ridiculously good idea if you’re running a large enough HVAC system - they can even lower capital costs compared to traditional systems. Unfortunately, many building operators don’t use them because they’re unfamiliar with the technology or because they take up more building footprint. https://en.m.wikipedia.org/wiki/Ice_storage_air_conditioning

Re: The humble water heater could be the savior of our energy infrastructure woes

#46

Post by coryrc »

deviledeggs wrote: post #42
temporallobe wrote: post #29

I have a tankless hot water heater system in my new home that runs on a city natural gas line. It’s super efficient and thus my energy bills are very low compared to what I used to pay for the traditional electric hot water heater in my previous home, however it’s not a silver bullet. I find myself running the water for a ridiculously long time in order for the water to start getting hot, sometimes for more than a mi…

Heat pump water heaters mentioned in the article are better for efficiency. They typically use half the energy of a normal water heater. And they cool the air around them, so if you live in a hot area they save more.

And if you live in a cold area, you get no efficiency advantage, pay more, and probably eventually leak coolant with a GWP of 2088.

Re: The humble water heater could be the savior of our energy infrastructure woes

#47

Post by gnicholas »

krrrh wrote: post #41
maxerickson wrote: post #32

Earlier quoted context omitted.

The problem is the cool water in the pipes. A typical solution is recirculating the water so that it stays hot. (I have a gas tank heater and the faucets far away take a bit to warm up, because of the water in the pipes)

I had a friend who spent months measuring the power output of all his appliances and lights trying to figure out where half his electricity bill was going. He finally realized it was the hot water recirculator.

We have an under-sink unit that has hot water ready 24/7. After hooking it up, I noticed it increased our monthly bill by about $15.

I bought a used Wemo plug for $10 and set it to only be on for 3 hours in the morning and 3 hours at night. Now we have hot water at any of the times when we actually would want it, and we aren't wasting money/energy to keep hot water on tap 24/7.

Re: The humble water heater could be the savior of our energy infrastructure woes

#48

Post by toomuchtodo »

jhgb wrote: post #43
toomuchtodo wrote: post #6

Earlier quoted context omitted.

Yeah, timer or grid controlled water heaters are old and busted (especially with bacteria concerns due to a lack of in tank convection). New hotness are heat pump water heaters that are very efficient and can even add cool air to a conditioned spaces by their inherent operation. Electric vehicle charging orchestrated as large aggregate loads are what replaces “the humble water heater.” Tankless heaters are great if y…

> timer or grid controlled water heaters are old and busted (especially with bacteria concerns due to a lack of in tank convection) This is literally the first time I'm hearing of this as a concern. Our local recommendations are to keep tank temperature above 70C and you should be fine.

https://patents.justia.com/patent/20180290899 provides background on the topic. Keeping your hot water tank at or above 50-55C constantly is a reasonable mitigation, anything hotter can cause scalding.

Re: The humble water heater could be the savior of our energy infrastructure woes

#49

Post by perihelions »

Scoundreller wrote: post #22
s0rce wrote: post #18

Virtual battery, there is an interesting project to do a similar thing with aluminum smelters where you heat them and operate at full capacity off-peak and then during peak electricity usage you run slower. Since a smelter consumes so much power this can significantly level the grid usage.

My dream was that you would exchange a bin of bauxite for aluminum for your home smelter. All the "waste" heat goes into heating your home.

Not sure there's currently any sane way to put that into a house -- the industrial process involves a hydrogen fluoride loop. It's a interesting idea though.

https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_proc...

Re: The humble water heater could be the savior of our energy infrastructure woes

#50

Post by hyperpallium2 »

temporallobe wrote: post #29

I have a tankless hot water heater system in my new home that runs on a city natural gas line. It’s super efficient and thus my energy bills are very low compared to what I used to pay for the traditional electric hot water heater in my previous home, however it’s not a silver bullet. I find myself running the water for a ridiculously long time in order for the water to start getting hot, sometimes for more than a mi…

One heater per tap.
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