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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

#61

Post by abakker »

coryrc wrote: post #46
deviledeggs wrote: post #42

Earlier quoted context omitted.

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.

Leaking coolant is a major problem. The standard for most small heat pumps is r412a and it is problematic.

To make the installs cheap, these systems use flare fittings that almost all seem to leak. Couple that with the fact the 412a systems run at high pressure and you get a lot of leaking refrigerant.

No HVAC techs I’ve met like the 412a systems and most seem to be hoping for more sanity from r32, though that will have its own set of problems (flammability)

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

#62

Post by nine_k »

selectodude wrote: post #52
elil17 wrote: post #45

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. Unfortunatel…

There is a large building in Chicago that basically contains a giant ice cube. https://www.enwave.com/locations/chicago.htm

From their website I gleaned that they have 5 facilities, and several miles of piping that carries ice-cold water to their customers, large buildings around.

It's the maximally outsourced air-conditioning solution I ever saw :)

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

#63

Post by nine_k »

jdsully wrote: post #33
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 majority of your savings are from switching to gas from electric. Gas is significantly cheaper per BTU. Gas tank heaters are still pretty efficient. Especially if insulated.

It's easy to understand.

First, a gas-fired power plant converts about 40% of thermal energy to electricity, discarding 60% to further heat the planet. Then a few more percent are lost in transmission lines and voltage-lowering transformers. Only then that electricity is used to heat water or air in one's house.

If you just directly burn that same gas in the house to produce heat, it's nearly 3x as efficient.

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

#64

Post by kube-system »

labster wrote: post #54
vl wrote: post #15

Earlier quoted context omitted.

> The good news about climate change is that I never have to worry about the pipes freezing any more. As they recently learned in Texas.

Nah, I’m in coastal California. The last frost here was in the 1990s, last time it snowed was the 1930s. Think I’ll be okay.

Climate change is making weather more extreme, in both directions. “Global warming” is a good descriptor of global climate as a whole but a bad descriptor of the effects on local weather. Many places are seeing higher highs and lower lows.

The only saving grace at the coasts is that you’re sitting beside a giant heatsink.

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

#65

Post by m463 »

perihelions wrote: post #58

Can you also store cold cheaply? For example, to run an A/C early in the morning, and put the cold in an insulated tank of a room-temperature phase change material [0]? [0] https://en.wikipedia.org/wiki/Phase-change_material#Common_P...

A long time ago I read an article that made an impression on me. This guy had developed a house using logs that were basically phase change material. I think part of the design was to build almost a house within a house. An inside wall made of the logs containing pine sap that would change phase at a comfortable temperature. So with sun it would reach that temperature then start absorbing it and becoming more liquid, then later slowly solidify giving off heat.

EDIT: it was the enertia house

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

#66

Post by injidup »

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.

I have worked in an aluminium smelter, given the heart stopping magnetic fields, toxic fumes and potential for explosion when even a small amount of water gets in I can say I really don't want this under my house

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

#67

Post by nine_k »

perihelions wrote: post #58

Can you also store cold cheaply? For example, to run an A/C early in the morning, and put the cold in an insulated tank of a room-temperature phase change material [0]? [0] https://en.wikipedia.org/wiki/Phase-change_material#Common_P...

Indeed! The most abundant phase-change material with enormous specific heat of both the liquid phase and the transition to solid is water.

Refrigerate water at night, use it during day heat. I see that many groceries use this technique; homes could, too.

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

#68

Post by _huayra_ »

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.

My parents got a heat pump water heater (electric) a few months ago and it's great. Definitely the priciest option, but it sips electricity and also cools the area around it (basically operating as an "inside out refridgerator").

In this same remodel I also convinced them to get heat pump / AC combo unit to replace the old gas furnace. Again amazingly cheap (even compared to gas), but also higher upfront cost.

This is in a coastal California region, so I'm not sure how well these heat pump solutions will work in colder places (ice would likely form on the heat pump near freezing, limiting its capability), but if anyone is looking to upgrade either a hot water heater or an AC unit, I cannot recommend the heat pump option enough (if you can get through the higher up front cost).

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

#69

Post by fy20 »

nine_k wrote: post #62
selectodude wrote: post #52

Earlier quoted context omitted.

There is a large building in Chicago that basically contains a giant ice cube. https://www.enwave.com/locations/chicago.htm

From their website I gleaned that they have 5 facilities, and several miles of piping that carries ice-cold water to their customers, large buildings around. It's the maximally outsourced air-conditioning solution I ever saw :)

District cooling (as opposed to district heating) is fairly common in Gulf countries.

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

#70

Post by SilverRed »

elil17 wrote: post #45

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. Unfortunatel…

For some places like Australia you would want to run it in the middle of the day when solar peaks and power prices go negative.
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