The humble water heater could be the savior of our energy infrastructure woes • Hacker News Board

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

#171

Post by pw262 » Wed, Jul 07, 2021, 12:51 PM UTC

What the enthusiasts for heap pump water heaters miss is the source of the heat they are pumping.

In the summer they are removing heat from a hot house, great - free air conditioning.

In the winter they are removing heat from a warm house, which then needs to be replaced by some other heating source to keep the house warm, great - you get to pay twice.

I tried turning the heat pump element on my heater off during the winter. However, it is programmed to automatically turn on again after 5 days.

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

#172

Post by bluGill » Wed, Jul 07, 2021, 12:58 PM UTC

xupybd wrote: post #5

"This approach can be deployed far faster than dam construction" Can we really manufacturer that many hot water tanks in less time than building a damn?

Hot water tanks are generally expected to last about 12 years. Some make it 40, but some die after 5. (replace your anode rod!) So we already make a lot of them.

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

#173

Post by matheusmoreira » Wed, Jul 07, 2021, 12:58 PM UTC

cycomanic wrote: post #88

In Northern Europe heat pumps are now pretty much standard for new homes. They reduce heating bills quite dramatically compared to other technology. In particular if combined with solar power. One big advantage is that they can also be run in reverse so you could cool the house in summer (although you might need a special heat pump to do this, especially to separate from the hot water). In areas where it gets very co…

Is it possible to hook up computer heat sinks to these things? I figure it'd be better to pump the heat outside my home instead of dissipating it into my air conditioned rooms...

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

#174

Post by LysPJ » Wed, Jul 07, 2021, 1:04 PM UTC

paul_f wrote: post #157

cycomanic wrote: post #88

In Northern Europe heat pumps are now pretty much standard for new homes. They reduce heating bills quite dramatically compared to other technology. In particular if combined with solar power. One big advantage is that they can also be run in reverse so you could cool the house in summer (although you might need a special heat pump to do this, especially to separate from the hot water). In areas where it gets very co…

Europe has milder winters than many parts of the world. A downside of a heat pump is the limitation on temperature range. A heat pump could never be used in Minnesota, people would freeze.

Heat pumps are very widely used here in Norway. I wouldn't class our winters as "mild" :)

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

#175

Post by mchristen » Wed, Jul 07, 2021, 1:11 PM UTC

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

The city of Austin has a chilled water loop and more. It's pretty neat how it all works. https://austinenergy.com/ae/commercial/commercial-services/d...

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

#176

Post by jffry » Wed, Jul 07, 2021, 1:16 PM UTC

pw262 wrote: post #171

What the enthusiasts for heap pump water heaters miss is the source of the heat they are pumping. In the summer they are removing heat from a hot house, great - free air conditioning. In the winter they are removing heat from a warm house, which then needs to be replaced by some other heating source to keep the house warm, great - you get to pay twice. I tried turning the heat pump element on my heater off during the…

> In the winter [...] you get to pay twice.

That heat in the hot water is coming from somewhere, and you're paying for it regardless of where it came from. The question is _how much_ you're paying.

The magic of heat pumps is that in many cases, they can move X joules of heat by expending less than X joules of electricity. As an extra bonus, in the winter, any "waste heat" from the heat pump doing its work is still inside your home and not wasted at all.

So you could view a heat pump water heater as a way of converting one type of heating cost (the fuel/electricity used in a conventional tanked hot water heater) into another type of heating cost (the fuel/electricity used to heat your home).

As long as the cost of the electricity used by the heat pump is not astronomically higher than the cost of whatever is heating your home, it should definitely be in the green.

edit to add: Many state and local governments along with utilities are offering incentives/rebates/discounts to install heat-pump hot water heaters.

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

#177

Post by bradleyjg » Wed, Jul 07, 2021, 1:16 PM UTC

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 :)

There’s versions of this in NYC that use the bay as a first pass heat exchanger. Not sure how deep or cold the Chicago river is but I’d think they’d be able to do the same.

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

#178

Post by ctdonath » Wed, Jul 07, 2021, 1:19 PM UTC

derriz wrote: post #139

stdgy wrote: post #108

Am I the only one that find this article incredibly confusing? It starts off talking about wanting to move energy production to renewable sources. Great, I'm with you so far. A major issue with renewable energy (solar and wind) is that they're variable, not constant. This results in uneven power. The wind doesn't blow, it's cloudy or it's night time. So we need a way to convert this variable renewable energy into con…

> The world needs a way to convert renewable energy into constant energy. Not really or at least that represents a gross simplification of the situation. Electricity demand is anything but constant - peak to trough intraday consumption can vary by up to a factor of 5. Grid engineering is all about matching lots of different sources with different generation characteristics with a varying (but quite predictable) deman…

My utility solar cost average 50% over regular electricity $ for 2 years.

Texas suffered a doomsday scenario last winter, power demand far exceeding renewables ability under prolonged bad weather. California has frequent rolling blackouts; bizarrely, solar roofs are disallowed to supply the homes they cover.

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

#179

Post by cmrdsprklpny » Wed, Jul 07, 2021, 1:20 PM UTC

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's a local university that uses this method to cool their musical performance space, which causes it to be comfortably cold but without the noise of AC.

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

#180

Post by bserge » Wed, Jul 07, 2021, 1:21 PM UTC

matheusmoreira wrote: post #173

cycomanic wrote: post #88

In Northern Europe heat pumps are now pretty much standard for new homes. They reduce heating bills quite dramatically compared to other technology. In particular if combined with solar power. One big advantage is that they can also be run in reverse so you could cool the house in summer (although you might need a special heat pump to do this, especially to separate from the hot water). In areas where it gets very co…

Is it possible to hook up computer heat sinks to these things? I figure it'd be better to pump the heat outside my home instead of dissipating it into my air conditioned rooms...

It would basically be a phase change cooler like the one used in a fridge. Very efficient, but quite big and unwieldy.