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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

#161

Post by JoeAltmaier »

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.

That would be an air heat pump. Water or earth-exchange heat pumps can work nearly anywhere. This article explains it well:

https://www.nordicghp.com/2017/01/heat-pump-effective-temper...

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

#162

Post by bluGill »

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…

> How do more efficient water heaters in any way, shape or form help solve the renewable variable rate energy to constant energy problem? I feel like I must be missing something obvious

A large portion of our world energy use is to make heat. Thus if you can make the heat you need when there is plenty of renewable energy available, and then store it for use latter that is a large win. Sure we can't turn that heat back into electricity (false, but they are not worth talking about), but since heat is the goal that doesn't matter.

This is well understood. My parents have been on a off-peak water heating program since 1988 (in all those years they only ran out of hot water 5 times, and nobody was trying to save water). Based on that experience, just the hot water a family uses in a day is in the 300-800 liters range (go high - running out of hot water for the day sucks). Heating your house is a lot more though - 40000 liters is a low end estimate I've seen.

You won't be cooking food, powering your car, or lighting your house this way, but it is still a cheap and useful way to store energy. It is also something we can do for the world using yesterday's cheap technology.

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

#163

Post by throw0101a »

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.

> He finally realized it was the hot water recirculator.

The problem is using devices that are either timed or (even worse) just runs 24/7.

Ideally you'd want one that runs on demand when triggered by a switch: hit the button, it runs for 30-60s while you undress, and then we you turn on (e.g.) the shower the water is already hot.

The hot water supply for the shower should be the same as the sink, and so when you go to shave or brush your teeth, that's then already primed as well.

Do a search for "Gary Klein", who has written a lot of designing good hot water systems over the years.

* https://www.garykleinassociates.com/videos.html

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

#164

Post by mcot2 »

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…

This guy has ice storage:

https://youtu.be/N3Em64OBGqI

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

#165

Post by bluGill »

konschubert wrote: post #149
z3t4 wrote: post #148

Earlier quoted context omitted.

The isolation is made to keep the house hot. About 10 degrees hotter then the outside (without the heater on). This is usually not a problem as temperatures are around 15 during the summer and you can open a few windows to let the hot air out. It does become a problem however when we get extreme temperatures like +30 C as you cant lower the temp by opening a window. Compared to south europe and other warm climates wh…

As far as I know, Insulation should keep the house cool in summer, because it keeps the heat out. Of course, once the heat is in, you need a way to get it out (at night, through windows). Unlike a greenhouse, insulation is not directional.

If you are only worried about natural cooling, insulation is not the answer. You want a poor insulated house with a lot of shade, and large open windows for the wind to blow through.

Most people these days want more than natural cooling. As soon as you decide to have an AC system installed more insulation is better for the reasons you state.

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

#166

Post by bluGill »

throw0101a wrote: post #160
paul_f wrote: post #157

Earlier quoted context omitted.

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.

> A heat pump could never be used in Minnesota, people would freeze. Heat pumps work in Alaska: * https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...

The more inhabited parts of Alaska are milder climates than MN, despite being northern they have an ocean to moderate the temperatures. Ground source heat pumps work fine in both MN and the most remote parts of Alaska - but at a much higher cost to install.

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

#167

Post by bluGill »

jcynix wrote: post #144
elric wrote: post #104

Earlier quoted context omitted.

> Good heat pumps aren't of the air conditioner type. Our heat pump uses two 60m deep drilled holes. Thus heat exchange happens in the ground, which is always more or less 10 degrees Celsuis. Good point. The source and destination of heat can be air, water, or "ground source". But it's still all just the same concept as A/C units. Pump heat to one place, using less energy than what it would take to heat it using resi…

There's no refrigerant here. Our heat pump uses plain water mixed with an anti-freezing agent. Just like the cooler in a car does. And there are control displays where you control all operating parameters. As for the "pump heat from here to there" ... while we are cooling we are warming the ground below. And as at our place, the ground's consistency keeps the warmth rather local, we reuse it later when we warm our wa…

There is refrigerant there. It is contained inside the system, and only your water mix leaves, but there is still refrigerant inside and it can leak.

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

#168

Post by Jyaif »

guerby wrote: post #152
nine_k wrote: post #62

Earlier quoted context omitted.

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 :)

Paris has a large cold water network: https://www.climespace.fr/en It's used by some datacenters IIRC.

FWIW they suck at their job. Every year there are some days where we don't have AC in the office during summer because they stop sending cold water to the building I work in.

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

#169

Post by bluGill »

WalterBright wrote: post #138

I've proposed this (water heater as battery) innumerable times here on HN. Glad to see it finally catching on! You can do the same thing with the HVAC system. For example, when the sun is high and electricity is cheap, have the A/C cooling a large mass of stone or concrete. Then, blow air over it at night to keep the house cool.

You are not the first to propose it, and won't be the last. It is obvious to any engineer who spends more than a few minutes thinking about the problem. It works in practice too, but the space needed means most people don't bother.

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

#170

Post by throw0101a »

manmal wrote: post #74

Most newly built electric cars have a 50+ kWh battery. Imagine if smart meters could use _that_, regardless of where the car is currently parked and plugged in. 50kWh is in excess of what most households use in electricity on most days.

> Imagine if smart meters could use _that_, regardless of where the car is currently parked and plugged in.

The US National Electric Code (NEC) has been updated (§625) so that electric vehicle charging can be used as a source of power (PDF):

* http://mydocs.epri.com/docs/publicmeetingmaterials/1112/PDNN...

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