Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

salon.com

Post reply on HN
Print view View original

191–200 of 258 posts

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

#191

Post by oscardssmith »

ctdonath wrote: post #178
derriz wrote: post #139

Earlier quoted context omitted.

> 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.

The main cause of Texas's blackouts were the grid losing about 70% of their natural gas power (and not having good inter-connects with the rest of the US). Also, it is a great example of where the ability to pre-heat a ton of water would have been really useful. If they had the ability to do so, it would have greatly reduced the demands on the grid when the storm hit, which would have prevented the problem in the first place.

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

#192

Post by sidewndr46 »

aaron695 wrote: post #30

https://archive.is/NrQQC for those who don't want to support Salon with clicks. The article just wanders aimlessly between lies. Pumped Hydro dams are tiny compared to hydro-power or water dams and are beautiful, the same size as solar or wheat farms. A cool seawater based one in Japan - https://www.google.com/search?q=okinawa+pumped+storage+&tbm=... A good example of a government doing something that worked is the A…

The one you reference is a very poor example of pumped hydro. It's nameplate capacity was only 30 MW, it was uneconomical to operate, and was dismantled in 2016.

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

#193

Post by elric »

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.

That many cars seem undesirable in urban areas (or anywhere, really, but let's not go there).

From a bit of quick searching, EV battery packs are roughly the same volume as a fridge, and weigh in around 300kg (that was a Nissan Leaf specifically, but I assume others are similar). I don't have enough room for a fridge sized battery in my house. It'd be nice if they could shrink a bit. With enough capacity to run a tankless water heater for the duration of a nice, hot shower. The battery can charge slowly whenever power is abundant.

The grid doesn't care about running a bunch of laptops. But a bunch of tankless water heaters quickly add up. Having a local buffer really makes sense there.

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

#194

Post by giantg2 »

plater wrote: post #189
giantg2 wrote: post #184

I looked at heat pump water heaters several years ago. They are massively expensive, have a little more risk of failure (potential for expensive repairs), and in many cases would only work for half of the year (basements are a common location and get relatively cold in the winter). I like the idea, the the ROI just wasn't there given the low cost of electricity, which green energy will continue to drive down. I don't…

Not sure what a cold basement has to do with it? You suck in air from outside, extract the energy, and blow out colder air. The warm water is stored in an isolated tank (sure if the basement is cold it might cool off slightly quicker, but you warm up the cold basement which is a good thing). It is then used for heating the house via radiators as well as for warm tap/shower water. We use it to warm a 240m2 house with…

"Not sure what a cold basement has to do with it? You suck in air from outside, extract the energy, and blow out colder air."

The water heaters I saw were not running ducts to the outside, they use the room air. The point is that heat pump efficiency is tied to the ambient temperature. The hotter the air, the easier it is to collect the heat from it. So when it gets cold enough the "emergency" or "auxiliary" heating coil starts to be used (resistance based). This is very common in cold climates. My house heat pump auxiliary tends to kick in when the tempature gets below 40. This would also apply to water heaters if using outside air than the warmer basement air. Of course you are heating that basement air with another source, so that efficiency should be evaluated too (likely a heat pump because if you have a gas furnace, one would be likely to have a gas water heater too).

"It's not controlled by any cloud. You can regulate on the control panel how and when you want it to run and it adapts with the weather too if you want."

The proposal in the article is that smart water heaters could be controlled by the utility companies.

"It is then used for heating the house via radiators as well as for warm tap/shower water."

That is one type of system. The article is talking the US, in which the type of system you describe is relatively rare. The 10 million annual water heaters they reference are overwhelmingly used just for tap/shower water.

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

#196

Post by NickM »

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 seems like it could backfire if we start to get the majority of our electricity from solar, though, right? Nighttime may not always be considered off-peak.

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

#197

Post by UI_at_80x24 »

bradleyjg wrote: post #177
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 :)

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.

Don't forget that Chicago has Lake Michigan too.

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

#198

Post by mabbo »

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…

You'd like what we have in Toronto- we use Lake Ontario as a heat sink.

https://en.wikipedia.org/wiki/Enwave#Deep_Lake_Water_Cooling...

75% less energy than traditional air conditioning.

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

#199

Post by acdha »

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.

Ground source heat pumps work anywhere. Also, it's common to have a heat pump paired with resistance heating for when you're pushing the bottom of the range where the heat pump is useful (somewhere between -10 and 20℉ depending on the hardware).

That has similar issues with peak load to AC in the summer but most people do not live in places which are consistently so cold that you don't have a significant amount of time where the heat pump efficiency savings are substantial. As a matter of public policy, encouraging systems which work for 90% of the population is an easy call — especially because that can pair with code changes and subsidies which work anywhere (insulation, install of ground cooling loops, efficiency improvements, etc.).

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

#200

Post by derriz »

ctdonath wrote: post #178
derriz wrote: post #139

Earlier quoted context omitted.

> 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.

Where in the world do you live out of interest? There must be some unusual local conditions that would cause that price discrepancy because I've followed the electricity prices in a number of European countries as they've increased their reliance on wind turbines and have seen no obvious kinks in the plots of prices as wind has contributed more and more. Certainly wholesale electricity prices - where I've followed them - are at a historic low at the moment but there is a lot on the demand side that could be causing this.

The Texas story actually reinforces one of my points - thermal fossil fuel plants are unreliable also as the failure of thermal plants caused a far greater loss in capacity than that lost by renewables.

California's electricity has been a mess for decades before the recent growth in solar and wind so I'm not sure how you can claim a causal relationship between what's happening now in California and the expansion of wind and solar.

Regarding domestic roof-top solar PV - I currently don't see it having any role to play in the march towards carbon-free energy - the cost per KWh is just too high and in many countries is only made viable by large government grants and feed-in tariff guarantees which effectively allow a domestic installation to exploit the grid like a giant infinite and free battery. Utility scale solar is completely different - it costs about 1/5 of the price per KWh compared to roof-top domestic PV and in many markets is now competing and beating conventional thermal generation on price without government support.

Post reply on HN