7 ms·

Perhaps I am missing something; this product already exists as the Sunamp Thermino. https://sunamp.com/en-gb/hot-water-solutions-thermino-range/ https://sunamp

Perhaps I am missing something; this product already exists as the Sunamp Thermino. https://sunamp.com/en-gb/hot-water-solutions-thermino-range/ https://sunamp.com/en-gb/hot-water-solutions-thermino-range/

ZeroGravitas 8mo ago
It also exists, as described in the headline, as a tank of heated water. The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.
- DrScientist 8mo ago
  Indeed. In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ). Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.
  - Xylakant 8mo ago
    it also reduces peak load - you can heat water up slower with a lower powered heater. I have a 35 liter warm water tank in my garden shed that pulls about 3.5kw - an equivalent on demand heater would need 14kw or more.
    - IshKebab 8mo ago
      I don't see why that matters. You use the same amount of energy and the demand is smoothed out at grid scale (yes I know about tea in ad breaks).
      - ifwinterco 8mo ago
        Houses in the UK typically have 100A supply and the whole local grid is sized assuming people use relatively small amounts of electricity. If everyone gets an electric car and a massive heat pump, lots of local transmission will need upgrading
        IshKebab 8mo ago
        Right but unless everyone is drawing large amounts of power at the same time it doesn't matter if you use 1kW for 10 hours or 10kW for 1 hour. To the grid they look the same. One interesting case where "at the same time" actually does happen is overnight car charging. Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.
        footydude 8mo ago
        > Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that. Here in the UK some electricity providers offer 'smart' charging (e.g. Octopus Intelligent Go). In that situation the energy provider controls when to charge the car - e.g. you say "I want the car at 80% by 7am tomorrow" and the energy provider controls the timing of charges. That's how my EV charges - I plug it in, and Octopus control it. Benefit for me is that whenever the car is charging my entire home's use gets the overnight rate (even if part of the schedule is charged during the day). Benefit for Octopus is they can use my car to balance grid demand / schedule the charge when it is most financially effective for them. I can - at any time - override that logic if I just want it to charge at a specific time for whatever reason. (I presume this sort of arrangement is becoming more common in other countries too)
        ifwinterco 8mo ago
        Yep but while that is true at the level of the overall grid, actually the nearest part of "the grid" might be a local transformer that only serves 10-100 houses. At that scale, it's definitely possible that you all plug in your electric cars and turn on your heat pumps more or less at once on a cold evening after work and start cooking your local transformer. Not my day job but I think it is a potential issue when everything is sized assuming ~2kW average demand or something
      - DrScientist 8mo ago
        You can get things like cheaper overnight tariffs when the demand is lower - if you have some sort of storage system - like a hot water tank - in effect the electricity company is distributing some of that smoothing function to things like hot water tanks, storage heaters or batteries. If you have your own solar ( either direct solar water heating, or solar electricity generation ), the hot water tank is a simple, cheap, reliable energy store. Sure capacity isn't that great - but pretty much every house in the UK used to have one, so it adds up.
  - a_better_world 8mo ago
    My hot water tank once fell off the wall. On Christmas day. Expensive repair. Hot water tank was in the basement, which was not insulated. So the mass of hot water contributed very little as a heat reserve for the house. House was in a northern clime.
    - manmal 8mo ago
      Those are great for buffering only a few hours though. That would help avoid the expensive electricity price peaks.
  - coryrc 8mo ago
    They don't work well with heat pumps. Heat pumps lose efficiency as the differential increases, so if you try to store heat in a tank, you quickly drop capacity and efficiency. Versus resistance, which is exactly as efficient at 0°C and 1000°C, and why those storage heaters used to make sense. (And storage is directly proportional to temperature differential above interior ambient)
    - ZeroGravitas 8mo ago
      Home hot water heating in the UK with heat pumps is about 250-300% efficient (slightly lower than the efficiency of home heating but still much better than resistive). No one is storing 1000C water at home. It is true that the temperature deltas affects efficiency. You can use the thermocline to draw from the cooler lower portion of the storage tank to push this further. Or less technically, just a bigger tank, though this has some tradeoffs. In warmer countries they are set up differently can act as free air conditioning by extracting heat from indoor air at the same time as heating water.
      - coryrc 8mo ago
        > No one is storing 1000C water at home. Right, but UK has/had "storage heaters" which were bricks with nichrome wire. They would heat the bricks really hot during cheap electricity times, and use that heat the rest of the day. EDIT: I misread "ripping out these energy storage devices" as https://en.wikipedia.org/wiki/Storage_heater https://en.wikipedia.org/wiki/Storage_heater Of course heat pumps for DHW should all have a tank for smoothing demand across several hours.
    - modo_mario 8mo ago
      Isn't it better to heat the water up to a point (let's say 40 or 50 degrees) and to heat it the rest of the way with resistance heating? >Versus resistance, which is exactly as efficient at 0°C and 1000°C It isn't. The difference is smaller than for a heatpump tho obviously.
      - leoedin 8mo ago
- vee-kay 8mo ago
  You are right in your analogy. Earth's oceans and seas act as giant heat sinks. And that means more trouble as global climate change impacts.. https://www.earth.com/news/ocean-warming-broke-records-for-450-straight-days/ https://www.earth.com/news/ocean-warming-broke-records-for-4...
  - vee-kay 8mo ago
    LOL, now why was this comment downvoted, when it is the truth?!
- Nition 8mo ago
  It's funny how useful water is for power generation. There's heat storage as discussed here. Or you can store cold water in a reservoir as a giant battery, pumping it up high when you've got excess power, and letting it back down to generate hydroelectricity from it later. Or you can boil water to make steam that spins a turbine and use it to convert anything that can heat water (coal, oil, nuclear...) to electricity.
  - themafia 8mo ago
    > It's funny how useful water is for power generation. It's gravity that does the generation. Water is convenient because it's weight per unit of volume is very high. Higher than most things we can get our hands on and it's also exceptionally safe. Since water isn't perfectly clean the main problem you face is corrosion. Which can take a great system and turn it into a nightmare of buried leaks and sudden problems. As far as our options go it _is_ really convenient.
    - wongarsu 8mo ago
      And maybe it's obvious, but the largest thing that makes water so useful is that on our planet it's usually liquid but has easy to reach boiling and freezing points. Most notably a boiling point that is easily withstood by most metals and trivially reached by most methods of heating. Chemically something like quartz would work just fine, but its heating and boiling point are way too high to be practical. Occasionally we do reach for molten salts like lithium chloride
- shellfishgene 8mo ago
  I think the advantage is that hot water loses heat over time, depending on how good the insulation is. However with phase change materials, the heat is trappped in the phase change and is stable until you release it.

ZeroGravitas 8mo ago

It also exists, as described in the headline, as a tank of heated water. The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.

DrScientist 8mo ago
Indeed. In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ). Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.
- Xylakant 8mo ago
  it also reduces peak load - you can heat water up slower with a lower powered heater. I have a 35 liter warm water tank in my garden shed that pulls about 3.5kw - an equivalent on demand heater would need 14kw or more.
  - IshKebab 8mo ago
    I don't see why that matters. You use the same amount of energy and the demand is smoothed out at grid scale (yes I know about tea in ad breaks).
    - ifwinterco 8mo ago
      Houses in the UK typically have 100A supply and the whole local grid is sized assuming people use relatively small amounts of electricity. If everyone gets an electric car and a massive heat pump, lots of local transmission will need upgrading
      - IshKebab 8mo ago
        Right but unless everyone is drawing large amounts of power at the same time it doesn't matter if you use 1kW for 10 hours or 10kW for 1 hour. To the grid they look the same. One interesting case where "at the same time" actually does happen is overnight car charging. Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.
        footydude 8mo ago
        > Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that. Here in the UK some electricity providers offer 'smart' charging (e.g. Octopus Intelligent Go). In that situation the energy provider controls when to charge the car - e.g. you say "I want the car at 80% by 7am tomorrow" and the energy provider controls the timing of charges. That's how my EV charges - I plug it in, and Octopus control it. Benefit for me is that whenever the car is charging my entire home's use gets the overnight rate (even if part of the schedule is charged during the day). Benefit for Octopus is they can use my car to balance grid demand / schedule the charge when it is most financially effective for them. I can - at any time - override that logic if I just want it to charge at a specific time for whatever reason. (I presume this sort of arrangement is becoming more common in other countries too)
        ifwinterco 8mo ago
        Yep but while that is true at the level of the overall grid, actually the nearest part of "the grid" might be a local transformer that only serves 10-100 houses. At that scale, it's definitely possible that you all plug in your electric cars and turn on your heat pumps more or less at once on a cold evening after work and start cooking your local transformer. Not my day job but I think it is a potential issue when everything is sized assuming ~2kW average demand or something
    - DrScientist 8mo ago
      You can get things like cheaper overnight tariffs when the demand is lower - if you have some sort of storage system - like a hot water tank - in effect the electricity company is distributing some of that smoothing function to things like hot water tanks, storage heaters or batteries. If you have your own solar ( either direct solar water heating, or solar electricity generation ), the hot water tank is a simple, cheap, reliable energy store. Sure capacity isn't that great - but pretty much every house in the UK used to have one, so it adds up.
- a_better_world 8mo ago
  My hot water tank once fell off the wall. On Christmas day. Expensive repair. Hot water tank was in the basement, which was not insulated. So the mass of hot water contributed very little as a heat reserve for the house. House was in a northern clime.
  - manmal 8mo ago
    Those are great for buffering only a few hours though. That would help avoid the expensive electricity price peaks.
- coryrc 8mo ago
  They don't work well with heat pumps. Heat pumps lose efficiency as the differential increases, so if you try to store heat in a tank, you quickly drop capacity and efficiency. Versus resistance, which is exactly as efficient at 0°C and 1000°C, and why those storage heaters used to make sense. (And storage is directly proportional to temperature differential above interior ambient)
  - ZeroGravitas 8mo ago
    Home hot water heating in the UK with heat pumps is about 250-300% efficient (slightly lower than the efficiency of home heating but still much better than resistive). No one is storing 1000C water at home. It is true that the temperature deltas affects efficiency. You can use the thermocline to draw from the cooler lower portion of the storage tank to push this further. Or less technically, just a bigger tank, though this has some tradeoffs. In warmer countries they are set up differently can act as free air conditioning by extracting heat from indoor air at the same time as heating water.
    - coryrc 8mo ago
      > No one is storing 1000C water at home. Right, but UK has/had "storage heaters" which were bricks with nichrome wire. They would heat the bricks really hot during cheap electricity times, and use that heat the rest of the day. EDIT: I misread "ripping out these energy storage devices" as https://en.wikipedia.org/wiki/Storage_heater https://en.wikipedia.org/wiki/Storage_heater Of course heat pumps for DHW should all have a tank for smoothing demand across several hours.
  - modo_mario 8mo ago
    Isn't it better to heat the water up to a point (let's say 40 or 50 degrees) and to heat it the rest of the way with resistance heating? >Versus resistance, which is exactly as efficient at 0°C and 1000°C It isn't. The difference is smaller than for a heatpump tho obviously.
    - leoedin 8mo ago
vee-kay 8mo ago
You are right in your analogy. Earth's oceans and seas act as giant heat sinks. And that means more trouble as global climate change impacts.. https://www.earth.com/news/ocean-warming-broke-records-for-450-straight-days/ https://www.earth.com/news/ocean-warming-broke-records-for-4...
- vee-kay 8mo ago
  LOL, now why was this comment downvoted, when it is the truth?!
Nition 8mo ago
It's funny how useful water is for power generation. There's heat storage as discussed here. Or you can store cold water in a reservoir as a giant battery, pumping it up high when you've got excess power, and letting it back down to generate hydroelectricity from it later. Or you can boil water to make steam that spins a turbine and use it to convert anything that can heat water (coal, oil, nuclear...) to electricity.
- themafia 8mo ago
  > It's funny how useful water is for power generation. It's gravity that does the generation. Water is convenient because it's weight per unit of volume is very high. Higher than most things we can get our hands on and it's also exceptionally safe. Since water isn't perfectly clean the main problem you face is corrosion. Which can take a great system and turn it into a nightmare of buried leaks and sudden problems. As far as our options go it _is_ really convenient.
  - wongarsu 8mo ago
    And maybe it's obvious, but the largest thing that makes water so useful is that on our planet it's usually liquid but has easy to reach boiling and freezing points. Most notably a boiling point that is easily withstood by most metals and trivially reached by most methods of heating. Chemically something like quartz would work just fine, but its heating and boiling point are way too high to be practical. Occasionally we do reach for molten salts like lithium chloride
shellfishgene 8mo ago
I think the advantage is that hot water loses heat over time, depending on how good the insulation is. However with phase change materials, the heat is trappped in the phase change and is stable until you release it.