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It sounds disingenuous to call one-way energy sinks 'heat storage'. Calling such a one-way sink a battery is even worse. On another note, I wonder how resisitv

• deleted 8y ago
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• ajross 8y ago
  Why, exactly? It's not electrical power storage, sure. But a water heater is by definition energy storage. You want hot water, it takes time to heat, so keep it in a buffer. And in fact a well-insulated modern tank is a very efficient store for energy that you're going to use at some point anyway. It makes perfect sense to use it as a flexible load to buffer grid management. > On another note, I wonder how resisitve heaters compare to heat-pumps. Heat pumps are sort of an orthogonal trick. Ultimately they work by using a lower temperature state to "steal" energy from the cooler outside temperatures. They don't make "heating" any more "efficient" per se. But if you have such an outside environment (i.e. colder than whatever the operating temperature of the heater is, but still warm enough to provide energy to the coolant) they are worthwhile.
  • SigmundA 8y ago
    Heat pumps are no trick any more than solar panels or solar water heaters are. Resistive heat is 100% efficient while heat pumps are over unity usually 300-400% efficient although usually denoted as coefficient of performance (COP) as number ex 3 or 4. For every 1 watt put in 3-4 watts of heat come out. Real efficiency in terms of energy paid for vs energy provided to heat is what matters. The reason they are over unity is they are taking heat from one place and moving it somewhere else. If they are pulling heat from outside air they are basically solar assisted. Technically anything above absolute zero has heat energy, even very cold outside air has plenty of heat to pump into your living space. Temperature is not heat, you can raise temperature by putting the same amount of heat in a smaller space, its like using a transmission to increase torque by lowering rpm.
    • ajross 8y ago
      Not sure you're disagreeing with me. That's indeed how they work, and it's... a pretty neat trick! So are phototransistors, for that matter. Not sure I'd put radiative solar water heaters in the same boat, but semiconductors and thermodynamics make for great tricks.
      • SigmundA 8y ago
        I am disagreeing with "They don't make "heating" any more "efficient" per se." They definitely do make it more efficient at least in the ways that matter to people, less energy paid for the same heat. I guess all technology is a trick, but normally that denotes its not really doing what is said, which you reinforced by saying it is not more efficient. Air source heat pump water heaters and direct solar water heaters are similar in they both utilize solar energy to heat water. Then again if you really get down to it you could argue everything is indirectly solar powered, just some forms you must pay for the energy, while heat pumps and solar collectors get it directly from outside your home heat pumps just require some energy to collect it.
        • dannypgh 8y ago
          I think you just mean different things by "heating" - if you're talking about heating in a closed system, they're the same - 5 joules of energy are needed to increase the total heat energy by 5 joules, with either approach. The advantage of the heat pump is that we are, for, say, 3 joules of energy, heating part of the system by 5 joules and heating the other part of the system by -2 joules. This is great for home heating and the like because we don't care about making the outside slightly colder.
          • SigmundA 8y ago
            Good thing we don't live in a closed system and instead have a giant fusion reactor in the sky to heat the outside air.
      • thatcat 8y ago
  • rocqua 8y ago
    There's a limit to the 'energy' the system can store: the amount of heating that can be pre-buffered and used effectively later. This comes with the downside of leaking energy a lot faster than batteries. Moreover, the more energy stored, the faster the leakage. All that is not to say this is useless. Just to say the role played by heaters is different from batteries. Notably, neither are a good solo solution to the volatility of renewables. I know that in the Netherlands, stuf like this would require infrastructure upgrades. There is simply not enough copper running to consumer houses to handle the amperages.
• Xylakant 8y ago
  > It sounds disingenuous to call one-way energy sinks 'heat storage’ One-way conversation of energy to heat is a very common use-case: Warm water, heating are all things a lot of people use. Currently, most of that conversion happens on-demand, when someone turns on the tap. Heat is a form of energy that is fairly easy to store. Have a large bucket of water, well insulated and you’re mostly set. It’s dead cheap. There are similar concepts that use a generator to provide electricity for buildings on demand and store the waste heat for warm water and heating. > Calling such a one-way sink a battery is even worse. The article does not. They are a replacement for batteries in some use cases. The article may overstate how often that’s the case but it does not pretend you could regain the energy stored as electricity.
  • ethagknight 8y ago
    The article headline is “BATTERY KILLER”
    • Xylakant 8y ago
      Yeah. It replaces batteries. It’s not a battery.
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      • ZoF 8y ago
        It doesn't replace batteries though. It is a method of storing energy that may or may not be provided by a battery. A battery is by definition something capable of storing energy and outputting it as electricity, this is not a replacement for that. I understand its semantics but it's a pretty important distinction, this is not a battery replacement. It's an alternative which for this usecase results in the same desired outcome(hot water). Tl;dr- it's a bad title
      • pofilat 8y ago
        It's far less useful than a battery, though, because heat is only good for heating things, which means you also need to provide fuel to convert it into electrical or motive applications. like computers and cars.