4 comments

  • elgertam 36 minutes ago
    > Some Japanese utilities have introduced tariffs designed to encourage daytime water heating as growing volumes of solar generation enter the grid. [Emphasis added.]

    I was quite confused at the use of "tariff" here, as it meant to me a "tax on a good crossing a political boundary." Turns out, 'tariff' has an older meaning: a published schedule of fees or taxes issued by some authority.

    • egeozcan 6 minutes ago
      I've read that the word is borrowed from Arabic, meaning notification, and I think at first it was price notifications and then people started using it to mean that the prices were bound to some schedule or condition.

      For example in Turkish, "tarife" means only that: Conditional / Schedule-based pricing, and according to Sevan Nişanyan (a language researcher), Turkish borrowed it from Italian, where it was being used similarly. Import tariffs are a completely different word.

      It apparently came to English through Italian -> Spanish -> French.

      So I'm not a native English speaker but as far as I understand, import tariffs are just one kind of tariff.

      ps. I just f'ing love Etymology.

    • myrmidon 10 minutes ago
      It's an arab loan word for ~"price list" (originally strongly suggesting an import-duty-like meaning).

      The same word exists in e.g. German or Italian, but mostly just means "pricing scheme" there, like in the article ("import duty" using a different expression in those languages).

      Might be a mostly/somewhat "false friend" for a German (pv magazine is german).

    • _joel 22 minutes ago
      I've seen 'tariff' used a fair amount here in the UK on price lists (taxi etc)
    • koito17 21 minutes ago
      The Japanese word used in the context of price lists would be something like 料金表 or 料金メニュー.

      When I see "tariff", my mind only thinks of 関税 , and I was just as confused as you were. Turns out its just an item in a price schedule.

    • Aboutplants 24 minutes ago
      US utilities also have Tariffs. It’s the statement of how the utility operates and charges users for service. Anytime a utility needs to adjust costs/rates, they need to file a Rate Case with the public utility commissions, and resulting in changes to the Tariff.
  • throw0101d 21 hours ago
    CO2 as a refrigerant isn't new:

    * https://en.wikipedia.org/wiki/R-744

    It's just not as prevalent in the residential HVAC market (which this product serves?), and more in the commercial/industrial space (probably because of the higher pressures needed to get into a liquid state).

    • alex_duf 23 minutes ago
      It's useful though, as I think (correct me if I'm wrong) that the gases generally used in HVAC tends to have much worse warming effect than co2 per volume.

      We do need heat pumps deployed at large scale, but sometimes I worry we don't understand they need to be handled with care at the end of their life

      • callmemclovin 7 minutes ago
        That's true, old school refrigerants like R-12 are awful. The downside of modern replacement refrigerants are high operating pressure (>100 bar for R-744/CO2) or high flammability for natural refrigerants like R-290 (Propane) and R-600a (Isobutane). But these are solely engineering problems, and I'm happy to know that my R-290 heat pumps at home (Panasonic L & Wolf FHS) and A/C (Midea Xtreme Save Blue) aren't awful to the environment, once they reach EOL.
      • moepstar 14 minutes ago
        Yes, that dangerous effect is indexed as GWP - global warming potential.

        CO2 has a GWP of 1 in this context, while other refrigerants are worse - for example, R32 has a GWP of 675 (so 675x worse if it escapes), not sure about R290 (Propane), which I believe is either about 40 or 14…

        Regarding EoL: At least around here, household appliances such as fridges are brought to a recycling yard and are properly taken care of in that regard… and as for heatpumps - those are only to be installed by certified professionals, for this very reason.

      • PunchyHamster 17 minutes ago
        If it is outside you can just use propane as refrigerant. Low warming value and it leaking to outside doesn't matter, not gonna catch on fire.

        There are indoor devices using propane but they generally come with caveat "must be installed on room at least this m3", precisely so if it leaks it doesn't get to density that allows explosion

    • arpinum 13 minutes ago
      CO2 does better with large temp deltas, like hot water tanks. Radiators don't produce large deltas - the inlet to outlet diff is typically under 10 degrees. But they run at higher pressures, making the manufacturing more expensive.
    • Lwerewolf 36 minutes ago
      There are resident systems, and they're of exactly the type listed in the article (i.e. water heaters). Residential... area heating pumps, so to say, are moving towards propane (afaik). I've been looking into getting a propane monoblock air-to-water pump, with an antifreeze loop towards an indoors heat exchanger / water tank.
      • adaml_623 4 minutes ago
        Trends for new refrigerant depends on country... some to R-454B, and some to Propane, doesn't seem like C02 is very common which is a pity because I love the idea of a non-toxic non-flammable super cheap refrigerant.

        This is for the Japanese market so perhaps the cons of the C02 systems are outweighed by the safety aspects.

  • EspadaV9 18 minutes ago
    I'm actually in need of a new hot water tank and have been looking for a heat pump one. Wonder if these will be available in Australia, and how they compare to the current range.
  • objektif 40 minutes ago
    “Hitachi has not yet disclosed full efficiency specifications for the two new models. Their predecessors, the BHP-FV37WD and BHP-FV46WD, have annual hot-water and heat-retention efficiency ratings under Japanese Industrial Standards (JIS) of 4.2 and 4.1, respectively.”

    What does this mean?

    • onedognight 24 minutes ago
      I believe that for every joule of electricity used, 4 or 4.1 joules are pumped from the environment into the water. This is contrast to conventional water heaters which are bounded by an efficiency of 1, where, for example, burning gas directly heats the water with some heat leaking into the environment instead of the water.
    • alex_duf 32 minutes ago
      If I'm not mistaken, it means 1kWh of electricity moves 4.1kWh of heat into your hot water tank. Heat pumps are amazing.
      • PunchyHamster 16 minutes ago
        well, in case of water heater it moves it from your room to the water.

        Which means in winter that is extra work for your heating system to compensate for

        But in climates where heating only really runs in winter it's great

        • slau 7 minutes ago
          Technology Connections has recently published an in-depth piece of the advantages and disadvantages of in-room heat-pump water heaters [1].

          The tl;dw is that it is significantly slower than a resistive or gas-powered water heater, and lowers the temperature of the room by a few degrees, but nothing major. You have to over-provision them compared to your needs. And they are way bigger.

          [1]: https://youtu.be/F_7B2shTPPU

        • Danoch 14 minutes ago
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