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That was my first question too. I found the following. Sadly, because journalisming is oh so hard, they omitted the actual innovations. TLDR: Novel liquid desi

That was my first question too. I found the following. Sadly, because journalisming is oh so hard, they omitted the actual innovations. TLDR: Novel liquid desiccant functions as a "humidity battery" (my phrase). A salt solution which captures and releases moisture. It's closed loop and doesn't need to be replenished. Claimed OpEx $/hWh (for just the dehumidifier) is ~ $20/hWh, vs > $600 for Li-ion and ~ $400 for ice thermal based systems. It's safer and more durable. Liquid Desiccants as Breakthrough Energy Storage [2021] https://www.youtube.com/watch?v=2SwMyGzXsuE https://www.youtube.com/watch?v=2SwMyGzXsuE Liquid Desiccants and Our Cooling Process - Blue Frontier, LLC [2021] https://www.youtube.com/watch?v=r8B4LQTQ94g https://www.youtube.com/watch?v=r8B4LQTQ94g https://bluefrontierac.com https://bluefrontierac.com "At Blue Frontier, our mission is to transform buildings into sustainable, comfortable, and interactive spaces. Our first step towards achieving this goal is the commercialization of a revolutionary air conditioning technology. Blue Frontier’s AC system combines dew-point-style sensible cooling with liquid desiccant dehumidification to reduce electricity use by up to 90% (non-fan). The desiccant is recharged and stored when electricity is the cleanest or lowest cost, and later used to deliver cooling when electricity is dirty or costly. These features enable our system to solve an array of today’s largest sustainability problems — from the Duck Curve to peak load management, from humidity control to integration of intermittent renewable resources." Note the "Duck Curve" bit. Their "humidity battery" (my phrase) allows them to do load shifting. In the actual AC unit(s). That's really bitchin'.

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Zancarius 3y ago
Okay, that's a shame. The most interesting part of the product is the part the article didn't even touch on! Thank you for finding this!
hinkley 3y ago
Heat batteries were tried in furnaces a couple of decades ago, but they used some sort of high heat capacity bricks and forced the house air through them. As GP asks, the matter of maintenance was forgotten. Recently I heard someone is trying this again with water heaters. The working fluid has roughly four times the heat capacity of water, so your “water” heater is substantially a fluid heater with either no water tank or a very small one. Incoming water is heated with the fluid, and the fluid is heated on demand. Only the heat exchanger has maintenance concerns. Driving the whole thing with a heat pump makes the math a little more fiddly, since peak pump efficiency and peak power prices overlap some of the same parts of the day. You’re calculating BTUs per dollar, not watt hours per dollar.
- Retric 3y ago
  It’s already cheap to just use a larger water heater as the thermal battery. Few households use more than 80 gallons of hot water per day which is still within the normal range of hot water heaters. Just add a timer so it doesn’t kick on until powers cheap and you’ll be good to go. At least assuming your cheap electricity window is long enough to fully heat the water. This is one of the reasons people overestimate the need for grid energy storage. People time shift electricity to the night because it’s cheap. If it was cheaper 10AM-4PM then significant demand would shift to that window.
  - deleted 3y ago
    [deleted]
  - criddell 3y ago
    > significant demand would shift to that window Sounds like we would need “smart” water heaters that can query energy prices. That most likely means they would be online sharing all kinds of data most of us probably don’t want shared and would have a small monthly fee. The water heater might even be very inexpensive because of this. I know it wouldn’t have to be implemented this way, but of course that’s how it would go.
    - Retric 3y ago
      Such things already exist: “ If applicable download the Time of Use schedule of your local electric utility to prioritize heating when the rates are most affordable” https://www.statewaterheaters.com/literature/spec-sheets/residential-hybrid-electric/premier®-al-smart-hybrid-electric-heat-pump-spec-sheet-(srxss00122)/ https://www.statewaterheaters.com/literature/spec-sheets/res...
    - MayeulC 3y ago
      Not necessarily smart. Here (France), most water heaters can be controlled with an extra "pilot" wire, or closing a circuit. It has been common practice since maybe the 60s to have multiple mettering rates, and a dry contact (relay) on the electricity meter to switch on/off some loads (mostly electric water heaters, though some electric space heaters can be connected as well). These days, rates can be more flexible thanks to "smart" meters (communicating via PLC). Just after the russian invasion of Ukraine, there were plans in place to open the dry contacts of customers outside of the scheduled hours in case the electricity grid needed to shed extra load. Thankfully this didn't end up being necessary. What I'm saying is that you don't really require smart end devices. Put the incentives in place (deep discounts) and the rest will follow. You probably need at least one smart device to control the others if a timer is not enough, and I think the electricity meter is a good fit for that role.

deleted 3y ago

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Zancarius 3y ago

Okay, that's a shame. The most interesting part of the product is the part the article didn't even touch on! Thank you for finding this!

hinkley 3y ago

Heat batteries were tried in furnaces a couple of decades ago, but they used some sort of high heat capacity bricks and forced the house air through them. As GP asks, the matter of maintenance was forgotten. Recently I heard someone is trying this again with water heaters. The working fluid has roughly four times the heat capacity of water, so your “water” heater is substantially a fluid heater with either no water tank or a very small one. Incoming water is heated with the fluid, and the fluid is heated on demand. Only the heat exchanger has maintenance concerns. Driving the whole thing with a heat pump makes the math a little more fiddly, since peak pump efficiency and peak power prices overlap some of the same parts of the day. You’re calculating BTUs per dollar, not watt hours per dollar.

Retric 3y ago
It’s already cheap to just use a larger water heater as the thermal battery. Few households use more than 80 gallons of hot water per day which is still within the normal range of hot water heaters. Just add a timer so it doesn’t kick on until powers cheap and you’ll be good to go. At least assuming your cheap electricity window is long enough to fully heat the water. This is one of the reasons people overestimate the need for grid energy storage. People time shift electricity to the night because it’s cheap. If it was cheaper 10AM-4PM then significant demand would shift to that window.
- deleted 3y ago
  [deleted]
- criddell 3y ago
  > significant demand would shift to that window Sounds like we would need “smart” water heaters that can query energy prices. That most likely means they would be online sharing all kinds of data most of us probably don’t want shared and would have a small monthly fee. The water heater might even be very inexpensive because of this. I know it wouldn’t have to be implemented this way, but of course that’s how it would go.
  - Retric 3y ago
    Such things already exist: “ If applicable download the Time of Use schedule of your local electric utility to prioritize heating when the rates are most affordable” https://www.statewaterheaters.com/literature/spec-sheets/residential-hybrid-electric/premier®-al-smart-hybrid-electric-heat-pump-spec-sheet-(srxss00122)/ https://www.statewaterheaters.com/literature/spec-sheets/res...
  - MayeulC 3y ago
    Not necessarily smart. Here (France), most water heaters can be controlled with an extra "pilot" wire, or closing a circuit. It has been common practice since maybe the 60s to have multiple mettering rates, and a dry contact (relay) on the electricity meter to switch on/off some loads (mostly electric water heaters, though some electric space heaters can be connected as well). These days, rates can be more flexible thanks to "smart" meters (communicating via PLC). Just after the russian invasion of Ukraine, there were plans in place to open the dry contacts of customers outside of the scheduled hours in case the electricity grid needed to shed extra load. Thankfully this didn't end up being necessary. What I'm saying is that you don't really require smart end devices. Put the incentives in place (deep discounts) and the rest will follow. You probably need at least one smart device to control the others if a timer is not enough, and I think the electricity meter is a good fit for that role.