Three Things

Just five posts in and I’ve already been seduced by my inner essayist. I don’t really mind, because Dave’s Made-Up Law of Pressure says that if you create an opening, what comes out first is what really wanted to come out. I didn’t know writing a blog would be this much fun. At the same time, I don’t want to keep eddying around in interesting side topics, without quite getting to the specific reason I started a blog.

That reason was to discuss possible technology ideas for addressing climate change. Some that I came up with, and some not, but in any case, ideas:

  • that just might work,
  • that just might have a noticeable impact on our climate disaster in progress, and
  • that some of us just might be able to get together and build.

There are three ideas on my list at the moment. (There are also some ideas on the scrap heap that I was excited about at one time, but I finally concluded that they wouldn’t work, they wouldn’t have much impact, or our society, in its current form, could never pull them off.)

My three contenders right now are:

#1: Superinsulation.

Making our houses, apartments, and workplaces so energy-efficient that “you can heat the place with a match.” This isn’t my idea; they’ve been doing it for decades in Germany and other places1. No technological breakthroughs are needed. Done correctly, it’s 100% upside and plenty of it. The only real question is why we aren’t doing it, and the short answer is that we expect individual property owners to take one for the team, and spend more of their own money than they’ll ever recoup, because it’s good for everybody else. We need to reject that magical thinking, and start using societal resources to achieve societal benefits.

#2: Household-scale thermal energy storage using PV + heat pump + thermal reservoir.

This concept may be out there, but I haven’t run across it. In sketch form:

a) you have a heat pump to heat and cool your house.

b) you have a good-sized array of solar panels on your roof. This means you’ve got your own cheap supply of electricity, part of the time.

c) you have a cistern in your basement or buried in your yard, which is well-insulated and holds a lot of water.

d) the heat pump is rigged to be able to exchange energy, not just with the living space and the outdoors, but with the cistern too.

e) on a sunny winter day, you can run your heat pump hard because you’re getting cheap solar electricity. The heat pump (in addition to heating the house) is taking energy from outdoors and moving it into the cistern, giving you a reservoir of very warm water. After the sun goes down, the heat pump (or just a circulating pump, when the water’s hot enough) moves this energy from the cistern into your living space, giving you heat almost for free—possibly right up until the sun comes back tomorrow, if the cistern’s big enough and warm enough.

f) on a sunny summer day, again, you can run your heat pump hard on cheap solar electricity during those precious midday hours when the sun is strong. The heat pump (in addition to cooling the house) is taking energy from the cistern and moving it outdoors, giving you a reservoir of very cold water. After the sun goes down, when your living space is at its hottest, the heat pump (or just a circulating pump, while the water’s cold enough) moves energy out of the living space and into the cistern, giving you air conditioning almost for free—all night if you need it, provided the cistern’s big enough and cold enough.

This is a short-term form of demand shifting—saving energy for a few hours later, when you need it more. Obviously, a bigger cistern would give you more duration, but I think the sweet spot is in the 3-to-12-hour range, like the scenario I’ve described. Many dwellings are heated by natural gas and cooled by fossil electricity, so the potential carbon reduction is considerable.

#3: Grid-scale electricity storage using encapsulated pumped hydro.

First we had hydropower (Grand Coulee Dam, for example). Electricity is generated by the force of water falling from a higher elevation to a lower one. It’s a carbon-free energy source, and because it dams a river to form an artificial lake, it has storage built in. Great stuff, except we’re out of rivers to build it on, and reluctant to devastate what rivers we have left anyway.

Then came pumped hydroelectric storage (often just called “pumped storage,” or “pumped hydro”). Dating back to 19072, this doesn’t produce energy, but it does store it for use at a more convenient time. Early examples were built around existing bodies of water, doing environmental damage similar to that caused by hydroelectric dams, though not on such a grand scale.

Later, closed-loop pumped hydroelectric storage was invented. This uses the same water over and over, pumping it between two elevations to alternately store and release electricity. A key benefit of this scheme is that it doesn’t have to connect to any natural bodies of water at all, so the environmental issues are lessened. A number of new projects of this type are planned or under construction, using moderately-sized dams in combination with natural terrain to build two artificial lakes at different heights.

Finally, my proposal, which I call encapsulated pumped hydroelectric storage (or “encapsulated pumped storage” for short). The motivation is that (a) the arid Southwestern U.S. has an abundance of great sites for closed-loop pumped hydro, on land of little competing economic value, but (b) open reservoirs in that climate would have unacceptable water losses due to evaporation. So, instead of reservoirs, store the water in a number of very large, individual, above-ground, flexible tanks (or “bags”).

This has many advantages besides preventing evaporation. The cost should be significantly less than the massive earth-moving and damming needed to make two large reservoirs. The carbon debt due to materials and construction would also be far smaller than with concrete dams. The system could be built out incrementally over many years, instead of requiring a decade or more of sunk costs before any benefit is returned. The environmental impact could be much smaller as well. Modularity means maintenance can take place without shutting down the whole system. And sites could be used that aren’t suitable for reservoir-building (particularly at the higher of the two elevations).

Those are three things I would like to try. I’ll look at each of them in much more detail in future posts. By “try,” I mean a series of actions: first, to build them, at mini-scale if necessary. I also want to “try” them in the judicial sense: examine and analyze them from every angle, look for flaws, run software simulations, compute the costs and the benefits as accurately as possible, and see if they really make sense. Finally, if some or all of these ideas still look good after that, trying them would mean writing proposals, seeking funding, and putting together resources and people to build them at scale, and find out if they can really make a difference.

And whether these ideas make the cut or not, I’ll be keeping an eye out for others. The challenge is big, and we need a network of many partial solutions addressing different areas, at every scale from individual to global.

  1. wikipedia: “Superinsulation is an approach to building design, construction, and retrofitting that dramatically reduces heat loss (and gain) by using much higher levels of insulation and airtightness than normal.”
  2. wikipedia

5 thoughts on “Three Things

  1. Excellent point about how we expect individual households to hop on the fiscal cross to save us from our collective consumption and poor design sins. One great thing about superinsulation is that it requires people to install it, so you create jobs that can employ multiple skill levels. There’s window replacement, pretty skilled, and wall insulation, maybe less so–you’d want a good drywall guy. But they’d need some helpers, so that supports apprenticeships. (Think if Hillary had gotten elected and proceeded with her solar energy plan…) Not everyone wants or needs to be a highly degreed digital vaquero.

    As a heat pump owner, and possible soon-to-be cistern owner, I was intrigued by the solar/heat pump/cistern loop. A bit skeptical too, about the efficiency required make it work. But then it hit me: if you have a superinsulated house, you don’t need a backyard Lake Mead and an antimatter heat pump. Also, it doesn’t have to be perfect: there’s a trade-off between the “x” percentage of time the loop works versus the “y” expense.

    Anyway, I suspect as you delve deeper into these ideas, you’ll find other synergies (which will be needed to correct the current sucky ones).

    Good stuff, Dave!

    1. Thanks for the comment. You’re hitting on all cylinders.

      Jobs: I can only conclude that “employment is a bug, not a feature.” Otherwise why wouldn’t we put thousands to work, in jobs that are satisfying and build community? Guess the Invisible Hand says no.

      Heat pumps: you’re right, the order is important. Insulate first, then the heating and cooling is so much easier. And it’s not one size fits all. Heat pumps aren’t as great in really cold climates (though getting better at that, rapidly). So there are a bunch more jobs, a little math-ier ones: tailoring solutions to individual microclimates. But the Invisible Hand says no to that too, apparently. No tailoring to circumstances! One Size Fits All!

      1. I was going to say the Invisible Hand wears a Rolex on it’s wrist, but it’s more like a Patek Phillipe, or an Audemars Piguet–at any rate, something that costs more than your house.

        It’s a big ball of wax, innit? A lot of political and cultural stuff as well as tech. Glad to see you’re looking at that, too (Elon post).

        Oh, and about the circulating pump–were you thinking about pumping water through a radiant floor system?

        1. Radiant floor system: it’s complicated (of course). Radiant-floor heating is king when it comes to heating your house with the lukewarmest [sic] water, because of the large surface area (and also because heat rises, so the floor is the best place to add heat). And heat pumps work more efficiently when they only need to change the temperature a little bit than when they have to change it a lot. Of course, a small amount of extremely hot water can be more valuable than a large amount of lukewarm water, in several ways: easier to store, easier to insulate and keep hot, less volume to move around, etc. So it’s “fair” in some sense that it takes more electricity to produce the smaller amount of hotter water–it’s a higher quality product. But all things being equal, you get the most bang for the buck by only heating the water as much as your particular heat distribution method needs, and no more.

          You would need very hot water if, say, you’re retrofitting a house that was built with forced-air heating, because you’d only have a small heat exchanger in a central duct, and you’d have to get the air quite warm to do the job. Baseboard heating is in between–the water needs to be a little hotter than for radiant floor, but not as hot as for the forced-air situation.

          Against all this is installation cost. Radiant floor is expensive, and doesn’t retrofit well. A forced-air retrofit would be cheapest, and baseboard again in the middle. For new construction, though, baseboard might be the winner.

          Then there’s the other problem with heat pumps, heating vs. cooling. Cooling via pipes in the floor is lousy, because cool air sinks. Cold feet, sweaty head. “Radiant ceiling cooling” would probably be really nice, but have never heard of it being done. (That plus radiant-floor heating would be the ultimate in expensive luxury climate control.) But cold air should ideally enter the room near the ceiling, and warm air near the floor. Hard to pull off when it’s the same heat pump driving both.

          Mini-splits (the usual kind that sit near the ceiling) can cheat a little using directional fans. In cooling mode, they should blow straight out across the ceiling. In heating mode, they should blow the air forcefully downward so it mixes more before rising. I don’t know if there are any that do this automatically.

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