Turquoise Energy Newsletter #142 - March 2020
Turquoise Energy News #142
covering March 2020 (Posted April 6th 2020)
Lawnhill BC Canada - by Craig Carmichael

www.TurquoiseEnergy.com = www.ElectricCaik.com = www.ElectricHubcap.com

Month In "Brief" (Project Summaries etc.)
 - Open Loop Air Heat Pumping - Better Peltier Modules for Solid State Heat Pumping? - Lawn Tractor Electric Conversion

In Passing (Miscellaneous topics, editorial comments & opinionated rants)
  - Catastrophes Galore (and gardening) - Curing Eye Floaters with Pineapple?: Bromeliads, Bromelaine - Small Thots - ESD

- Detailed Project Reports -
Electric Transport - Electric Hubcap Motor Systems
* Lawn Tractor as "Rototiller"?

Other "Green" Electric Equipment Projects
* Very High COP Open Loop Air Heat Pumping -

Electricity Generation
* My Solar Power System: - Monthly Solar Production log et cetera - Notes.
* Stirling Engine Electric Generator with Hot Water Solar Energy Storage? (Concept)

Electricity Storage
* Turquoise Battery Project (NiMnOx-Zn in Mixed Alkali-Salt electrolyte)
 - New Case, 3D Printed from PVB - Base for electrode Compactor

March in Brief

   (I Can't believe it's April 6th. I could have put out this newsletter by the 3rd. Some strange lethargy has come over me.)

   The first half of March stayed cold, with heavy frosts every night, snow now and then and a couple of good windstorms. When I found time to work on anything, it was the open loop air heat pumping.
   When it finally started warming up after about the 15th and one could spend time outside, I looked around and felt overwhelmed by all the projects I'd set aside waiting for warmer weather. Not for the most part energy projects, but gardening, greenhouse improvements, making a "chicken sled" enclosure that I could pull around the yard for a few chickens to forage in safety from hawks and eagles (for eggs of course), and then there was that roof over the travel trailer to put walls on and turn into a house. Then there were optional projects like a rabbit enclosure and plowing a field to try out growing different strains of wheat. (Barley grew well even in the cloudy summer of 2019. Quinoa did well in sunny 2018, but poorly in 2019. Potatoes always do well. I think I got 4 Kg of them just digging the compost pile.) And I either have to cut more firewood than last year (by thinning out some of those scrawny alders so the others have more room) or buy some more.

   Then after a pretty decent week or so, the weather turned cold again and stayed that way into April. It didn't feel like spring.
   Having started some seeds and seedlings indoors, in spite of the cold some had to get planted, so I started transplanting them into the greenhouse. I had meant to fill one area with corn since it won't grow outside here, but I'm not sure there'll be room. With the cold I planted a potted cherry tree I bought last year inside the greenhouse, in the shadiest end. I figure I'll have about 2 years before it gets too tall and I need to remove that part of the greenhouse so that that (not very productive) area is outside. Cherries do grow around here. In the meantime, unless the summer gets warmer than last year, it'll probably give more cherries in there than out in the cold. And the birds won't get them.

   There's plenty of work for the whole summer - assuming there is one. So now I have to find time for energy projects in the midst of all that. Perhaps the next battery experiments and the (almost ready to fly) ground effect vehicle should get priority. For that last project I put in some brass tubes for hinges in conjunction with the wooden dowels that went through each hull into the ends of the canard. But that was it.
   On the batteries I made a little progress on cases, and made the base for the 50x50mm electrode compactor.

   But mostly, although I was pretty busy, somehow other things besides energy projects seemed to be getting priority, especially in the letter part of the month.

Open Loop Air Heat Pumping

Enclosure with Makita air compressor (as first made);
ducts at right loop back to outdoor heat exchanger underneath compressor box.

   I found a bit more time for the heat pumping, seeking to tweak the performance of the one made with the big Makita air compressor by adding baffles inside to direct the air flow past the hot components. Keeping everything cool, blowing heat out before it's very warm, is a key to higher COP. This seemed to meet with some success. But I doubt I was getting 3 - perhaps not even above 2. Some temperature readings compared to the built-in baseboard heaters suggested as low as 1.25, but the room felt warmer than the thermometer said and the large volume of air blowing out of the unit was quite warm. There are a lot of uncontrollable variables and I wasn't convinced it was that low. On April 4th I had several new digital thermometers for improved measuring. I changed the fan back, so it now had the big fan (blowing inward - the "wrong" way), but now plus the baffling and slots in the box. Comparing it with 920 watts of radiant heat, it seemed it might be COP 2, or perhaps a bit higher.

   It seems there are potentially two main ways to do the heat pumping. One is to cludj it with an existing air compressor. This has the advantage that the heart of the system is ready made. Here one get's what I've been getting: from COP of perhaps 2 to - maybe, or seemingly - about 4 or 5, tops, which I seemed to get with the refrigerator type compressors. But a regular compressor, regardless of efficiency, expects the compressed air to be used by some other destination. In heat pumping, the compressed air is simply allowed to hiss out at the end of the pipes. That is quite a lot of wasted energy.

   The other and far more effective way would be to make an air compressor designed especially for heat pumping. Thanks to some great info sent in by a couple of readers after my last two newsletters, I discovered how to do it: after the compressed air has done everything else, given up its heat to the house and then to heat the incoming cold air in the outdoor heat exchanger, it can still be used by its decompression to assist the compressor.
   This ROVAC (Rotary Vehicle Air Conditioner - or it could as easily heat instead) design from the 1970s uses the cooled, decompressing air to help compress the incoming air. That gave me the idea, but my simpler way of doing the same thing would be with two pistons. The outgoing air would fill the second, in-line cylinder that has a rod connected to the compression cylinder. When the same amount of air has filled the outgoing cylinder as is being compressed in the incoming cylinder, it will have compressed it most of the way to the desired pressure. This now cold air will have slightly less volume at the same pressure because colder air is denser, but the motor is only needed for (eg) the last 10% and is pumping, and to only 10% additional pressure over the other cylinder's, rather than all the way up from atmospheric pressure.
   Imagine a COP even of 2 being raised closer to 20 because so much less additional energy is needed by the compressor. 100 watts to heat instead of 2000: there's the very cheap building heating!

Better Peltier Modules for Solid State Heat Pumping?

   In January or February I checked on line to see if there were and better Peltier modules with higher COPs. The Wikipedia article said some were under development with COP as high as 3. I found some "high performance" peltier modules that looked better than most. (A COP of 3 appeared on the graph lines, but that was with only a 10° temperature differential. The fridge needed 30° or more.)
   Another change from 2012 is all the low cost DC to DC converters now available on line. One isn't "stuck" with using 12-14 volts from a battery or putting two modules in series for 6-7 volts. If the best choice looks like 9.5 volts, that's now a simple screwdriver adjustment.

   They were from USA rather than China and hence quite pricey and pricey to ship. Typically US companies refuse to use the post office even for the smallest things.
   This month I finally ordered four small ones. To my surprise they arrived on the day a UPS e-mail said they would, instead of weeks later. (But: 40 $US shipping for 80 $US of parts, and a further bill for 33$ UPS collect charges (far more than the tax itself - 6$) came in the mail.) That's certainly how to make your product uneconomical for the purchaser!

   I'd like to say I tried them out, but I threw them inside the solid state fridge and there they sit. I'm sure I'll get around to trying them, uh... soon!

Lawn Tractor Electric Conversion

   I started looking on youtube for some reasonable way to break up the grass on part of the mossy turf lawn, in order to turn it into a garden to try growing grains. Instead I found a conversion of a lawn tractor to electric. Then another one. The second one was a guy, Brian Edmund Electric in Ontario, who had done more than one and who offered a conversion kit.
   Much as I had idly thought of converting mine with my forklift motor and controller on the cheap, the kit had a 24 volt motor[, reduction gear for sure] and differential already mounted with axles for the lawn tractor rear wheels, a one-piece assembly. That should be quite an efficient drive. And of course all the required parts for the conversion. That got me. I ordered it (1400$; so much for "cheap"). In addition it had two more motors for the two mower blades. No drive belts anywhere. (Later I thought the motor/reduction/differential/axles assembly might be made for some model of mobility scooter. That would have been the place to find that finished assembly. Oh well!)

   The message from all sides was that I wouldn't be ripping up turf with a lawn tractor. For that I should go up to a garden tractor - and a 48 volt motor - and "tractor" tread tires instead of "turf savers", which tend to slip even going up hills. Unless I can find an old dead one, those cost real money.
   But I got the idea (thinking of "tractor tread tires") that instead of pulling a plow, I could weld up steel wheels with protruding (bars or spikes?). The (side to side) bars would go down vertically at the front of the wheel as it rolled, digging in. They would rip up the turf and twist to horizontal as they came back up behind, scooping up clods of dirt. It should take less power to drive, or at least, the power (and tilling depth) would depend on the length of the bars and they could be made any reasonable length. I could call them "turf ripper" wheels.
   The tractor place had thrown out their old rims. ("Try the dump?" Nope, none to be seen in the vast pile of tires at the refuse transfer station.) Rats!

   Alternate plan... maybe my neighbor with a real tractor and plow will do it for me?

In Passing
(Miscellaneous topics, editorial comments & opinionated rants)

Catastrophes Galore (and gardening)

   I think I've spoken of all or most of these things before, other than the "black flamingo" corona virus event.

Many have been expecting some sort of "Black Swan" event, but...
"No one expects the Black Flamingo!" (...a la Monty Python)

   Now, suddenly, some of the problems anticipated for some years now are getting real, looming right in front of us.

   How bad is the corona virus? Predictably, it is worst in crowded cities. New York is a prime example. That doesn't mean it isn't spreading everywhere via air travel, or that one will be entirely safe even out in the countryside. Much depends on proximity to others and much depends on careful sanitary measures after being where people are, or when people come to the door and touch your doorbell, doorhandles, and so on. Keeping 6 feet distance from others is a big help, apparently. (It figures that the drug store here is closed and the groceries are out of sanitation products. Earlier I had asked about masks but they were already sold out. No one has been the least bit prepared!) Evidently the almost universal wearing of masks in public has greatly blunted the spread in Korea. Someone has said that if no protective measures were being put into place, there would be 40 million deaths. That is almost equivalent to the Spanish Flu of 1918-1919. (50 to 80 million dead, from a global population then under 2 billion) Hopefully it is also wildly exaggerated. This virus, while wildly contagious, has only a 3-4% mortality rate. (A nephew of mine who works at a hotel in Victoria had it. Apparently he had one very bad day with a high fever, but he recovered. I didn't ask, but no doubt he had very good medical care.)
   Many expect this epidemic is likely to abate in warmer months while people are outside in the sun, and return for winter 2020-2021. The Spanish flu was also worse in its second season.

   It has been warned by more than one source that with the present density of the human population, inevitably some disease will come along that will kill billions of people. This virus is, then, just a foreshadow of what's to come. Or perhaps it will mutate and become more lethal itself. Hopefully that's a decade off, maybe even two, but we have no guarantees.

   On top of the corona virus two other catastrophes are looming. One is potential - now seemingly inevitable - famine. This too has been warned of for some years. We are so used to having an abundance of food this seemed - still seems - inconceivable to the majority. But kicking it off rather suddenly, agricultural production globally was devastated in 2019. (EG, go over some of the video reports of the past year and more on youtube by "Ice Age Farmer". Real figures and articles from credible sources.) For 2020 we again face outrageous predicted (and already actual) weather, widespread shortages of seed of many types owing to drops that didn't grow last year, and even shortages of farm equipment and repair parts owing to the virus related shutdowns, plus farmers everywhere who are now bankrupt after last year, and so many farms won't be planted this year regardless. And each foolish edict from governments seems exactly calculated to make a bad matter worse. (I'm sure it's not deliberate, but no kidding: for example even many retail and mail order garden seed outlets stopped taking orders in March or they are out of product. Then at the start of April, some US state governments had also banned sale of "non-essential" items... which included garden seeds already sitting on store shelves! As scarcities begin to manifest, food, seeds and the spring planting season are going to waste. Milk is being poured down the drain at dairy farms owing to shortage of labor at the dairy plants and in the UK eggs are rotting simply because of an egg carton shortage. All while purchase quantities are being limited in the groceries.)
   People wanting to get a little ahead on food for whatever emergencies are now being called "hoarders", and they are being blamed along with the virus, but if the warehouses weren't getting empty already the supply lines could handle these things.

   The other catastrophe (along with economic collapse) is financial collapse. In Y2K, US dollar base currency was something like 850 billion dollars total. Now the US central bank is nonchalantly printing 6 TRILLION dollars almost overnight to prevent collapse? That's over 18,000 $ for every American man, woman and child, on top of all its other egregious money printing. Bank of Canada is now also going to purchase assets - in accord with all the other central banks. As the central banks print enough money to buy every investable asset, everywhere, from everybody, and the price of food keeps going up, how long will confidence in the currency remain? And how do banks make money with negative interest rates?
   And now that I've hit 65 and have received just two fabulous monthly pension deposits of 1200 $, the Canadian government is going to give lots of people all over of any age (excluding the retired) over 2000 $/month "pensions" owing to the virus.
   Unless some very different directions are suddenly chosen, the banks are going to collapse and the money will hyperinflate and become worthless. In what order those happen or with what speed I won't try to guess.

   But even these may not be all the troubles that we experience in the coming seasons. Volcanic activity and earthquakes have seen a steep increase in recent years. Some places are already suffering from such activities. If a huge volcano like Yellowstone were to go off in a major eruption, anywhere 100 miles around it could be a death zone, and with the ash clouds it could disrupt life in much of the continental USA and probably not leave Canada untouched.
   And recent measurements of the ocean water temperatures and undercutting of ice sheets in Antarctica and Greenland are warning us that 3 meters or more of sea level rise may come much more rapidly than any past predictions.
   And if the ice is thinned substantially over Antarctica and Greenland, they are sure to rise up in compensation as the immense weight of the ice is reduced. When they do, other areas will have to subside. So probably some continental lands and coastlines will sink by still more than the 3 meters of actual ocean rise. Along with storm surges and tsunamis, hundreds of millions could be displaced and become internal or migrant refugees. Maps or satellite images of the world are likely to look visibly different by the middle of the century.

   Through all these causes, the population will be much reduced - to under three billion, perhaps even under two. In the middle of what looks like unmitigated disaster, the silver lining is that if and as much of the façade of today's civilization is ripped away, it is only in order that it be replaced with something much better - a world and society more humane and equitable, without wars, with a higher quality of life and plenty for everyone, stable and sustainable. In order to renovate, some of the old and inferior aspects of the dwelling must be torn down in advance to make room for the new and superior construction to come.

Addendum: Here's another aspect to the farm production crisis that has "cropped up". Plants need phosphate, the "P" of the three main "N-P-K" fertilizers. It is mined, and it's getting harder to extract. (What about that is sustainable in the first place?) Last year with the bad growing season, demand from US farmers was down, and so costly phosphate mining operations shut down. Now there isn't enough available in the USA for this year. China, a very large producer, has banned exports owing to their own needs. It has been said that US farm yields could be down as much as 50% from low phosphate levels in the soil alone. (And they banned phosphates in laundry detergents because the fertilization effect caused algal blooms in a very few streams or rivers!)

And to bring that down to the practical level:

* I call nitrogen, the "N" of the above main fertilizers, "vitamin P for plants". Actually that's spelled "Pee". While I wouldn't add it to growing garden plants, it's the easy and free way to fortify garden soil in the winter and when and where there's nothing planted.
* Here on the BC north coast where it's deficient in soils, lime (calcium compounds) can be added as broken or crushed seashells.
* Potassium ("potash" - the "K") compounds can come from wood ashes.
* Other than buying "bone meal" (pricey) I don't know where to get phosphates.
* Seaweed is a great fertilizer. (Maybe it has phosphates?)

   Fertilizers aside, if it would just warm up above near freezing with frost at night and occasional snow flakes in the cold rain (this is April?), I could put some of my seedlings out in the garden. Now I'm wondering if I should concentrate on greens in the house. Here's some of my indoor gardening work.

Some seedlings. They have become "leggy" - tall and scrawny - owing to
insufficient light before I finished the "LED wall garden".

Here are some quinoa seedlings where the lack of light earlier really shows.
(The onion bulbs quickly became rootbound and had to be planted in
the greenhouse. They didn't died of exposure and are growing. Yay!)
The coffee bushes lost a lot of lower leaves owing to having light coming
only from straight above.

Some readers will remember my old "LED garden": a table with
lights underneath (here turned off) and some rolling dollies for planters.
I started trying to put some shelves on the wall in the corner, with
some real "grow light" panels. It wasn't as wide to the window as
I had been visualizing - not enough room for two columns of shelves.
(Under window are heat pumping radiator pipes.)

I ended up taking the legs off the 'light table' and mounting it up high on the wall.
I can't help but think the 20 LED "light bulbs" (~170 watts) look like a lot more
light than the three grow lights beneath (84 watts).

The setup by the start of April.
The kitchen/dining area is pretty cold if it's cold out,
so the curtains help keep heat from the lights in.
(They meet quite nicely, but the left end has a gap
caused by the "U" end of the heat pump pipes. But it's a
couple of degrees warmer inside when the lights are on.)
The cherry tomato on the left in the square pot, left over
from last spring, pollinated with a brush, and draping over
the spinach box on the table, is producing enough for salads.

Here it is open to view with the curtains open and the lights out.
There are now three levels of lights with plants under them.
(More light panels are to be added under the middle shelf.)

Curing Eye Floaters with Pineapple?: Bromeliads, Bromelain

   Youtube suggested a video by a doctor whose videos I'd seen before. He was commending a recent study where people ate pineapple, and their eye floaters disappeared. It wasn't a large enough sample size to wake up the AMA, but the success ratio, near 100%, sounded very convincing.
   Pineapples are a member of the recently evolved (12 MYA) bromeliad plant family from South America. It seems the active ingredient in pineapple is bromelain, which can be extracted from the stems. I looked that up, and it seems bromelain can dissolve proteins. What are eye floaters? Dead proteins ("and other debris" - Wikipedia) inside the vitreous humor in the eyes. So this seems to make sense.

   Not being much of a fan of eating pineapple (and invariably getting cold sores in my mouth), I ordered some bromelain capsules. (Actually they were "turmeric and bromelain" capsules from CanadianVitaminStore.ca in Victoria just before they stopped taking orders owing to unprecedented demand. ...And I thought that was just garden seed companies!) I'm taking one every day. I (very much) hope to be able to report good results in 2 or 3 months.

Small Thots

* People always matter more than things. If costly jet liners have to sit on the ground to slow the spread of the virus, that is better than having to raise and train new flight crews, and also to replace all the talent and experience of the passengers who will die.

* OTOH with food already in short supply, the world can't afford another bad harvest season. If farm labor isn't out there to plant in a timely manner this spring, as it appears various factors are causing, the harvests could be even worse than last year.

So, people are at risk in more ways than one. Where is the "best compromise" line to be drawn?

* US Government: We're closing the border to Mexican migrant workers because of the corona virus.
   US Farmers: We need our trained, willing and able labor force! If we don't have farm labor, we won't be able to plant, and Americans won't eat next winter.
  (US Government reaction?: Farmers are threatening us again! -- Actually I think in a brief fit of realism they lifted the ban. But if the workers have to undergo 14 days quarantine they may be available pretty late - and will they even come?)

* How might corona virus rate in causes of death in the overall scheme of things? Respiratory diseases and infections were third and fourth in 2017. Hopefully at worst the virus just might double that, reaching 5 million or more, or it might be under a million. (300,000 people drown every year?!?)

* Another addendum to the hair care bits of recent months: There is a slight feeling of soreness, tenderness, discomfort (I can't find the right word) of the scalp which I have come to associate with scalp conditions improving after having been poor, rather than with it getting worse. I like to think it happens because previously dormant or damaged hair follicles are coming back to life. I had my hair cut very short, almost shaved (she called it "shaved") because I had heard it can help with hair loss (the one thing I hadn't tried in recent years), and also to better see what hair loss I had.
   I found the whole top, at the middle, from almost the front to the back seemed thinner. (the top-back is where I had previously noticed it in double mirrors.) With 3/4 inch at the front being just fine, and with my hair normally combed sideways, I might never have noticed the rest until it was virtually bald. Without treating it, I might have been headed for the "Telly Savalas"(sp?) look. After that, I noticed that "discomfort" of the scalp at times in that area. So I'm not holding my breath, but I'm hoping it will come back to full thickness eventually. After a month or so, it finally occurred to me to take a couple of pictures. It's less obvious but still visible. So if it does get noticeably thicker, I'll have "before" as well as "after" pictures to show it. (Ug! The photos showed more thinner areas on top than I had been aware of. They looked worse in the straight-on images than in the mirrors.)

(Eccentric Silliness Department)

* There is not much silly this month. Swallowed overdose of "serious" and "viral hysteria". (I thought of two good puns at some points, but I didn't get them written down... gone. I'm sure they must have been fantastic!)

* In a video about grid tied plus battery solar in Australia (or was it New Zealand?) a screen flashed up "5¢ earnt". I laughed for a moment at this weird spelling. But if money is "spent" why isn't it "earnt"? Apparently it is in Australia. And why do we use "ed" for all "regular" past tense verbs anyway? The "e" is often silent. Why is it (eg) "relayed" and not "relayd"? (Not to be confused in either case with "relaid".)

* The kitchen table was stacked with debris, largely from 3 months worth of heat pumping builds and experiments. They being mostly finished, one day I resolved to clear it off. I didn't get far. I would take something out to the workshop or the greenhouse and get sidetracked there on something else. Finally I decided to set myself a more realistic goal: I cleared off a small but somewhat cluttered end table in the livingroom instead.

(I did eventually finish clearing the kitchen table, some days later, bit by bit.)

   "in depth reports" for each project are below. I hope they may be useful to anyone who wants to get into a similar project, to glean ideas for how something might be done, as well as things that might have been tried, or just thought of and not tried... and even of how not to do something - why it didn't work or proved impractical. Sometimes they set out inventive thoughts almost as they occur - and are the actual organization and elaboration in writing of those thoughts. They are thus partly a diary and are not extensively proof-read for literary perfection, consistency, completeness and elimination of duplications before publication. I hope they add to the body of wisdom for other researchers and developers to help them find more productive paths and avoid potential pitfalls and dead ends.

Electric Transport

Lawn Tractor "Rototiller"?

   I ordered a kit to turn my lawn tractor electric. 24 volts. Charge with solar panels and run it for free. Regardless, I want to use it to turn some lawn into a garden plot.
   But the message from all sides was that I wouldn't be ripping up turf with a silly little lawn tractor. For that I needed to go up to a garden tractor - and if it was electric it needed a 48 volt motor - and "tractor" tread tires instead of "turf savers", which on the lawn tractor tend to slip even just going up hills.

   But when I wrote the above line, it struck me: ...want to rip up turf ..."turf saver" tires. What's wrong with that picture? Then I thought, in fact, maybe that's the key: instead of just "tractor" tread tires and making an attachment to plow or till, I could make a welded steel rear wheel (or two?) with spikes/special blades or something to plow/till/harrow the turf simply by driving over it. Maybe something like diagonal "tractor tread" pieces but hard steel, longer sharp thin "treads", angled toward the rear. They would dig down almost vertically into the dirt, then as the tire continued to turn, the "blade" would twist to almost horizontal at the back as it lifted out of the dirt. That should really rip up the moss and ground simply by driving over it. (If you drove fast clods might even be flying into the air behind!) I would change the regular tire(s) for the special wheel(s) after driving out to the intended plot. The wheel(s) sure wouldn't slip while plowing when the plow is the wheel! And they wouldn't tax the motor like dragging a plow. Gosh, I may have something here!
   The rims of the tires are much smaller than the tire outer diameter. Some old regular rims that already fit the tractor might be perfect. Instead of tires I could attach the ground ripping components to them.
   I found a catch: the tractor place had thrown out all their old rims. "Try the dump." I suppose I could do that. (Nope, couldn't find any there.)

   Hmm... OTOH... I found a youtube video where someone had sprayed his overgrown gravel driveway with salt water to kill the grass. Maybe that would be an easier way than mechanically ripping up the dirt: just spray salt water and kill the grass, moss and weeds a few times to prepare the soil for planting? Hopefully by the time one was planting the old stuff would be pretty dead and a new lawn wouldn't quickly overwhelm all attempts to weed the garden.

Other "Green" Electric Equipment Projects

Simple Air Compression Heat Pumping
- or -
How to Heat a Building Almost for Free

   The fridge compressor was pretty quiet and I couldn't hear it with the warm air "computer" fan running on the heat pump radiator duct. I had put a 15 ohm, 5 watt resistor in series to slow it down, but it only slowed it a bit. The fan wasn't loud but it was continuous with an "edge" to it, and it was so cold out I left it running to help heat whenever I was home to monitor it. By the 8th I noticed that my tinnitus had gone wild. I was listening to a piercing tone in my ears at all times, especially when it was quiet. A much quieter fan arrangement was needed.
   I didn't dare run the system when I wasn't there. On one evening I had caught the air pressure rising and I turned it off, and on another I noticed the compressor sounded labored. It had pinned the needle on the air pressure meter. (and in fact bent it. I had to get a new one.) It must have been well over 250 PSI - maybe 300. A pipe-clamped plastic-on-copper join was hissing air, which is probably the only reason it didn't go even higher. Air compressors compress humidity along with air, and when it reaches the outside exit, decompresses and cools perhaps below outdoor temperature, it condenses and the water was apparently freezing and plugging up the outlet. I opened the tap later and a tablespoon or more of water came out.
   Ideally one would have a little pipe heater at the exit, perhaps activated by excess pressure, to prevent freezing. Failing that, something to shut the system off if the air pressure was too high. Nobody in town had an air pressure switch. I ordered one from China (3$) which... hopefully... should arrive by summer.

   I rather dreaded hooking up the loud Makita compressor. I had, or did have, a larger fan that was probably quieter, but I couldn't find it. One advantage however is that the Makita has its own shutoff at 120 PSI, and so can safely be left to run unattended. I could leave it running when I went out. And it had more power. I could close the kitchen door to block the noise and the kitchen would get warmer instead of colder. It would (surely!) even want a thermostat which would shut it off part of the time.

(8th) I cut the pieces of plywood to make the compressor enclosure, and screwed the bottom and three sides together. The last side needed cutouts for the warm air duct and the fan and the top would go on after that.

(10th) Where was that fan? I thought I had seen it, but perhaps I thew it out when I moved? Not finding it anywhere, I went to Skidegate. Co-op didn't have one (no surprise), Fields didn't have one ("wrong season") but said I could go to Fields.ca and order one, to be shipped to the store. I picked one out and got to the "checkout", where I discovered there were shipping charges ("under 50$"). I looked again at the choices... "oscillating pedestal fan". Maybe that would be quieter?...
   Wait! I already had an "oscillating pedestal fan"! Someone had given it to me a few years ago. The pedestal had broken, and the front of the fan cage had fallen off. But somehow it hadn't got thrown out in my move. Wasn't it sitting somewhere in the corner of the shop? Sure enough! I guess I just couldn't see a white fan in 1/2 a cage in the clutter when I was looking for an open black fan. So I already had one, and plugging it in and on "low", it proved to be as quiet as a fan is going to get. I cut a big round hole in the box and mounted it by putting screws on the outside of the cage rim.
   The motor was too fat to mount inside to blow outward, so once again it blows into the box and from there into the duct rather than sucking through the duct and blowing outward. Having determined that all the pipes (and hence the duct) should gradually slope down to expel moisture, I'm pretty sure that's backward, trying to push warm air downward instead of pulling it upward. Maybe later I'll figure out a mounting so it can work the other way around.

(11th) Much of the day was occupied with making a stand for the compressor box. (It takes longer when you're planing your own lumber that you milled.) Like the last arrangement (with the fridge compressor on a chair) I wanted the compressor highest up with the pipes gently sloping down all the way so moisture would flow along them and go out the outdoor end. Otherwise quite a lot builds up and burbles in the pipe. I put the box on the stand and then lifted the compressor into it.
   Then I laid out my finned pipes and found fittings to connect them all together, and did some required soldering. There were too many to simply have a straight line, and anyway I wanted some of the wall space for a new LED indoor garden setup with adjustable shelves. So the compressor is at the same end as the outdoor heat exchanger and the pipes do a U-turn and are double along the wall.
   The elbow I wanted to use didn't fit properly into the "drain" hole in the compressor. It only went in 1/2 a turn and ended up pointing the exact opposite to the desired direction. I got a "1/4 inch NPT threading die" and expanded the hole in the compressor a bit.
(12th) I uncovered a way to make a far higher performance compressor, by making it with a decompressor to help drive the compression cycle. Efficient air heat pumping is possible after all! A COP of 10 started looking minimal. It might not attain to 100, but that's the direction it's headed I've written that up down below. But it was still frosting and snowing and under 5°C this far into March. To have heat in the meantime before I ran right out of firewood, I still had to get the Makita compressor connected and pumping heat, even if it was only COP 4 or 5.

   One thing I wanted was to make the 180 degree bend at the far end as a smooth curve without any sharp corners where the air would make a hissing sound, as I heard in the first couple of experiments with a 90 degree pipe bend. From the sound I had suspected a leak at the elbow.
   I wished I had some gallium. I've heard of that from brass musical instrument makers: heat up the gallium in warm water, pour it into the tube of the instrument, then dip it in cold water. The gallium freezes, making the tube into a solid rod which will bend nicely. Then dip it in warm water again and pour the gallium back into its bottle.
   I hoped the building supply would have a pipe bender. They didn't, but someone suggested a place that did. I went there and a guy grinding a piece of metal said he didn't think theirs would work for it - it would probably kink. He said to fill the pipe with water, put it in the freezer, and with frozen ice in it, bend it around something the diameter I wanted.
   Brilliant! Exactly what I needed! Why did I have to think "gallium", expensive and hard to get, when there was water and ice? Perhaps the instrument makers are afraid of freezing water splitting the pipes - or just that ice expanding them a bit might change the tuning and gallium doesn't expand when it freezes? I cut a block of wood to the right shape and drilled a hole in it for one end of the pipe. I clamped it to a workbench. After I waited long enough and the ice was solid (2nd try - and the unpressurized ice didn't split the short pipe), I took the pipe out to the workshop and bent it around the wood. It worked beautifully! The quite steeply bent soft (annealed) copper pipe wasn't flattened at all, and had had no tendency to kink. (Now I know how to make brass instruments... or maybe a shower pipe more to my liking for the bath, aimed down a little steeper!)

The "U-turn" pipe at the middle of the radiator pipes.
I used a threaded pipe union on one end so the two
lengths could be handled separately until assembled.
(Egads, the plant grow lights really make the colors weird!)

Hooked up and running.

With the fan that draws instead of pushing.

(18th) I finished putting it together, and I tried it out 2 or 3 times. The compressor uses so much power it makes the plant lights (probably on the same circuit) flicker a bit.
   Before the last test I found a different fan at the refuse transfer station. The blades and rotation were set to draw air through the motor instead of pushing it away, so I cut a new piece of plywood (as it was smaller than the other one) and put it on to blow the air outward instead of inward. (It seems to blow it out the sides more like a centrifugal fan. Perhaps it can't get enough air through the duct - one can really feel the air sucking into the end of the duct.) The results seem puzzling. When it's turned on, the room temperature seems to rise quickly. That seems really exciting. Then the rise slows dramatically. After an hour it's gone up maybe 2 or 2.5°.
   It uses around 900 watts (the fan accounting for 65). When I put in 920 watts of electric heaters, the temperature only rose somewhere over one degree in an hour. So it would seem the COP is at least better than 1. But it seems more like 2 than 4 or 5.

(22nd) Similar results. It rose a full degree in 8 minutes, then slowed down and hit 2.5° in an hour. There are any number of wild variables:
 - outdoor temperature
 - temperature of the livingroom: if the livingroom is colder than the kitchen it definitely heats slower.
 - The fridge: when the fridge runs, the room temperature goes up in a few minutes by about 1/2 a degree. (Amazing!)
 - door openings and closings (livingroom door, door to cold entryway, patio door to outside).
 - wind chill.
 - sunlight coming through the patio doors
 - Whether or not the plant lights are turned on. (270(?) watts of extra heat)
 - trying out different air pressures
 - The heat pumping blows air, while the electric radiant heat doesn't. So the heat pump air was probably more heating all the walls and furniture. The temperature gain might last longer than from the radiant heaters. Or not - heating the windows is a losing proposition.

   I thought about the air flow. I opened the top of the box and set it slightly askew so it could pull some air through the box as well as through he duct. Sure enough, the air started blowing out forward from the fan instead of coming out sideways around the edges. It must have greatly increased the flow. The compressor heat - both from its power consumption and from compressing air - must have been building up in the box instead of blowing into the room.
   With the change, the room temperature started rising rapidly, degree after degree. It soon seemed to be up from 18.2° to 21.0° - notably warmer than the livingroom where I had fallen off on tending the woodstove and there wasn't much fire. That seemed really exciting until I realized that the fan was now blowing the warm air across the room onto the temperature sensor 6 feet away. So that was really the "warm air out" temperature. That was probably the same reason as for initially getting better results than later in previous tests, too. Still, it was blowing a large volume of warm air and could hardly fail to be raising the room temperature. I opened the crack a little wider and the air blew even more straight out.
   The finned radiator pipes beyond the air duct actually felt like they were probably above room temperature, too; not really warm, but not cold either. But the far end was cooler than coming out of the compressor, so it was radiating.
   After the time spent writing this, the air coming across the room was 22.1° instead of 21.2. That would be because the whole room was actually warmer by that amount. I turned the noisy thing off. After a few minutes the temperature read 19.8°. Still, it had started off at 18.2.

   In the evening I ran it again, this time with the thermometer aside from the warm air stream. Outdoors it was +3°. Room temperature went up by 1.2° in 45 minutes (from 17.8 to 19.0). Then I turned it off and put on the 920 watts of electric plug-in heaters. In 45 minutes they raised the temperature a further .5° to 19.5°. Does that make the COP 1.2 / .5 = 2.4? probably something like that. That's disappointing, but perhaps some parts of the compressor are still getting too hot?

   It would seem that the next thing might be to make some strategic holes in the box - maybe even put short ducts or shrouds inside - so that the air flow would be directed right across the compressor elements making and having the heat. A coefficient of performance of 4 to 5 or more from a regular air compressor just might be in there!
   On the 23rd the house was cold and I decided to run it while I took a bath. I had taken the lid off. This time I put it back on with a bigger gap at the back. And I realized that was the right place: the fan had to draw the air through the box from the back. If I also put in a baffle or two, it would have to draw it right past the compressor. The blow from the fan was stronger with the larger gap and I realized I hadn't had it open wide enough previously.
   I checked the initial temperature: 16.7°. After I came out of the bath I turned off the racket, and checked again: 15.5°! Well, it might not be super, but it couldn't be cooling instead of heating! What was that I said about too many variables? The sliding door was open to the cooler entryway/alcove area. I guess the fan blowing so much air had caused more cold air to blow in faster from there. (Okay, that particular variable should have been under my control. But I didn't notice.)  In fact, that door being open was probably why the house was cooler in the first place. I closed it, and soon the kitchen was reading 16.6° again.
(24th) I made the air baffles and tried it out during the day, for an hour. The room went from 17.8° to 20.1, a 2.3° rise. Of course, it was +7° outside and some sun was breaking through the patio doors. Then again, the fire was out in the livingroom so it was cooler than the kitchen. Variables!
   Soon after I turned it off, I opened the lid and felt the components. The compressor heat sink fins and its ouplet pipe's fins were too hot to rest one's fingers on. Clearly the COP would be much better if those could be kept cool. That meant finding some way to get air blowing right across them at a good speed. Since they were inside a box and under a shroud aimed sideways, that was going to be tricky. On the 26th I fussed around and cut some pieces. I arranged them so they would try to push air through the shroud the same way as the motor's fan. That should be a fair reinforcement.
   Outside it was +7° C. The room went from 17.8 quickly to 17.6. Grr! Then it started to rise, and in an hour it hit 19.3°. I was disappointed. But it felt warmer to me. Then I realized that in spite of all the moving air, the dining area on one side seemed warmed than the kitchen area where the temperature sensor was. I moved it and soon it was reading 19.8°! Since I don't think the temperature - in this single "two cubes" space - was stratified before, that was 2.0° degrees warmer than it had been - except the kitchen was only up 1.5°. I moved it in front of the fan, five feet away, and it soon read 22° - the warm air out, even at that distance, across the table. I shut it off and opened the lid. The compressor fins still felt hot, but I don't think they were as hot as before the baffles. That might be about the best that can be done without going to great lengths. If I'm going to go to great lengths, I might as well do so making a heat pumping air compressor that would really perform and give far better performance - very high COP.
   I then turned on the baseboard heaters that I almost never use. (8:47 PM) I had checked the ratings: 1250, 500 and 500: 2250 watts total. In 1/2 an hour temperature went from 19.8 to 21.8; 21.9 or 22.0 on the dining side where the heaters were. That would have been 4° in an hour, where the heat pump had got about 2°. So perhaps it was heating around 1125 watts, and using about 900. 1125/900 = 1.25 COP.  That was pretty disappointing - and it certainly didn't seem as good as I had been getting from the fridge compressors. Still, with the heat I could feel in the cast alloy fins after it was running it was obvious it wasn't working as well as it ought to be. The cast cylinder and fins probably didn't even transmit the heat very well, so the cylinder and piston were running even hotter than anything that could be felt on the outside, instead of cool.
   A compressor made for the job would give far better results. The potential to change the whole outlook for heating in the north (and doubtless air conditioning in hot climes) is still epic and untapped.

I noted previously that while an electric air compressor seems to use an amazing amount of power even to blow uncompressed air, a bicycle hand pump takes virtually no effort until it is actually compressing. I found one in the garage, so here it is for anyone who hasn't seen how simple they are. The tapered rubber piston seal presses against the cylinder wall on the power stroke, but lets air pass on the back stroke.

April 4th - Another Test

   As I still haven't got this newsletter out... on chilly April 4th morning I thought to try out the Makita system again, this time with the large fan again, now that I had made the slot and baffles in the compressor housing. It looked the same as originally except that I opened the slot in the lid still wider. And it had the baffles inside. It seemed to work better.

   An improvement to the testing was that the previous day the digital thermometers I had ordered had arrived. As one might expect, they didn't seem to entirely agree with each other to .1°, but 3 out of the 5 were within .2°. The others were "add .3" and "subtract .2" - at room temperature. Things changed somewhat outdoors at around +2°. They all read about 1° higher than the old one, so it's probably the old one that's off. They took those horrible little button cells instead of (rechargeable) "AA" or "AAA" cells. Those will become an annoyance. Maybe I'll still look for some others and pay attention to what batteries they take?
   After some use, it seemed the amount of disagreement between units wasn't constant. Perhaps the readings vary a bit depending on the state of the batteries, among other things?

   I started about 11 AM PDT (9:12 AM actual local time). Outside was +3°. The kitchen was 14.9°. Once it had been running for a bit, the warm air out the rear slot was 7° warmer than that going in: eg, 22.8° versus 15.8°. As well as saying the 900 watts was making more heat than the 150 watts of the fridge, that higher rise cuts in half the potential COP compared to 3° rise from the small fridge compressors. In addition, the air coming out at the left of the rear slot was much warmer than that from the right (around 4° warmer than the incoming), which suggests that the airflow inside the box is still less than even or optimum. Perhaps I should examine the baffles carefully. Either that or... have an even bigger, faster fan? Or another fan inside the box, blowing right on the compressor? In half an hour the room (and intake air) was up to 16.6° or so. It didn't seem like much performance.
   I discovered that the farther into the housing I put the sensor (even being sure it wasn't touching or right next to the compressor), the warmer it was, until it was as high as about 9° above the incoming air. Yes, definitely the circulation was not the best in there, and that's partly what was killing the COP. Maximum potential COP with 10° rise is only 30, where with 3° it's 100. And the poor efficiency of a regular air compressor of course brought either of those figures way, way down, but more so with 10°.
   I felt the radiator pipe where it came out of the duct (which was much shorter than the pipe - another inefficiency) and near the end where it went out the wall into the outdoor heat exchanger. It definitely got cooler as it went, so it was radiating some small amount of heat. But it seemed trivial compared to the warm air blowing from the enclosure.
   In an hour the room was up to 17.1°. The kitchen area wasn't as warm, 16.5°. In spite of an open passage and being open between the countertop and the upper cupboards (at eye level to the ceiling), it was taking a while to catch up to the dining area. After about an hour and a half I turned it off. The room hadn't quite hit 18°.

   In about 20 minutes the room had already dropped to 16.6°. At 12:36 I turned on the two portable radiant heaters totaling 920 watts. In half an hour it was up again to 17.1°. Soon after that it was 17.5° -- because the fridge had come on. It shut off again having added .4°. The fridge (itself a heat pump) is a wild card. Had it been on with the Makita heat pump? Probably, but in the noise there was no way to hear if it was running. And the plant grow lights had been on part of the time with the heat pump, but I had turned them off to take a picture. When was that? I put them back on for the last 15 minutes of the one hour radiant heating test. Also, I had put a fire on in the livingroom (long common wall) and it was substantially warmer, and it had gone up to 4° outside, so the kitchen should be easier to heat. The the end of an hour, the kitchen was 17.7°, up 1.1°.

   Hmm... about 2.2° rise in an hour with the heat pump, compared to 1.1° for the radiant heaters of very similar power that should have had a slightly easier time heating the kitchen. That made it better than I had thought - maybe 2.5 COP or at least over 2. It wasn't a stupendous unit that would make the room comfortable in a short time using just 950 watts of power. And it was very noisy. Perhaps it's practical except for the noise, but if I want to heat the house, the workshop, and maybe the garages and the greenhouse as needed, all very cheaply, then creating air compressors made for heat pumping is really the key.

Designing a High Performance Heat Pump Air Compressor/Decompressor

(11th) Could there be better ways to make an air compressor specifically for heat pumping? A couple of readers sent me some little known or obscure information on compressed air systems. (Wow, thanks!) Apparently way back, even before 1900, people were experimenting with complex air compression and decompression systems. And there was at least one gem, and probably some more that I didn't get as far as reading and comprehending.

   In 1926 someone apparently made a car that needed gasoline to get up to 10 MPH, but above that it used a complex system to propel the car on air alone, and it could get up over 60 MPH - a very high speed at the time.
   It was explained that this wasn't perpetual motion, it was actually solar energy propelling the car. Acoustics were involved: a complex mechanism put more air into the pressure tank when the sound wave created a low pressure point. I didn't follow all of this document which was whole chapters out of a book, but I suppose - assuming it actually worked (I'm not 100% convinced as the inventor didn't disclose all the details) - that the air came out the end cooler than ambient after going through three compressed air tanks and various heating, cooling, compression and decompression cylinders in the engine, so it was the ambient temperature and pressure of the air that was being used to drive the car. Wow! (I wonder what happened to him? Instead of becoming rich and famous, people who have invented such things usually seem to have disappeared from view soon afterward with no further news.)
   Apparently Nicola Tesla was quite involved in the technology around 1900. There were compressed air railway locomotives. I expect they had to start with a charge of compressed air, but by going through different stages of expansion, compression, heating and cooling, with three tanks at changing pressures and temperatures, evidently they got a lot more out of a tank than (eg) Tata Motors compressed air powered vans in India do today.
   Anyway, that info was a couple of chapters from a book. I'll get around to reading it carefully sometime. Soon!

   Another reader sent a document describing "ROVAC", ROtary Vehicle Air Conditioner from the 1970s. Since it had a heat radiator (here outside the cab), it could have been used either for heating or cooling. Of most interest was the heart of the beast, the rotary compressor itself. It looked like it would be pretty quiet. In one half, the air was compressed (and sent to the pressurized radiator). In the other half of the rotation that air (after cooling in the radiator) was decompressed again (making it even cooler than ambient, for the air conditioning).
   I thought that the design seemed needlessly complex and lossy by friction. Air can be decompressed just by letting it out through a valve. Why waste half the rotary compressor mechanism to do it? Was it just to decompress it gradually and hence quietly?
   I looked at it again in the evening (still 11th) and suddenly realized it had a huge advantage: The decompressing air helped power the compression! If air compression was akin to trying to lift up a heavy elevator in a shaft, the decompression was a counterweight dropping down on the other side, balancing it all out. The whole system would use far less energy.

   It failed to become commercial. One suspects the compressor was just too complex mechanically to really work well. It must have had a lot of friction with all its moving, sliding vanes having to seal on all sides in the elliptical cylinder. And no one thought of it potentially for building heating, owing to it being intended "for vehicles" and "for air conditioning". On a petroleum vehicle there's no use for heating because most of the energy from the fuel becomes waste heat anyway, readily available to heat the cab.

   Someone on a discussion list had mentioned using decompressing air to power a turbine to recover compressor energy. This did it all in one unit! It compressed air, which takes energy, but it would more freely turn because it was equally decompressing it and returning much of that energy on the way out. The main work of compression was done by the decompression.

   There is a loss in the air itself. Heat pumping isn't magically free. The pressure is equalized throughout the radiator section, but cold air is more dense than warm air at the same pressure*. To maintain pressure, no more molecules of air can be decompressed than were compressed, so the volume or air to be decompressed must be less than that being compressed. How much less? If the air temperature goes from 300°K (when compressed) to 275° (27°C to 2°) through the radiator and outdoor heat exchanger pipes on a cold day, I expect the cooled air should be 275/300=92% of the volume of the room air at the same pressure. If I have it right, ignoring incidental losses the compressor motor has to provide 8% as much energy as an ordinary compressor's motor. So even if not magically free, heat pumping could get really cheap!

   With a truly efficient air compressor made specifically for heat pumping, suddenly a heating COP of 10 looks puny! Suddenly the supposed "inefficiency" of compressed air heat pumping is exposed as misinformation, perhaps innocent owing to lack of imaginative thought, perhaps perpetuated by corrupt vested interests - or clumsy attempts at implementation that were considered failures - a century ago until no one remembered what was possible. And there are probably more ways to do it - maybe there's a simpler sort of mechanism - two (or more) connected pistons compressing and decompressing simultaneously, perhaps? How is it possible with such promising beginnings and designs dating back to the late 1800s all this simple yet fantastic technology has been overlooked and then forgotten for over a century?

   It was getting very late. I started trying to think of simpler ways to do the same thing. I took a clipboard, paper and pencil into the bath, and then to bed.

(12th) Okay, how about this:

   A cylinder has a piston in the middle. The two ends are separate, and both will hold pressure. One is the compressor end, similar to other compressors; the other end, instead of being open to outside air, is the decompressor end.

   The center piston may perhaps be screwed in and out as I proposed last month. or some other mechanism. It pushes air into the radiator pipe and a one-way flap prevents the air from returning. The air intake can be a one-way flap at the same end that only allows external air (indoor air) to come in from outside the unit. That's pretty standard.

   The other end of the cylinder is the decompressor. Here the one-way air flaps seem to be backward and I haven't thought of a way to make them automatic, so they will have to be some sort of activated valves. It works like this:
   On the compression stroke, a valve opens and this cylinder gets its air from the compressed air radiator pipes. The compressed air helps push the piston to compress the next 'batch' of air in the compression end. In fact, for most of the stroke it will power the piston forward. When the decompression cylinder has filled with as many molecules of air as are being compressed, the valve closes. A microcontroller controls the timing of this based on the desired air pressure. Then in the last bit the motor needs to power the piston in, and then only against the pressure difference, not all the way from ambient air pressure. It is going to compress the same air as any compressor, but using much less power!
   At the end of the power stroke, the piston pauses for a moment. The air inlet valve to the decompression cylinder closes, and then the air outlet valve opens, releasing the compressed air to the outdoors. After the air is decompressed the piston does its return stroke, with both sides of the cylinder open to ambient air pressure. The return stroke expels the remaining uncompressed cold air from the decompression piston. The compression side is refilled with new (indoor) air.
   In a short pause at this end the outlet valve is closed and then the inlet valve is opened to allow more compressed air into the decompression end. Then the next compression cycle starts. (I am imagining that somehow the shaft and piston just freely slip to where the compressor motor needs to cut in and push, toward the end of the stroke.)

   The compressed and hence heated air enters the ducted radiator pipes, where it radiates away its excess heat ideally down to room temperature. Still compressed it then goes through the outdoor heat exchanger, warming the air coming into the house (to feed the compressor) from outdoors. But the still compressed air, instead of being directly expelled to the outdoors, is then routed to the decompression cylinder. It's already cold, perhaps not much above outdoor temperature, and it gets even colder in the decompression cylinder before it is exhausted outdoors.

   I should think this compressor would be much quieter than a 'regular' one:
1. The outgoing compressed air pushes the compression cylinder most of the way to the end even before the motor does any work. That surely has to be quieter.
2. Because it does far less work, the motor would be much smaller and hence (presumably) quieter.
3. The planned screw piston moving mechanism should be quieter than a crank arm type.
4. Large cylinders with long strokes will move a greater volume of air per stroke, so the speed is much less. That just has to be way quieter.

   For a bit I thought maybe if the air had to be routed back into the house and then out again anyway, the compressor could be situated outdoors and make its noise (however much or little) out there. That would actually shorten the piping. But then the warm air ducts would have to go out through the wall and back in again. That would make for two big holes through the wall, and the compressor noise would inevitably come right through those holes anyway.
   There may be a more optimum way: Put the compressor through the wall. Have the compression cylinder indoors, linked by a push rod in a thin cylinder to the decompression cylinder outside the wall. Then the outgoing pipes don't have to come back into and out of the house again to get to the decompression cylinder.
   And if that rod in a cylinder were positioned next to the outgoing air pipe to the outdoor heat exchanger, it would also be in the same incoming air duct, so there would still be only one hole to drill through the wall. Of course if the compressor's (small!) motor was on the outside, it might pay for noise minimization to position the compressor away from the open air duct with a separate small, sealed hole for the rod connecting the two halves.
   The blower fan will still make noise.

   Two concerns will be:

1. elimination of moisture in the pipes, which can't all slope gently down when they must return to the same compressor/decompressor unit they started from. A big manual drain (or with an automatic drain mechanism) water catcher container at the lowest part of the pipes may be necessary.

2. lubrication of the piston, which being in the middle of two air cylinders can't have oil sloshing against one side. For this the most practical solution might be a really long piston with sealing rings at both ends, whose center is never in the air cylinders, so it can be in oil. Or it could equally be two separate in-line cylinders with a rod between them, so that one end of each cylinder is exposed. (That could fit with the indoor-outdoor, through wall, idea.)

* On Earth the air pressure is ~15 PSI. On Titan it is ~22.5 PSI. But Titan is 1/3 of Earth's temperature, under 95°K versus 285°. So the air would be 3x denser at same pressure, then times 1.5x pressure, so Titan's air has 4.5 times as many molecules per cubic meter as Earth's. In the heat pumping differences are of course much less extreme: unit percentage differences like 95% or 105%, rather than 450%.

Electricity Generation

My Solar Power System

Month of February Log of Solar Power Generated [and grid power consumed]

(All times are in PST: clock 48 minutes ahead of sun, not PDT which is an hour and 48 minutes ahead. DC power output readings - mostly the kitchen hot water heater for some months, then just lights - are reset to zero daily (for just lights, occasionally), while the others are cumulative.)

Solar: House+DC, Trailer  => total KWH [grid power meter reading(s)@time] Sky conditions
February 29th 09.00,-, 972.49 => 4.33 [55Km,chj; 72475@19:00] At one point, the sun came out.

1st  10.36, 973.25 => 2.12 [40Km,charging; 72500@19:00] Heavy overcast, rain: dull.
2nd 14.06, 975.32 => 5.77 [72528@18:30] Mostly SUNNY!
3rd -  Power failure and huge windstorm brewing. I decided to unplug the grid tie inverters and leave them off for now. I don't want them damaged by power bumps.
4th --
5th -- I turned them back on mid-late PM on the 5th. I also put a "watch" battery in the house power logger so it wouldn't lose readings during power failures (they did again start at 0). Probably about 3/4 KWH attributed to the 6th was actually collected on the 5th.
6th 05.88, 979.21 => 9.77 KHW [35Km,Chj; 72665@18:30] Sunny (with a few light snow flurries). (Includes ~3/4 KWH from 5th PM.)
7th 11.13, 983.09 => 9.13 [55Km,chj; 72695@18:30] Sunny.
8th 15.68, 986.18 => 7.64 [72715@18:00] Sunny AM, cloudy later.
9th~17.10,~987.05=>2.29 [70Km,chg; ~72750@---] Cloudy. (~estimated AM of 10th)
10th 21.00, 989.57 =>6.42 [40Km,chg; 72782@18:30]     Clouds, a bit of sun in PM.
11th 23.86, 991.32 =>4.61 [72804@18:30] Cloudy. A bit of sun.
12th 26.39, 992.79 =>4.00 [60Km,charging; 72835@18:30] Clouds & snow. (Soon after last snowfall at dusk, clear - stars & moon for whole night.)
13th 31.35, 997.35 => 9.52 [~72915] Sun. Very cold 0°. Discovered one inverter of 3 at the house wasn't working. Looking at readings, the house started producing less than the trailer on the 11th. It probably quit then. Everything LOOKED great, the lights were blinking normally, but it was contributing 0 watts and not loading down the panels at all. (The manual said if that happened it had probably failed, to "return it for analysis".) So the house system was running on 4 panels, the older 250 watt ones, instead of all eight. I swapped 3 new ones and disconnected 2 old ones on another inverter so it had 5. Apparently I need another inverter... or perhaps two more would be better, to keep the load on each down.
14th 34.20, 1002.03 => 7.53 [55Km,Chj; 85Km Charging; 72941@18:30]
15th 38.35, 1006.52 => 8.64 [72975@20:00] Sun! 6°. Sometime in the afternoon I hooked up the two other panels from the DC system to the grid tie inverter. Now making good use of the two remaining inverters, with 7 panels of 8 connected. Somehow I was reluctant to attach the 4th 305 watt panel since that inverter had (?)blown. OTOH that was the same arrangement as at the trailer - four 305 W panels on one inverter, still working fine. Instead I hooked the last panel to the DC system in series to get the PowMr solar input to over 50 volts. I opened up the dead inverter. With lights blinking normally, it seemed to me it was probably a blown power transistor. I tested them with a meter. It was hard to be sure, but they all seemed okay except a couple I couldn't get at. I couldn't see how to get it the rest of the way apart. All the screws were out but the board wouldn't slide out. I gave up and put it back together. Then there were some powerline light dimmings and I turned the other two inverters off. (Turned trailer heater down from 500W to 250. Should reduce daily power consumption by 6 KWH/day.)
16th 41.56, 1010.92 => 7.61 [55Km,chj; 73016@19:00] Sunny. (Pattern is setting in: Frost AM -2° but warmer during day) I didn't turn the house inverters back on until afternoon and missed some power collection. I tried the non-functional one again but it still didn't seem to work. But, but, but... nothing seems to be wrong with it!
17th 46.77, 1015.40 => 9.69 [73033@18:30] Sunny. I had left the non-working inverter on and in the morning the cooling kept cycling on as if it was getting too warm, but it was stone cold, no watts output. It's certainly pretending it's working!
18th 50.69, 1018.25 => 6.77 [55Km,chj; 73063@19:30] Sunny AM, cloudy PM.
19th 56.23, 1022.62 => 9.91 [73084@20:00] Sunny... and (gasp!) somewhat warm!
20th 62.10, 1027.39 => 10.64 [85Km,Chj; 73113@19:30] Sunny, rather warm.
21st 66.52, 1030.63 =>   7.66 [50Km,Chj; 73134@19:30] Sun & clouds.
22d  70.08, 1033.21 =>   6.14 [73155@18:30] Clouds & sun ending with rain.
23rd 74.37, 1036.36 =>   7.44 [55Km,chj; 73184@19:30] mixed clouds & sun.
24th 80.47, 1040.41 => 10.15 [73205@18:30] More sun than clouds and jet trails.
25th 85.88, 1045.04 => 10.04 [73231@18:00] More Mixed Clouds and Sun.
26th 87.89, 1046.40 =>   3.37 [73264@19:00] Overcast.
27th 90.55, 1048.32 =>   4.58 [55Km,chj; 73289@19:00] Dang clouds.
28th 93.72, 1050.59 =>   5.54 [45Km,chj; 73321@19:00] Mostly more clouds.
29th 96.25, 1052.42 =>   4.36 [73346@18:30] Clouds, wind and rain.
30th 99.78, 1054.91 =>   6.02 [73382@18:00] More of the same.
31st 106.26,1059.54 => 11.11 [55Km,chj; 73434@19:30] Some sun again at last!, dull sun, and clouds. High 5°

1st  113.68, 1065.07 => 12.95 [73454@19:30] SUN! At last a full sunny day! High 3°, low -2. (still feels like winter somehow.)
2nd 117.00, 1067.38 =>   5.63 [73485@19:00] CLOUDY! I guess yesterday was a one-off. High 4°.
3rd  121.55, 1070.89 =>   8.06 [55Km,chj; 73516@19:00] Clouds, 4°. A bit of misty rain and snow to end the day.
4th  124.63, 1072.63 =>   4.77 [35Km, chj; 73562@20:00] Mostly clouds, 4°, a few snowflakes.
5th  131.00, 1077.17 => 10.91 [73587@20:00] Pretty much sunny, all day! Even a bit warm.
6th  134.87, 1079.83 =>   6.53 [73608@19:30] Mostly clouds, a little sun. But getting warmer at last!

Daily KWH from solar panels. Compare March 2020 with March 2019 & February 2020.

March 2019 (10 panels)
March 2020 (11 panels)
February 2020 (12 Panels)
Total KWH

Monthly Tallies: Solar Generated KWH [Power used from grid KWH]
March 1-31: 116.19 + ------ + 105.93 = 222.12 KWH - solar [786 KWH - used from grid]
April - 1-30: 136.87 + ------ + 121.97 = 258.84 KWH [608 KWH]
May  - 1-31: 156.23 + ------ + 147.47 = 303.70 KWH [543 KWH] (11th solar panel connected on lawn on 26th)
June - 1-30: 146.63 + 15.65 + 115.26 = 277.54 KWH [374 KWH] (36V, 250W Hot Water Heater installed on 7th)
July  - 1-31: 134.06 + 19.06 + 120.86 = 273.98 KWH [342 KWH]
August 1-31:127.47 + 11.44+91.82+(8/10)*96.29 = 307.76 KWH [334 KWH] (12th panel connected on lawn Aug. 1)
Sept.- 1-30: 110.72 + 15.30 + 84.91 = 210.93 KWH   [408 KWH] (solar includes 2/10 of 96.29)
Oct.  - 1-31:  55.67 + 13.03 + 51.82 = 120.52 KWH, solar [635 KWH - from grid]
Nov. - 1-30:  36.51 +   6.31 + 26.29 =   69.11 KWH, solar [653 KWH - from grid]
Dec.  - 1-23: 18.98 +   .84* + 11.70 =   31.52 KWH, solar + wind [711 KWH + 414 (while away) = 1125 from grid]
Jan.  - 6-31: 17.52 + ------* + 10.61  =  28.13 KWH, solar+ wind [1111 KWH from grid]
Feb.  - 1-29: 56.83 + ------* + 35.17  =  92.00 KWH, solar + wind [963 KWH from grid]
March - 1-31: 111.31 + ----* + 87.05 = 198.37 KWH solar total  [934 KWH from grid]

* Solar hot water tank removed because the mineral-rich water stank. (Why doesn't it stink in the main house tank?) Now the solar DC system is only running a couple of lights - not worth reporting. So there's just the 2 grid tie systems, house and "roof over travel trailer".

Things Noted - March 2020

*  The increase from 5.xx KWH on the best days in February, to about 10 KWH on good days in March, is substantial. (I'm not sure there was a single day in February without some clouds.)

* The increase is even greater because the angle of the panels, layed flat on the south facing roofs, is too flat, 15°, (even for June) and the sun is so low in winter. A steeper angle would work better in all months, but especially in winter. OTOH, no panels have been blown off the roofs in windstorms. The two steeper panels propped up on the lawn are in shade much of the day - and they did blow over in a windstorm. (Hence, with one roof panel off, the house didn't fare as well as last year.)

* Overall collection was 89% of March 2019, and 216% of last month, February - just over double.

* There was less sun - far more cloudy days - during March than in March 2019. There were fewer quite good days with 8 to 12 KWH - 10 versus 17, and they were more at the lower end of that. In 2019 6 days were 11 or 12 KWH, while this year only one hit 11 - the last day of the month. (Maybe a cloudy spring means this summer will be better than last, which was very dull and cloudy? Well I can dream...) April 1st was finally sunny and it passed 12 KWH - almost hit 13.

* Perhaps because of having more panels there were fewer days when less than 5 KWH was generated - 7 instead of 9

   If I do put up more panels, I'll definitely try to mount them at a steeper angle. (I'll also need more grid tie inverters!)

* After a little over a year, the four panels on the trailer roof passed one megawatt-hour of energy production. From the 5th to the 31st of March, the seven panels at the house passed 100 KWH.

* As the month passed, the tree shadows shortened rapidly and left the house roof in the first few days of April - but mostly clouds meant there weren't any shadows visible.

FWIW: Here's a picture of the grid tie inverter with the bottom cover off.
It all looks fine!

Stirling Engine Electric Generator with Hot Water Solar Energy Storage? (Concept)

   A friend sent me a link to an article about storing solar energy as melted aluminum, pumped into a storage tank. It would be all sealed to keep air out of course. The phase change from solid to liquid aluminum was said to store a lot of heat. Then a Stirling engine was used to convert the heat into electricity at night. The article said it was "scalable" - but from 100 KW to 100 MW: huge to humongous. I suspect 100 KW would be pretty minimal for such elaborate equipment.
   Molten aluminum is HOT. The radiation losses through the insulation must be immense, so one would need a huge storage volume to make it practical. And to attain such levels of power overnight would need a huge amount of solar energy in the day - staggering amounts for an individual installation. My 3.4 KW of solar panels wouldn't even "light the pilot light". This struck me as one of those "Do not try this at home!" type of ideas.
   One could of course pick a metal with a lower melting point: zinc, or maybe an alloy like tin-lead solder. At least solder can melt at a temperature where it doesn't glow red and oxidize.

   But what would make way more sense to me would be to use water. Even without a phase change (to ice or steam) water stores a lot of energy per degree of temperature change. People on youtube have described putting a very large, insulated, unpressurized tank of water in their basement to store heat - an insulated plywood "hot tub" with a lid. (Indeed, one could probably use a discarded hot tub if one was available. I might fill my 14 foot aluminum boat with water for all the use I've been getting out of it!) This is heated by solar energy - even perhaps by coils of black plastic pipe on the roof, or else by solar PV with an electric heating element. And these are all relatively safe temperatures to deal with - nothing like molten aluminum.

   Once there's hot water, a Stirling engine runs on any sort of heat, so it would be a matter of picking one that's suitable for the desired power and expected water temperatures. Or perhaps a simple design like my "closed cycle pressure cooker steam engine" drawn up in December (TE News #139) - which shouldn't actually have to have steam temperatures to run. Just heat should do. (A bit of steam and phase change was expected to improve the performance.) The engine would sit in the lid with the bottom of the pot collecting the water's heat and the top being outside with heat radiating fins.

   For now these are just musings, not something I'm planning to build. But it would be a way to make electricity at night from solar collected energy.
   In existing or proposed pumped water for hydro electricity storage, perhaps it's surprising that no one has created or at least proposed such a system. If one is making a reservoir for hydro storage anyway, a smaller one could do double duty: The bottom and sides could be insulated and it would be covered with an insulating blanket of some sort. When there is excess electric energy, first pump water up into the reservoir, and then heat that water. When power is needed, (a) use the heat to make electricity with the heat engine, and when it's no longer warm enough, (b) drain the reservoir through a turbine to make more electricity that way.

Electricity Storage (Batteries)

Turquoise Battery Project: Long lasting, low cost, high energy batteries

   The PVB filament arrived from filaments.ca and the zinc plated copper sheets arrived from Peter in Portland.

New Case, 3D Printed from PVB
First try PVB 3D printed case                                         
   On the 23rd I (finally) 3D printed a 50x50mm battery case in PVB filament. I still had to use Skeinforge slicer as the more modern and configurable Cura didn't seem to do what I wanted.
   I was pleased with the printing. It really did seem smoother than other plastics, it didn't need higher temperatures and it showed no tendency to warp and lift like ABS. It could be solved and glued with alcohol rather than acetone or methylene chloride. (Luckily there's no alcohol in the battery!) And it was stiffer than ABS.
   Perhaps the person from the factory was pretty accurate when he said it was a "dream 3D printing material".

   The cell bottom, four layers/1.6mm thick, was pretty rigid. The porous inner separator piece less so, but better than ABS. It's probably the best I can get and I'll hope it's good enough. "Thin & porous" and "stiff" are somewhat mutually exclusive. Four stiffening posts in the middle is already a lot to accommodate.
   The two pieces were a bit of a tight fit. I lightly sanded the outside edges of the separator to get it to go in easily, and when I pulled it apart one of the center stiffening posts broke off in the hole. I'll adjust that diameter a touch for the next one.
   Then I realized I probably couldn't or at least shouldn't use a piece of ABS sheet for the top cover, when it is solved by methylene chloride and the PVB by alcohol. Well, I could easily 3D print one - in the same print as the other two pieces. (The print would take about 50 minutes instead of 35.)

(24th) I added the top piece. Instead of having it fit flat over the whole top as I had originally planned, I made it to fit inside the lip. (I made the side walls 1.6mm taller to accommodate its thickness.) That way it could be pressed down until it was pressing everything together nicely and glued, instead of either leaving a gap or not being able to fit on, if the thickness of the electrodes and current collectors wasn't exactly right.
   There were a couple more very minor adjustments to be made, and I made them in OpenSCad for next time. (The inner holes and support posts didn't quite line up - that must be why one broke off.) They weren't going to stop me from using this case. It weighed 20.25 grams. Of course all weight that isn't active electrode only decreases the energy density. But it does need a case. In fact, it's becoming increasingly evident that a case that is pretty much sealed, and that holds the internals pressed together, is the key to making a practical cell that performs well.
   One thing I hadn't accommodated: a filler hole and plug for it. I think a little hole with a rubber stopper like under the button on the NiMH "D" cell I took apart is the simple thing. An eyedropper or a syringe isn't the hardest thing to come by as a filler tool for such tiny volumes. Now... where do I get a tiny rubber stopper, and just where do I put the hole? Since I don't know where I'd get them, perhaps I should put a very short nylon bolt in a threaded filler hole?

   I had designed the cells to open on the broad face and lie flat. But the case looked pretty good standing upright. Setting them that way presumes no glued-on flat faces will ever leak. Well, that's supposed to be the case anyway, isn't it? If they leak and they're not just test cells, they need to be fixed.
   Then it would make sense to have the filler hole on the same edge as the two terminals, with that being the top edge.

   Peter's electrodes having the tabs on the opposite side compared to my case design, I typed in "mirror([1,0,0]) { ... everything ... }" in OpenSCad before I printed the usable cell. This gives me the idea that making half of the cell mirror shape from the others would mean that one could simply stack the cells together and bolt the electrodes together back to back to get higher voltage batteries. That, compared to any batteries I've seen or had, would much simplify assembling a larger battery.


   The first step was to cut, drill, clean and fit in the cupro-nickel positive current collector. The drill wandered and I had to file out a couple of the holes a bit. Then it fit. The metal was much heavier than it needed to be. In the small cell it was like "plate" metal when "foil" would have been more appropriate. It weighed 14.0 grams - more non-producing weight. Why I bought so much of such a heavy gauge of cupro-nickel, intended for something to do with batteries, escapes me. Perhaps I should get some that's thinner? The alternative would be to cut it down to 50mm wide, probably have to anneal it, and run it through the jewellers rolling mill to thin (and lengthen) it. Yetch!

   The second step was to make a nickel-manganates electrode. That meant I had to make the base for the electrode compactor. Oops, big diversion! (25th) I found a rusty looking piece of 3/8"plate for the base and got that done, amongst all the other things I was doing.
   But I didn't get any farther.

   The copper current collector of the negative electrode was also much heavier than it needed to be, again like "plate" instead of "foil". The electrode weighed 15.55 grams. This time, I wasn't sure how much was zinc and how much was copper, but the shiny dip coated zinc from Peter had some extra thick patches, too.
(26th) I had thought of filing off the thickest patches of zinc. Then I thought it might be better to squash the thickest spots in the rolling mill. Then I thought if I was doing that, I should take the smallest one (they being irregular sizes) and squash it until it was longer and thinner. I did that, but some small areas of the zinc delaminated from the copper.

Haida Gwaii, BC Canada