Sunamp Thermino Thermal Battery for Hot Water
So I was watching a video on the Still to Be Decided Podcast about the things Matt Ferrell would have changed in his new net zero home and he said that he wished he could have put in a Sunamp Thermino hot water battery instead of what he did choose but the Sunamp wasn’t available in North America at the time – apparently now it is. It uses an “energy dense phase change material and will work with grid energy, solar PV, boilers or heat pumps.
https://sunamp.com/hot-water-thermino-overview/
https://sunamp.com/en-us/
Matt Ferrell video on phase change materials.
https://www.youtube.com/watch?v=OsiW3fqt2PI
Anyone else used one or knows anything else about it?
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Replies
Rockies63,
Why do companies have such a hard time describing what they sell? I poked around the link a bit and am no wiser. I hope someone here can explain it in simple terms.
What I can gather is that they use a phase-change material to make a storage tank that's about the quarter the size of a water tank of similar capacity. We've discussed a lot here the way that domestic hot water is a high-intensity use, you either need to have a high-output heater or some way of storing heat. So a heat pump water heater isn't really feasible without a tank.
The use cases they talk about seem to be replacing a domestic hot water tank, and that seems pretty fringe.
I noticed that too. I did find some good information in their Blog section.
https://sunamp.com/blogs/
Also their news section.
https://sunamp.com/news/
There's a brochure that can be downloaded on the en-us site.
And some info about the company in the US.
https://sunamp.com/en-us/about-sunamp-in-the-usa/
And some info on "Plentigrade" which I think is the phase change material.
https://sunamp.com/en-us/plentigrade/
I don't know this product, but I do know that Matt Ferrell is a complete hack and if he's talking it up it's probably a scam.
The operating principal is that materials release/absorb a lot of energy during a phase change. Unless you are really cramped for space, a second water heater can store water for DHW usage at a much cheaper cost.
For example, it takes 212 BTUs to raise 1lb water from 0*F to 212*F. It takes another 970BTUs to convert the water from a liquid to a gas. If you ever need to calibrate a thermistor on the fly, stick it in boiling water and ice water. The respective vessels will be at exactly 212*F and 32*C because it takes significantly more energy to actually change phase.
This is essentially the same concept that a heat pump works on. Refrigerant changes phase through the heat pump cycles to move energy from one place to another. Also the same concept that power plants operate on via the Rankine cycle. Phase change is an excellent way to store/move energy... once it costs the same as a normal water heater.
This is a great concept! By using a phase change material, you can A. Store more energy in the same volume (this probably doesn’t matter for most Americans) and B. You can store more energy at the temperatures heat pumps can achieve, which is a bigger deal. For central heating, this could help with peak demand and allow you to charge during the day time hours when COP is higher, on average.
The cost vs. electrical batteries must be MUCH cheaper though. For every 3kwh of heat stored, you’re only storing 1kwh of electricity. And that electricity can only be heat, not cold, so you’re not storing much during the summer. So if an electrical battery is $1000/kwh, this needs to be <$200/kwh.
An excellent point. EG4s latest powerwall battery is down to ~$275/kwh. Battery prices continue to fall in general as production massively increases.
I would say storing at a constant temperature is the big win. People who are seriously into heating with wood build elaborate systems with water storage tanks, because it's hard to match the supply of heat from a wood fire to the demand in real time. I could see something like this being a game-changer for them, trying to store heat in a tank of varying temperature gets very involved.
Lloyd wrote about these awhile ago on Treehugger: https://www.treehugger.com/sunamp-heat-batteries-can-help-electrify-everything-5116606
I looked into them for my house. They're only recently available in NA. In theory it's a good idea, but currently way too expensive. Unless you're really pressed for space (e.g. a UK flat) you're better off just getting a standard DHW tank.
I don't see much point here unless you're really, REALLY tight on space. It's simpler to just use a larger water tank as a "thermal battery", since water it pretty good at storing heat too, and it's cheap, safe, and readily available.
Note that I have often designed chilled water systems for datacenters with a large, insulated, water tank to provide a "thermal battery" (but for cold, instead of hot, water), to keep temperatures under control during the period before a chiller can restart after loosing power (i.e. the power fails, the chiller stops, the generators start, but the chiller can't start right away after the generators restore power). I usually have to maintain reasonable temperatures for around 5-10 minutes or so. An insulated water tank works well for this, it's cheap, and there is no concern with using any hazardous materials.
There are plenty of nifty ideas out there that just don't make a lot of sense in practice.
Bill
About 18 months ago I wrote about calcium chloride hexahydrate:
https://www.greenbuildingadvisor.com/question/calcium-chloride-hexahydrate-for-phase-change-heat-storage
It's a mixture of water and calcium chloride, both of which are cheap and abundant. At a 50-50 mixture it freezes at 84F. You can adjust the freezing point by adjusting the mixture, more water raises the freezing point, less water lowers it. The heat of fusion is lower than that of ice, but it is denser, and it has about the same heat storage capacity per unit of volume as ice.
If what you want to do is store heat locally this sounds more promising than the "thermal battery."
This Page: I wouldn't say Matt Ferrell is a complete hack. Yes, sometimes he can get pretty far out into the future, describing things that would take millions of dollars of research money and decades to develop (only to then discover that they don't work nearly as well as first hoped) but I usually find that by the time someone gets ready to put down their own money for their own house they tend to look for something that is available now and will work efficiently and cheaply.
DC: I think the phase change substance they use is a mixture of salt (sodium acetate trihydrate) water, and some patented formulations of additives.
Here's the Sunamp Youtube channel (I should have looked for it sooner).
https://www.youtube.com/@SunampLtd
This first short video is kind of a folksy chat about their company vision.
https://www.youtube.com/watch?v=JP2Xpv9vXss&t=14s
This video has some excellent background on how they developed their Phase Change material.
https://www.youtube.com/watch?v=5r5QgFjkEQI&t=15s
This video explains how a thermal battery works.
https://www.youtube.com/watch?v=2v_uiqqgCY8&t=15s
How phase change materials work in the Sunamp battery.
https://www.youtube.com/watch?v=XFl4TxfBPOU
I'm sorry, I just have no patience for YouTube. The signal to noise ratio is just too low. I'm wired so that I have to be continuously learning, that's why I like this site and ones like it. Even at double speed most YouTube videos take way too long to get to the point and gloss over the important stuff.
FWIW I haven't watched TV in about 35 years either, I just find it way too slow.
My Tube habits have ebbed and flowed over the years. Short attention spans has brought us the 'shorts.'
I think the well produced science videos are generally where it's at. (Or any well produced video that keeps tempo and interest).
Some building videos can be really good, but many do indeed wander. It's the videos where the maker thinks we're just there to watch them chatter where it goes downhill.
I do find myself watching less and less of it with a one year old. Shorts can come in handy here.
DC: That's unfortunate, in my opinion. I've found that the wonderful thing about the internet is that once you find one great resource, like this site, it leads to others, like the Journal of Light Construction website, and the Green Building Science website, then on to Dr. Joe Lstiburek, and through this site to Matt Risinger, and through him to Architect Steve Baczek, and then back to Youtube and the Unbuildit Podcast, and on and on.
Yes, Youtube can be annoying, especially if all your looking for is cat videos, but it still has a wealth of information and who knows, you may also find a great product that improves your life, or the lives of your clients.
You know, the more I look into this the more I'm impressed. Additional benefits of a phase change hot water battery are that since they don't "hold" a tank of water there is a greatly decreased risk of Legionella developing due to water temperatures not being high enough to kill the bacteria, testing has shown that at roughly two cycles per day the battery can perform for almost 55 years, and all the materials in the battery can be fully recycled at the end of its lifespan.
Here's a video from a trade expo explaining how it works.
https://www.youtube.com/watch?v=t1x4J2c7v9I&t=24s
This video features the General Manager of Sunamp North America talking to the host and then they go through the installation process and open one up to show how it works - and if you pay special attention you'll see the hosts Tim Horton's coffee cup! Yea, Timmies (it's in Canada, eh!)
https://www.youtube.com/watch?v=IA15VkLlx-w&t=25s
I just saw that Arctic Heat Pumps is advertising one of their 2-stage heat pumps packaged with a Thermino for DHW. Presumably they believe in the technology...?
https://www.arcticheatpumps.com/high-temp-hot-water-heat-pump.html
So once again, the only benefit cited is that it takes up less space. And in the marketing material they show it in the same footprint as an equivalent water tank, only less than half as tall. So they're able to put three shelves above it -- one of which is empty in the photo!
It just doesn't seem compelling.
I think there are other benefits. In addition to taking up less space, they would avoid the noise, air exchange requirements, and potential comfort issues of having a heat pump water heater indoors, which at least in CA, are essentially the only kind of tanked water heaters you can use under Title 24. As others have mentioned, there are also potential load shifting benefits and the ability to charge the PCM using a heat pump. I particularly like their potential in small areas (ADUs, pool houses) or for a bath located far away from a primary water heater, where initial cost may be secondary to space or usage/operating costs concerns.
How does a different storage medium change what kind of heater you can use?
I'm not sure Title 24 would catch the difference in storage medium. The difference would be whether it's charged via heat pump.
I still don't get it. You wrote: "As others have mentioned, there are also potential load shifting benefits and the ability to charge the PCM using a heat pump."
Does a plain old water storage tank lack the ability to be "charged" with a heat pump?
Chris: Thanks for the link. I like Artic Heat Pumps and the nice thing about their high temperature model is that it can heat water up to 185 degrees F (which I believe will prevent Legionella disease) with outdoors temperatures as low as -22 degrees F.
The entire system can be used for space heating as well as DHW.
rockies63,
You are good with any heater that will keep the tank hotter than 120F for Legionella.
Arctic Heat Pumps is still in the middle of setting pricing for the Thermino, but it does appear to be a very interesting product.
Digging around, I found it for sale already on a couple of sites in the UK, with pricing seemingly comparable with similarly-sized regular thermal indirect tanks with and without integrated electric backup.
What was really interesting was some performance (and price) data from posted installation manuals from an online shop in the UK:
https://midsummerwholesale.co.uk/pdfs/sunamp-uniq-hw-ilthp-heat-batteries-installation-and-user-manual.pdf
which also includes data like this:
https://midsummerwholesale.co.uk/pdfs/sunamp-uniq-hw--ilthp-samsung---daikin-heat-batteries-datasheet.pdf
about the capacities of the various models.
I'm not sure why the Sunamp corporate website itself is so obtuse. The combination of pricing plus hard numbers, to my mind, is a much better sell of the product than all of the fluffy case study information.
I guess we'll see when the product really makes it over to North America, as to what exactly the price point after import ends up as.
For my particular application (ATW), I'm seriously considering waiting till the new year for this, as the form factor (half as tall, but rectangular footprint) happens to make it fit easier into my utility room, if only I could get my hands on it. In my case, the manifolds and pumps would be able to fit on the wall above the Thermino box and still be fairly easy to access. Otherwise, I'm fighting to fit everything into the space and my only other alternative is to use a dual-tank tank.
I like discussions like this because it brings a product or technology to a lot of people's attention and then they go out and find research or information about it that I hadn't found.
Billdoors: I think the Sunamp is already available in North America - at least there's contact info for their office in New York on their US website.
https://sunamp.com/en-us/contact-us/
We are the distributor for the Thermino and I would be happy to answer any questions that anyone has about it. With respect to DCcontrarian, we are best financially evaluated against a higher technology unit (condensing, heat pump, etc) than the most basic possible. The Thermino qualifies for the ITC with a few limited caveats. Feel free to call me at 973.978.5942 at any time to discuss. Thank you
"With respect to DCcontrarian, we are best financially evaluated against a higher technology unit (condensing, heat pump, etc) than the most basic possible. "
Could you say what you actually mean?
Hi Tom, I like this product!
However, a minimum charge flow temp of 149F is just too high. Are there plans for a lower temp PCM?
149F would seem to obviate the use of heat pumps or anything other than combustion.
Even if it didn’t, it makes it inefficient!
Specifically, if you are looking for the lowest cost option we may not be that. But if you are looking to time shift your load, reduce your peak usage, size your heating equipment for less than would be required by covering intermittent peaks, etc we have a lot to offer. Our PCM is stable for >50,000 cycles, so it would outperform a homemade solution, although we tip our hat to anyone who is inquisitive enough to put their own PCM together and manage their electric loads that way.
OK. So how does your PCM do all of that better than a bigger tank full of hot water?
You can use a big tank of hot water but you will lose sensible heat faster than the Thermino will lose its latent heat. Also a big water tank is big and has a risk of leakage and also Legionella risk
I can't tell which comment of mine you're taking objection to. I think it might be #11 or #20.
"Specifically, if you are looking for the lowest cost option we may not be that. "
This is a really confusing thing to say. Why would anyone ever go to the trouble of time-shifting their load except to save money?
If you had said, "we don't have the lowest installed cost but we might have the lowest total cost of ownership over the life of the equipment if you live in a place with time-of-day metering," then that's at least a defensible position and we can argue over how much lower your off-peak rates have to be in order for that to be true.
The only other reason besides costs savings would be if you have a limited energy supply available, such as may be the case with an off-grid home. In those situations, you have a hard cap on how much power you can use at any given time, likely limited by the inverter. In those cases, a pricey water heater that can time shift loads may help to make the overall energy system of the off grid home appear larger than it actually is, effectively saving money on avoiding an electrical upgrade.
With utility power available, the only reason to time shift loads is to save money using cheaper off-peak power at night. I've found that commercially it can be hard to make this make economic sense, even in very large facilities with 6-7 figure monthy electric bills. The problem is that the on and off peak rates aren't as different as they used to be, especially in many commercial areas, unfortunately.
Basically time shifting loads is a neat idea (one I happen to really like, BTW), but it often doesn't make economic sense and thus isn't worth doing, which is unfortunate.
Bill
I think one of the other things happening is that as more solar comes on line the supply of daytime electricity more closely matches the demand. And as heat pumps become more popular the demand for nighttime electricity grows.
I'm not a big believer in on-site power storage for residential customers. I'm not even sure that in the long run on-site solar power generation is going to make sense compared to centralized facilities.
I don't doubt that the Sunamp device works, it just seems to be a solution in search of a problem. An expensive solution at that.
Solar lines up pretty well with daytime air conditioning load in warm climates. It's biggest drawback is storage, since there is no solar output at night.
Personally I think distributed solar is better than centralized facilities, because the roof is already there -- why not put solar panels on it? Use that sunlight that is otherwise wasted heating up your shingles. Centralized facilities require massive amounts of land, and there are big downsides to that at utility scale.
Bill
Keep in mind that at least in CA under current net metering rules, credits for solar generation are not time-matched with loads and reimbursements are now at wholesale rather than retail rates. A residential home's solar generation credit stream is entirely independent from it's usage stream. Onsite battery storage helps with this issue and allows users to also time-shift loads. Also addresses the utilities' duck curve issue, which is why they changed the net metering regime.
Even in the off-grid situation you're still making a cost/benefit analysis of the SunAmp vs adding more generating capacity vs other ways of shifting the load -- for instance, just a bigger conventional tank.