Mixergy Water Storage. Smart technology for grid stability.

  • 🎬 Video
  • ℹ️ Published 1 years ago

Renewable energy sources like wind and solar are here to stay, and their dominance on global electricity grids is growing every day. But for them to work, grids also need energy storage and the ability to respond instantly to fluctuations in frequency. Lithium batteries provide a lot of that functionality today, but now a new smart domestic hot water storage tank has been developed that not only heats water 20% more efficiently, but can also use electrical energy when it's free or even negatively priced. Plus it can talk to the grid and store energy when renewables are producing too much. Edward De Bono would be proud! (look him up).

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💬 Comments

This thermal time shifting reminds me of an MIT project from the 70s. There were some unused tennis courts behind a gym and in the winter they would spray water over them to create a giant snow hill. When the weather warmed up they would use the melting snow to cool off the gym using some pipes that ran under the snow hill to the AC unit for the gym. As I recall the hill used to last almost all summer, providing (nearly free) cooling.

Author — Michael Crumpton


Very interesting as usual, I have a heat pump hot water and I must say my energy usage is way down, and I would also like to thank your patrons for keeping these talks add free,
All the best Jules

Author — Juli Caru


Yes, I have the 150 litre Mixergy tank in a new high performance home in Christchurch, New Zealand after seeing it on Fully Charged years ago. Still the only one outside the UK I imagine. Works a treat at only 30% heated for two adults and the odd visitor.

Author — Thomas Evans


When I bought my home it had a hybrid solar/gas hot water system which reliably delivered hot water with very modest gas consumption, but had other problems, including that the supply charge for gas in my city (and I suspect most of Australia), is about $1 per day on top of my modest consumption. As part of a household solar electricity project I replaced it with a highly efficient heat-pump storage hot water system, PV solar panels, household battery and disconnected the gas. I've set the water heating to be active between 10am and 3pm, of which it only uses a fraction, so it rarely places any load on the battery and I it almost never uses mains power. (The hybrid system was well into it's anticipated life span, which when combined with other issues meant that I didn't feel too guilty replacing a functional system as part of the bigger sustainability project.)

Author — Kenna Morrison


Something similar was done in the northern US, years ago, where the utility company would supply a large, highly insulated water tank, along with solar panels, in exchange for the ability to manage the output from those panels for the consumer. Customers of this service received "free" hot water and the utility company was afforded a great deal of flexibility, in terms of generation and storage of energy.

Author — Jason Broom


I would love to see heat pumps and aircon all put into complex loops where heat and cold can be applied wherever is necessary from other parts of the house. Maybe if you're fortunate enough to own a swimming pool a heat exchanger in there would make use of any excess heat produced.

Even a tumble drier can make use of a heat pump to make venting it to atmosphere absolutely minimal.

Closed loop heat pump/aircon systems would be fantastic in places like leisure centres where you need to keep different rooms warm and cool simultaneously.

Author — S D


These technologies are really very good. I've seen Mixergy on Fully Charged as well. I can't help but think that with all of this smart technology there will be no cheap electricity overnight within another 5 - 10 years as energy demand will flat line.
Thanx once again for your time, energy, and commitment to the cause 💖✌️💖✊💖

Author — Dr. Jaxon's Elixir Of Life


I had a similar system back home at the farm, but simpler. The wood fired boiler had a built-in hot water tank, but it was severely annoying to have to fire it up every time we needed hot water, so I installed a little electric water heater. But avoid that it used electricity when we had a fire going, I simply took the cold water from the boiler, a water which sometimes already was hot. And that also meant that we could use a 50 liter heater for the whole household, since we quickly could heat another 110 liters if needed. The plumber was fascinated, and we both wondered why nobody had thought of that before. Flexibility often makes superb economy, and simple solutions usually work best.

We had accumulator tanks too, 1500 liters. I wanted the two tanks in serie, bottom to top, exactly because it meant that it didn't heat water that would get cold before it was pumped out into the system. That plumber refused to install them that way, so I had to hire another one. And truth was that it worked brilliantly well. I could choose only to warm up the first tank and there was always that flexibility which meant it was very little risk to overheat the system. Before they were installed, it happened sometimes that the whole system began boiling, and it sounded like the house was falling apart.

I really believe this flexible tank is another simple solution, and it only shows how important it is to think before installing things. Everything in the field of house and heating is dominated by people who may be good at what they do, but they usually are very conservative and often enough don't really understand how the things work. If I pay a lot of money on something I'll use for decades, I want the best function for the money spent. That's hard to achieve without understanding what really happens, and how it all interacts with the system you have since before and how you use it. It's two different things to have a heating system if you are at home and can maintain a fire, compared to having a house that's empty for twelve hours a day. The old-school solutions often means gas or electricity heating a system that really isn't made for that source. And it will cost you dearly. Understanding the real reality and the real needs you have can do wonders for the economy in the end. Farmers tend to forget that woodfire heating isn't for free, even if you have your own wood. And the fact is that we in the end got more than double the usable effect out of marginally more energy input when everything was in place.

Extremely effective were the Andersen 4kW woodburner and the old Kockums kitchen woodstove I installed in the two houses attached to the systems. Those two gave huge heat (and I never used the electric stove during the winter in the old house) from only a few cubic meters of firewood. The indoor temperature never feel beneath +18°C thanks to the central heating and whenever someone was home, we had a fire going in the stove or the woodburner.

The old thumb rule about effectivity is this: it's a matter of delivering WHAT you need, WHEN you need it, WHERE you need it and AS you need it without unnecessary costs. I always get a bit frustrated over how often that's forgotten... and how well it covers everything produced.

And lastly, a huge Thank You for this brilliant channel. There can never be enough of good thinking in this world. Especially in the situation we are facing, and the need to do things right for the sake of our children and grandchildren.

Author — Fredrik Larsson


Thanks for this great explanation of this great idea. I've been harping on about water thermal storage being the cheapest form of energy storage for a long time. I'm sure I've commented this before, but you could also store cold water for air conditioning. In South Africa this makes sense, as a lot of places are ~25C on an average summer day. With a 1000l tank, you could run at 12000BTU for 3 hours and 40 minutes to get the water temp from 5C to 16C. That's not brilliant, but a low pressure storage tank can be made really cheaply. Edit: An application is if you use solar power to cool the water.

Author — Jodie Robinson


So fantastic that companies are bringing these devices to market. Thanks for sharing all this great info and bringing this knowledge to the world.

Author — jupiter909


In ≈1980 I did some experiments with gray water heat recovery and published an article in Solar Age. For my own home (ground water temperature 7° C) the system provided about 25% of the energy used to heat water. Cost was about $150. No moving parts. Commercially produced systems are now available from several companies.

Author — Glenn Nelson


Great video - especially the animation showing the cold being pumped to the top of the tank as it heats up to maintain the stratification. I've never seen this animation before even on Mixergy's website, but it makes the operation of the tank much easier to grasp. We are moving into a new-build house later this year and I have asked for a heat pump with a Mixergy tank instead of the combination boiler that the builder would have fitted. They have been happy to do this and I think they want to use our place as a way to promote this to future customers if the government follows through with the promised ban on gas in new-builds. We will have solar PV and eventually a domestic battery, so one of the things I am looking forward to is experimenting with the Mixergy and heat pump timing to try to optimise our use of solar energy and time-of use tariffs for hot water, space heating and other loads. This is a bit of a hobby for me as well as my job (as an academic) but eventually the complexity of all this will have to be hidden from consumers and they will be expected to trust their utility company (or landlord...) to control this stuff for them in a way that provides heat, saves money and reduces emissions. A tricky balancing act!

Author — Richard Greenough


Oh my gosh. I’m becoming an efficiency critic from watching your presentations. I’m not impressed with solar panels unless they have a recycling program as part of the installation package. A building is just a tower of doom unless it’s utilizing a heat pump.

Author — truerthanyouknow


The Mixergy tank seems like a brilliant device, if the price is right and the reliability is there. It will not, however, make any difference in how long it takes to get hot water at the tap, compared to a conventional tank. That depends entirely on the volume of water in the pipe between the heater and the tap, and on the heat capacity of the pipe material, as well as the insulation around the pipe. The worst case scenario is a long, large diameter metal pipe. The best is a short, small diameter non-metallic pipe, with insulation. Using a 3/8 inch (9.5 mm) diameter PEX pipe about 30 feet in length, I get hot water in 5 or 6 seconds. I really appreciate fast, energy efficient hot water, so I wouldn't put an on-demand heater or combi-boiler if you paid me. Dave gave a good description of the problem with those.

Author — IncognitoTorpedo


I remember when me and the family lived in Britten, we were amazed at how badly energy was managed. There was no insulation in the houses, single glassed windows, and the hot water tank was covered 11 mm of madras foam that was beginning to disintegrate. Being a son of the first generation of renewable engineers, this was quite shocking to us. Alot of research has been made in energy optimisation, and swapping one tank with a better managed and insulated one is a step in the right direction.
The problem is that you are solving a problem at the wrong level. This needs to be addressed at energy production or grid level. Not household layman, students and drunks.

Author — johiidk


We can vouch for the effectiveness of these tanks. They perform as advertised.

Author — C Bromley


An interesting idea I heard of years ago was to have a cellar sized, well insulated tank beneath a house, filled with pebbles. Solar heated hot water was to be circulated through it during the warmer months. The stored heat could be utilised at cold times of the year. Perhaps spare capacity electricity could be used. New build or garden, and, certainly, not cheap to install.

Author — tom ellis


I would love to see a combi heater made more efficient, because the space saving plus not running out of hot water quickly (as with a necessarily small tank) would make it much better for small spaces. I guess ideally, we'll be more efficient in water usage, and in everything really.

Author — KAri


I enquired about these when I saw them on Fully Charged. I'm waiting for a quote for installation along with an air source heat pump. The business development manager, James Hoople said a medium sized tank was around £1, 000, which for a smart system like this which will save you money seemed very reasonable to me, and with a short pay back time.

Author — Alan Easthope


This appears to be an excellent idea. There are heat losses from the cylinder to the tap, but this is a big step forward. I changed my hot water cylinder to a Sadia Megaflo about 8 years ago, with hindsight I wish that I'd waited for Mixergy to be developed, bad timing as usual.
I wonder if there is some way of making my existing cylinder much more efficient? Maybe an Eddi controller to control the immersion heater and several thermostats up the side of the cylinder to allow different amounts of water to be heated together with some kind of raspberry pi app to control the primary hot water valve. I can see a little project coming. Thanks for the inspiration Dave!

Author — Peter Flower