Modular Heat Storage 

Glad to have discovered this channel but sad to discover that John is no longer with us. May he forever remain immortalized by his very educative and innovative videos. Rest In Peace John, I hope to meet you in heaven

Excellent informational video John. I designed a house with the entire roof (single slope, south facing) covered with a trickle down system, during my second year of architectural drafting. The only difference was that the arrays I had used were flat black piping with photovoltaic cells covering the bottom of the enclosures to generate current for the pumps and the surplus to charge high density batteries along with small wind turbines.

Totally enjoyed your film! We have now begun our second year of solar panels and having recouped our outlay on the water heater power diverting system are enjoying free hot water deep into October and having had the sunniest January this year have been at it for 10 months in southern England!!!

Be nice to people who know more than you. This guy is a scientist, not a entertainer. RESPECT, learn about it!

Nice work John, great detailed video that leaves me in no doubt how to progress my own system, and your audio is clear and easily understood... exactly what I want from a technical documentary.

Don't listen to these so and so's who say that your voice is boring or they don't care for the intro, they are likely government trolls that want to see us all become ever increasingly dependent on them and all the things that are destroying this planet! These are FANTASTIC ideas and solid science! And I assure you, the more intelligent people here are appreciating and thinking about the ideas and ideals you are pressing forth. And DON'T quiet down about these issues! If things continue the way they are going, I think there'll be no possibility of recovering the planet within 100 years with the population increasing exponentially! ~love, one smart lady

I am impressed with the concepts and innovation. Thank You. It is a disappointment that some humans are so critical of others of the same species. It is a matter of opinion and some have no innovation or little personal talent so they choose to belittle others who have developed those traits and characteristics. Kudos to you Sir, for your efforts to educate others on a sometimes difficult subject matter to understand due to the science and engineering of the systems and implementation. Hats off!

Hey guys, don't forget the wonderful IBCs. My homebuilt gasifier wood stove stores heat in a 330g IBC that then distributes to radiators. A copper coil in the IBC heats the domestic hot water. like the drums the IBC will handle 150F easily. I have an alarm set to 155F or at least I am about to. Controllers should be here today. Ck out my build vids under fiskfarm. 2nd Winter and working GREAT. More vids on operation and fire tools, etc. coming soon. Thanks John for sharing. Lots of great advice here. Great music to boot!

Your voice is better than a warm glass of milk. I'm ready for a good nap now.

Half a million views. Well done. I would like to reiterate the note of caution about using plastic parts in a solar hot water system. While doing my research for my solar hot water system, I ran across a "lessons learned" document based on analysis of systems installed in the 1980s. One of the take away lessons was to only build these systems out of durable materials like metal, glass, and concrete. Other materials like plastic and wood are typically poor choices for these hot/wet environs.

Nice info BUT John I hate you as I was listening intensely on headphones and the burst of music after 09:10 just about deafened me its just about guaranteed to wake any one up. I too use a solar heat collector and am just about to add a air source heat pump to the system with an extra 400 Imperial gallons of storage and your info on non turbulent layering is Very useful. Thanks

Whatever was missing in form - was more than compensated for in substance. That seems to have escaped the “FORM” people. I really enjoyed this video and hope to see more like it! P.S. Like to see the critics do better!

There are many ways to store hot water. Recycling plastic drums to store solar heat is one practical method ESPECIALLY if you get the drums for free.

Cutting holes in the sides of the storage tanks for pipe connections is a recipe for leaks. Keep it simple and only penetrate the top of the tanks.

Oops! Typo on that final sentence, this makes more sense. Thermal mass and adequate insulation are the key factors and you've helped me a lot with the thermal layering problem. Cheers! :)

Really good information , sounds like you studied it thoroughly. Most of us just want to build something like that if it works really good. I might say it would help to say it in common terms in the next video. We appreciate the detail though.

John, I have studied your experiments for quite some time now and have started to construct a 36 square foot 200 gallon SHW system. I will be using three poly drums in my basement connected together to stratify the hot water as you have outlined in this video. I will also be using a conventional natural gas water heater that has been converted for use as a heat exchanger to provide pre-heated water for my conventional electric hot water heater. The idea is that the collector will provide the hottest water to the inner tank core that has been capped off and provided with threaded taps to put hot collector water in the top and extract it from the bottom of the tank, heating the domesic supply water in the conventional part of the tank. That collector water would then travel through the three tanks before making it back to the collector. At night, a circulator will move the stored water through the pre-heater as needed, on demand in order to take advantage of the stored heat and keep the supply water pre-heated. I am wondering if you have any experience with converting natural gas water heaters for this purpose. Thank you.

Guys, not everybody is a born storyteller. This guy obviously reads what he has written down and kudos to him. I don't see any of you making better or any vids for that matter.

Thanks for confirming for us that you would be the asinine bored kid at the back of the class who would get at minimal grade during exam time. You would be one I'd consider one of the "sheeple" that the rest of us would ignore and distrust if it came to needing this knowledge in a real world application.

this is cool I can't tell you how many of these drums I chucked out. We use them for Prop Glyol for refrigeration. This is a neat relatively cheap Idea.

I did essentially the same thing with 1,500 gallons and 34 Evac tube collectors in a commercial application and found that trying to maintain stratification proves far less effective then merely increasing the flow rate through the collectors. more flow rate means lower DeltaT across the array and a more efficient collector for a longer period of the day. I used 3x 500 gallon Plastic Tanks and a VFD powered 3hp Pump to give me the flex to try different configs.

Actually this is a relatively good presentation - it has a direction, theme, is concise and gives simple enough instruction. The fact some people are ADHD doesn't mean the thing they are incapable of paying attention to is bad.

good idea indeed- look likes the bell masonry stove concept- thermal stratification of fluid- Tks for sharing your work

That's the beauty of the drain-back system. You don't need glycol or an expansion tank, however, you do need a higher head pressure pump than what you would use with a pressurized system where the collector stays filled. I recommend reading up on this at builditsolar dtcm.

The concept is right on. We think the concept can be achieved most efficiently when the solar array is connected to a cistern tank which is connected to a heat pump. This way we can maximize the delivery of the solar element because our heat sink in colder and larger that other systems.

Good stuff John. I want to have a 720sq ft super insulated Quonset hut style SteelMaster house. With all the sunshine in my area this is my choice for heating not just the house but an additional greenhouse too. Thermo-siphoning would be handy during a power failure. I might put together a small system for a raised garden bed early spring and late fall crop for greens. Thermal mass and adequate insulation are the key factors and you've helped me a lot thermal layering problem. Cheers!

great video bud, your spot on btw ive worked for the oil industry and have been privy to certain knowledge, i think just about everyone knows were being kept in the dark on free energy. in the meantime we'll have to use methods like these to offset the ever increasing rise in the cost of living, thanks for sharing

Great video. Next step is to insulate it with a larger piece of KD pipe, having reducers top and bottom to connect to the inner pipe above and below the copper line. You can also fill the empty void inside with many different things ranging from expansion foam to dirt; to make it even more efficient.

Thanks, I found this very interesting. I have been looking at a system that has a small PV cell array in one corner of the solar collector to power a small pump that circulates the primary heat collection medium which can then be freeze-resistant to prevent damage to the collector during extreme winter periods when there may be insufficient sunlight.

Excellent work in building the system and in making this video. However I have to disagree with the premise. Modular heat storage is unlikely to ever be as cost-efficient or energy-efficient as a single storage unit. Why? Surface Area. (SA) The surface area determines both the rate of heat loss, and the amount and cost of materials to build the system. The more SA, the more heat loss, and the more materials required to build it. The shape that encloses the most volume with the least SA is a sphere (which is hard to build), so the next best thing is a cylinder tank of roughly equal height and diameter (an approximate sphere.) The third-best choice would be a cube, and the fourth best would be a rectangular tank. A modular system (several small containers) will always have much more SA than a single large container of an equal volume, so not only will a modular system lose heat faster, it will cost more because it will require more total material mass, and also require more materials in terms of plumbing connections & fittings. A single large tank would require only one set of fittings, whereas a lot of small tanks requires many sets of fittings (with many more chances for leaks.) It is not easier to assemble, it will not cost less, and it will not perform as well. And a modular system will probably occupy more floor area because of all the unused space in between the modules. (Solar collectors are the opposite: they require high surface area with the least possible enclosed volume. Thats why they're flat & thin.) For a heat storage system, get as close to a sphere as you can. A single large cylinder tank is almost always the best choice in terms of performance, materials cost, ease of construction. For a modular system to be advantageous, there have to be extenuating circumstances that override the above considerations. Such as if you can get the drums for free. But of course that's a method that will only work for one or a few people in the underground economy, it will not work on large scales, so cannot be expected to be part of a sustainable society.

Thank you Bushdoctor. It's becoming more difficult to make these kinds of videos.

I so much agree - a model for others - not a Beauty Parade for the presenter, rather a professional presentation. One item: Hot water isn't '' lighter'' than cold - it's not as dense - tho' your easy to understand explanation for the density change as temp rises is most welcome - t y.

John.... fantastic video.... I am very encouraged by what you have demonstrated here! I am now tempted to build a project. However I would be interested in knowing your thoughts on collecting hot ait and piping it through the house.

Am I correct in saying your objective is to return colder water to the collector? That is instead of using say one tank and quite a bit of heat being returned to the collector you get to keep the heat. This would of course be wise if you return colder water you can then get more heat from the collector. It increases the efficiency of the cycle. Another question is the array is trying to achieve high temperature difference is that for air heating which would rely on this.

wow it's awesome ~ collecting solar heat by this system may help us reduce a bunch of troubles

Hi John, Well done, good presentation for those interested to learn. Have you considered using coils of pex pipe in each tank? The idea being that the water (heat store) is not disturbed thereby allowing natural stratification, the coils can also allow the insertion of a second coil to draw off hot water from the store without the turbulence of a pump to disrupt the stratified layers. Just thinking out loud.

Interesting! I'm in the process(well, thought process) of designing a solar water heating system for both the home and an aquaponics system. A 'daisy chain' of tanks could prove very useful! Some people complain about the expense of setting up such a system. Sadly, they fail to see the benefits. Once setup, the only outlay is the running costs. Lets face it, running a small pump costs far less than an electric or propane heater.

From a smaller passive solar heating array such as the ones John mentioned in the video, the potential to generate super-heated steam is almost nil. To accomplish that, you would need an active array of parabolic mirrors that are setup to follow the sun, and directing the focused light onto a heat exchanger made from steel. But unless you plan to run a steam turbine, why would you be inclined to generate super-heated steam?

Thought about this but worried about the weight of tanks on the concrete slab. I am looking at 1-3 tons of weight in a relatively small area. I don't think the floor slab was poured back in the day with that in mind.

Have you tried using a mesh in your outlet pipes to prevent turbulence?- I'm guessing most the flow exits out the first one or two holes in your series of holes so it's only helping so much. Perhaps try using a 2" to 3" or 4" expansion joint to slow the velocity of the water entering the tank to prevent causing any current in the tank. And perhaps try using a plastic mesh in the expansion joint (similar to mesh used as baffle material in a fuel tank / fuel cell).

There is a difference between being entertained and informed. This is great information. But only 1 in a 10 thousand will try this...fewer will succeed.

Could tall and narrow water cylinders (about 7 feet tall and 12-18 inch diameter) be daisy chained and still support heat stratification? What kind of flow rates support stratification? Are there any good reference books?

N9QJA As a person whose input to RU-vid seems inordinately concentrated on the use of guns and other weapons of death and violence, one could expect little else than the type and tone of your contribution. Some, such as Mr Canivan, are dedicated to Enthalpy, and disseminating his findings FREE Others, like yourself, to Entropy - Have a Happy Zero Kelvin.

It looks great, but is the water circulated through the house, drank, used for cleaning or just blowing the air over it and circulating that through the house? Where I live the solar panel will freeze between dusk and dawn and crack the thing. I could fill it with anti-freeze but them we can't use it for showering. Boy, much is left for guess work!

A material like polyester fiber fill added to the tank might help tremendously.

You mentioned 160 deg. until the barrels begin to soften. Couldn't you add a 90 F. to 130 F. Degrees Adjustable Therm-O-Disc to the pump wiring for both temp. control and eliminate barrel issue or would it take to much away from the original concept?

Thank you Mike. Hope this video has a positive influence.

@dadigitechman Thank you DAD for your comment. The reason I use large 2" PVC connectors is to create less turbulence in the water. Turbulence causes the hot water to mix with the cold water and this lowers the heat collection efficiency.

I'm thinking about adding solar heat to my home. I found a great deal on 330 gal totes the contained food grade silicone used to manufacture non stick baking items for $65 each. Their high capacity and square shape will make them easy to insulate. I want to run the circulation system off a few 100 watt solar panels as well now that solar panels are finally reasonable, around a buck a watt these days... I'd love to go totally off grid someday. Forklift batteries are the best deal going too, in stationary use they last nearly forever, 15 years easy. I've already upgraded all my appliances and lighting to high efficiency and led and only pay $58/mo on budget year round so the expenditure for the initial setup seems hard to justify at the moment. It would mainly be just to help the environment a little and the added bonus rush of not having a bill. Hopefully solar panels continue to fall in price. The planet could use a break too for sure...

hay John, I like what you did it is amazing.it is clear that you put a lot of work and thought into what you've done.i didn't know how ugly all the haters were gonna get ...sorry bout that.i just can't buy into the man made global warming,of course the climate is changing it always has and always will.but I'm no fan or big oil.so keep up the good work!!

Clive Adams Stratification is important because it reduces the amount of heat that can be stored per unit volume. It's like only having a half barrel instead of a full one. As far as it being expensive, it isn't. You can find these barrels for a very reasonable price.

You have a point. It can be difficult to know of the right way to encourage people to become more free from the system though. By getting the majority of your energy and food needs directly from the NATURAL RESOURCES from the Earth, you eliminate many of the middlemen, become more self-sufficient, and become more free. I think he was just trying to describe this basic concept. Not all corporations are bad though. That's true. Many of them are not efficient. Many care about money more than People

Where do you get these boots for PVC penetrations of tanks? I've struck-out so far. I'm only finding boots for roof penetrations and landfill/pond liner penetrations.

To reduce turbulence I highly recommend you install some straw filters into your pickup and fill tubes. These are nothing more than a bundle of plastic straws fitted down into the dip tubes so the water has to pass through all the straws This creates more laminar flow, forming a more coherent stream.

Great idea! The only problem I see is the loss of heat by the plastic barrels. is this a big problem is this system? Is it also posible to buy a professional kit of this three barrel system? If you know the awnsers to these questions you would really help me.

Brilliant, but what is the comsuption finallity'? this hot water, can be used, for comsuption, and for ambient heating, and seems to me that we are looking for only hot water production system. what all of us need to know, is that the inventor, try to get maximum efficiency, for the solar colector, and so try to get the maximum solar energy possible in a day, (I guess)

Nice setup, free energy is always good.

Fifteen years ago, I was Involved in an experiment to use parabolic troughs 2.5 meters in length to raise useful steam. Result, a very large array of troughs (5) was needed to create steam that was sufficient for practical use.

I can't find in your video Why you want to increase temperature stratification.

I'm no plumber or expert on thermal heat exchange systems, but what is the potential of such a passive solar array from generating super-heated steam to be used in the same way as a steam engine generator?

I do like this idea. But how may this idea be altered for storing heated water for using? This seems to be only geared toward heating the air. We live off grid and I'm curious how to get a good hot water system going and have looked at so many options. My head is spinning!

Have you ever tried a system using the "heat rises" and "cold falls" effect for the water to be circulated between the collector and the storage tank??

OK, I like this. I like this a lot. However, I'm still missing a few pieces of the puzzle. If I just used one large drum, the water would stratify according to temperature. What is the advantage of using three drums? Clearly the drum with the input to the hot water heater would be the warmest. I'm just not understanding what that buys me. Thanks much.

Oh please. This is just incredible. Get back to the roots. Connect to the universe. Build our own goodies that cost money to save money. Trap heat from sunlight. Spend more and more money to get less and less return. This is phenomenal. I love it. The polar icecap is going to melt in 200 years. I won't be around to see that.

I'm amazed at how negative these people are at your presentation. Communicating the idea of modular storage of hot water for heat is great. It could be piped through radiators to disperse heat for use in living spaces. Thanks for your input.

Good info. Taking advantage of the natural vertical thermal stratification or multi-reservoir horizontal stratification and then going from the lowest to highest grade heat when heating air / DHW is brilliant. John: have you given consideration to using a similar method with, for example, in ground tanks (at or below the frost line) to provide cooling & dehumidification? Where I live the frost line is about 2m (6') down and the temperature peaks out at 15C (60F) in late August. Using just night time ventilation my house is quite comfortable most of the time but there are generally about 5 three day periods between late July and early August where the temperature hits > 30C (86F) with > 70% RH and night time lows are 22C (72F) & 100%RH. Using a Water - Air heat exchange coil in the furnace and a circulating pump to provide cooling and dehumidification would mean using 120V @ 0.008 A (1 W) rather than 240 V @ 35 A (8.4 kW) for a traditional AC. Even with a 100% vs 25-30% duty cycle, that's still a *big* difference.

Hi John. I've enjoyed your videos over the years. I'm refreshing my research now as I'm just finishing a 16'x36' greenhouse that I don't want to freeze during winter here in the Colorado mountains. One of the heat sources I'm planning on using is warm water storage in recycled IBCs painted black on the insulated north wall of the structure. Aside from them being heated passively, I'm also considering building one or more collectors to aid in heating the water. My question for you is about stratification. Is there a specific reason to not have the temperature buffered by mixing the hot incoming water with cooler, but warm tank temperatures? I would think that keeping any "hot spots" of freshly heated water from stratifying would lower risk of damage to a plastic tank. I've not done or seen any research that would suggest that either way (stratified or mixed) would release energy into a space more efficiently from a tank open to the room.

@photoimagedisplay Does this system need a pump to pump water (or fluid) or is there some kind of advantagous syphoning that goes on just with the difference in temperature in the water?

Thank s for music too !! I love it ! 😀

Excellent ! thank s ! I had the same idea since a long time ! but only in my mind !!!

thinking about building a mass heater and heating hot water to send to plastic barrels in the back of the house do you think the water would get to hot for the barrels

To prevent water mixing I would fill up a storage tank with a rough plastic foam. The hot water will find a way to the top. No need for a multi-store.

Why not install a radiator before the first drum? You could hook it right up to your air handler in the house.

Would be nice to see working prototypes. It's easy to draw, but hard to implement.

I have a 300 gallon plastic water tank I'd like to use for storage. I want to heat the water and then run it through a radiator at night. Would it really matter whether the hot water stratified? After all, 300 gallons of heated water is still going to give off its no matter what. Can I use PVC pipe for a collector? . . .Thanks

Hi John. Great video. I wonder if you have data on how long your peak heat values are retained? Would additional insulation ( the plywood box scenario ) surrounding the water tanks give more than a day's worth of space heat?

I dealt with John, once. Would never again, despite his information.

I'm also working on a system that will use thermal variations between cool air & hot air in an inclosed system to drive a wind turbine in order to generate electricity any ideas on a good bottom feed vertical spin turbine design?

I've been researching various DIY a solar heating unit to heat out buildings. One thought that has crossed my mind is to use a 'solid mass' heat storage 'tank'. Effectively building a large insulated box filling it with rocks, and passing the air through the 'rock box' before letting it flow into the building. The reason I thought of a 'rock box' instead of a liquid solution is building and insulating a 'rock box' should be easier for most DIY'ers and should theoretically be LOT less maintenance once built. I haven't yet seen any serious solutions along this line and was wondering if you had an opinion on the matter.

Did anyone use plastic barrel storage system at a temperature of 90 degrees Celsius at a pressure of 2 bars?

John, how can I use this idea to keep my above-ground 1000 liter rain tanks from freezing solid and rupturing during the frigid northern winters? I would love to stop having to drain my tanks each fall and retain that water source for spring water needs in the garden, in case we experience super dry spring weather. Any thoughts on this?

Awesome. Could also use "fins" to reduce water velocity on inlet?

I don't get it. Why would it even be important to stratify the water into different temperatures? I don't see what problem this solves. Why wouldn't it be just as good and a lot simpler to have one large water reservoir instead of several drums?

This blue print is a great start for a heating system I am working out to heat the floors of my house and shop thanks. Was also thinking of thermal mass wall panels with water piped through the panels. Thanks

I am interested in incorporating simple sand as a heat storage method! Why? Because the sand will hold or store the heat for longer periods of time say for say the case of any heat source gas oil. So what ever fuel you use will be lessened simply because of the energy stored in the sand by say pipes or radiators should lessen the number of times your boiler or furnace has to cycle on and off too heat your home.This is only an idea for an experiment!

thanks a lot . I am just worndering is it possible to have this design in file format like pdf etc..

salt filtration for heating?

This is an excellent, thought-provoking video. Kudos & thanks.

Why not insulate old 200 liter steel oil drums? They are abundant, cheap and easy to come by. Rust might be an issue, but maybe treating them would fix this?

Its funny how people still call oil, fossil fuel. That's long ago disproved. Thanks for making this. I watched it all

why not using a countercurrent heat exchanger instead of water stratification? Countercurrent heat exchanger have an almost 100% CoP, I believe

My plans are insulating my 1700 sqft, 2 story home with 3" of closed-cell foam on all exterior 2x4 walls & rafters, then replacing the FA system with a PEX tube underfloor radiant system. I'm not too keen, however, on the idea of JUST replacing the NG furnace with a NG boiler. I'd like to add an alternative heating source (e.g. solar panel or wood burner) to supplement... or perhaps even replace it completely. I'd prefer to add a solar panel, but the problem I'm having incorporating it is in two areas. First, I live in a 4A hardiness zone and the extremely cold temperatures will freeze any system based solely on water as the thermal conductive material. If I isolate the solar panel portion of the circuit, I was thinking I could use a 50/50 of propylene glycol/water to solve that issue. Thoughts?!? Second, I'm also not keen on the idea of saving the cost of heating fuel, only to add to the cost of my electric bill running pumps or with the added cost of purchasing photovoltaic panels (and their peripheral components). Is there a way to incorporate a thermosyphon system with storage tanks located below the panels... say in the basement?

Great plans!

Unless the system is very well controlled, it is possible to get temperatures above 220°F on occasions and that can instantly ruin most plastics. Make sure the materials that you use are suitable for solar applications or else you will have a long term maintenance problem and possibly a lot of water to clean up. Many materials for domestic hot water are not rated for solar applications.

Nice , But where did you get the rubber boots?

You have wonderful ideas

I guess John's just an old hippy relic. I like this idea. I have a bunch of the plastic drums but maybe I'll get some more of the steel ones to put at the hot end of the chain. How is this better than having all the water/heat storage in one big tank, like the ones they are doing at builditsolar website? I guess the more cold water that enters the collector, the more the heat transfer as opposed to having more even heat across the tank.

Listening to the intro narrative reminded me of being in church with a bubble-thumping "sin is everywhere", child-torching priest.

sorry to disagree with you JB but actual cost is about $75 per tank in the system. As to the warm and cold tanks, When the hot tanks equalize in temperature at top and bottom the next one in turn gradually gets warmer till it equalizes as well and the heat is then put into the 3rd, 4th, etc. If you use 20 50gal steel drums in succession it is capable of storing approximately 1.25 Million BTU's at a temp of 160deg F. As long as the glycol/water is pumped in above temp that you are storing energy.

doesn't compressing water to make heat out of it take lots of energy?