Cheapest Energy Storage Off-Grid
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- เผยแพร่เมื่อ 14 ก.พ. 2019
- What is the cheapest way to store energy when off-grid?
This is part 4 of my series on Solar Thermal vs. Solar PV to electric water heating. We all use hot water and it's cheaper to make it directly and then store that thermal energy.
I discuss making a thermal battery. This is a concept of storing your hot water for several days in a well-insulated tank. Sometimes called thermal energy storage, or hot water storage. I use my own tank as an example. With the knowledge of how to calculate it, you can make your tank even better.
I'm passionate about finding the most efficient and cost effective ways to produce your own energy using renewable sources. Couple this with storing that renewable energy and we can go off-grid. Disconnecting myself and family from the power company is my ultimate goal.
There is a lot of math in this video, which is fun for me. I hope you enjoy. Thanks for watching.
First three videos in the competition between Solar PV vs. Solar Thermal for heating water:
#1: • Solar PV vs. Solar The...
#2: • Building a Solar Hot W...
#3: • Matching Water Heater ...
Videos about making my thermal storage tank:
• Framing solar DHW tank...
• Framing Solar Thermal ...
• DIY Hot Water Solar Th...
• Heat Exchanger for Sol...
Please help support the channel by using our amazon link:
Tank Liner: amzn.to/2GueVA3
Mixing Valve: amzn.to/2EfBcPV
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Here in Nordic parts of Europe, we have had separate heat collecting systems for decades. Electricity is only used for water pump and there is a heat harvesting unit on the roof.
I was just thinking the same thing: Instead of electric solar panels could use heat collecting systems. Wouldn't that be much cheaper / more efficient?
@@maciekmnyt Go and watch his project from the start. He does both ways and if you watch it all, you will see what he is really getting at in this video.
Pretty much, he would be filling his batteries up and when they are full, the rest of the power produced by his solar is dumped into heating his water, great idea really...
Yes, 20 years ago those systems were much cheaper than PVs, but now it is the other way around.
In Mexico some places still have water running to the roof into a tank that gets water hot with just sun light as well. for hot showers during the day and at night they turn on the water heater. I had no idea insulation can store that heat for 4 day holy shit.
Back when Discovery Channel still had "The Green Channel," one show featured a DIY home inventor who cooled his photovoltaic array with water (using pipes on the back of the panels as the heat-transfer method, causing more electricity to be produced) and simultaneously pre-heated his hot water. Such genius!
Your enthusiasm is infectious ! Now I want to build a heat battery for my apartment !
1 gallon of diesel fuel has 139,000BTU and costs about $3.00 but the true cost has been placed squarely on the future. Thank you for fighting the good fight.
Tall storage containers easily develop thermal stratification, but this is less pronounced in short wide containers as found in your crawl space.
Instead of putting all your thermal mass in one box, consider several (n) thermal storage containers. By connecting the primary thermal loop to each box in series, you can achieve a higher temperature stratification. This allows faster (t/n) recovery times in the first tank. This also allows prioritized temperatures for thermal conditioning: one for hot potable water, another for heating the floor.
You reduce the primary [closed loop circuit] flow rate so the first box gets up to the minimum temperature first. The flow rate is proportionately increased as the tank inlet (collector outlet) temperature approaches the maximum set point, dumping hot water into the successive containers. This works especially well if your final collector is a vacuum insulated type.
Of course, the secondary (potable) water circuit is also connected to the successive tanks in series, but the direction is reversed. You should use series-connected thermal mixing valves at the outlet of each tank, so the hot water is drawn from the earliest tank that produces the minimum necessary temperature. As tanks drop to the minimum setpoint, the flow is drawn from the next, hotter tank. [The mixing valves use multiple tanks at once if the flow rate is too high for the heat exchangers, so you may perhaps economise on PEX loops.]
You could just [leave off the mixing valves and] connect them all in series, but this *may* produce a long slug of smelly water that has been breeding bacteria before being heated enough to be safe.
The mixing valve setup gets cold relatively -quickly- suddenly as only the last tank in the set can become chilled by cold ground tap water. The other tanks are just locked-out at the minimum safe setpoint.
John Canivan as done video on storage to avoid stratification with multi storages th-cam.com/video/n90Y6Qwab_8/w-d-xo.html
Smart man Dave, I've been experimenting with solar water heating too & had a less than 2x2 collector circulating in & out of my water heater giving me scalding hot water all summer but from late fall to early spring it didn't cut it so & built a collector about 4 times bigger & that fixed it but your idea of storing in bigger tanks & the heat exchanger idea for non sunny days has got me rethinking how I should go about it. Your video gave me much to ponder, thx!
Awesome, I've wondered why this isn't a more common way of storing energy, seeing as 100 gallons of water can store as much energy as a Tesla Powerwall. I'm putting up solar soon and I'm going to seriously consider doing this. Thanks for a very clear explanation!
I'd love to see some pictures of your project as you get underway.
Why not oil?
8
Gattz Oil has a lower specific heat capacity than water. Plus, it's a nightmare to clean up if things go wrong, not to mention costs more than water which is practically free.
How would you convert it back into electricity? I see how heat is "easy" to capture and rather easy to store, but how do you make use of it other than warm water?
amazing and inexpensive way to store heat energy vs battery , basically 14 times more efficient , great work David thanks for posting and sharing your ingenuity here .
David you explained this brilliantly. I love this kind of practical math.
Love your calculations!
I use 3 255w solar panels in series with an electric clothes dryer thermostat to run my hot water heater in the pool house. I get 20gallons of hot water a day for showers out there.
Rockstar....you got this down and display it like a boss.
Very good job.
I really enjoy your information. My daughter ask why I know so much I just smile. I’m 65. Thank You
I watched this video over a year ago and it changed the way I think about energy storage so much. I found you again and this time I was sure to subscribe! Thank you!
Love it - love to see people thinking ‘outside the box’ - using both hot water and batteries is really smart
Great job David. You are an inspiration. Making ice with excess solar power is also a great way to store energy for cooling and refrigeration.
How many daytime ice machines to cool a big house, 100?? If you freeze water tank would it bust so need inch walls? …. Would compressing gas like air then to cool expanding it be more feasible, but it would be loud compressor.?
That's also a great idea!
Ammomia
In the summer I like to make ice in my 12v fridge/freezer during the day with my excess solar power.
Very good idea! We froze two half gallon containers of ice, kept one in the freezer and the other in the other compartment, and it kept our food perfectly cool. We plugged in the refrigerator at night and plugged it out in the morning and repeated the process each day. We cut off more than 50% of our energy bill! The utilities company came twice to investigate!!
Recall my father having his hot water at about 151°F... just needed a little bit of hot water and a lot of cold to feel warm lol. Rewatching this video after about a year or two when I last saw it as I'm getting back into home energy storage projects.
Fantastically clear simple explanation of this whole concept, which albeit I had not really considered til i watched this video. Very clever! Also i liked your placement of the thermal battery since the heat loss then travels through the floor of your home. Smart guy!!
I use PV to heat my water... The rest is The same principal as yours! I also use a rocket stove for backup...
Awesome video!
Thank you for sharing with us your cost effective thermal storage and the math to get us there.
I was converted to the idea of using solar thermal heat back in 1967, when I visited an outdoor swimming pool in Southern England that used the sun as its heating . The pool was approx 20x 5x 2mtrs. There was a small changing room/ pump room which had a copper sheet roof with a glass over roof, The filtered treated water from the circulation pump was allowed to trickle down the roof and by gravity into the pool. It was warm enough to swim even in winter, The owners had a family tradition of swimming on Christmas day.
In my own home I use solar thermal in the underfloor heating in winter and to heat the hot water in summer. The rest of the time I use air source heat pumps, often powered by PV .
But the best way to cut heating costs is of course Insulation.
I love that. Water flowing over copper. Just add some silver along the edge, and you have a Roman water treatment system and a heated swimming pool.
Wow this is a big eye opener. going to now spend hours researching this. thanks for the idea
Extremely good video. I thought I was an eco geek using mirrors to reflect light on to my solar pv array but you have taken it it to a whole new level, clever stuff.
I just became enlightened. Thank you.
I have an old plunge pool in my basement and i think you have just given the solution to how to best use it. I intend heating it via a compost water heater and then running it to my boiler to bring up to final temps. cheers dude
I have been contemplating this for some time now. I am going to go forward this ASAP. Nice video and great job
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....another great video. Numbers aren't exciting to some, but necessary if success is the goal. Thanks.
Never heard of this you are a genius.
Clear and easy for the understanding of folks like me who know little of the math involved. Thank you kindly.
Down here on the gulf coast we have the opposite problem . Eight months of the year you would swear you lived off planet but mostly just swear a lot . I thought about chilled water but along with the sweat mosquito's chiggers flees just to name a few there is humidity around ninety six percent matching the temperature . Thank God for modern heat pump technology . Your on track and in the correct part of the country . Thanks
Something I never even took into consideration glad this popped up while I was looking up solar very good information and a bunch more I shall add to my build ideas thank you definitely subbed and will keep an eye on your channel
Great video, thanks.
Over here in Turkey we have a water solar panel on the roof , it's great ,free hot water every day, on cloudy days in the winter I have to use the electric to heat it up a bit but it's rare.
Love the water storage idea , and impressed by the calculations..
This is really good! Thanks for the numbers!
I have been thinking about running a mini split during winter for supplemental heat, but thanks to you, I am now also considering using solar heated water for space heating. I can see the benefits as long as the water is heated with solar and not the grid. After all, panels are becoming cheaper and cheaper.
Sounds good. I have had trouble with my miini-split.
There may significant thermal capacity benefits from using brine. You'd have a greater thermal capacity for the same temperature delta. That may get you the extra day's capacity you'd like. You may have to take steps to prevent excessive crystallisation either through evaporation or lower solubility at low temperatures, but I don't think that should be too problematic. It's probably worth trialling. .... Oh! and it's also cheap!
I like the idea for the pex heat exchanger but I wonder if corrosion would be an issue if the heat exchanger was upgraded to copper (as is his plan). Whadda ya think?
@Jason Stanley...except for the steel wire ties he used in securing his pex. But then that could be quickly solved by using zip-ties instead. As long as zip-ties can take the heat I have to agree with you... pex is good, copper could complicate things.
@@ScottyDMcom would there be a need for a pump at all... opening the faucet would allow the pressurized tank to push the "potable" water thru the loops in the heated water in the tank, would it not?
I was trying to find a better substance for heat storage than water and I did t find one readily. I suppose the advantage you would have with oil would be that you can store at higher temperatures to achieve a better energy density.
All the PEX couplings can be above the waterline, or even outside the brine/water storage box. Putting more PEX in parallel not only reduces water pressure drop, but also increases heat transfer, so a pair of external manifolds seems great.
Good discussion, this is why i went the route of Grid Tied when i built my solar system, granted i do have a battery bank i built from 18650 cells i got for free, but i broke down the cost and just accepted the cost of the $27/month connection fee for the ability to have access to grid power, and pump my excess power into the grid for a credit. I just kept adding solar panels to the system tell i no longer had a bill above $27, the past year i have developed a credit of nearly $90 on my bill, so my monthly connection fee is wiped out and i dont have to worry about the cost of buying batteries for my system. Granted i did have a LOT of issues with grid tied inverters overheating, but i cured that by watercooling the mosfets with mods to the inverters. I made good friends with the local solar companies and solar warehouse in my city that most use for purchasing of solar panels. I found they are constantly discounting and clearance panels all the time, because they were returned due to a connector not working, or box was damaged, or even a few panels had a crack in the glass. I just poured superglu into the cracks and run them. Ive gotten 300watt panels for as little as $50 because the panel was cracked during shipping.
You Sir are taking Advantage of the power companies, Shame on You LOL HAHAHAHA i Like, OLE!
water dissolves superglue :p
Can't you also use polyurethane?
Sounds smart, i've been talking to people and considering doing the same thing here in Austin Texas. However in order to feed back to the grid to start accumulating a credit you must use one of the cities certified contractors and it has to be inspected. How did you get around this? Which power supplier do you have?
@@epicdeuce the inspection are for making you didnt do that islanding mistake that might kill grid operators
this video is SO FANTASTIC i cant even tell you. I have been thinking about making a system like this and I am also very excited about solar thermal energy storage!
For off grid, I would consider adding another loop that comes from an indoor or outdoor rocket mass heater for those long stretches of no sun or excessive hot water use. Rocket mass heaters use little wood relative to normal fireplaces/wood stoves. So one burn of a small amount of wood would yield a lot of BTUs to bring that thermal storage tank back up for hot water and space heating.
If it was me off grid I wouls just go with solar panels and power a heater or air conditioner as I wanted. maybe heat sink extra solar to heat, but for $2000 you could live modern world off grid....
This made me remember when I failed my heat & mass transfer class. Btw you look just like my professor.
Darn thought of this a few months back! I reckon thermal water energy storage is so much more viable than people probably think...
Especially with Vaccuum sealing!
Thanks David. Well done.
Great video as usual. Thanks for math. Panels are already lower priced, but batteries and components are going to drop in price the most and are the largest expense. Wait if you can. That’s why I like this idea , especially since I’ve done hydronic radiant floors before. Wood fire is the next option of stored heat energy and can work in combination but has disadvantages. Wood can’t be economically converted to electricity yet. I have the big soapstone fireplace but it’s really just a luxury. I love it. Any wood boiler is going to start at $10k too.
lived in a walk-up 3 story 21 apartment house in San Diego in the early 60s all of the hot water was supplied a cistern painted black on the roof. One of the most efficient ways to use solar power
In San Diego ... Yes! Just like they've been doing all around the Mediterranean and Southern Europe for decades ... EVERYBODY has a solar HW heat exchanger on their flat rooves. Try finding the same thing North of say Frankfurt, you'll be hard pressed except on fairly modern multi apartment buildings. When the outside nighttime temperatures can drop to -35°C or lower MUCH bigger, MUCH larger area heat exchangers are required!
@@boblewis5558Solar panels that heat water work great even in Scandinavian winters.
@@0ooTheMAXXoo0 Depends on the weather too. Had 2 weeks straight of almost no sunlight. Constant snow storms and cloud cover. Not to mention getting 30cm of snow can really cover your solar.
@@Azsunes hot water is for pussies
@@Azsunes …. Yes north can be dark, in MN we have dark weeks after month of sun but people can for week skip shower or take cold shower or do tramp-shower in sink. Not to be macho but I am in a camper and heating up the shower water aint worth the propane-hassle so I take annoying cold shower. Honestly is hot shower worth it, 5 minutes of cold annoyance is not worth 100 hours set-up time (6,000 mins or 1200x the annoyance time!!1) of setting up time for Solar Heating setup time, plus there's $5000 cost of solar ($5000 for 5 minute shower, or if 100 showers that's $50 a shower, damn!!!). I am not macho but I am lazy, so again is hot shower worth all this effort. Jeesh. I am half-serious but still wonder. : )
Great video! Now I understand a lot more about energy storage.
For the cloudy days, a battery bank can be boosted from an idling car. A typical car alternator can put out about 1000 watts. Some alternators can output 2000 or even 3000 watts. For non 12V battery banks (such as 24V or 48V), each 12V subbank can be boosted in turn by just moving the clamps from one subbank to the next until all subbanks have been boosted. It is not critical that all subbanks be boosted at the same time.
The heat from an idling car can be harnessed too, especially in a cold state like Mass.
That's an excellent idea, which is using thermal storage as you mentionned, or phase change cooling/heating.
Knowing heating/cooling can easily take 30-40% of energy consumption, that is one good move if you can store either hot water during the winter, and cold water during the summer.
Very interesting, thank you for your enthusiasm and your informations!
Recovered and reconditioned forklift batteries are perfect for this application. Additionally telecom batteries are removed on a lease basis and are perfectly good used batteries to use. Both options are a fraction of what you can build your own systems for. Im a battery technician in Canada and my primary work is building motive batteries.
Lithium?
Thank you for this video ! I love micro heat storage system for home and apartments ! I d like to do a system like this this too !
good explanation with your thermal info, few years back I had a similar idea about the thermal heat my plan was to take the heating elements and place them in the center of a room under the floor the main tank would be setting on top just like a water heater except the tank would be about 1/4 or a 3rd of the size of a existing water heater tank the rest of the tank would spread out above the main tank in a coil pattern of car radiator tubing(lots of tanks to choose from), solar or alternator ect.. gravity fed circulation into main tank. possibly interlocking matts and interconnecting piping combined, with a rubber material like floormat for installation, at the local hardware store. I didn't know this could be considered thermal maybe explaining it to someone to put it together so others can, heat radiating from the floor is excellent. The mass and volume of the original size of the water tank would be spread out in a equal amount of mass and volume of the piping, fabrications will be necessary in the design depending on mass and volume of the room or structure. An electric heater would operate well in this application with lithiums or even lead acid with solar collecting plenty of potential energy with parallel capacity storage.
Awesome DavidPoz a lot of informative info here thanks
FINALLY a DIYer that gets how to do the cost/ benefit analysis. As for those people who say "you can do this with solar PV too" remember please the following points:
1. Solar heat collection can achieve better than 80% even on a DIY solution whereas the MOST efficient solar PV (
What about using Epson Salt as the phase change material?
Again; people are missing the point of specific heat capacity of water been really high - density is not the dominating factor.
I wish people would do the calculation rather than simply assuming high density is better.
Well, lets deconstruct your argument.
"whereas the MOST efficient solar PV (
Thanks Bob, lots of food for thought there.
Thanks mate. Great stuff.
Interesting analysis. I always suspected as much. Stands to reason if only 'cause you are eliminating all the inefficiencies inherent in the electronics. Cheers and godspeed good sir.
Excellent video, really clear explanation for a novice like me
I've had a similar idea but using a buried (never been used) concrete septic tank or similar to store the heated water. A waste heat generator can make electricity from it also.
Earth will suck the heat right out of your concrete. Probably near impossible to insulate. Now with a heater exchanger cooling your home in the summer with this set up would definitely ease the burden of your AC if you live in hot summer climate.
Another brilliant video. Thank you. Water has such an enormous specific heat capacity, it really is extraordinary that people don't store energy this way much more.
p.s. Your daughter is very lucky to have you as a dad.
p.p.s. I wish the US would go over to SI units. kWh and then BTUs... it's so crazy mixed up units you have over there.
So do I.
That's awesome! I personally try to minimize my hot water usage, but I hear that it's a great way to heat a house. Using it for in-floor heating, an efficient means of allowing the heat to build-up and rise
Explained so well! This time TH-cam got a recommendation exactly right, I subscribed.
Thank you for subscribing.
Some people make hay while the sun shines, you make hot water ;-) Great video, well explained, I liked your mathematical break down.
Easy to understand, and utterly logical. Thank you
Great! Looking forward to seeing the system & schematic (simple drawing) !!
Hi Harm Hoeks, I shared a very simple drawing when I started the build, way back in this video: th-cam.com/video/jKr4An8m_tM/w-d-xo.html But most things I just build strait from my head. I do have a whole series of building the DHW thermal system.
Great effort David, certainly the drawback in this is the large volume you need, but that won't be a problem for a stationary system at home. Look forward to see another video of on monitoring the system behaviour, like temperature in the tank and in the house taps over time. Nice work!
Liked your heat exchanger a lot. Heat pumps should not be dissmised - they do add complexity and cost, but also efficiency.
I second that motion and add:
Solar hot water can get the water up near boiling. You want to store water this hot when the sun is out but not deliver that hot of water to the taps. This adds a bit more complexity in requiring a mixing valve. Don't cheap out on the valve because the bad ones stick at one extreme.
Lead acid batteries may cost less per KWH of storage even through they need a lot more room.
Extra very hot water can provide space heat on cool sunny days. Keeping the house warm stores energy too.
The benefit of a heat pump is you are creating heat but gathering it and moving it into a storage device (tank). Where electric heating is 100% efficient by directly heating water, the heat pump water heater has an efficiency expressed as a coefficient of Power equal to 2 or 3 which is 2-3 times more energy efficient that direct electric heating. Definite applications for it with solar, particularly if we can use the solar dc power directly without an inverter.
What a great idea! Thank you!
Bravo. Genius. Love it.
Glad to see other people doing the math and coming to solid conclusions
A good point well made. Thank YOU!!! :-)
I do not understand why this video would be disliked, makes a lot of simple sense
this is so much the way to go. Thanks for sharing.
We are perfecting a way of turning the energy stored in the hot water to electricity!
Great video ! I will use the info to help lower my electrical storage requirements where I live. I live in Northern Thailand & Sun is usually intense with not many cloudy days in the year. Thermal storage will keep hot water demands from coming from solar electric bank. Hot water will be separate system and lessen my electrical needs of household. Thx , NavyBlueSmoke ......
I live in Florida. We have plenty of water and plenty of days in a row to keep it hot. Why wouldn't I use this? Are there any downsides? Is anyone doing this already?
Pleas what are the names of all equipment used
Wow, this is great. Thank you for walking through the equations and calculations you used. I've been curious how to get some of those numbers, but haven't gotten around to figuring out how to find that information. I feel like with several of your videos, I just want to save and rewatch a few times later to make sure I understand everything from it. I'm also interested in how to use energy from wood (like Garn and other wood gasification options), but so far I haven't found the right cost/benefit I'm looking for.
Good video, info rich and well presented. Thank you. Quite refreshing.
You could also use this theory to cool a large mass down to use when it gets hot in Summer.
This video earned my subscription. Keep up the great work.
Same here. Liked the topic and the math/ explanation
I'll third that reply, it was complicated but it all made sense. And definitely earned my subscription.
Count me in as well.
Yup, same, same. Plus a like
9
Amazing! You just discovered hot water!
You're right. Is so cheap and easy and we still don't use it enough.
Thanks for taking the time to explain in simpler terms so it can be understood, a well presented demonstration.
Your Welcome. Thanks for watching.
Very good presentation. I love your diy heat exchanger! I wish you would have talked about cost savings with building your own thermal solar panel. You spent $900, but I think you can build a lot cheaper. No one is build their own PV panels right now, built anyone can build a thermal panel, so its does seems to be a better solution with way may return on investment then PV's
Awsome explanation of why use H2O math really good at showing us
Real deal thank you
Your energy is really good for teaching these things your passion shows love it. 😊
Good info. Thanks for making the video.
Back in the 70s I was shown a setup by a plumber. He had a wall of old water heater cores that produced hot water for three baths and one shower a day, during freezing winter months. Cores were in direct sunlight behind glass during the day. I can’t speak to cloudy days, but the plumber said it worked.
Water is the answer how you get it hot is the question. Luv your videos keep up the good work
Thanks for watching.
You heat it with the sun... On sunny days. There is a house that is heated by hot water most of the year in Colorado.
Excellent video & with such a great explanation of the maths in a simplified format. Also well done for your designs & ingenuity; brilliant.
I reside in the UK & I don't know how my climate or PV costs compare to the US. Had my system installed just over 7-years ago & have added to it & tweaked it (it's become an obsession to some extent - lol).
5.75kw of PV squeezing through a 4-kwp inverter. I use two Immersun units to sense the export of surplus power to the grid. This surplus power then is connected to either an insulated immersion water heater, or 2x electrical storage radiators for room heating. I don't have any battery storage of surplus power as yet but am looking into it & probably waiting for the battery prices to drop, (will probably buy SMA Sunny Island & SMA Home Manager with 8kwh of usable battery storage), still too expensive at present.
I think insulation is important also, as you address with the insulation of your thermal storage water tank. My house has cavity wall insulation, double thickness loft insulation, triple glazed windows & double glazed doors. My job for the summer is to open-up my floorboards & stick mega insulation under the ground floor floorboards, (horrible job for an agoraphobic).
In the UK there are just a few electricity utility companies that offer a zero standing charge tariff but the trade off is a higher day rate per kwh. You may wish to search for such an option in the US for you.
My system generates just over 5000 kwh pa & my grid tied electricity bill is only around £20 pa zero standing charge (125 kwh), although in fairness I do tend to live quite an alternative lifestyle these days which helps.
Great video again & thank you,
Regards to all,
JohnnyK.
John Kay hi John, I’ve had pv installed recently (South Wales) and started thinking about storage heaters but quickly realised that they are both expensive and (from what I’ve found) seem to only allow charging at night on economy 7.......am I wrong? How much did you pay for yours please? Thanks
You got it in one mate. There are lots of ways to store energy, that's one of the best.
Thanks for articulating in this mini-series what I've been thinking for quite a while. The thermal battery, even if it's 'leaking' heat a bit, as you said, is a net positive in the winter because it's leaking heat into living space and that just translates into less load for whatever the home's heating system is. It's the summer time when the thermal battery leaking heat is an issue (for the home's cooling system) -- maybe the thermal battery's site could be located on the periphery of the home and you rearrange some physical baffles or walls or something twice a year to vent heat into, or out of, the living space as the seasons change.
Basically, the most efficient way of storing heat is storing heat.
lol .. but true
no it has 7,000 btu per day loss which is 25% of the system. lithium batteries have very little self discharge per day. if you could reclaim that heat for your house i guess you could say its even but in the summer that wouldnt be fun and it would make the system more complex. it also isnt usable to power anything. so its not exactly a fair comparison to the batteries which generate electricity.
@@danielroden9424 The batteries take energy and cost and pollution to produce. PV cells also have a life span and take energy and cost and pollution to produce. Thermal storage is cost-effective in the long run. Having the battery bank is for your electronics, and then all of your water heating can be taken care of by the thermal storage. The other added bonus of the thermal battery is that you can make it with easy to produce and make materials, and the whole system is much more sustainable. If you have the money though, I suppose you can just do everything with PV, but PV is also not really that efficient, and you lose out on a ton of energy that you could have captured as thermal energy.
check cold steam Tesla turbine, where you can use the stored heat as electricity.
@@danielroden9424 It is a fair comparison if heating is something you're guaranteed to need to do every day. Even in summer people want hot baths and showers, and if you fill your kettle from hot water you spend less energy boiling it. Same for the hob. Less gas or electricity used depending on which one you have.
Just add vacuum tube solar heating system to run hot water, space heating and even space cooling or fridge.
The vacuum tubes are really great as the final collector when several panels are connected in series. It seems that the flat plate collectors are very cost effective for raising the temperature of cold water and the vacuum tubes excell at high temperature differentials, so they work very well together.
Due to inefficiencies, flat panels self-shed snow fast when hot water is circulated. Very handy if they are on a roof difficult to access.
For tubes, just mount them vertical and well above potential snow banks. Sloping them to perfectly match the sun is a very minor advantage compared to keeping them snow-free with little labor. And you may actually have too much heat in the summer, which would require the safety system to dump heat.
It is Awsome!! Got my wheels turning. Ty4 the vid.
Good vid David, thanks !
This took me back to my physics classes in college. Ohh the memories!
Good memories I hope.
The maths would be so much simpler if you used metric units. Give it a try, you will never go back to imprial.
I am from the UK, I don't understand why people in the USA don't use metric, they already use it for their currency! 😉
this otherwise great vid was painful to watch
But most of the people watching this video would have no clue about metrics!!!
@@nickbird7742 Those of us that went into engineering freaking love the metric system.
Those of us that grew up in this unit system had no choice.
Honestly who want's to convert newtons to our F'ed up "system".
You can to chemistry but when you get to physics you're like screw this I WILL ALWAYS LOVE THE METRIC SYSTEM.
P.S. I'M AFRAID TO EVEN WATCH DOCTOR WHO AGAIN PAST THE 3RD EPISODE. DID THEY RUIN IT?
The last doctor was so bad but I suffered through it now they bring out an abomination and scrips that I wouldn't use as toilet paper.
Has it gotten any better? I don't want my DW ruined for me.
All I have now is Red Dwarf, Sherlock, and that is about it.
Metric and imperial can be used side by side easily with a conversion table. All simple math. I like knowing and using both, but Metric being scientific is far easier to use.
Good video. You might have geeked out, just a tiny bit. You know how to talk to people about somewhat esoteric material. The enthusiasm for solar is very evident. I felt good after watching this production. Thank you!
Excellent presentation. Thank you.
Nice vid, David. Thanks. Tease by introducing the economic savings at the beginning of the vid: $300 vs $4.000.
Great video man! I've seen some somewhat negative comment here about your hydronic adventure. Forget these narrow minded peoples! You are right - BTU's are BTU's. When you go without hot water even once you realize how tough cleanliness is in the kitchen and in the bathroom. Then you finally calculate how much energy your water heater SUCKS. (I find its about $1-$2 per person per day, every day adds up quick)
Great job on you water heat battery... I agree you should drop a copper coil in there...a much more powerful conductor of heat than HDPE pex.
have been long time considering building a very large semi insulated storage pool under my trailer house to be used for central heating. Your math is going to help me size and build this tank!! I think it is viable but need more collector power!!
Glad to help. Are you in New England?
Very thought provoking, thanks.
Cool, I wanna say, great idea, clear equation, will most certainly pay off. And yes indeed, such a storage tank can be that cheap.
Hello, Awsome video, just wish I could see more how you did that in detail, or how it works. Could you tell me what is heating your battery coil. Are you going to change your battery coil to copper, if so could you do a video about that also. Thank you
I have a few videos building the system. The sun heats the thermal collectors, which heats the tank. No plans to change the coil right now. I will change it if I need to do something else, but the system is pretty hands-off.
Your math is excellent. I came to very similar conclusions about 40 years ago. My solutions were along the lines of heating the home, the air. My solution to the battery was window placement and thermal mass used in the construction of the house. You live in the solar collector. The energy is stored in the body of the collector. Remarkably,, or maybe not so remarkably,, people have been doing this for millenia. I have engineered many things,, but the story of one engineering job is noteworthy.
I was asked to design the system for a house in New Mexico. Passive or ambient heating and cooling. The mechanical HVAC systems were to be there to suit sales, building codes, local officials,,, but the design was to have them be the backup. No computers,,,no internet (1983) , calculators, paper, pencil, and multiple computations to find the middle ground where cost, usefulness, and available materials and subcontractors all worked. I came to the conclusion that the house need X in heat,, solar heat gain,, but the job of cooling was the greater portion of the year. Nominally I need 6 inches of fiberglass filled wall, inside of 9 inches of masonry thermal mass for the exterior to absorb the day's heat and give it back to the night sky. I was so proud of a simple and brilliant solution, arrived at by a week's worth of calculations,,,,,, calculations not dissimilar to yours. But,,
What are the dimensions of an adobe brick? Hmmm 9 Inches. and then I found some of the dimensions of stone walls of the Ancients in SouthWest cliff dwellings,,, 10 inches is very common... And then I knew,, I was not so smart. SW natives have been building to those specs for a few thousand years. Annnnd a really good passive solar super insulated house,, really good,, really efficient, can look just like a Cape Cod,, or a Salt Box that you might find in Andover, MA. with very few modifications and use of modern materials and tech. Build on the shoulders of those who have come before you.
Good point.
This sort of thermal heating storage was the big thing back then, rather than solar electric, a reaction to the 1973-74 oil crisis. And quite a few things lingered from that, at a rather minimal level. There was a TV programme in the UK which described what could be done, A House for the Future. Apparently the solar thermal system chosen then didn't last.
I can't help but think that building design still doesn't take into account the potential for solar energy. I see new construction with a poorly-aligned roof, and other fairly simple details that could be improved, such as larger windows on the sun-facing side. The structures you describe are closer to the usual in the UK, but not the same. Cavity walls are usual here, and that puts a big chunk of the wall mass outside the insulation, where it isn't of much use as thermal storage. The insulation thickness also looks lower.
Thank for this great video 100 points surley is not enough thinking outside the box for sure...
Your enthusiasm is awesome.... keep it up fun to watch....