Myth Busting Solar Thermal

[@estqwerty]

hi from the other side of the world! great presentation, i'm allays happy to see something from you. happy to see that you have new and finished projects. greenhouse is very interesting please post more info about this project.

[@glenni8835]

Danke Schön for brining that capability to Alaska. After visiting Germany when I returned I realized how much we do not make the most of solar and wind power. It was unfortunate that some people did not fully appreciate the capability that this system could provide.

[@mushroombeans123]

Terrific presentation by both presenters and the questioners. So much can be learnt by lower latitudes from this experience in Alaska. We are in Dundee, Scotland, 56.5 degrees latitude. Totally agree storage is all, and water is the best solution at present. Only problem is my storage is only 1/10 of the systems described here, but I can try and do better. Love the stratifier and the open sharing of this technological approach. Theoretical, experimentation and experience - wow! The question I would of ask is what is the efficiency of the foot thick EPC insulation. If a tank of specific size is at say 130 degrees, how many degrees does it lose per day, without input or output?

[@mcarling6495]

That’s a fairly simple calculation, but it depends on the dimensions of the tank.

[@douglasthompson2740]

Good work. I just wish that someone was doing the same for us here in Southeastern with the high rainfall and overcast days exacerbated by high winds. Brings a whole new set of problems to the equation. It seems to me that during the wet I lose more heat than even the cold. Conductivity would perhaps help explain it? Which raises the question of what would the best building envelope? Alternative energy is also a different problem here. I have seen the U/A Juneau crawl space series but that seems to be the only information directed specifically to Ketchikan/Juneau area. Juneau being a bit colder and Ketchikan quite a lot wetter. Thanks for your work and experimentation. Doug

[@coltmypit]

Imagine how fractional distillation works multiple plates in a cylinder ... if you put perforated plates in your tanks and had 4,6,10 ? valves that would open at the corresponding temp zone.... (ie the fluid from the sun god heater is at 160 deg) at 12 feet from the bottom the temp is 160 deg, open that valve to fill....... very little thermocline disruption . Enjoyed your video, Thank you for sharing your ideas

[@thomasgarven129]

Where I live in Western Arizona every contractor I know has stopped even selling solar thermal water heating systems. Now everyone just goes grid tied solar PV and they never have to worry about freezing pipes, leak, bad pumps, sensors and controllers. And you don't have to buy a new $1000 water tank. And solar PV will not only heat your water but it will also run your TV, a fan, hair dryer or even run your AC in the summer to keep you cool.

[@williamweatherall8333]

This is in Alaska. They get way less sun

[@thorthunder3227]

Dig a hole, put in lava rock and green chip wood and tubes and you will have a lot of heat transfer and storage for the night as air heating but you could use old commodes broken up in small gravel and use that too along with sawdust or wood chips as these decompose they generate tremendous heat.

[@litelog8045]

Very good video - understand it's a few years old now and Reina / ArcticSolar is a bit on standby due to health reasons. I would like to add a few things here. We agree that storage is very important for solar - just like for electric cars, it's not the production of the energy, but keeping it from when it's abundant until it's needed. A guy called Don Stephens did (and still does) research on Seasonal Heat Storage, and I have let myself inspire by him to make my own project. I learned quite a few things about the matter by simply having a good think about it, then building it. The optimum solution for most solar thermal systems is not to pick a technology to focus on, but to make the best use of several technologies. On a grand scale, the idea is to reduce the load as much as possible (like insulation), while not only increasing the supply but especially the storage capacity (and how long it lasts). As for the load, besides the obvious one of insulation, I have cut down the need for domestic hot water by using Drain Water Heat Recovery, thus reducing the load on domestic water requirements by around 35-40%. When you want to maximise thermal solar - including domestic hot water - this is very significant. As you say in your videos, the higher temperature requirement of hot water vs space heating is a major concern in the dark period. Thermal storage - yes, water is a good medium for storing heat, but it does have some disadvantages also. I know of several projects that failed because water was chosen for long term storage. I know you are well versed in this already, but let me make a list of pros and cons where you know most of them already: Water vs concrete/sand/dirt/rock: Pros for water as storage - - - - Fast heat transfer, as the medium of storage itself can be pumped directly - Allows stratification - Higher energy density PER MASS than solids - Readily available (although water in larger amounts needs to be taken out of the eco circuit which is significant on a larger scale) Pros for solids as storage - - - - Naturally insulated (heating the center of a large solid mass, there is a natural temperature gradient towards the edges) - While not being able to stratify, it doesn't shift around which means insulation works better. Things slow down, compared to water - and for long term storage, that is an essential property - Readily available in vast amounts under most buildings (issues exist where permafrost carries a building foundation, when ground water level is shallow and when underground is solid rock) - While water has high thermal capacity per mass, consider that most solids in the ground have a density 2-3 times higher than water. This means that for a given volume, the difference in capacity isn't that mush (roughly 2:1 in the favour of water). All you need to do for succesful Seasonal Thermal Energy Storage is 1) Insert a number of tubes into the ground below a building, preferably sectioned in layers so you can use more shallow in winter and deeper in the summer. Depths vary by location and other conditions 2) Insulate the house around the foundation, into the ground All that excess thermal energy you have in the summer, for which you complain you can't get rid of and that your water tank boils out if you aren't careful ... you can now use that to heat up the ground beneath your building. Since the solids in the ground are all natural insulators (to some extent), you need quite a lot of tubes to take up the heat as the pipes do saturate if there aren't enough of them. Or as I did, you need a temporary short term storage, like water tanks, to store solar heat temporarily, then push it into the ground at night (or on cloudy days). You are now charging up the ground over the summer, like a huge battery. How do you get the heating back? You don't really need to. It is essential that the building is ON TOP OF the heat storage, not net to the building. The thermal energy will slowly diffuse up through the ground - so all you need to do is have the system at the right depth (various by location), and you will now get the excess summer heat back in the winter. Yes, it's all possible. All you need to do is get the dimensions right. And yes, there is plenty of earth - a whole globe of it - below any building (highrises need more complicated solutions though)

[@solarheat9016]

Yes we do think twice about boiler based systems: they are way more complicated than forced air and more can go wrong.

[@govardhanagopi372]

its very gooodd

[@buffalo_chips9538]

Im really surprised your still using flat plate collectors. Evaporative tube collectors are much more efficient and still produce about 55% in cloudy conditions

[@REINALLC]

In our extreme climate Flat plates simply work better from our experience, especially in the shoulder season when it matters the most. In other regions and climates tubes certainly can be the better match.

[@buffalo_chips9538]

Ya I watched a different lecture of yours later where you explained your reasons so I totally understand now why the flats are better for you. Especially considering how they are roof mounted and hard to get at. I hope to be using this technology in the next few years to heat a home and possibly an Aquaponics greenhouse In Saskatchewan. Unlike your greenhouse project this would be a solar banking design with a hydronic heated slab. I was wondering if you had given any thought into using wind power to substitute the heat in your tanks through a double coil water tank and a heating element. Missouri Wind and Solar has nice inexpensive reliable wind turbines. www.mwands.com They also have DC water heating elements taht can be used as a dump load for the wind turbines taht retrofit any existing HWT

[@DJRikSparta]

I was wondering... could you not incase the evacuated tubes inside a flat panel case with a black background so if snow accumulates it would melt from the heat generated from the black background and the tube would generate heat as suppose to but without the worry of snow accumulation. Just a thought.

[@brucea550]

@@DJRikSparta How is the black background going to generate heat when the sun is blocked by the snow cover?

[@thorthunder3227]

What about ceramic or just liquid sugar? Salt?? why just water? why not heat up something like this and then do a heat exchange from the storage in the salt or ceramic or liquid sugar which gets super hot. Just try a jelly filled donut inside a microwave. The outside is cool and if you bit into it you might say damn this thing is hot. so, maybe sugar is th answer or salt?

[@2112jonr]

Salt can be used, but it's corrosive. I like the sugar idea though, never seen anyone explore the SHC of sugar, but it must be higher than water?

[@RichardKingADI]

Maybe solar thermal is not the right way to go? Having a solar PV system means that in the summer you could be selling (or 'storing') excess electricity to the grid. Then buying it back in winter. If you had a secondary wind generating system, you could also be able to collect some energy in the dark of winter - something you can't do with a thermal system. Maybe a communal system makes more sense than individual home systems?

[@ecoshah]

One advantage of solar thermal is that the materials of construction are aboundantly availlable and cost effecteive. PV panel have a substantial amount of silver metal that is in very short supply and will soon be cost ineffective once . Check ECOSHAH for solar furnace and air conditioner.

[@orcoastgreenman]

How would the grid store all that electricity everyone is producing in the winter and using in the summer... part of the point of this is to not be dependent on off site resources and infrastructure. If a power line goes down in a winter storm, he has no issues. No grid tie system can say that. PV to heat the water directly has some benefits, in that there is no worry about water outside the structure freezing, so can be a great solution for a lot of people, for instance DIY’ers who are better with electrical than plumbing.

[@ajarivas72]

@@orcoastgreenman PV is very expensive and ineffcient

[@orcoastgreenman]

@@ajarivas72 - solar thermal is the way to go efficiency wise... However in cold climates, PV panels have the advantage of NEVER freezing. I’ve seen used 250W PV panels as cheap as $50... so that can actually be a good option for heating water for some situations.

[@ajarivas72]

@@orcoastgreenman Thanks for your message. Efficiency of PV is around 10%. Efficiency of solar thermal is around 75% Efficiency defined as the energy captured divided by the solar energy irradiated on a square meter.

[@jimmyneighbors4943]

I know get solar panels to make hydrogen to store for the two months

[@maccafan10]

The first guy is so hard to listen to without falling asleep. He is the guy who is always in left the kitchen at parties.

[@DDDarray]

Instead of a giant tank in the house, what if you used the floor space for a rental apartment, and then used that theoretical income to buy firewood? That would be part of how the economics inside a big city would have to work out.

[@reto-fassbind]

Inside a city a _district heating system_ is certainly the better option than a in-house tank. See: en.wikipedia.org/wiki/District_heating

[@McNea1234]

+Reto Fassbind Germans have perfected district heating

[@2112jonr]

Because you're STILL burning a fossil fuel.

[@captain42979]

Good talk horrible audio and I'm not even a picky person...

[@MrHarpette]

One hour and a half listening to this awful audio? How about listing the myths in the video description, along with their respective timestamps, to make it easier on us?