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Hybrid Electric-Thermal (PV-T) solar panel

Discussion in 'Energy, Environment, and Policy' started by DITB, Aug 27, 2014.

  1. DITB

    DITB Charged.hk co-founder

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    #1 DITB, Aug 27, 2014
    Last edited: Aug 29, 2014
    I have been working on an extensive renewable energy project located in Scandinavia, for about 5 years now, which involves

    - Solar electric
    - Solar thermal (space heating and domestic hot water)
    - Underground Seasonal Heat Storage (store excess summer heat, get it back in the winter)
    - Drain Water Heat Recovery
    - Rain Water Harvesting (toilets, washing machine, irrigation and "utility water" for now, later on 90+ % of domestic use)

    ... and more.

    The hybrid electric-thermal panels are a beautiful symbiosis where thermal heat extraction doubles as solar PV cooling - that way, the solar PVs, while being cooled off, 1) yields more here and now 2) degrades slower - all the while thermal energy is extracted for instant use, or stored for later use.

    Here is 1 of the 12 panels I finally got - waited more than 4 years from the original estimated delivery date. It's all very exciting - more later, when I have more to share:


    Solarus hybrid thermal-electric PV-T panel.JPG

    There are air condition units out there, which are also hybrid thermal-electric, in a slightly different way in that it is a compressor running off a heat differential, while electricity is only used for the control system as well as a backup when there is insufficient heat differential. With a solar panel, you would normally have plenty of heat differential when you need to cool the most, obviously. This house is located in a region where cooling in the summer isn't normally applied to private residences. I will add humidity control, to keep the comfort level even in the summer (as well as help preserve the building against mold and similar growths).

    In many modern households, there are cooling facilities for food, i.e. fridge and freezer. In turn they add heat to the living area, while a hot water tank is using it's own energy source (often electricity as well), to heat up water. Finally, all that excess heat is cooled off by a heat pump as well (air condition), to expel excess hot air. This is another greatly under-utilised area of energy, especially in the more hot regions. For this purpose, I have seen new developments of units that combine all said units: Fridge-Freezer-Water heater-Air Condition - where the domestic hot water is heated by the three others.

    All in all, there is so much to be done. It's fun to play with, see how much you can hack out of it, eventually reaching a level where you can be more or less independent of external energy and water supplies.

    Later as things are under control, the website will be highly graphical to illustrate how the systems interact - writing it like this will only reach a small minority out there.
     
  2. Cosmacelf

    Cosmacelf Active Member

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    It all sounds very interesting. How do you store summer heat for winter usage? Are you making this system just for your own use, or are you planning on commercializing it?
     
  3. DITB

    DITB Charged.hk co-founder

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    I am not sure if I can or will make money on it. To begin with, it is my personal quest, a proof on concept, to show the world how much potential we are - and have been - missing out in the area of solar power, whilst burning away fossil fuels. One thing is a car, train, boat or even an airplane, where solar energy is difficult to implement. But a stable building that's not going anywhere, where weight and space is much less critical than on a vehicle - oh so much is wasted, and this is a huge percentage of the world energy consumption. Heating and cooling of buildings. Water is scarce yet many places, pristine drinking water is used to flush turds away, and into the oceans, while weather related flooding is harder and harder on the sewers.

    There will be a web page showing by instant as well as historical measured data that it actually works, then a description how it's built. I hope anyone and everyone will benefit from it, kind of like Elon Musks crusade, all our patents are belong to you. This is really a combination of mainly known technologies, some more and some less known, which applied together makes for a solution where most or all the needs of energy and water usage can be produced locally. Imagine what consequences it would have for the environment, as well as world peace, if almost every person, government body and company, were able to produce their own energy and water? All the conflicts over energy and water would lose some of the coal to the fire, and hopefully the world would become a better place for all.

    Today, every time someone talks about "solar" it's implied that it's solar electric photovoltaics. PVs are great, but there is a lot more to be gained. Using a straight PV is like drive an ICE car with only first gear and a very small gas tank. Putting gears on solar, and using a huge "gas tank" (or battery), solves several areas of what was until now perceived as limitations in solar energy. Solar thermal energy is much more than just "hot water for showering in the summer" (depending on local climate obviously)

    The house is insulated around the walls and foundation, into the ground, to encapsulate a mass of around 300,000 kg of clay/earth/gravel/stone (contents may vary). A direct hydronic transfer (NO heat pump here), slowly charges up this huge chunk of earth, during the summer mainly, but also trickle charge when available, even at times into the winter. With the right depth and insulation, the heat will slowly come back into the house from below, as well as available to pump back as needed. Seasonal Heat Storage is all about slowing things down, flattening the offset supply-demand curve of available and desired solar energy.

    It's all very exciting. One man army here, with the help of a few friends and family members.

    We all have our quests, and this be mine.
     
  4. Raffy.Roma

    Raffy.Roma Active Member

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    @DITB

    Good work. It sounds interesting. Keep us informed about the developments. A commercialization would be ok IMO.
     
  5. Cosmacelf

    Cosmacelf Active Member

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    Do you have calculations on that earth based heat storage mechanism?
     
  6. Denarius

    Denarius Active Member

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    Sounds very interesting. I'm planning on attempting to do a lot of what you are when I build my next home, but thats a few years out. I'm subscribing and will definitely be watching your progress!
     
  7. DITB

    DITB Charged.hk co-founder

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    it's highly experimental and thus not well documented. Water based heat storage has several problems that have proven hard to deal with, and one of the essential differences to many other heat storage solutions is that as this is located under the house, most of the heat loss is going straight up - into the ground floor.

    It's about large mass and surface, lower temperatures. When you add thermal energy to a house to offset thermal loss, you can use air ducts (widely used in North America especially, smaller heated surfaces (radiators), or a large surface/mass, like radiant floor heating. I am using a huge mass and surface, hence the temperature is much lower than in a radiator system. Solar heating can make lots of lower temperature heating, but normally requires a heat pump or equivalent if radiators are used.

    There is a lot more to it, I'll get back later.

    Btw, the capacity of the ground storage alone is between 2000 and 3000 kWh, depending on how high I raise the temperature.

    Denarius, for sure check me out before you build anything. See, this is a modification of an existing house. If you build from scratch, including the foundation, it's much easier, cheaper and efficient.
     
  8. MikeC

    MikeC Active Member

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    Very impressive, DITB. Good luck! I'm subscribed.
     
  9. richkae

    richkae VIN587

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    Very cool. I dabbled with building some combined PV and thermal panels when I had solar put on my house 3 years ago.
    My plan was to take a normal PV panel and attach a "water jacket" to the back of it, cooling the panel while extracting heat.
    I didn't get to an actual testable prototype because I am easily distracted by new squirrels.

    As a proof of concept I mounted lawn sprinklers onto my roof to bathe the PV panels with water. On warm summer days I got 16% more output out of the panels immediately after a quick cooling bath. ( No idea how much better it could have been without droplets on the panels ) Even though it was only 80F ambient, the roof and solar panels were well above 100F before cooling.
     
  10. DITB

    DITB Charged.hk co-founder

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    #10 DITB, Sep 11, 2014
    Last edited by a moderator: Mar 13, 2016
    Here is an updated video



    There are a few annotations in the video (they won't show if you use html5 to view), feel free to ask more questions here or in the video comments.

    The system is NOT yet operational, and even when it is, it will have to be running for a while to really prove it's worth (the ground will be "charged" with heat during the summer, supercharging here is not counted in minutes, but rather in months).

    When it is really up and running, I will explain further - it's a quite comprehensive system - there will be an entire web site dedicated to explain in graphics and text, how it works and how it performs.

    When I do something like this again some time, it will NOT be a modification but a new house, built from scratch implementing the principles and lessons learned during this experiment above.
     
  11. DITB

    DITB Charged.hk co-founder

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    Update - to those of you who are interested in the progress.

    After multiple "challenges", and with limited time to work on this project, it is now operational with both thermal and electric. Of all the heat storage, only the central unit (275 USG / 1000 litres) is connected.

    Electricity came online in the afternoon, and it was quite cloudy. For those few dark hours, it produced a meagre 0.023 kWh, enough to drive a Tesla Model S about 100 yards only (!). With a full day of sunshine, it should be more like 10 to 15 kWh, still not a whole lot, but the imagine that on top of that, about 5 times as much heat energy will be produced as well - from the very same panels.

    There was an issue with the main hydronic system (glycol-water mixture for anti-freeze properties), some gaskets were damaged in the mounting process - but that is fixed now. The secondary internal heat transfer system (purely water based), is still not resolved, and will have to wait. There is, however, connection between the solar panels and the main hot water buffer. As it is deep into the fall, the other heat storages aren't essential YET, got another half year to sort that out.

    I made a video explaining how they work, have a look here:

    [video]https://www.facebook.com/video.php?v=462339323905143[/video]

    Not sure if I can link a Facebook video, otherwise have a look here https://www.facebook.com/video.php?v=462339323905143
     
  12. Agoro

    Agoro New Member

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    Hello to all,

    I have been following Solarus products since 2011 but it is the first time I see a residential use in a integral project, since there are not well documented success stories. I congratulate you for choosing this inspiring technology.
    I visited Solarus in Sweden in 2012 and I wished to have this solution at hand at home. I met Stefan Larsson and the team and I wanted to bring the concept to South America.
    I know they are just since last year delivering panels. The performance in the papers is promising but I waited to have more field data to decide to advance.
    Also it is a challenge to find applications where you can profit efficiently from heat and electricity, your choice to store heat is a wise one, but I have some concerns on how to convert heat in something else as just warm water, to get some energy conversion in a mild warm environment like in South 34.5° latitude.

    Please share your experiences and results. Greetings from Uruguay. José
     
  13. DITB

    DITB Charged.hk co-founder

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    I ordered the panels (12 units) way back at the end of 2009. I was told delivery to be expected "April, possibly May". 2010, that is. I got them in August 2014 (!), one month before I got my Tesla Model S (RHD/Hong Kong version). I think I learned a thing or two about patience, waited 21 months for the Model S and 52 months for these 12 panels! R&D is expensive, and it took a few restructuring exercises of the company before I could get these panels. Now I hope I can have the system successfully operational soon, so the worth of these panels can be sufficiently proven.

    Things are going well, unfortunately I don't live in Denmark any more, so ... it takes quite a bit of logistics to get there and get something done. The system is up and running, and I am pumping heat into the ground big time already. It's so very exciting, just wish I could spend time 24/7 on it, until it is entirely finished.

    Surely, it's a bit - eh - over the top, but the idea here is to prove to what extent you can take solar thermal power. The missed potential is humongonormous. That word just popped up, I can't think of any word that fits the amount of energy wasted in electric or even heat pump installations - when all you gotta do is have sufficient and correct thermal storage.

    This is from the afternoon (local time) right now. A mediocre day, yet giving lots of yield.

    SB102 28-4-2015_.png

    I found that I just need about 200-250 W/m2 sustained to produce thermal energy (measured in the plane of the solar panels, not horisontal). That is like a meagre 20% of full intensity sunlight! Outside temperature just above freezing, and yet I can get 25 C or so (77 F) - enough to transfer heat into the ground as it is right now. Later on, when the ground heats up, I will need a higher temperature.


    Please note that there are many uses for thermal solar power, other than hot water and space heating:

    - Water desalination (requires more focusing to be 100% powered)
    - Air conditions units driven by heat differential (usually hybrid electric-thermal units)
    - Industrial processes

    More projects on Solarus website.

    I hope to be able to update the flow sensor. At the moment I can see and measure temperature differential, and even compare it to pump speed. But since I don't know the actual flow rate, I cannot calculate power (W) and energy (kWh) yet. I am going to measure the output of the panels, as well as how much goes into the various parts (Earth, foundation, hot water buffer - and later on temporary storage and "inter floor heating"

    I have never in my life been more caught up in any project. Seeing the heat of the sun heating up the house and storing the heat long term for the next winter is more exciting than I have thought of.
     

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