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Chinese evacuated tube solar collectors

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Comments

  • Kevin_in_Denver_2
    Kevin_in_Denver_2 Member Posts: 588
    PV pump

    Another excellent solution. No controller, so sensors, no power grid requirements.

    If all this stuff comes with the Solarmax system, they are getting close to my "solar appliance" ideal.

    I'm sort of like Woody Allen in Sleeper, waking up 22 years later. Thanks for helping me catch up.

    There was an error rendering this rich post.

  • RadPro
    RadPro Member Posts: 90
    pv pump here

    has been running for 7 years powered by a 18 watt panel.Control is therefore linear base on the amount of sunlight and the volume of pump rating. Check out the pic...Paul
  • Kevin_in_Denver_2
    Kevin_in_Denver_2 Member Posts: 588
    more info

    You said, "The Thermomax /Solarmax tubes (see my other posting for the picture)will continue to heat well past the boiling point as an open loop system with glycol"

    I don't quite follow that... is your collector loop open to atmosphere?

    If there's an online installation/owner's manual for the system, I'll study it and stop asking dumb questions.

    There was an error rendering this rich post.

  • RadPro
    RadPro Member Posts: 90
    solar is closed

    loop Kevin. Sorry for the mix up on this. Solarmax runs the fluid up and back down inside the center section of the Evac. tubes unlike the regular thermomax. My mix is closed loop 50/50 glycol and distilled water to a Heat exchanger in the double coil (solar)tank this tank is 120 US gal and my tank regularly goes into the 200 deg. mark so I may need to dump heat or better yet add more storage for later use Maybee another project for next year ...Paul
  • David Woycio
    David Woycio Member Posts: 107
    PSI

    The weak link in ALL closed loop systems is the expansion tank. 100 PSI max.
  • JB_7
    JB_7 Member Posts: 14


    Bailey: what company's solar tank did you use?

    thanks
  • RadPro
    RadPro Member Posts: 90
    Solar tank

    is a Jass/Tam Manufacturing SS 120 double coil 1 1/4" pipe,I think each coil in the tank is 30 feet. I've since been advised that this may not have been a good choice for longevity but so far so good ...Paul
  • JB_7
    JB_7 Member Posts: 14


    Thank you Paul: Trying to find out the best way for the winter months since the coldest possible water must be sent to the collector,maybe a separate preheat tank for the solar might be the better way , Your thoughts

    P.S using Propylene glycol should the coil be double walled?
    J.B.
  • RadPro
    RadPro Member Posts: 90
    Solar in winter months

    In my area isn't that great due to lack of sun hours mostly.My old data showed that 85% of my sun(run hours on pump)was from March 15 to October 15. The rest of the the year fall/winter provided only 15%....this is my own number and 5 years worth of data. If you are from the Mid U.S. and further south you would of course have much differant data. I'm in southern Ont,Canada Now as far as the gycol goes just change it every few years as it tends to get acidic over time. And some of the Solar exchangers are now going to double wall but it may not be the law as yet.My old solar tank with copper coil in the bottom lasted 30 years in service before a leak. Paul
  • JB_7
    JB_7 Member Posts: 14


    Paul: Thanks for the information, 30yrs of solar, You are a wealth of experience I am just a rookie put my system in service SEPT 1 (30 Thermomax tubes with superstor tank) I am finding this is not a good solar tank its the commercial model the two coils are wound together and they reach to the top portion of the tank, when the pump comes on I find glycol is returning to the collector too hot on low sun conditions. I have many questions but I don't want to inundate you I'm in New York city. I am glad I invested in solar I ran the boiler only once for DHW since Sept 1. I am thinking of adding a preheat tank for winter operation.

    again thanks for any tips JB.
  • boazatcedarmountainsolar.com
    boazatcedarmountainsolar.com Member Posts: 6
    this PV pump

    uses an MET pump head, which is not rated for extremely high temperatures.

    We use the Hartell HEH-10, which, when Hartell's quality control is good, can handle higher temps. We put a 30-watt PV panel on it to help it get going when the glycol is cold and slushy. A low-limit can be added to prevent the collectors from cooling the primary loop early in the morning before the collectors warm up. For large arrays, we either use multiple pumps or go to the Dankoff Suncentric high-temp models.
  • RadPro
    RadPro Member Posts: 90
    Solar pump has run for 10 years

    The pump is a brass body, vane-type, positive displacement pump. The pump has special clearances and seals for high temperature protection up to 212 deg f. It has a maximum output pressure of 100 psi.

    This Solar Pump is engineered for long life and super efficient operation to enable you to use the lowest possible power PV module. The Solar Pump is equipped with a built-in stainless steel strainer. No parts are subject to corrosion - all wetted parts are stainless steel, brass or carbon. Oh I would also be leary of more PV since it would definately run to long at the end of the day and take your BTU's back out to the collectors I've seen it. And I do like Hartell pumps as well.... Paul
  • boazatcedarmountainsolar.com
    boazatcedarmountainsolar.com Member Posts: 6
    MET pump head

    the nice thing about these is that they are positive displacement, rotary-vane pumps, so you actually DO get linear heat control - the variable speed of the pump is proportional to PV voltage, which is proportional to heat absorption. The Hartell is a centrifugal, so the flow rate drops exponentially compared with voltage - not quite as slick, but it works. We prefer the Hartell because it's brushless, eliminating maintenance. An old associate of mine uses these Thermodynamics pumps religiously, has been for 15 years, and swears by them.
  • Ron Schroeder_3
    Ron Schroeder_3 Member Posts: 254
    am I allowed to dissent here?

    IMO at any price, goods that are manufactured by slave labor in a country that rejects our family, moral, cultural, and political values may not be a "good deal"?

    Is it in our individual and collective self interest to be financing the worlds greatest standing army with trade subsidies?

    Remember the tanks?

    The advise to mind our own business, when the Chinese were called on the carpet on Human Rights questions, might be good advise indeed.
  • Joe_55
    Joe_55 Member Posts: 62


    Fred: That was the deciding factor when I purchased the Thermomax system (made in the free world) by a U.S.A. friend. J.B.
  • Ron Schroeder_3
    Ron Schroeder_3 Member Posts: 254
    And thank-you for doing so.

    > Fred: That was the deciding factor when I

    > purchased the Thermomax system (made in the free

    > world) by a U.S.A. friend. J.B.



  • Ron Schroeder_3
    Ron Schroeder_3 Member Posts: 254
    And thank-you for doing so.

    > Fred: That was the deciding factor when I

    > purchased the Thermomax system (made in the free

    > world) by a U.S.A. friend. J.B.



  • Ron Schroeder_3
    Ron Schroeder_3 Member Posts: 254
    And thank-you for doing so.

    I thought I was alone in my concerns. It gets lonely here.
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