GSHP + Thermosiphon + Hydronic

Discussion in 'General Discussions' started by de_nogent, Apr 21, 2010.

  1. de_nogent

    de_nogent New Member

    Is this feasible? Do you really need a pump for efficient heat transfer?
    Last edited by a moderator: Aug 29, 2010
  2. Looby

    Looby Member Forum Leader

    Heat won't flow from the cooler to the hotter
    You can try it if you like but you far better not-ter

    - Flanders & Swann

    ... Not just a good idea, IT'S THE LAW!

  3. de_nogent

    de_nogent New Member

    So, if I understand this correctly:

    According to the Second Law of Thermodynamics, heat cannot spontaneously flow from a colder location to a hotter area - work is required to achieve this.

    But depending on the climate, there will always be a warmer side of the GSHP/Thermo/Hydro system. So, therefore there will always be heat to flow, unless the temperature outside is the same as the temp underground.

    Does gravity have an effect on this system/thermodynamics? What would happen in the summer when the house is 100 degrees and the earth is 70: Wouldn't the heat from the house flow down into the GSHP?

    What kind/how much work is needed?
  4. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Yes air rises

    Not as fast as the house will be heated up.
  5. de_nogent

    de_nogent New Member

    Ok, I'll believe that ;)

    So what kind of pump would be the most effective/efficient? How many gal/min would need to be pumped?
  6. Looby

    Looby Member Forum Leader

    Give me ambiguity, or give me something else.


  7. de_nogent

    de_nogent New Member

    Sorry for the ambiguity; I'm new to all of this wonderful geothermal stuff.

    Hypothetical situation:

    Shipping container house
    Passive solar design
    GSHP + Hydronic + Solar Thermal
    South Louisiana
    ~2,000 sq. ft.

    I plan to build a house with recycled shipping containers utilizing passive solar orientation. I would prefer a GSHP and hydronic system as the main source for space conditioning, augmented with solar thermal panels, and maybe a few PV panels and wind turbine.

    Drillers are not hard to find around these parts, so vertical/directional installation of the GSHP is a possibility. And I would prefer this method as it takes up less land area and causes less property damage.

    I would like to know more about the best ways to insulate the house. One method I plan to incorporate is a green roof with rainwater collection system. Radiant barrier and cellulose insulation seem like good options, as well as insulating paint. I'm not sure about the type of windows to use, which will be abundant on the South side of the house. Any suggestions?

    After the house's energy needs are met I plan to install additional solar PV and/or wind turbines to generate surplus energy to sell to the utility company.

    I think that just about covers everything. What do you think? Any comments or questions would be appreciated!


  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Mike, I've been to NOLA

    Our daughter is a Tulane and Katrina alum.

    I like your idea.

    I will think on it and be back soon.

  9. de_nogent

    de_nogent New Member


    Thanks for the encouragement. I'm eager to hear your opinion on this idea. I'm new to this information and would appreciate any guidance or advice you can offer.


  10. zacmobile

    zacmobile Guest


    The formula you seek for required flow to a heated space:

    BTUH required to satisfy heat loss ÷ (density of pumped fluid, water is 500, antifreeze mix would be different X temperature drop between your supply & return temperature to the space)

    an example would look like: 36,000 BTUH ÷ (500 X 20ΔT) = 3.6 GPM

    I would be tempted to insulate the outside of the can to conserve interior space, they are narrow enough as they are. Also it would be nice to have that metal mass inside the envelope.

    Here is some excellent info on passive house construction: PassivHaus UK
    Last edited by a moderator: Apr 30, 2010
  11. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I like

    the idea of keeping the steel inside the conditioned space, but that may not go well with the reason for using containers.

    Well swamp coolers are out as you have a big RH issue in LA, so we need to do the cooling right.

    I end up back with water to water. Radiant panels to take advantage of active solar thermal. High velocity chilled water cooling with an ECM blower drive should do well as it does a better job of dehumidification.
  12. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Shipping Containers

    The refrigeration containers come insulated. Don't know what the R-value is though. Some even are water cooled so there may be some pre-mechanics already in place.
  13. de_nogent

    de_nogent New Member

    Thanks for the info. I discovered Passivhaus a while back, and I'm glad you reminded me about it. I think it seems more natural and logical than LEED. Those Germans know a thing or two about this stuff ;).

    I am aware of the insulated/refrigerated containers, but I'm not sure of the R value. I'll research. Regardless, there are plenty of the standard used metal containers piling up in shipyards all over the country, and they're cheap (~$1500 - 40' x 8' x 9.5'). I want to incorporate as many recycled materials into the house as possible.

    I found a link to a new modular building block on the forum:
    GREISEL - KLIMANORM: Product catalog

    I think this cellular concrete/calcium silicate material would make a great exterior cladding for a shipping container structure (installed "floating" over the corrugated metal to create an air barrier) As for the inside, perhaps a stucco finish?
  14. zacmobile

    zacmobile Guest

  15. de_nogent

    de_nogent New Member

    fresh water tank

    I wonder if those fresh water tanks could be used in reverse to cool/temper incoming city water/harvested rainwater? Could this be used in place of a GSHP? If it was installed underground it could do the same job, right?

    I guess the whole concept of "fresh water" wouldn't apply in this situation since there is no heat to sterilize it, but it would only be used for space conditioning through a hydronic system anyway. There could be a second tank used as intended to supply potable water.

    Do you know of any other emerging technologies that involve heat exchangers (ground/air/water source or otherwise) and space conditioning?
  16. zacmobile

    zacmobile Guest

    fresh water tank

    I thing the name 'fresh water tank' is a bit misleading, it is a heating buffer/DHW tank w/auxiliary solar water heating. It would be used coupled with a GSHP. I don't think I would install this underground, however you could construct a tank that would serve similar functions out of concrete and place that underground. I'm sure you've probably seen waste water heat recovery exchangers: Water Cycles | Drain Water Heat Recovery

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