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    Mark Franks (5 Posts)

  • Zman Zman @ 7:37 AM
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    Mark Franks

    As much as I love my Thursday new letter. this one is simply not true.
    http://www.earthtechling.com/2013/05/new-york-city-could-turn-to-geothermal-heating/

    Henry Gifford does a great job explaining this one http://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/ground-source-heat-pumps-don-t-save-energy

    Carl
  • SWEI SWEI @ 9:18 AM
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    Tough One

    Let's start with the clear factual error: the earth's core temperature has absolutely nothing to do with the suitability of an area for geo-exchange.

    Geo-exchange is not the universal solution many proponents claim; nor is it the scam which opponents sometimes make it out to be.  It works best when annual heating and cooling loads are *roughly* balanced (say within a 2:1 range)  and when soil moisture is high.  Payback over a modern ASHP can take quite awhile depending on the local climate.  Ground loop installation costs -- especially on existing sites -- can be prohibitive.  Depending on the source of electricity, it can produce less (or more) carbon impact than burning natural gas will.

    When correctly applied (sometimes in a hybrid system with GSHP plus a high efficiency boiler) and competently installed and managed it can produce excellent results.
  • Robert O'Brien Robert O'Brien @ 9:26 AM
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    COP

    What is upper limit on COP of ASHP,particularly mini split? I see this being the eventual "winner"
  • Zman Zman @ 9:35 AM
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    Facts

    My point is that their is not a correct fact in the article. The heat pumps run on electricity which is produced in a fossil fuel burning power plant. As Henry points out the net efficiency and carbon footprint doesn't change. A 3 COP from a 30% efficient power source is no different than a 90% efficient boiler. A 3 COP running off PV panels is a different matter.
    CArl
  • hot rod hot rod @ 12:25 PM
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    instead of a loop field

    This company uses a fence as the loop field. Clever idea.

    A GSHP heat pump is really moving solar energy. The energy from the ground to provide heating is from the sun.

    I suppose you could make an argument that the coal is also a result of solar energy, from vegetation that grew 400 million years ago :).

    A heat pump powered by PV modules would be a nice, but currently expensive, option.



    http://www.hautec.co.uk/#fence
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