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Re: mini solar collectors - opinions?

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  • jay.ring@ymail.com
    I am not an expert on passive cooling, but as I understand it from Mr Bachman s lecture: The passive cooling works by bringing the house temperature closer to
    Message 1 of 3 , May 14, 2009
      I am not an expert on passive cooling, but as I understand it from Mr Bachman's lecture:

      The passive cooling works by bringing the house temperature closer to equilibrium with the average ground temperature. In Houston, that temperature is about 71F, if I am not mistaken. So, in summer it can cool your house to 71F, and in winter it can heat your house to 71F.

      Now, as to assisting vs antagonizing, there is an issue there. If you have air flow through the house, adding or removing heat from the air as it passes through accomplishes nothing.

      However, Mr Bachman described several techniques to help. One of these was, for example, just using passive cooling to cool the attic. Or you can have the cold air pass under the floor boards and let it conduct through into the house without having air flow. You could also close a duct at the intake or exhaust and essentially deactivate the passive cooling, so you could turn on active cooling.

      You might also consider the option of using a ground source heat pump, which uses the same technique but in an "active" way. It uses energy, but can force the indoor temperature to wherever you want it and is still probably a lot more efficient than your existing air conditioner.

      On the other hand, if you could realistically keep your house withing a few degrees of 71F, I would say, "why bother with active". Keep it around for backup, and the rest of the time use passive.

      I hope that helps!





      --- In hreg@yahoogroups.com, Andrea Wisner <amwisner@...> wrote:
      >
      > Anyone have an opinion on items such as this:
      >  
      > http://www.amazon.com/Sunforce-50044-60-Watt-Solar-Charging/dp/B000CIADLG/ref=pd_sim_auto_4    ?
      >  
      > Is it enough to run an AC system (assume at 1500 sq ft house in Houston set at 82-degrees) throughout the heat of the summer, if I can set it up to track the path of the sun?
      >  
      > Amazon had a $75 special on this today: http://www.amazon.com/Sunforce-50032-Solar-Battery-Charger/dp/B0006JO0X8/ref=xs_gb_ASYR1SS5VN95C?%5Fencoding=UTF8&pfRdReplace=1, but it didn't impress me. The other is more interesting.
      >
      > The passive cooling, as described below, is very interesting to me too, but I wonder to what degree passive cooling also assists passive or active heating in the winter, and to what degree it antagonizes it.
      >
      > --- On Tue, 5/12/09, Tyra Rankin <tyra@...> wrote:
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      > From: Tyra Rankin <tyra@...>
      > Subject: RE: [hreg] New file uploaded to hreg
      > To: hreg@yahoogroups.com
      > Date: Tuesday, May 12, 2009, 12:28 AM
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      > I just returned from a trip to Iran , where in addition to visiting parabolic concentrated solar thermal plants, I toured ancient sites, some dating back 400 BC.   In an arid desert environment, ancient homes were cooled using all the methods you mention below, every house had a wind chimney, rooms dug into the earth for cooling, and water frequently channeled underground.  Open courtyards included pools and fountains that cooled and provided air movement.  Wind chimneys were the most amazing â€" like standing under an attic fan.  The architecture was fascinating, simple and beautiful. 
      >  
      > Tyra
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      > From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of mkewert@comcast. net
      > Sent: Monday, May 11, 2009 9:43 PM
      > To: hreg@yahoogroups. com
      > Subject: Re: [hreg] New file uploaded to hreg
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      > I just uploaded the slides that Leonard Bachman used in his fantastic presentation on Passive Cooling at our last HREG meeting on April 26th.  His talk on cooling started on slide 51, but here you have his full set including  Passive Solar Heating (slides 1-50).
      > http://groups. yahoo.com/ group/hreg/ files/Bachman04- 26-09rev. pdf
      > Here are a few notes from the talk in case you missed it.
      > Leonard is with the Univ of Houston School of Architecture and directs their Building Performance Laboratory, which he invited us to tour sometime.
      > Passive heat sinks (for cooling) include air motion, the ground, bodies of water and the night sky.
      > Try planting okra in front of your west windows for shading; it grows fast.
      > He likes vented skin envelopes and conditioned space ducting; he has a whole house fan in his home.
      > "Climate Consultant" is a great free software from UCLA: http://www2. aud.ucla. edu/energy- design-tools/
      > He endorsed radiant attic barriers and evaporative roof cooling.
      > Suggested reading: thermal delight in architecture by lisa heschong; Integrated Buildings by Leonard Bachman
      >
      > Mike
      > ----- Original Message -----
      > From: hreg@yahoogroups. com
      > To: hreg@yahoogroups. com
      > Sent: Monday, May 11, 2009 9:26:40 PM GMT -06:00 Guadalajara / Mexico City / Monterrey
      > Subject: [hreg] New file uploaded to hreg
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      >
      > Hello,
      >
      > This email message is a notification to let you know that
      > a file has been uploaded to the Files area of the hreg
      > group.
      >
      > File : /Bachman04-26- 09rev.pdf
      > Uploaded by : mkewert <mkewert@comcast. net>
      > Description : Passive Solar Heating & Cooling - Bachman
      >
      > You can access this file at the URL:
      > http://groups. yahoo.com/ group/hreg/ files/Bachman04- 26-09rev. pdf
      >
      > To learn more about file sharing for your group, please visit:
      > http://help. yahoo.com/ l/us/yahoo/ groups/original/ members/web/ index.htmlfiles
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      > Regards,
      >
      > mkewert <mkewert@comcast. net>
      >
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